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Tuesday, 2 December 2014

3G standard essential patent valid and infringed: irrelevant whether Vringo is a troll

With all Kats working flat out, it's always a relief to know that we have our friends who help us out from time to time. One such friend is former guest Kat and PatLit team member Stefano Barazza, who is now Lecturer in Law in the Faculty of Business and Society at the University of South Wales. While blogposts on this weblog are often pretty cheerful and humorous affairs, it does sometimes happen that we encounter a case that is very difficult to present in anything other than in terms of the grim reality of a dispute that turns on some detailed analysis of facts and the application of the law to them. This is one of those cases.  Stefano explains:

On Friday, Mr Justice Birss delivered a dense, well thought, albeit perhaps slightly unexpected, judgment in Vringo Infrastructure Inc v ZTE (UK) Ltd [2014] EWHC 3924 (Pat). The 27 page decision examined the validity of the European patent EP (UK) 1 212 919 ("Relocation in a Communication System"), which disclosed, inter alia, a method for relocating a protocol termination point in a communication system. The patent, with a priority date of 14 September 1999, was originally obtained by Nokia. It was declared essential to the 3G standard, as its method is employed in the context of the handover of a mobile phone call from one cell to another. In this action Vringo alleged that ZTE’s 3G (and 4G) products infringed the patent, while the defendant disputed the validity of the patent, in light of the prior art. The court upheld Vringo’s complaint, finding the patent valid and infringed by ZTE.

Before examining in depth the patent at issue and its validity, Birrs J addressed some preliminary, yet admittedly irrelevant, questions. First, he briefly dealt with ZTE’s allegations that Vringo was a “patent troll”, observing that, regardless of the truthfulness of such allegations, the defendant had failed to plead any relevant defence (e.g. under competition law) related to this point (as readers probably remember, this is not the first time that Vringo has been accused of being a patent troll, most notably in relation to proceedings brought in the US against Google and AOL, although an interesting post on Patentology questioned the appropriateness of such accusations). Secondly, the judge acknowledged that, during the trial, ZTE had suggested that Nokia’s conduct might have misled the standard setting body into including the invention in the 3GPP standards. However, he concluded that the defendant had again failed to put forward any valid defence related to such claims.

Technical background

The court engaged in a detailed reconstruction of the technical background of the invention, finding that, by September 1999, the second generation cellular mobile systems (2G) were well established and widely used internationally, while the process of standardisation for the third generation networks (3G) was well under way and its structure already clearly defined. In the 2G system, each mobile phone established a radio connection with a cell, equipped with a BTS (Base Transceiver Station); multiple BTSs were controlled by a BSC (Base Station Controller), forming a BSS (Base Station Sub-System). The BSCs were connected to a network sub-system, which hosted two units, the MSC (Mobile Switching Centre) and the SGSN (Serving GPRS Support Mode), respectively used to route calls and Internet traffic. The 2G system implemented a method to handle handover between cells, which happens when a mobile phone user moves from one cell area to another. As the 2G phones could only communicate with one BTS at a time, the switching method (known as “hard handover”, or break-before-make) involved either an inter-BSC handover, if the cells were controlled by the same BSC, or an external handover, in the opposite case, which required the use of the MSC.

The 3G system, or UMTS (Universal Mobile Telecommunications System), which was under development in 1999 by the 3GPP (3rd Generation Partnership Project) standard setting organization, used a basic structure similar to that of the 2G system, albeit employing different terminology: the BSC became the RNC (Radio Network Controller), while the BTS was renamed as “Node B” and the BSS as RNS (Radio Network Subsystem). The whole network of RNCs and Node Bs was called UTRAN (UMTS Terrestrial Radio Access Network). The handover in the new 3G system, however, was handled differently, as new 3G phones were capable of communicating with multiple cells simultaneously, and the RNCs could connect directly to each other. This allowed the implementation of a “soft handover”, or make-before-break method, in which the connection to one or more target cells is made before breaking contact with the source cell.

In the handover procedure in UMTS, when a phone user moves so as to be within the range of two cells, a new, simultaneous connection with the second Node B is made, and the signal to and from the phone runs both through the original Node B, up to the serving RNC (sRNC), and through the new Node B, up to the new RNC, known as the drift RNC (dRNC). The dRNC, via the new inter RNCs connectivity provided by the 3G standard, passes the signals received from the phone to the sRNC, which combines them and routes them externally (e.g. to the MSC).  When the phone moves closer to the new Node B, the connection with the original Node B is dropped; however, the old RNC remains the serving RNC, on account of the continuing connection (not to the phone, but) to the drift RNC. Essentially, SRNS (serving RNS ) relocation intervenes, at this stage, to ensure that the dRNC (also known as target RNC, tRNC) becomes the new sRNC, to the effect that all signals from the phone are managed by the real cell to which it is connected and that connection to the old RNC is dropped.

In UMTS, the communications between the RNC and the MSC are governed by the RANAP (Radio Access Network Application Part) protocol, while communications between the UTRAN and the mobile phones are governed by the RRC (Radio Resource Control) protocol. Of relevance here is the use of the RANAP protocol to transfer information from the sRNC to the tRNC in the handover procedure. Such information would include a message known, in the prior art, as a “relocation required” message, whose elements would comprise a “Source RNC to target RNC transparent field”.

The judge discussed two possible interpretations of the term “transparent”:

* “network transparency”. This is the idea that some data is passed through an entity in a network without being altered or acted upon in any way by that entity. The information element or message is said to be transparent to the network. As a matter of language it is a bit like saying light is transparent to glass but those skilled in the art know what is meant.

* “protocol transparency”. An example of this idea occurs when a higher layer protocol passes a PDU [Protocol Data Unit] down to a lower layer protocol in the protocol stack. The PDU is said to be transparent for those lower protocols. The lower protocols cannot change the contents of the PDU or even understand them.”

Prior art

The judge examined three potentially relevant items of prior art all three documents related to the WG3 group, which was responsible at the time for developing specifications for the UTRAN. The group, which held regular meetings since February 1999 and included more than 50 delegates (and representatives of the leading telecommunications companies), focused, inter alia, on SRNS relocation and the RANAP protocol.

The first document, “359”, dated April 1999, contained NEC’s proposed RANAP message parameters to be transmitted by the serving RNC to the target RNC, during switching. The second document, “413”, was the first draft of the technical specification TS 25.413, to which the patent at issue was declared essential. The 413 document contemplated that some relocation information would be sent by the sRNC to the tRNC using the RANAP protocol, including an information element called “Source RNC to Target RNC transparent field”. The third document, A61, dated August 1999, contained Nokia’s remarks on the progress made within the WG3 concerning the transmission of RRC information during handover, through the RANAP protocol. In particular, it discussed the information to be transmitted, during relocation, in the proposed “Source RNC to Target RNC transparent field”.

The judge sought to examine the relevance of this prior art to Nokia’s patent which essentially taught, in the context of UMTS, how to implement a method in which the information to be transferred through the RANAP protocol, in the phase of SRNS relocation, did not need to be defined in RANAP itself, but could be defined in a new set in the RRC protocol. Such information, known as Protocol Initialisation Unit (PIU), would be carried by a message defined in RANAP, but not included in the RANAP specification itself. According to the patent, the PIU would be transparent for the RANAP protocol.

Novelty and non-obviousness

Having identified the person skilled in the art as a system architect, with an electronics engineering or computer science degree, employed by a mobile telecommunications manufacturer or network operator in an interdisciplinary team, Birss J turned to the construction of the relevant claims. First, he noted that “[a]lthough the generality of the patent is wider than SRNS relocation in UMTS, the preferred embodiments and many dependent claims are limited to that”. Paragraph 7 of the background section, in particular, described one of the issues that was being evaluated within the WG3 group at the time, namely the inclusion of the parameters to be transferred from the sRNC to the tRNC in the RANAP protocol (the patent refers to the RNSAP protocol, but the difference was immaterial here, said the judge). According to its summary, the invention aimed, inter alia, at addressing this issue; specific embodiments described the idea of using a special PDU or PIU defined in the RRC protocol to identify the information to be encapsulated in a RANAP message and transferred from the sRNC to the tRNC during SRNS relocation.

Claims 1 and 6, read together, described:

A method in a communication system for relocating a protocol termination point, characterised in the steps of:
(a) using a first protocol to define a protocol initialization unit (20) at a first termination point of a first protocol (34), said protocol initialization unit containing predefined information pertaining to initialization of a second termination point (36) of said first protocol;
(b) transferring the protocol initialization unit from the first termination point to a second termination point by a second protocol; and
(c) initializing the second termination point based on the protocol initialization unit (38);
(d) wherein the protocol initialization unit (20) is transparent for the second protocol.

The claims related to a method for relocating a protocol termination point in a communication system. Read in the context of SRNS relocation in UMTS, the first protocol, which includes the PIU, would be RRC, and the second protocol would be RANAP; the PIU would be transparent for RANAP. The parties disagreed on whether the definition of a PIU in a protocol was an attribute of a standard or of a system, though the judge chose the first option. He noted that Vringo’s disagreement on the point was probably related to the potential non-technical character of the claim at issue, under this interpretation, but concluded that “[p]rotocol definitions are not merely administrative documents, they are specifications which define how a system has to perform [and] are highly technical in nature”. The patent is addressed to skilled persons involved in the definition of protocols, for example in a standard setting context, without further consideration of the hardware or subroutines involved in the application of such protocols.

Assessing novelty in light of the prior art mentioned above, Birss J first recited the teaching of Synthon that novelty is excluded when the prior art provides an enabling disclosure. In relation to the 359 document, he focused on the proposal of a “relocation required” message, which included an RRC Information parameter which “is transparent field”. Did the term “transparent” refer to network transparency, as suggested by Vringo, or protocol transparency, as argued by ZTE? The latter interpretation would have implied that the contents of the RRC information had to be defined in the RRC protocol and transferred through the RANAP protocol like a PDU. The judge observed that the relevant question was not “[w]hat did the writer intend?”, but “[w]hat would a skilled reader think the author mean?”  This being so, since the skilled person would have had no way to know exactly what the writer meant and had no knowledge of the content of all the discussion of WG3, he would have understood the document as referring to network transparency. The same conclusion was reached in relation to the A61 document and its reference to a “relocation required” and a “relocation request” messages.

Before tackling obviousness, Birss J reconstructed the applicable legal framework, reciting the well-known four-step test elaborated by the Court of Appeal in Pozzoli v BDMO: (i) identify the person skilled in the art and its common general knowledge, (ii) identify or construe the inventive concept of the claim in question, (iii) identify the differences between the prior art and the inventive concept of the claim, and (iv) enquire whether such differences, viewed without any knowledge of the alleged invention as claimed, would have constituted obvious steps for a person skilled in the art (see also Generics v Lundbeck, and MedImmune v Novartis).

Document A61, said the court, would have been understood by the skilled person as implying the relocation of “one or more protocol termination points from the sRNC to the tRNC by transferring predefined information pertaining to the initialisation of the second termination point from the first termination point to the second termination point”. Such transfer of information would have been carried out through messages defined in RANAP, in the element called “Source RNC to Target RNC Transparent Field” (with “transparent” referring to network transparency, as held above). The judge found that “[t]he real difference between A61 and proposed claim 1 is the requirement for protocol transparency being added into the claim from old claim 6” (the document also did not disclose defining a PIU in the RRC protocol, but this would have been a necessary step for a skilled person looking to implement protocol transparency). In this view, at least initially, the skilled person would have looked at defining all the information to be transferred through RANAP in the RANAP specification itself.

Addressing ZTE’s argument that the use of protocol transparency would have been made obvious by reference to the GSM external handover (which implemented it), Birss J made a thorough comparison between the relevant 2G and 3G handover mechanisms: generally, the skilled person would have taken the 2G system into account. “However”, he added, “I am not satisfied they would extract from it the idea of using protocol transparency in order to send RRC information from the sRNC to the tRNC via RANAP”. This conclusion was mainly based on the different context surrounding handover in a GSM system (where, for example, there was no need to define a new termination message).

ZTE’s secondary argument concerning the fact that the potentially large number of RRC parameters to be transferred through RANAP would have suggested, to the skilled person, the opportunity of including their definition in RRC, rather than in RANAP, was also rejected. The judge’s reasoning is particularly interesting:

“The skilled person, without hindsight, would not have any reason to think that a decision about whether to use protocol transparency had anything to do with the answer to the question: what needs to be transferred? They would know they needed to know what had to be transferred but their working assumption would be simply that they would acquire this information so as to put appropriate definitions in RANAP.

In some cases a skilled person knows they need to find something out, perhaps in a chemical case by conducting an experiment testing possible candidate active agents and knows before they do the test that they need to know the answer before deciding  how to move forward. That is not this case. In this case there is no a priori link between the decision and the answer to the question.”

Reference to the options proposed by Nokia to the WG3 after the priority date, in relation to SRNS relocation, was also found to be irrelevant to prove obviousness. The judge therefore concluded that the claims at issue were not obvious in light of the prior art, adding that “the obviousness case here is an argument tainted with hindsight”.

The judgment did not discuss the issues related to infringement in detail. Since ZTE had accepted that on the claim construction advanced by Vringo in this jurisdiction
there was no separate point on infringement, the judge merely accepted the opinion of Vringo’s witness, finding that both the UMTS and LTE (the fourth generation system, 4G, which implements a similar method to handle relocation messages) products manufactured by ZTE infringed the patent.

The decision represents a significant victory for Vringo, especially considering that the equivalent Chinese patent (CN00812876.6) has recently been declared invalid. Despite its technical complexity, which may make the judgment complex to follow for readers who are unfamiliar with the technological issues involved, Birss J’s decision provides a useful roadmap to untangle the complex evaluation of novelty and obviousness in the context of telecommunications standards. However, it also signals the difficulty of evaluating, ex post, the validity of a patent, especially when, as in the present case, subtle changes in the approach, knowledge and characteristics of the fictional person skilled in the art make all the difference between losing and winning.

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