England and Wales High Court (Patents Court) Decisions

IN THE HIGH COURT OF JUSTICE
CHANCERY DIVISION
PATENTS COURT

		Royal Courts of Justice Strand, London, WC2A 2LL
		20/02/2012

Mr Justice Floyd:

Introduction

1. In this action, Nokia GmbH seek revocation of European Patent (UK) No. 1 018 849 ("the patent"). The patent, which is in the name of IPCom GmbH & Co. KG, relates to a method of handing over communications between a mobile telephone and a first base station to a second base station. The action is another battle in the war between Nokia and IPCom about the royalties to be paid on IPCom's portfolio of patents which they acquired from Robert Bosch GmbH.
2. The validity of the patent in the form in which it was granted is not actively defended by IPCom. Instead IPCom put forward three alternative sets of proposed amended claims. The first of these sets of claims is the main battleground on the issue of validity. Nokia contends that the second and third sets of amendments are not allowable, but, if they are allowable, does not attack their validity on other grounds.
3. Infringement is not directly in issue, but Nokia seek declarations that the patent is not essential to various international telecommunications standards. Such a declaration implies that it is possible to sell a device which conforms to the standard without infringing the patent. IPCom advance a positive case that the patent is essential to the UMTS standard, but no case that it is essential to the GSM or LTE standards.

Witnesses

4. I heard evidence from only one expert witness, Dr Alastair Brydon, called by Nokia. Although IPCom served several long expert reports from a Dr Heinz Ochsner, they elected not to call him. I had read Dr Ochsner's reports before the trial, as I was invited to do, but I have not relied on them. In the end, I heard less than a day of cross-examination of Dr Brydon, and no other oral evidence. IPCom say that the case turns largely on issues of law and construction; that they had obtained all the evidence that they needed from Dr Brydon; and that there was therefore no point in calling their expert. That is a course which they are perfectly entitled to take. I will have to decide whether they were right.
5. Having obtained a PhD in wireless communications in 1989, Dr Brydon worked successively at BT, Cellnet (now Telefonica O2) and Nokia. At BT Dr Brydon was, amongst other things, responsible for pursuing the development of standards for mobile network architecture. In that capacity he participated in ETSI^[1] standards meetings on 2G systems including DECT (explained below). At Cellnet, from 1995, he was Network Architecture Manager. At Nokia, from 1997, he worked on various projects to develop business cases for investment in telecommunications technologies, including 3G. In 2001, with a colleague, he set up a research and consultancy business for the mobile telecommunications industry.
6. Dr Brydon was a model expert witness. He gave me the impression that he was being entirely fair in addressing the issues which he was called upon to address. He accepted that he was rather more skilled and insightful than the ordinary unimaginative person skilled in the industry which patent law requires one to consider. He pointed out, however, that he had had extensive contacts with technical people in industry in many different companies. His experience shows that he was well placed to help the court on how engineers addressed matters in this field, and how an ordinary unimaginative one would behave. I formed the view that he was striving to perform that task to the best of his ability throughout his reports and whilst giving oral evidence.

The skilled addressee

7. I consider the patent in more detail below, but for present purposes it is sufficient to say that it is concerned with "handover", or in American parlance "handoff", in mobile telecommunications networks. The patent is therefore obviously addressed to an engineer working in the mobile telecommunications industry. Such an engineer would have knowledge of the structure and operating principles of the mobile radio networks and in particular of the handover methods used in such networks. He would have experience in radio resource management as well.
8. There was a dispute about whether the skilled addressee would be a person with knowledge of more than one standard, and in particular whether those concerned with the DECT system, which is a "low mobility" system, would have knowledge of GSM which is a higher mobility system and vice versa. IPCom submitted that real engineers would be immersed in only one standard.
9. Mr Purvis reminded me of what was said by Laddie J in Inhale v Quadrant [2002] RPC 21 at [42]. That case involved prior art from two fields, namely "freeze drying" and "spray drying". Experts were called from each of these fields. It was submitted by the patentee that the only relevant common general knowledge was that shared by those in both fields. Laddie J rejected that approach saying this:

"[42] In my view these arguments are misconceived. In some cases a patent claim may cover a wide field so that some parts of it will be obvious to the notional skilled person in one field and other parts will be obvious to the notional skilled person in another. This is not unfair to the patentee, as Mr Waugh suggests, but simply a reflection of the fact that the scope of protection sought is wide. I accept, of course, that in some cases there will be invention in marrying together concepts from two unrelated arts, but that is not what Mr Carr is arguing for here. He says that the notional skilled worker in the art, whether he comes from the freeze-drying field or the spray-drying field, would find it obvious to work within the wide limits of the claim. When considering what would be obvious to the notional uninventive but skilled spray-dryer one must have in mind what would be common general knowledge in that field. Likewise when one is considering what is obvious to the notional uninventive but skilled freeze-dryer."

10. Mr Tappin accepts that in the present case there would, historically, have been those who were working so directly on either the DECT type systems or the GSM type systems that they would not have been concerned to look outside those systems for alternative handover designs. But he submits that there were other groups who were looking at matters at a higher level, across different standards. He says that groups of this kind must have been one of the groups to whom the patent was addressed. He also points out that this is not a case of the kind mentioned by Laddie J, and expanded on by the Court of Appeal in Schlumberger Holdings v Electromagnetic Geoservices [2010] RPC 33, [2010] EWCA Civ 819, in which the invention lies in bringing together two unrelated disciplines. At [42] in the latter case, Jacob LJ (with whom Waller and Sullivan LJJ agreed) said:

"[42] I think one can draw from this case [i.e. Inhale] that the Court, in considering the skills of the notional "person skilled in the art" for the purposes of obviousness will have regard to the reality of the position at the time. What the combined skills (and mind-sets) of real research teams in the art is what matters when one is constructing the notional research team to whom the invention must be obvious if the patent is to be found invalid on this ground."

11. Dr Brydon was cross-examined about his own assessment of the person to whom the patent was addressed. It went like this:

"Q. I am just trying to get to the bottom of what the average person would as a matter of his day-to-day experience actually be aware of. What I am suggesting is that he would be aware of the way handover worked in so far as it mattered to him in a particular system within which he was working.

A. Taking, for example, the people that I worked with day in and day out at BT who were developing standards, and when I say developing standards that was not just a matter of turning up at an ETSI meeting and then going away again, their day-to-day job was thinking about the requirements of that standard and understanding the mechanics required to make that standard work. So it was not just a matter of taking the way that it has always been done and let us slot that into the new system. There was a need to understand what is going on, to understand handover and its characteristics and the nature of different ways of doing it if you were going to implement a new handover method."

12. Dr Brydon rejected the suggestion that his BT experience was in some way unique. He said that there were other network operators around Europe "who would want to take a broad view as well".
13. In my judgment the skilled person would not have the narrow outlook contended for by IPCom. The skilled person envisaged by the patent was an engineer of the kind described by Dr Brydon with a broader outlook of handover systems in general, and not confined in his or her thinking to the rigid parameters of any existing standard. I am entirely satisfied that such a class of engineers existed in the real world at the time.

Mobile telecommunications standards

14. I start with a very general outline of the mobile telecommunication standards of relevance to this case: GSM, DECT and UMTS.

GSM

15. Global System for Mobile Communications (GSM) is a European standard for digital mobile communications initially developed in the 1980s. It is commonly referred to as a second generation or 2G system. There were 11.6 million users of GSM in the UK at the priority date in 1999.
16. The principal components of the GSM system are the mobile station (MS), base transceiver stations (BTS), and base station controller (BSC). Behind these radio access components is a core network switching subsystem which controls all the calls in the network.

DECT

17. Digital Enhanced Cordless Telecommunications (DECT) is an ETSI standard for digital cordless telecommunications of the kind that might be used for domestic cordless phones. By the end of 1998 the annual number of DECT products shipped was about 13.5 million. DECT is only a radio access specification, which is in contrast to GSM which is a complete system.
18. The components of a DECT system are the fixed parts (FP), such as a residential base unit, and the portable parts (PP), such as the roving cordless domestic handset.

UMTS

19. Work was under way in January 1999 to standardise a third generation of cellular mobile radio communication systems, building on GSM. In Europe the focus was on the Universal Mobile Telecommunications System (UMTS). The first full standard for UMTS was not however completed until the end of 1999 and the first commercial networks were not launched until 2001 (in Japan).
20. In UMTS the mobile end user device is called the user equipment (UE). The UMTS Terrestrial Radio Network (UTRAN) comprises NodeBs and radio network controllers (RNC). The NodeBs are the conceptual equivalent of the BTS in GSM and the RNC is the equivalent of the BSC.

Technical background

21. There was no dispute about the technical background. The following borrows heavily from the expert report of Dr Brydon. It would all have formed part of the common general knowledge of the skilled person at the priority date of the patent.

Handover and handover types

22. In order to maintain continuity of reception and transmission in a mobile radio system with multiple base stations, it is necessary to devise a protocol for transferring the radio connection from one base station to another. This procedure is known as handover. There were a number of types of handover protocol of which the skilled person would have been aware in 1999.

Handover design considerations

23. Dr Brydon explained that there were some fundamental elements which needed to be considered by a skilled person when designing a handover method. His evidence was that these aspects were discussed extensively in the 1980s and 1990s and the skilled person would be aware of the implications of the different approaches.
24. Handover initiation is an important part of any handover method. The quality and speed with which the system decides that a handover is required and instigates the handover process makes the difference between a poor service, where calls are dropped as mobiles move between cells, and a good one where the user is unaware of the handover taking place. Well-established handover methods took account of (i) handover reason, (ii) mobile or network initiation, and (iii) handover decision criteria.
25. Reasons for initiating a handover could include a fall in signal level, interference, availability of better radio propagation or traffic congestion. The skilled person would understand that responsibility for initiating a handover could reside with either the base station or the mobile. For example a mobile station could initiate a handover based on a survey of the signal strengths of surrounding base stations. The network could support the process by providing information about the signal strengths it received from the mobile at various base stations. The advantages of mobile station initiated handover included the fact that in general the mobile could react more quickly and flexibly to changes in the radio conditions. Thus mobile station initiated handover was well suited to systems where the signal strength could change rapidly, such as small cell systems deployed indoors or in dense urban environments.
26. Alternatively the network could take responsibility for initiating a handover. This arrangement would be less responsive to rapid changes in radio conditions. Against this, the network could keep tight control of the handover process and accordingly over its radio resources and the distribution of traffic over the network. Accordingly network initiated handover was suitable for larger networks.
27. Handover decision criteria included the quality of the existing connection, the estimated quality of connections to surrounding base stations and the level of traffic at the original base station.
28. Once the need for a handover had been established, it was necessary to identify a suitable target for the handover. The handover methods used in January 1999 generally selected the target on the basis of the radio channel and base station most likely to offer the best quality of service, based on measurements of signal strength or delay. The information used to select a handover target was usually the same as that used to trigger a handover, and it was therefore common for the same entity both to initiate the handover and to select the target. In GSM both functions were undertaken by the network, whereas in DECT both functions were normally undertaken by the mobile. However, as discussed below, the network included the facility to prompt the mobile to undertake a handover, whereupon the mobile would set about selecting the target.
29. To undertake a handover between base stations it was also necessary to create a new radio connection between the mobile station and the target base station and a new terrestrial connection between the target base station and the call destination.
30. To create a connection between a mobile and a new base station by handover, the new base station had to be provided with information about the mobile and the connection, including the identity of the mobile, its authority to connect to the network, the type of connection required and the encryption parameters for the connection. This information could be obtained by the new base station from the mobile or from the network, or a combination of these.
31. The skilled person would also know that handover, in a real network, could fail. By January 1999 it was common practice to include a means for a mobile station to return to its original connection if a handover failed. Thus it was known to avoid re-allocation of the original connection until the handover had succeeded. GSM and DECT both included the facility for a mobile to return to its original connection if a handover failed. Once the handover had succeeded the original connection would be cleared down.
32. During the handover, the network and the mobile station need to exchange information, such as the instruction to instigate the handover, the identity of the target base station and radio channel, information about the mobile required by the new base station, the command to the mobile or to the network to switch the connection from the old to the new base station, the instruction to terminate the old connection and potential failure messages.
33. Quite apart from handover initiation, there were two approaches to the way in which a handover process would communicate the need for a handover. In one, as used for example in GSM, this information would be transmitted on the old radio link. With this approach the network has the opportunity to prepare the necessary transmission links to the new base station and warn the new base station of the imminent arrival of the mobile. In the other approach, as used for example in DECT, the mobile station would move straight to the new base station without any preparation, and announce that it wanted to effect a handover.

The patent

34. The patent is entitled "Handover procedure, mobile station for handover and base station for handover." It claims a priority date which is not in dispute of 8^th January 1999.
35. The bulk of the description of the patent is concerned with two exemplified handover methods. In the first method, described by reference to Figures 2 and 3, the handover method adapts to the level of communication available between the two base stations involved. It is made clear in the specification that this method is not the subject of the claims. The second method, described by reference to Figures 4 and 5, focuses on the process by which the mobile station reverts to its original base station if a handover fails for some reason.
36. At [0004] the specification describes a number of distinctions in types of handover. I set out some of these descriptions below. There was originally a dispute about whether these statements were definitions in their own right of the way in which these terms were used in the patent, or whether they were something else. In the end IPCom was content to accept them as definitions. The dispute then resolved itself into a dispute about the meaning of the definitions. The listed distinctions include:

Forward handover: the mobile station searches for its destination base station itself and registers there directly.

Backward handover: the mobile station registers the HO with the old base station, which takes over the search for a new, suitable base station.

Mobile-station-initiated handover: the mobile station establishes that an HO is required and initiates this process.

Base-station-initiated handover (forced HO): the base station wishes to release capacities, or it establishes that the radio connection is deteriorating and notifies the MS that it should carry out an HO.

37. At [0006] the specification claims that the invention:

"offer[s] the advantage that a handover is possible even in networks in which only restricted communication is possible between the individual base stations."

38. At [0007] it is explained that "new methods are proposed which solve some of the existing problems of forward HO…". In relation to the second method, it is explained that it:

"enables the combination of base-station-initiated and forward HO. This was previously possible only if it is accepted that the mobile station which is intended to carry out the HO finds no new base station and thus ends its connections."

39. At [0009] the specification sets out the point of the second method, namely that "a forced forward HO is carried out, in which the probability that the MS must end its connection is significantly reduced."
40. The specification then proceeds to set out details of the two methods. That described by reference to Figure 4 onwards is the only one which is claimed:

"The method shown in Figures 4 and 5 thus makes it possible for an MS to make a test attempt to carry out a handover to a different base station. If this handover fails, the MS can return without problems to the original old base station BS 1, without this procedure taking much time. The handover attempt does not therefore result in any long interruption in the data stream, as no elaborate authentication procedures or re-storage of the connection data are required. This method can therefore be used advantageously in networks in which the network is not able to prepare the handover for the mobile station. This is particularly the case in networks in which base stations with different capabilities operate alongside one another. This may, for example, be the case if, in the event of a conversion from one mobile radio generation to a next mobile radio generation, base stations according to the new standard and base stations according to the old standard are temporarily present, with which the mobile stations can communicate, but which are not able to communicate with one another to an adequate extent. Here, the mobile station may be requested by a first base station BS 1 to hand over to a different base station on a test basis. If this handover then fails, the mobile station can return without problems and without significant interruption of the data flow to the old base station."

41. Thus the patent is at least in part addressed to handovers between different mobile radio generations. Figure 4 of the patent is a logic block diagram which, read in combination with the specification, explains the claimed process in more detail. A more helpful version of Figure 4, with the function of the various messages annotated on it, was produced by Dr Brydon and looks like this:


The claims

42. IPCom advance no positive case that the claims as granted are valid. I have no doubt that, in the context of this dispute, if there had been anything which could have been said to support the validity of these claims, IPCom would have said it. IPCom did not seek to cross-examine Dr Brydon on his careful evidence that all the features of these claims were disclosed in the cited art. I accept that evidence. Accordingly I hold those claims to be invalid and need say no more about them.
43. As I have mentioned, IPCom have advanced three alternative sets of claims, which it calls its "main request", its "first auxiliary request" and its "second auxiliary request", following the terminology used in opposition proceedings before the European Patent Office. I will use the terms "main", "first auxiliary" and "second auxiliary" to distinguish these multiple applications to amend. Nokia raised no specific objection to the existence of this proliferation of alternative claims. In fact, it has not caused excessive difficulty in the present case because Nokia do not challenge in these proceedings the validity of either set of auxiliary claims, although they do challenge their allowability as amendments. Moreover the second auxiliary set of claims is put forward to meet a specific added matter objection only. Accordingly the main focus of the case is in relation to the claims which are the subject of the main application to amend.
44. I would only add that litigants should not regard this case as giving any encouragement to a practice of advancing a cascading series of alternative amendments to a patent specification. Just as with multiple prior art citations, each alternative claim set multiplies the number of issues which the witnesses have to consider and the court has to resolve. This leads to a corresponding and undesirable increase in cost and complexity. The burden on the party seeking revocation or seeking to avoid infringement is proportionately increased. I appreciate that the discretion to allow amendment after a judgment of invalidity is sparingly exercised. But those who seek to defend or enforce the statutory monopolies conferred by a patent should be prepared to identify the concept which they contend is really inventive, and not present the court with a smorgasbord of alternative monopolies in which they have incrementally greater confidence. In the present case, for the exceptional reasons I have indicated, this has not given rise to such problems.
45. The claims of the main application to amend are as follows:

1. Method for handing over a connection of a mobile station to a network from a first base station (BS1) to a second base station (BS2) of the network,

wherein, when there is an existing connection in the respective base station, connection data for the connection is stored and the resources of the base station are reserved for the connection,

wherein the handover is carried out as a forward handover initiated by the first base station,

wherein when a connection is handed over the connection data in the first base station (BS1) remains stored at first and the resources of the first base station (BS1) remain reserved at first

and in that at a later time the connection data is deleted and the resources are released,

wherein the later time is defined by a communication of the mobile station or the second base station about the successful handover.

3. Method according to claim 1 or claim 2, wherein if the handover fails the mobile station can restore the connection to the first base station (BS1) wherein the stored connection data and the reserved resources of the first base station are used for the connection which is restored in this way.

46. The claims which are the subject of the first auxiliary application to amend are:

1. Method for handing over a connection of a mobile station to a network from a first base station (BS1) to a second base station (BS2) of the network,

wherein, when there is an existing connection in the respective base station, connection data for the connection is stored and the resources of the base station are reserved for the connection,

characterised in that

when a connection is handed over the connection data in the first base station (BS1) remains stored at first and the resources of the first base station (BS1) remain reserved at first,

in the method the first base station transmits to the mobile station a request asking the mobile station to perform a handover,

the mobile station confirms this message via a message to the first base station,

the first base station then stops the data transmission via the radio interface,

the mobile station searches for a second base station and synchronizes itself therewith and

transmits a handover query to the second base station and simultaneously transfers the address of the first base station, and

wherein if the second base station accepts the handover of the mobile station the second base station transmits a message to the first base station to enquire whether the first base station will support the handover,

the first base station transmits a message to the second base station indicating a positive response that it supports the handover, and information required for the connection is sent from the first base station to the second base station,

and in that at a later time the connection data is deleted and the resources are released,

wherein the later time is defined by a communication of the mobile station or the second base station about the successful handover.

3. Method according to claim 1 or claim 2, wherein if the handover fails the mobile station can restore the connection to the first base station (BS1) wherein the stored connection data and the reserved resources of the first base station are used for the connection which is restored in this way.

47. The claims which are the subject of the second auxiliary application to amend are:

1. Method for handing over a connection of a mobile station to a network from a first base station (BS1) to a second base station (BS2) of the network,

wherein the network is not able to prepare the handover for the mobile station and

wherein, when there is an existing connection in the respective base station, connection data for the connection is stored and the resources of the base station are reserved for the connection,

characterised in that

when a connection is handed over the connection data in the first base station (BS1) remains stored at first and the resources of the first base station (BS1) remain reserved at first,

when the first base station decides that it will release the connection to the mobile station the first base station transmits to the mobile station a request asking the mobile station to perform a handover, and

the mobile station confirms this message via a message to the first base station,

the first base station then stops the data transmission via the radio interface,

the mobile station searches for a second base station and synchronizes itself therewith and

transmits a handover query to the second base station and simultaneously transfers the address of the first base station, and

wherein if the second base station accepts the handover of the mobile station the second base station transmits a message to the first base station to enquire whether the first base station will support the handover,

the first base station transmits a message to the second base station indicating a positive response that it supports the handover,

authentication parameters of the mobile station are then exchanged between the first and the second base stations,

the second base station then signals to the mobile station that the handover is supported by the network,

the second base station then requests the information required for the connection from the first base station and such information is then transmitted bv the first base station to the second base station,

and in that at a later time the connection data is deleted and the resources are released,

wherein the later time is defined by a communication of the mobile station or the second base station about the successful handover.

3. Method according to claim 1 or claim 2, wherein if the handover fails the mobile station can restore the connection to the first base station (BS1) wherein the stored connection data and the reserved resources of the first base station are used for the connection which is restored in this way.

Construction

48. There was no dispute about the correct approach to construction. It is that set out in the judgment of Lord Hoffmann in Kirin Amgen v. TKT [2005] RPC 9. The task of the court is to determine what a person skilled in the art would understand the patentee to be using the language of the claims to mean. A helpful summary of the applicable principles is to be found in Virgin v Premium Aircraft [2009] EWCA Civ 1062; [2010] RPC 8 at [5]. I do not repeat it here. I turn to the numerous features on which there is a dispute about the application of these principles.

"from a first base station to a second base station of the network"

49. In a system such as GSM, the transceiver station (BTS) is connected to a base station controller (BSC). One BSC may have several BTSs under its control. The dispute on this point concerns whether a handover between BTSs under the control of the same BSC is a handover between base stations. Or to put the matter more neutrally: what does the claim mean by a base station?
50. IPCom submit that the base station referred to in the claim is a base station sub-system which incorporates the BSC and any associated BTSs. Nokia submit that a base station is the BTS and a share of the BSC.
51. Nokia rely on the following passage in the specification at [0003]:

"This means in each case that one access point (referred to below as a base station (BS)) in each case forms one radio cell. … Since these cells must have a very limited size in current systems due to the high frequencies and high numbers of mobile stations, the transfer of a mobile station from one cell into an adjacent cell is of great importance. This transfer of the connection of the mobile station from the radio cell 1 into the radio cell 2 is referred to as a handover (HO)".

52. Nokia submit that this means that each cell has a base station, and handover is the process of transferring a connection on moving from one cell and its base station to another. They say this is reinforced by the description of Figure 4 which refers to "the radio cell formed by BS1"; in other words one base station is equated with one radio cell.
53. Both sides agree that a base station is more than a transceiver, and includes the telecommunications links to the network. IPCom rely, firstly, on the description of Figure 1 which states:

"Figure 1 shows schematically a cellular mobile radio system. Figure 1 shows, by way of example, two base stations (BS) 1, 2, which in each case form two radio cells."

54. Accordingly IPCom submit that the patent recognises that a single base station may have two radio cells.
55. Next IPCom submit that Figure 1 makes clear that the base stations are connected to a single switching unit, forming "a permanently installed network". They suggest that this reference to the network is picked up by the claims in referring to base stations "of the network", and that therefore a transfer from one base station of the network to another is necessarily a transfer between separate BSCs. Lastly IPCom submit that the only purpose discussed by the patent for the invention in the passage at [0006] (referred to above) is to deal with networks in which only restricted communication is possible between individual base stations. They say this is not the case with handovers between BTSs within the same BSC.
56. I prefer Nokia's submissions on this point. Taking IPCom's points in turn:

i) The description of Figure 1 does not clearly suggest that each base station has two radio cells. Even if it did so this would not be a strong indicator that intra-BSC handover was not contemplated as being within the scope of the invention. Figure 1 is expressly stated only to be by way of example.

ii) The fact that the base stations are referred to as being "of the network" is entirely neutral. The base stations would be "of the network" whichever interpretation of base station was adopted.

iii) The fact that both base stations in Figure 1 are connected to the same switch does not help either. Figure 1 would be understood to be depicting, by way of example only, a simple architecture sufficient to illustrate the principle of the invention. It is wrong to use this to import unnecessary limitations into the claims.

iv) The passage relating to the purpose of the invention at [0006] shows that the invention is useful even in cases where there is limited communication between base stations. I consider that this passage assists Nokia because it contemplates that the invention may be useful in cases where communication between base stations is not limited, as would be the case where they share a BSC.

57. I agree with Nokia when they submit that it is impossible to see any valid technical reason why the patentee would have wanted to exclude the class of intra BSC handovers when the method works for that class.

"connection" – claims 1 and 3

58. There is no dispute that, in claim 1, "an existing connection in the respective base station" means an active connection from the mobile to the network via the base station. There is however a dispute about the connections referred to in claim 3. Claim 3 refers to a connection in two places: firstly requiring that the mobile can "restore the connection to the first base station" and secondly requiring that the stored connection data and reserved resources are used for "the connection which is restored in this way". IPCom submit that the connection which has to be restored – the first mention of a connection in claim 3 - is only the radio link from the mobile to the base station. They rely on the fact that the claim says "restore the connection to the first base station". I reject this construction. The claims are speaking throughout about the active end-to-end-connection. IPCom's construction, as they acknowledge, involves giving a different meaning to "connection" in the early part and the later part of claim 3. There is nothing in the point about "to the first base station". It makes perfect sense to speak of restoring the active end-to-end connection to the first base station: it just means that the end to end connection, whilst remaining the same at both ends, goes through BS1 rather than BS2. In the context, which includes claim 1, the latter part of claim 3 and the frequent references in the specification to routing the end-to-end connection via one or other of the base stations, it would be abundantly clear to the skilled reader that the patentee is referring throughout to the active end to end connection.

"forward handover"

59. Nokia contend that the term "forward handover" is to be construed in accordance with the passage at [0004], and means that the mobile station "searches for its destination base station itself and registers there directly". IPCom now accept that the term is to be construed by reference to that passage, subject to a reservation about what is meant by "search". According to IPCom, there is a relevant search even if the mobile is given the address of the new base station by the old one, leaving the mobile with no decision to make. IPCom say that there is a forward handover whenever it is the mobile station and not the base station which makes the first unannounced contact with the new base station.
60. The patent describes the "search" in the following terms:

"In the step 102, the MS searches for a new base station and synchronizes itself with this base station. However, it is similarly possible that the MS, for example by measuring the field strength of the BS 2, has already identified the station with which the BS 2 [semble MS] intends to re-register, so that the search for a new base station is then no longer required."

61. IPCom relied in opening on the second sentence of that passage to suggest that the search operation was optional. I do not accept that interpretation. I think the correct reading of the passage is that the process of identification of the target base station, which the patent calls searching, may have occurred at an earlier stage than step 102. A search is thus "no longer required" at the point when the mobile first contacts the base station, because the search has already occurred. The skilled person would understand that some mobiles keep themselves regularly updated on the availability of alternative base stations, so that a target candidate is always known to it. There is nothing in the passage to suggest that the task of identification of the target base station can be undertaken by anything other than the MS.
62. I think the requirement for the mobile to search does include the element of the mobile being responsible for identifying the target base station. The skilled person would see nothing unusual about this, as he would know that the allocation of responsibility for identification of the target base station was one of the basic considerations in the design of a handover process. I do not think it is realistic to say that the mobile conducts a search when the target station has been pre-identified by the old base station. If that is a search, then so also would be the process of locking on to the new base station pre-identified by the mobile itself. The passage cited above is plainly inconsistent with that.
63. Mr Purvis sought to rely on his cross-examination of Dr Brydon on the meaning of "search" in the context of the DECT standard. In that standard, PP is the mobile and FP is the base station:

"Q. As I understand the distinction that you are drawing, you are saying if the PP gets a list of two FPs from its FP-1 as candidate FPs for a handover, then the choice between them is a search operation. But if it only receives one, then it does not carry out a search. Is that essentially what you are saying in these paragraphs?

A. To me the search is going to have a look at what is out there, so you are given a list of, these are potential targets for a handover. The mobile then needs to go and look at those potential targets and take a decision on which is the best one. If there is only one, then it may still decide, "Well, actually, I cannot see that base station, so I cannot perform a handover –"

Q. Is that still a search?

A. It is still performing the search process, but, I agree, it is not much of a search.

Q. It is not actually any more of a search or any less of a search than in the case of getting a list of two, is it?

A. The process is a search. The process of looking out there to see what is available in order that the mobile can decide what is the best handover target, that is what I regard as a search.

Q. Or whether to go with the handover target that it has been offered.

A. If it is given a single target, you mean?

Q. Yes.

A. Yes.

Q. Or whether it can communicate at all with the target that has been given

A. Absolutely. As I said, it may well be that you are given a list of candidates and none of them are available to you.

Q. All that to you is a search?

A. The process of going to look for those targets is a search, yes."

64. I do not think this helps IPCom. Firstly, the terms "forward" and "search" are ordinary English words. Their meaning is therefore not a matter for direct expert evidence. Secondly, it is the meaning of these words in context which is important. These answers were given in the context of a different document. It by no means follows that the words mean the same thing in the context of the patent. I have relied in reaching my conclusion on passages in the specification which throw light on the meaning of search in the context of the patent. Thirdly, Dr Brydon, at least in the earlier answers, clearly maintains that the mobile is still responsible for making a decision based on the available base stations. Lastly, even if one were to ignore the fact that this cross-examination was in relation to words which were not terms of art, it was not clearly suggested to Dr Brydon that his evidence in respect of the meaning to be attributed to the words in the patent was wrong.

"initiated by the first base station"

65. Nokia contend that "initiated by the base station" means that the base station will normally attempt a handover when prompted to do so by the base station, but may nevertheless decline to do so on fixed criteria.
66. IPCom originally contended that the expression "initiated by the base station" means a forced handover. A forced handover, they submitted, is one where the mobile station actually attempts a handover when required to do so by the base station, and only fails to do so when it cannot communicate at all with the new base station which it is required to contact.
67. Although the patent refers to a base station initiated handover as "forced", the language used to describe the base station initiated handover in the specification is less dictatorial in character. The specification says that, when "requested", the mobile station "should" perform a handover, and refers to the specific instruction as a "request".
68. At [0024] the patent refers to the handover in GSM as being "forced". In his written evidence, Dr Brydon pointed out that in GSM the mobile station does not always perform a handover in response to a handover instruction from the network. This passage is therefore not obviously consistent with IPCom's construction.
69. The patent envisages circumstances where the base station initiates a handover because it wishes to relieve overloading. As Dr Brydon points out, it is not therefore essential to the utility of the method that the mobile station should unquestioningly obey the handover request. It would remain useful if only a proportion of mobiles, for which handover met certain criteria, were to hand over in response to the request. Moreover it would only be sensible in very limited circumstances (e.g. where the old base station is being taken off line) to require the mobile to hand over in a situation where there was no available target. In other circumstances it would be wasteful of resources.
70. IPCom's argument, as it emerged in closing submissions, was that base station initiated handover covered the situation where the mobile did not initiate the handover. Building on this, IPCom submitted that the prior art made it clear that the term "mobile-station initiated" covered all cases where the mobile retains the ultimate decision to hand over, even where that decision had in some way been suggested by the old base station.
71. I reject IPCom's submissions on this point. It seems clear to me that the terms "base station initiated" and "mobile station initiated" focus on the instructions to attempt a handover and not on the control of what happens in response. To initiate a transfer the base station (or mobile) must send a message requesting a transfer with which the mobile will normally comply, subject to any criteria which it may impose. Beyond this I do not think that the patent requires any particular degree of compulsion to be exerted. I reject the suggestion that there is an established meaning to be gleaned from the prior art. The patent does not require the base station to have absolute authority over whether a handover takes place.

"communication about the successful handover"

72. There is a further dispute about what is meant by a successful handover. Nokia submit that the purpose of the invention is to reduce the possibility that the mobile must end its connection through failed handover, and therefore to retain the radio resources in the first base station until the entire handover process has been successfully completed.
73. IPCom focus on the fact that the passage at [0009] says that the probability that the MS must end its connection is "significantly reduced": it does not say that it is removed altogether. They submit that the claim covers a case where a communication is sent reflecting some success in the handover process. They rely on the fact that the setting up of the new radio link with the second base station is the most risky part of the handover process. Thus they submit that the purpose of the invention is satisfied if the safety net is retained for some part of the handover process.
74. To reinforce this position, IPCom rely on a passage in the patent at [0011] which states:

"The interruption of the radio link between BS1 and the MS3 and the activation of the radio link between the BS2 and the MS3 are normally regarded as the handover."

75. IPCom submit that this passage indicates that something short of an entire handover, including the switching of the connection through the network, will do.
76. I do not accept these submissions. The patent makes clear that it is concerned with switching an active end-to-end connection of a mobile station to a network, routing it through BS2 instead of BS1. Accordingly handover is not completed until the active end-to-end connection has been re-established. Consistently with this, communication about a successful handover does not occur until the handover is complete. This significantly reduces the probability of a failed handover, as the patent teaches, not because the patent contemplates announcing a successful handover before it is complete, but because a major cause of failed handover is eliminated.

Claim 3 – "if the handover fails the mobile station can restore the connection to the first base station"

77. The latter part of claim 1 is concerned with what is to happen when there is a successful handover: the connection data and the resources are to be stored and reserved until the communication about the successful handover. Claim 3, by contrast, is concerned with what happens if the handover fails: the mobile must be able to restore the connection to the first base station, using the stored data and the reserved resources.
78. IPCom submit that this phrase means that the mobile can restore the connection at any time until the "later time" defined by claim 1, namely when the connection data has been deleted and the reserved resources released. Of course, the handover is not going to fail after the "later time", because the later time is when a successful handover has occurred. I understood IPCom's point to be that the mobile must be able to restore the connection at any time up to that later time. Given that the data and resources are being stored up to the "later time", there is force in the suggestion that the skilled person would want to arrange matters so that the connection could be restored so as to make use of those resources for as long as they are stored. However I can see nothing in the language of the claim to compel that conclusion. IPCom's submission involves writing into the claim a requirement which is not there, namely the words "at any time up to the said later time".
79. IPCom also submit that the claim implies a causal relationship. It does not cover a method in which the mobile is required to return to BS1 before the later time, whether the handover has failed or not. I think the claim is clear: if the handover fails, the mobile must be able to return to the first base station. There is no causal requirement.

Lack of novelty – law

80. To deprive a claim of novelty, the prior document must contain a clear and unambiguous disclosure of, or clear and unmistakeable directions to do or make, something falling within the scope of that claim: Synthon v SmithKlineBeecham [2006] RPC 10 at [21] to [25]. If there are gaps in the disclosure then the claim will not fail on the ground of lack of novelty.

Obviousness – law

81. In Conor v Angiotech [2008] RPC 28, [2008] UKHL 49 at [42], Lord Hoffmann approved Kitchin J's statement about the approach to obviousness in Generics (UK) Ltd v. H Lundbeck A/S [2007] RPC 32, para. 72:

"The question of obviousness must be considered on the facts of each case. The court must consider the weight to be attached to any particular factor in the light of all the relevant circumstances. These may include such matters as the motive to find a solution to the problem the patent addresses, the number and extent of the possible avenues of research, the effort involved in pursuing them and the expectation of success."

82. The court should normally adopt the structured approach endorsed by the Court of Appeal in Pozzoli v BDMO [2007] EWCA Civ 588; [2007] FSR 37. I have endeavoured to do so here.

Lack of novelty and obviousness over DECT

DECT disclosure

83. The starting point for the attack based on DECT is ETSI standard document 300-175-5. In section 15.7 the DECT standard specifies the handover between two different DECT fixed parts (FP1 and FP2), described as an external handover. There is no detailed explanation as to how the two FPs communicate, beyond saying that a common management entity above the two fixed parts is necessary.
84. Handover in DECT can be initiated by the PP. The specification also says that "the FP may also suggest that a PP initiates an external handover".
85. The PP monitors the quality of its existing connection and estimates the quality of its handover candidates. If it determines that an alternative candidate would give it a better quality of service, it commences a handover process. If it does not already have a handover reference, it requests one from FP1.
86. The FP may suggest to the PP that it undertakes a handover by sending a message {MM-INFO-SUGGEST}. The message contains all the information required for the handover. The information contained within {MM-INFO-SUGGEST} may contain information for an external handover, including a handover reference and one or more external handover candidates.
87. Section 15.7.3 describes what is to happen on receiving {MM-INFO-SUGGEST}:

"The FP has the option to propose an external handover by using the FP initiated procedure for parameter retrieval, sending {MM-INFO-SUGGEST} containing all the information (handover reference, handover candidate) necessary to enable the PP to initiate an external handover. The PP should then initiate a handover using the procedures of 15.7.4."

88. The use of the words "suggest" and "should" are indicative that the PP is free to ignore the message in some unspecified circumstances.
89. When the PP starts to set up a link with the new FP it sends a {CC-SETUP} message to the new FP. If FP-2 is able to accept the handover, it responds with {CC-CONNECT} to which the PP responds with {CC-CONNECT-ACK}, indicating that it accepts the handover.
90. During an external handover, data and resources relating to the connection through FP-1 are maintained within FP-1. Upon establishment of a connection with FP-2, FP-1 sends a message {CC-RELEASE} to the PP indicating that the link should be released. The PP responds with the acknowledgement {CC-RELEASE-ACK}. At any point up to the PP sending the {CC-CONNECT-ACK} acknowledgement, the PP can fall back to FP-1, terminating the handover.
91. DECT contains recommended receive and transmit paths for the user data (e.g. voice traffic) during external handover. In DECT the uplink (PP to FP) and downlink (FP to PP) are carried on separate channels, each on separate time slots. Accordingly the link between PP to FP-1 has an uplink and a downlink and that between PP and FP-2 also has an uplink and a downlink.
92. The table of the recommended transmit and receive paths is as follows:

93. Note the difference in the last two columns between the "and" in the PP transmit path and the "or" in the FP receive path. From this table (PP receive column) one can also see that, until PP sends {CC-CONNECT-ACK} (step 4) the PP is listening to FP-1 on the downlink side. On the uplink (fifth column), the PP transmits to both FP-1 and FP-2 until it receives the {CC-RELEASE} message in step 6. The network, however, is only listening to the data received via one of those FPs (see the right hand column – "or"). In step 1 the uplink connection is through FP-1, in step 5 it is through FP-2, and in steps 2–4 the uplink connection to be used is an implementation choice. One implementation is, therefore, that during steps 2 to 4 the uplink connection from the PP to the network is via FP-2.

Initiated by the base station?

94. IPCom submit that {MM-INFO-SUGGEST} does not give rise to a base station initiated handover. They draw attention to the language used in section 15.7.3: the suggestion is made to the PP to initiate the handover. The suggestion is not said itself to constitute initiating the handover. I do not regard this point as persuasive. The passage is using the term "initiate" to refer to the commencement of the negotiations with the new base station, rather than to the instigation of the handover. There is no suggestion that the term "initiation" had a uniform meaning in the art.
95. On the view which I take of the meaning of the term "base station initiated" as used in the patent, DECT discloses base station initiated handover. The purpose of {MM-INFO-SUGGEST} is to prompt the PP to undertake a handover that it would not otherwise undertake. Just as in the patent, the skilled person implementing the disclosure of DECT would have to specify the circumstances in which the PP will make the handover. There is no viable distinction between the two documents on this basis.

Restoring the connection

96. IPCom's case on this feature depends on their argument that the connection referred to in the early part of claim 3 is the radio link between the mobile and the old base station. They submit that in DECT the radio link between the old base station (FP) and the PP is not dropped. Only the link between the base station and the call destination is broken.
97. I have explained that one option disclosed by DECT is that the network uses FP-2 as the receive path from step 2 onwards. Dr Brydon explained that in those circumstances the uplink user-data connection via FP-1 would be broken at that point. He accepted that the radio link between the PP and FP-1 would remain in place (subject to some special cases where this would not occur). If the PP subsequently terminated the handover attempt, for example by sending a {CC-RELEASE} message to FP-2 before step 4, then the network would revert to the uplink user-data connection via FP-1.
98. IPCom submit that this is not restoring the connection within the meaning of claim 3. If the radio link remains in place, then nothing is restored.
99. I reject IPCom's submission. It has to be remembered that the connection in question is the active end-to-end-connection. In the circumstances discussed there is no doubt that the connection on the uplink is broken. The fact that the PP continues to transmit as far as the base station does not alter that fact. As Mr Tappin put it graphically, the data is going into a drain. Once the PP reverts to FP-1 the connection is restored. I am satisfied therefore that there is no distinction to be made based on this feature.
100. It is therefore not necessary for me to decide the two further points based on synchronisation and ciphering. I will deal with them quite shortly. They both raise short points on obviousness.
101. The point on synchronisation is that it is one example of a situation in which it would not be practical to follow the recommended paths in the DECT table set out above. Where the two FPs are not synchronised, the PP will not, unless it is highly sophisticated, be able to communicate with both FPs as required by the fifth column of the table. It will have to choose. Nokia, on the basis of Dr Brydon's evidence, suggest that one obvious choice is via FP-2.
102. Dr Brydon was cross-examined about this suggestion. He accepted that one possibility was to bar handovers to non-synchronised base stations. However he made clear he thought that would not be a desirable option. He also accepted that the standard setting organisation may have expected that mobile stations could cope with handover between non-synchronised stations. As I have already said this would have required sophisticated technology.
103. I have come to the conclusion that the step of implementing DECT in the case of non-synchronised base stations by taking the decision to communicate on the uplink through FP-2 was an obvious one for the skilled person to take. The Table in the DECT standard is accepted to be a recommendation and not a mandatory part of the standard. The skilled person would easily have recognised that it could not sensibly be complied with in the case of non-synchronised base stations. Dr Brydon's suggestion does not involve an inventive step.
104. The point on ciphering is that it is a further example of a case where it would not be practical to follow the recommended path in DECT. If the PP contains only one cipher engine, the manufacturer can either decide to send data to one of the FPs "in the clear", or cease to communicate user data to one FP or the other. Again it is suggested by Dr Brydon that one obvious choice is to communicate with FP-2 and break the link with FP-1, thereby avoiding transmitting in the clear. In his written evidence he took account of the specific suggestions for ciphering made in paragraph 15.7.6, but said that "a more likely implementation" would be to cease transmitting any user data on FP-1.
105. Dr Brydon was cross-examined on the basis of paragraph 15.7.6 of the DECT standard. It was suggested to him that the skilled person would use one of the options disclosed in that paragraph, rather than the suggestion which Dr Brydon made. Dr Brydon did not retreat from his view that his suggestion was a valid implementation of DECT. In the absence of any evidence to contradict him, I consider that it is established that implementing DECT in this way did not involve an inventive step.

Conclusion on DECT

106. Claims 1 and 3 lack novelty, or are alternatively obvious in the light of the disclosure of DECT.

Obviousness over Ojaniemi

Ojaniemi disclosure

107. Ojaniemi is a published PCT application emanating from Nokia dated 29^th January 1998, No WO 98/04094. It discloses a variety of ideas in relation to a mobile radio system aimed at reducing the number of connection losses incurred and to decrease unnecessary interference during handover.
108. The core handover process in Ojaniemi is explained by reference to Figure 2, reproduced here from Dr Brydon's report:

109. As Dr Brydon explains, the core handover process is as follows:

i) The MS measures pilot signals of surrounding BTSs and reports these to its serving BSC;

ii) If a pilot signal of a surrounding BTS exceeds that of the serving BSC, the serving BSC initiates a handover via a mobile switching centre (MSC);

iii) The MSC then requests a handover from the target BSC, which reserves resources in the target BTS;

iv) After receiving confirmation that resources have been reserved, the MSC sends a handover command to the serving BSC, which then commands the MS to perform the handover to the target BTS;

v) The new BTS informs the new BSC when it detects a transmission from the MS, and the new BSC then invites the MS to complete the handover. The MS replies with a "HANDOFF_COMPLETION" message which the BSC acknowledges;

vi) Finally the new BSC sends a message to the MSC to indicate successful completion of the handover. The MSC then starts to release the reserved resources associated with the original connection by sending a CLEAR_COMMAND to the original BSC. The BSC passes on a RESOURCE_RELEASE command to the original BTS, which then releases the relevant resources in the BTS.

110. At page 10 lines 7-11 Ojaniemi explains:

"…if establishing a connection to a new base station BTS_2 fails during a hard handoff, the method will return to the initial connection between the subscriber station MS and BTS_1".

111. The flow of messages for this case of failure during hard handoff is explained in Figure 3. Ojaniemi states that "When no connection is achieved between the subscriber station MS and BTS_2, the original base station BTS_1 will continue communicating with the subscriber station."

Difference from Ojaniemi

112. There is no allegation of lack of novelty over Ojaniemi. The sole issue is whether the invention was obvious in the light of it.
113. The difference between the disclosure of Ojaniemi and the patent is that Ojaniemi does not disclose forward handover. Although the handover is initiated by the first base station, it is not a forward handover: the mobile station does not search for its target base station itself and it does not register there directly when a handover is required. Instead the mobile is given a target base station and the network undertakes a variety of preparations before instructing the mobile to execute the handover.

Was the difference obvious?

114. Dr Brydon's evidence, as explained in paragraph 327 of his report, was that one of the significant types of mobile radio system was the type which used small to medium size radio cells, for example for use on a campus or in a densely populated area. His evidence was that in a network of this type the most obviously suitable choice of handover was for the mobile to be responsible for handover initiation and choice of new base station. In any such system it would be normal in his view to provide also for network initiation of handover, for example to cater with base station overloading, or to allow balancing of the traffic on the network.
115. Dr Brydon continued as follows:

"Ojaniemi clearly explains the idea of reserving resources and storing connection data at the first base station until a handover had been completed successfully, so that the call could fall back if necessary, along with the release of the resources (and deletion of stored data) on handover completion.

In my opinion, it would have been apparent to the skilled person that this idea explained by Ojaniemi could equally be used to reduce call dropping on handover in other types of system, including a system of the type to which I have referred in paragraph 327 above.

I do not think that there would be anything inventive in the skilled person (who had read Ojaniemi) deciding to design a system which allowed base station initiated forward handover, implementing the idea in Ojaniemi."

116. Dr Brydon was not cross-examined on any of the detail of this evidence. Mr Purvis submitted that the project described by Dr Bydon was a wholly unrealistic "blue skies" approach which was incorrect in law. What the skilled person would in fact do is to start from one of the existing standards. He relied on a sentence from paragraph 116 of my judgment in Nokia v IPCom [2011] EWHC 1470 Pat, in which I was dealing with an allegation of obviousness in the light of the common general knowledge. I set out the sentence in context here:

"[115] Nokia's fourth and final attack on the patent was from common general knowledge alone. In short it runs as follows:

i) A lottery method for controlling access to the RACH was common general knowledge;

ii) It was also common general knowledge that the emergency services might require immediate access to the RACH;

iii) If it was thought to be a problem that the emergency services had to do the lottery, one could devise a system in which the emergency services were told by a signal on the broadcast channel that they did not need to.

[116] This is a very simple and attractive argument, untrammelled as it is by any of the details of a practical working system. Mr Gould's fundamental position was that the skilled team would be much more likely to start from one of the known standard proposals, such as GSM/GPRS or IS-95. His cross-examination required him to clear his mental decks of all such proposals and start with a system solely based on the lottery. He plainly thought this whole exercise unrealistic, as I believe it to have been. The skilled person's first port of call would have been to see what methods of control had in fact been used in the past. This is particularly so in a case where such methods have been through standardisation processes. I have already considered whether the methods disclosed in GSM/GPRS or IS-95 would have led to the invention and concluded that they would not. The obviousness argument from common general knowledge requires instead an a priori re-assessment of the problem without reference to these methods. I must take this decision into account in assessing whether the approach adopted in the patent is inventive."

117. The position is not the same here, not least because there is no expert evidence to suggest that the proposal which Dr Brydon put forward was unrealistic. To the contrary, I have Dr Brydon's evidence that this was "how an engineer would think about it."
118. Mr Purvis submitted that what was at stake was essentially a proposition of law. I cannot accept that submission. Whether an invention is obvious from a given starting point is a question of fact to be decided in the light of the available evidence in accordance with the principles which I have outlined. Moreover, as Mr Tappin pointed out, if the only obvious thing to do is to use an existing standard, then any technical difference from an existing standard would be inventive. That is not the law, nor should it be.
119. I think it is very clearly established that the invention of claims 1 and 3 is obvious in the light of Ojaniemi.

Lack of novelty and obviousness over PACS

PACS disclosure

120. PACS or Personal Access Communications Air Interface Standard was an American National Standards Institute (ANSI) standard for a mobile radio system. It was aimed to be complementary to large cellular systems such as IS-95 and GSM. The proponents of the system were of the view that these large cellular systems were less suitable indoors and for the delivery of high speed data. The system was not widely adopted because of the advantages of systems such as UMTS which were deployed in the early 2000s. It did not form part of the common general knowledge.
121. In PACS the mobile is referred to as the SU. Each radio port (RP) is connected to a radio port control unit (RPCU). Handover is known as Alternate Link Transfer or ALT.
122. Figure 3-2.1 shows the basic layout, reproduced here from Dr Brydon's report:

123. The handover protocol looks like this:

124. Usually the SU is responsible for instigating a handover in PACS. The SU chooses the target RP. An ALT_REQ message is sent by the SU to the new RP.
125. ALT can also be stimulated by the network by the transmission of a PERFORM_ALT message. Depending on the setting of the "TYPE" field in this message, the request can be a mandatory or optional request.
126. When the SU receives a PERFORM_ALT message, it synchronises with the new RP. It is the SU which decides which RP to hand over to. At the start of the ALT the SU suspends the voice communication with the message LINK_SUSPEND sent to the old RPCU. The SU then sends an ALT_REQ message to the new RPCU. The new RPCU responds by sending an ALT_ACK message back to the SU. The SU will not commence communication with the new RPCU immediately, but will, if possible, resume communication with the old RPCU while the network arranges for the ALT by transferring the information relevant to the call to the new RPCU. The switching function of the network inserts a bridge to the new port, which enables the SU to switch quickly.
127. Once the preparations are complete the network tells the SU to complete the ALT, using both the old and new channels. This is accomplished by sending an ALT_EXEC command from the old RPCU and a series of START_CIPHER command from the new RPCU. This is a fail safe approach to cater for the possibility that the SU will lose its connection before the ALT preparations are complete.
128. Ultimately an ALT_COMP message is sent to the new RPCU to indicate that the ALT process has been successfully completed, whereupon the network releases the resources on the old RP.
129. If the radio link to the old RP fails before the SU receives ALT_EXEC, it synchronises to the new RP and waits for the START_CIPHER message, whereupon it begins encryption and decryption, resumes voice communication and sends ALT_COMP to the new RPCU.
130. Having received ALT_COMP, the network can remove the bridge and free up the resources associated with the old channel. The standard does not specify how this should happen, but Dr Brydon's understanding was that the new RPCU relays its knowledge of the successful handover to the old RPCU over the network.
131. In the case of ALT failure, for example because the new RPCU does not have sufficient resources, the SU returns to the old channel, using the reserved resources and channels.
132. When a mandatory PERFORM_ALT is sent by the network, the SU must attempt an ALT. If the SU is unable to complete an ALT within a fixed time (of the order of one second) the call is dropped. Until the time expires, the SU performs the normal ALT procedure.

Base station initiated?

133. IPCom submit that optional PERFORM_ALT is not base station initiation within the meaning of the patent. Dr Brydon accepted that in order to implement optional PERFORM_ALT means would have to be provided to determine whether or not the SU would accept the suggestion of the handover. This could be based on parameters such as the signal strength of the target RPCU.
134. I have dealt with the issue of construction of "base station initiated" above. In my judgment, optional PERFORM_ALT is base station initiated within the meaning of the patent. I cannot see any sensible distinction between optional PERFORM_ALT and what is described as a base station initiated handover in the patent. Optional PERFORM_ALT creates a situation in which the mobile will perform a handover unless it determines that no suitable destination port is available. I accept Nokia's submission that such an arrangement is within the patent.

Restoring the connection if the handover fails

135. IPCom next submit that in PACS there is no suggestion that the connection data is kept after the ALT_EXEC message is sent. This point is related to a point that they make on claim 3, that in PACS there is no ability to return to the first RPCU at all times prior to the completion of the ALT.
136. This was not a point which Dr Brydon, or Nokia, had seen coming. It only emerged with any clarity in IPCom's opening skeleton argument. Dr Brydon provided a fourth expert report after the trial had started which I admitted without any opposition from IPCom. Dr Brydon's evidence was that it was clear that an SU can fall back to the old channel, even after receipt of the ALT_EXEC message during an inter-RPCU ALT.
137. IPCom accept that prior to the ALT_EXEC message being sent, the SU can return to the old RPCU. They say that this does not satisfy the claim, because the link is resumed whether or not there is a successful handover in progress. I have rejected this construction of claim 1 – the causal "if". It follows that this point does not provide a distinction over PACS.
138. The second question is therefore whether the PACS document clearly discloses that the link can be resumed after the ALT_EXEC message. Dr Brydon clearly interpreted it in that way. He was cross-examined on the protocols.

"Q. Not all ALT fails, for example, could be interpreted as ALT abandoned, could they?

A. No, but I would not necessarily assume there would be a separate list of activities, all of which would be exactly the same for each of those cases, so I think this ALT abandoned message from the higher protocol level is catching all of those failure cases and saying, "Right, this has failed, this is what you do." Therefore, that middle column, showing the retuning and resuming the link, is what is intended to happen in each of those failure cases.

Q. That is just an assumption on your part?

A. It is, but based on the fact that the SU has to do something in its SU ALT permitted state. It has been left floating. The handover has failed. It is in a state, it is still in a call, so my interpretation is, in the context of the rest of the document where it does talk about the fact that the SU is able to fall back to the original RP, that this is the mechanism for doing it...

Q. What it comes to is this. Although there is an explanation here of how you can return to the old RPCU in the early stage of handover, prior to the ALT_EXEC -- and we can see that really easily from these SDLs -- there is no actual explanation of how that happens in respect of ALT_EXEC. Correct?

A. You mean a textual description of it?

Q. Yes.

A. That is true, so there is the general statement earlier on that the SU is able to return to its original RP, which certainly, when you first read that, you would assume that applies throughout the handover process. The document does not talk you through this SDL diagram and explain how it works, but my view is, that is how it is meant to work. That is the purpose of that middle column on page 121."

139. I think that in the light of Dr Brydon's cross examination it is not possible to say that there is a sufficiently complete description of the fall-back process to amount to an anticipation of claim 3. However, in my judgment, Dr Brydon was doing no more than explaining how an uninventive person would in practice understand and apply the teaching. Given that there is a difference here between what is expressly taught by PACS and the inventive concept of claim 3, I will have to return to this issue under the heading of obviousness. I would merely record at this stage that the difference merely relates to filling in the interstices of the disclosure of PACS.

Communication about the successful handover

140. IPCom submit that in PACS there is no communication of the mobile station or the second base station about the successful handover defining a later time at which the resources are released. They accept that the evidence shows that, on receipt of ALT_COMP, the network takes down the network-side elements. However, they maintain that there is no clear and unambiguous disclosure about what is to happen to the radio link between the network and the SU. Dr Brydon accepted that there was some ambiguity about this:

"Q. Yes. It is not as clear as you suggest, is it, because it appears that the PACS standard distinguishes between resources on the old RP, which is slightly ambiguous, and all the radio resources associated with the call? Do you recall that? If you look, for example, at page 128, which is the network SDLs. Just look at the bottom network ALT proceeding.

A. Yes.

Q. So when the network gets an ALT_COMP via the new RP, stops the timer, TN202, "release resources on old RP"; that is the step that we are looking at, is it?

A. Yes.

Q. But if we look across at the right-hand column, on a TN202 expiry -- and we see there a counter in the next diamond, so you can count the clock on -- if you have not received any message at all within a certain period of time, it then says, "Release all radio resources associated with the call."

A. It does.

Q. There is clearly a distinction being drawn, is there not, between the resources at the network level and the radio resources associated with the call?

A. Well, I did not pick that up, but my interpretation was based on the story that runs from the early stage, when it talks about the ability to return to the original RP if a call fails, so I think that the interpretation I have given is consistent with that. You know, resources on old RP is ambiguous, I agree with you, but I would regard the radio resources as being resources on the old RP.

Q. This is perfectly consistent with just the network taking down the network side elements of the connection with the old RPCU and saying nothing about the radio link. Correct?

A. That is another possibility, yes."

141. The skilled reader would approach the document with an understanding that there is plainly no reason to retain the radio link after a successful handover. No reason was suggested why the radio link should be retained after this time. That was Dr Brydon's understanding expressed in his written evidence. I think that the effect of the cross examination relied on is that Dr Brydon fairly accepted that there was some technical ambiguity associated with the phrase "resources on the old RP" in isolation. That may be so, but it is not the correct approach to the interpretation of the document. In my judgment the skilled person would understand from the document read as a whole that the radio resources were to be released on receipt of ALT_COMP as well.

Intra base station handover

142. There is no dispute that fall back is possible at all times with an intra-RPCU ALT. IPCom submitted that intra-RPCU ALT did not comply with claim 1, on the basis of their argument as to the correct construction of "base station" in the claim. I have resolved that point against them. In case I am wrong on that point I have considered (above) the case based on inter-RPCU as well.

Differences from PACS

143. It was not suggested by Nokia that if they were wrong on "base station initiated", that they could succeed on obviousness. The remaining differences or potential differences between the disclosure of PACS and the inventive concept of claim 3 are the points about fall back after ALT_EXEC and release of the radio link by ALT_COMP.

Were the differences obvious?

144. In my judgment, there would have been no invention in seeking to implement PACS in the manner claimed in the patent. The differences, if they exist at all, are merely implementation details, filling in gaps in the express disclosure of the document in an obvious way. Given that Dr Brydon's understanding was that the standard would be implemented in that way, and in the absence of any coherent suggestion of how or why the skilled person would have wished to implement it any differently, I conclude that these differences would have been obvious to the skilled person without any knowledge of the patent.

Conclusion on PACS

145. It follows that claims 1 and 3 are obvious in the light of PACS.

Amendment- law

146. Amendments cannot be allowed if their effect is to extend the disclosure. In Nokia v IPCom [2011] EWHC 1470 (Pat) at [126] to [136], I attempted to pull together the authorities on the law as it applied to the objection of added matter. I referred to what Pumfrey J said in Palmaz's European Patents [1999] RPC 47, 71 about intermediate generalisation:

"If the specification discloses distinct sub-classes of the overall inventive concept, then it should be possible to amend down to one or other of those sub-classes, whether or not they are presented as inventively distinct in the specification before amendment. The difficulty comes when it is sought to take features which are only disclosed in a particular context and which are not disclosed as having any inventive significance and introduce them into the claim deprived of that context. This is a process sometimes called "intermediate generalisation"."

147. I also said this at [132] to [134]:

"[132] Where a claim is being narrowed by the addition of features, there should, as Pumfrey J pointed out in Palmaz, normally be no difficulty provided that what is being done is to amend down to a distinct sub-class of the inventive subject matter, and provided also that one avoids intermediate generalisation. This problem may arise where, as in this case, it is sought to add to the claim features only to be found in the specification as part of the description of a specific embodiment, and where they are technically or functionally connected to other features which are not sought to be claimed."

[133] The EPO also apply a general rule where a claim is restricted to a preferred embodiment. In T0025/03 the Board said:

"According to the established case law of the boards of appeal, if a claim is restricted to a preferred embodiment, it is normally not admissible under Article 123(2) EPC to extract isolated features from a set of features which have originally been disclosed in combination for that embodiment. Such kind of amendment would only be justified in the absence of any clearly recognisable functional or structural relationship among said features (see e.g. T 1067/97, point 2.1.3)."

[134] I think this is what Pumfrey J meant by introducing features into a claim "deprived of their context". I do not think he meant to establish a rigid principle of "all or nothing" in relation to taking features from a specific embodiment. Both Houdaille and T0025/03 recognise that presentation of a feature in combination with the claimed features may nevertheless permit the skilled person to recognise that the feature is not functionally or structurally essential."

The main and auxiliary applications to amend

148. Nokia did not persist with any objections to the amendments the subject of the main application to amend, save only to point out that the claims so amended are invalid. On that ground I refuse to allow the patent to be so amended in accordance with the main application to amend. There remain to consider the objections to the first and second auxiliary applications to amend.

First auxiliary amendment application – added matter

149. I have set out the form of this proposed set of claims above. The features which are sought to be added are to be found only in the description of Figure 4. But many other aspects of that example are omitted. Thus, for example, the claim does not include the features:

i) That the first base station decides that the connection of the mobile station should be handed over;

ii) That the authentication parameters of the mobile station are exchanged between base stations;

iii) That the second base station signals to the mobile station that the handover is supported by the network; and

iv) That the second base station requests the information required for the connection from the first base station.

150. Nokia first make a pair of points under the heading of intermediate generalisation. The first of these is that the proposed amended claim includes a feature that the first base station transmits a request to the mobile to perform a handover whereas in the description of Figure 4 the first base station first decides that the mobile station should be handed over. These features, they submit, are functionally and technically linked. Accordingly claiming one but not the other leads to added matter.
151. Nokia's second intermediate generalisation point is that features equivalent to messages 306 and 310 in Figure 4 (which is reproduced above) are included in the claim, but features equivalent to the intervening messages, 307, 308 and 309, are omitted. These are all aspects of network support which are technically and functionally linked. Picking out only two messages is, they submit, not permissible. That is particularly so when message 310 is the response to the request in message 309, yet only the response is claimed.
152. Nokia submit that these are examples of impermissible generalisation. The claim is in effect a disclosure of a process which is nowhere to be found in the application as filed. The process disclosed in the application as filed has additional features which are technically and functionally related to the features which have been inserted in the claims.
153. IPCom submitted that the present case was distinguishable from Palmaz. Palmaz involved mechanical features which were plainly functionally dependent on one another. In those circumstances it was accepted that there could be added matter by taking some of those features into the claim whilst leaving behind other, mechanically interrelated features. In the case of a handover process such as that described by reference to Figure 4, where one is concerned with messages going between base stations and a mobile, there was not the same functional or technical interdependence. I reject that submission. There is no difference in principle between claims of the kind with which I am concerned and claims of any other kind.
154. IPCom's answer to the point made in paragraph 150 above is that the requirement for a decision by the first base station is implicit in the features which have been imported into the claim. I do not accept that submission. Decisions can be made at different points in the network: only a decision taken by the first base station is disclosed by the application: it is not implicit in the amended claims that the decision is taken in the first base station.
155. IPCom submit, in answer to the point made in 151 above that there is nothing in the specification to suggest that the omitted messages are technically significant or necessary. I cannot accept that submission. The features sought to be claimed are closely interrelated in the description both technically and functionally with other features which have been left behind.
156. In my judgment, in neither of the examples relied on by Nokia, would the skilled person be able to recognise the sub-class of processes now sought to be claimed from the application as filed.
157. The second set of objections arises in the following way. At page 15 lines 16-20, the description of Figure 4 emphasises that the fact that it is shown as network supported is by way of example. It goes on to say that this is "in no way relevant, as the method described also functions with other handover variants". Nokia point out that some of the features sought to be introduced relate to network support. Thus, they say, by introducing these features into the claim, the amendments are giving the features of network support inventive significance.
158. Secondly Nokia draw attention to the passage at page 3 lines 7-11 of the patent, where it says that "the inventions with the characterizing features of the independent patent claims offer the advantage that a handover is possible even in networks in which only restricted communication is possible between individual base stations". In the application, when the features of the independent claims did not contain features related to network support, that statement was true. With the amendments, say Nokia, the patent would be teaching something new.
159. IPCom submitted that both of these points were purely technical, in the sense of lacking any real substance. In any case, they offered to delete the sentences in question. In the absence of any more convincing answer, I think Nokia are right and there is added matter in these respects. Were it the only objection, I would have allowed IPCom the opportunity of applying to amend to remove the offending passages, a course I am prepared to permit in relation to the second auxiliary application.
160. The final point made by Nokia is that the description of Figure 4 contains no mention of a communication from the mobile station about the successful handover, yet this feature is combined in claim 1 with features extracted from Figure 4. I do not think there is anything in this point. The feature requiring a communication from the mobile station about the successful handover has always been a feature of claim 1. The skilled person would therefore have understood that that feature would be used in combination with the Figure 4 embodiment, including in combination with the features now added to claim 1.

Second auxiliary amendment application – added matter

161. In the second auxiliary amendment application further features are added to the claim which overcome the intermediate generalisation objections made in relation to the first auxiliary set of claims, and which I have held to be justified. The objection I have dealt with in 159 above remains.
162. The only new objection arises out of the introduction into the claim of the requirement that "the network is not able to prepare the handover for the mobile station". The basis for this requirement is the description at page 13 lines 9-12: "This method can therefore be used advantageously in networks in which the network is not able to prepare the handover for the mobile station". Nokia submit that this is a reference to a lack of network support. Yet the amendments seek to introduce features into the claim which expressly depend on network support.
163. IPCom's answer is that there is a difference between the kind of network support needed to prepare the handover for the mobile station and the kind needed to support the communications identified in the amended claims. There is accordingly no contradiction in the claims.
164. I think that in this instance IPCom are right. The feature complained of does not require a complete absence of network support. It can therefore properly subsist with other messaging features which depend on network support.
165. In the result, and subject to IPCom putting forward an amended specification in which the passages cited in paragraphs 157 and 158 are removed, the claims of the second auxiliary application to amend are allowable.

Essentiality

166. There is no dispute that the court has, as part of its inherent jurisdiction, a discretion to grant a binding declaration as to whether the claims of a patent are essential or inessential to a particular standard. Whether or not a patent is essential to a standard may be important. If it is essential, you cannot make apparatus or operate methods in accordance with the standard without infringing the patent. Accordingly the patent will inevitably be a source of licensing income for the patentee. Nokia seek declarations that the claims are not essential to three standards: UMTS, GSM and LTE.
167. One reason why the main claims and the claims of the first auxiliary application to amend are not essential to any standard is that they are invalid. However I will deal with the essentiality points on the basis of the claims of the main application to amend, on the assumption that I am wrong about validity.

Essential to UMTS?

168. I have explained the UMTS-specific terminology above. In UMTS the CELL CHANGE ORDER FROM UTRAN is used to transfer a UE which is on a packet switched connection to another radio access technology (RAT). The particular change of operation mode focused on in this case is where the CELL CHANGE ORDER FROM UTRAN is being used to move the UE from UTRAN to GSM EDGE Radio Access Network (GERAN). In UMTS, the UTRAN defines the specific target cell in the CELL CHANGE ORDER FROM UTRAN message, and the UE does not search for the destination base station.
169. I will not burden this judgment with a lengthy description of the handover process in UMTS. For present purposes a number of discrete points have emerged.
170. First, Nokia contend that CHANGE ORDER FROM UTRAN is not a forward handover. It is common ground that the mobile is given the target base station which it is to use in the handover process. It is therefore not responsible for identifying the target base station. This point turns entirely on the issue of construction dealt with above. On the view which I have come to on the meaning of forward handover, the UMTS protocol is not within the claims.
171. Second, Nokia contend that UMTS' CELL CHANGE ORDER FROM UTRAN is not "base station initiated" on IPCom's construction. I have rejected IPCom's construction, so this point is not necessary for my decision. If I had accepted IPCom's construction on this point, the patent would have been inessential on this ground. As Dr Brydon explained, the mobile station can reject the cell change order in more than one situation: this is incompatible with IPCom's construction which involves a mandatory requirement for base station initiation.
172. Thirdly, Nokia contend that in UMTS the release of data and resources is not at a time defined by a communication about the successful handover. The short point is that the message which causes the release of the data and resources, message 13 in Figure 54 of UMTS Technical Standard 23.060, is sent before the completion of the handover process. Importantly, the handover can still fail after the release has taken place. This again turns on construction. I have accepted Nokia's construction of what is meant by a communication about a successful handover. It follows that it does not matter that message 13, is sent at a time when the difficult or risky part of the handover is complete. The handover is not complete.
173. It follows that the claims of the main application to amend are not essential to UMTS.

Essential to GSM?

174. IPCom did not advance any case of essentiality of the claims of the main application to amend to GSM. I can therefore deal with this very shortly.
175. In GSM there are three processes used to transfer a call between base stations:

i) "handover" which is used to transfer a dedicated mode connection between base stations;

ii) "cell reselection" which is used to transfer a packet mode connection between base stations;

iii) "network controlled call reselection" which is used by a network to prompt a mobile to undertake a cell reselection.

176. In relation to each of these Dr Brydon advanced one or more points why the claims of the main application to amend were not essential to GSM.

i) For handover, he said that the handover was not "forward" in either of the respects identified in the patent, namely searching for the target or registration at the new base station. Instead the first base station defines the target and undertakes the preparations before the MS is made aware of the handover.

ii) For cell reselection, Dr Brydon pointed out that the cell reselection was not initiated by the first base station. The process is entirely driven by the mobile. Moreover there was no reservation of resources, or release of resources as required by claim 1. There is also not the facility to return to the use of the original resources as required by claim 3.

iii) For network controlled cell change reselection Dr Brydon pointed out that the cell reselection was not forward. Moreover there was no reservation of resources, or release of resources as required by claim 1. There is also not the facility to return to the use of the original resources as required by claim 3.

177. I accept all these points. They are consistent with the view which I have come to on construction. The claims of the main application to amend are not essential to the GSM standard.
178. There was a dispute as to the width of the declaration that Nokia was entitled to on the basis of this evidence, which had been resolved by the end of the trial.

Discretion on LTE

179. LTE is a standard still in the course of development. LTE stands for "long term evolution". The network operators do not yet support it. Nokia do not manufacture phones designed to comply with it. This gives rise to points on the exercise of the court's discretion to grant a declaration of inessentiality in a case where a party is not at immediate risk of infringement proceedings if it manufactures and sells equipment in accordance with the standard. I consider these first before coming to the technical points. If I were to do it the other way round I run the risk of pronouncing on the very issue which IPCom say I should not pronounce upon.
180. The grant of a declaration of inessentiality is of course not available as of right to any party who applies for it. The court retains a discretion not to grant a declaration if it considers it would not serve a useful purpose: see Nokia v Interdigital [2006] EWCA Civ 1618; [2007] FSR 23.
181. IPCom submit, in essence, that it would not be useful to grant a declaration that equipment manufactured and sold at some date in the future would not infringe the patent because it is in accordance with the standard in its present form. What Nokia will need to know is whether the patent would be infringed because it is in accordance with the standard as it exists when the equipment is sold. A declaration granted now, when there is no equipment, is useless and cannot anticipate the form of the standard when the equipment actually comes to be marketed.
182. I accept that a declaration granted now, in relation to the current release of the standard, is not as useful as a declaration granted at the time Nokia place their equipment on the market. But that does not mean that a declaration granted now would be useless or not serve a commercial purpose. There is no dispute that LTE is a major standard likely to dominate the future of mobile telecommunications. Businesses have to plan for the future. If Nokia knows that the claims are not essential now, they can monitor changes to the standard from that starting point. There is no reason why their technical and commercial planning should take place without the benefit of a declaration. Furthermore there is no reason why the court should assume that the standard will change in any respect material to the issue of essentiality.
183. I think I should exercise the discretion to grant the declaration if the technical facts are established. I should add that after the trial ended, and while I was considering this judgment, the solicitors for Nokia sent me some further evidence on this issue. I have not taken this further evidence into account. I would not have done so without a further hearing allowing IPCom to be heard.

Essential to LTE?

184. Again, IPCom advanced no technical case. Dr Brydon focused on the parts of LTE which IPCom had previously identified as coming within the scope of the claims. This is the MobilityFromEUTRACommand. The purpose of this command is to move a UE to another radio access technology (RAT) such as GERAN or UTRAN. This covers two types of process: a handover and a cell change order.
185. Nokia submit that the claims of the main application to amend are not essential to either handover or a cell change order. Neither is a forward handover. Moreover there is no indication in either process that the UTRAN should delete the connection data or release the resources associated with the old connection at a time defined by a communication from the new base station. There is also no fall back as required by claim 3.
186. I accept all these points. They are consistent with the construction of the claims which I have held to be correct. It follows that the claims of the main application to amend are not essential to the relevant releases of the LTE standard.

Essentiality of claims of first and second auxiliary applications to amend

187. IPCom advanced no positive case that the claims of the first or second auxiliary application to amend were essential to any of the three standards. That is because large swathes of these amended claims find no counterpart anywhere in any of these standards. There was no challenge to any of Dr Brydon's evidence on this. These claims are not essential to any of the three standards.

Overall conclusions

188. My conclusions are:

i) The claims of the patent as granted are invalid.

ii) The main application to amend is not allowable because the claims so amended are invalid for lack of novelty and lack of inventive step.

iii) The first auxiliary application to amend is not allowable as the amendments add subject matter.

iv) The second auxiliary application to amend is allowed, subject to an application to amend to remove the passages I have identified.

v) None of the claims the subject of any of the applications to amend is essential to the UMTS, GSM or LTE standards and Nokia are entitled to declarations to that effect.

Note 1   ETSI is the European Telecommunications Standards Institute.    [Back]