The first of Unwired Planet’s standard essential patents held valid and infringed

December 2015

This action stands out because it involves an acquired patent declared to be essential to a wireless telecommunications standard, where the Patent was held to be valid and used in the standard, which means that anyone operating in compliance with the standard will need to negotiate a FRAND licence with the Patent proprietor.  A priority claim was held valid despite the priority document having no claims, heralding an approach that is more pragmatic than strict.  Reassuring guidance was given regarding novelty of an invention for which a patent application was filed later than, but on the same day as, an internet disclosure of that invention.  Circumstantial evidence of the skilled person missing an invention allegedly pointed to by the closest prior art convinced the judge of non-obviousness where the primary evidence of non-obviousness was less than conclusive.

In a Judgment handed down on 23 November 2015 (Unwired Planet International Ltd v Huawei Technologies Co Ltd & Ors [2015] EWHC 3366 (Pat) (23 November 2015)) , Mr Justice Birss has held that one of Unwired Planet’s standard essential wireless telecommunication patents was valid and infringed by Samsung and Huawei.  However, as Birss J held that the Patent (EP (UK) 2 229 744) was essential to the standard 3GPP TS 36.322 release 8 version 8.8.0, his Judgment has wider implications for all wireless telecommunications networks that operate in accordance with the relevant LTE (Long Term Evolution) standard.  The LTE standard is a successor to the Universal Mobile Telecommunications System (UMTS) standard.

The Patent

The Patent claimed priority from a US application and was one of a portfolio of Ericsson patents acquired by California-based Unwired Planet in 2013.  The problem addressed by the invention was to avoid the risk of stalls during continuous transmission of data, which can arise due to both sequence number limitations and memory limitations.   Claim 1 of the Patent combines into a single mechanism a first triggering mechanism that counts the number of transmitted data bytes and a second triggering mechanism that counts the number of transmitted data units and this single triggering mechanism is used to coordinate the requesting of a status report by the transmitter to determine whether or not transmitted data has been received, i.e. to coordinate “polling”. 

The Patent had been declared by Ericsson in 2010 as essential to the LTE 4G telecommunications standard TS 36.322 and was declared by Unwired Planet as being essential to the same standard in 2013.

Unwired Planet contended that because their Patent was essential to the standard, anyone complying with the standard would infringe the Patent.  On that basis, Unwired Planet alleged that Huawei and Samsung infringed the Patent by manufacturing and selling equipment that operated in accordance with the relevant LTE standard.  Google were also originally sued by Unwired Planet but that action settled before trial.  

The Patent had two independently valid claims (claims 1 and 9) both of which were method claims.  The defendants raised priority, novelty and (different) obviousness attacks.     


It was common ground that on the broad construction of claim 1 of the Patent that a telecommunications system compliant with the LTE standard 3GPP TS 36.322 release 8 version 8.8.0 and in particular section 5.2.2 would infringe the Patent.  Birss J preferred Unwired Planet’s arguments in favour of a broad construction of claims 1 and 9.  


The priority document did not contain claims, which can prove problematic for a patent proprietor if later-filed claim language is not fully supported by the priority filing.  However, the Summary of Invention section in the priority document did disclose in general terms the key concept of two triggering mechanisms being used for coordinating polling.   This is reflected by claim 1 of the Patent which combines into a single mechanism a first triggering mechanism that counts the number of transmitted data bytes and a second triggering mechanism that counts the number of transmitted data units.  

Although the language used between claim 1 and the priority document disclosure was different, in view of the broad summary statement, looking at the whole priority document, rather than specific detailed passages, Birss J held that the key concepts were disclosed in the Summary section in a general way.  To the extent claim 1 had a wider scope than the detailed description in the priority document, the claim scope was still commensurate with the technical contribution made by the priority document.  In that respect there was nothing in claim 1 that was not clearly and unambiguously derivable from the priority document.  The same reasoning applied for claim 9. 

Novelty and “frame of reference” 

Birss J had to decide whether an Ericsson 3GPP technical document R2-080236 (the “TDoc”) was prior art (it was accepted to be novelty-destroying if it was).  

The TDoc describing the invention was first uploaded onto an ETSI file server in Europe on 8 January 2008, where it became available worldwide, including in Hawaii.  The US priority document was subsequently filed at the USPTO on the 8 January 2008.  Therefore, Birss J had to consider a number of different time frames that might be relevant: (i) central European Time (CET) was the frame of reference for the person who uploaded the TDoc; (ii) Eastern Standard Time (EST) was the frame of reference of the USPTO; (iii) Greenwich Mean Time (GMT) was the frame of reference applicable on the relevant date in the UK in which the Patent was in force; and (iv) Hawaii where the TDoc was accessible on 7 January 2008.  

EPO case law on this issue was inconsistent and Birss J held that the only frame of reference which made sense consistently was that of the patent office at which the priority document was filed.  The date and time at the location at which the prior art was made available to the public was irrelevant.  Using any other approach would mean that an event that happened after the priority document was filed could be prior art, which Birss J considered would be a very odd result. 

Therefore, the priority document was filed in the USPTO on 8 January 2008 and the frame of reference of the USPTO (i.e., EST) was the correct one.  The TDoc was deemed to have been made available to the public at 02.36 on 8 January 2008 EST and was not available to the public before the priority date.  


The invention specified triggering polling depending upon both a transmitted data unit counter and a transmitted byte counter. The closest prior art, a Motorola TDoc, disclosed the idea of a poll trigger based on a byte counter but did not propose counting Protocol Data Units (PDUs) as well.  However, Huawei argued that it would have been common general knowledge that UMTS used a PDU (data unit) counter as a trigger for polling.

In the prior art UMTS system, the data units typically had a fixed size but in LTE, the data units can vary in size. Birss J accepted that the common general knowledge at the priority date included knowledge that variable sized PDUs in LTE made for a problem with the two aspects of bytes and sequence numbers. 

However, despite considering the issue in detail for many months, experts from the relevant standards committee had failed to arrive at the solution according to claim 1 of the Patent and the trial witnesses referred to the need for simulations and modelling to be performed in order to evaluate whatever triggers were proposed, indicating that their impact was not trivial to predict.

There was a prevailing view amongst those skilled in the art at the priority date that a window-based trigger was the way forward in contrast to the counter-based triggers of claim 1 of the Patent.  Birss J found that, while there were good reasons why the skilled person could arrive at the invention based on the identified prior art, the “secondary” evidence of what those skilled in the art actually did pointed to non-obviousness, the conclusion being that those working on the problem at the time did not propose the claimed solution because they missed it. 


Many patentees will welcome the pragmatic treatment of entitlement to priority applied by Birss J in this case in which, despite the absence of strict literal basis for the wording of claim 1 in the priority document and despite the priority document having no claims, the claims of the Patent were found to satisfy the clear and unambiguous disclosure test in view of a general statement in a summary section of the priority document disclosing key concepts of a solution to the relevant technical  problem. 

In this action, the issues focussed on by parties and Court were whether or not the invention was valid and used in the standard.  On that basis, any wireless telecommunication networks that operate in accordance with the relevant LTE standard would necessarily infringe the Patent.    Therefore, the implications of the Judgment, and any later decision on a FRAND licence, will be of interest to more than just the defendants Unwired have chosen to sue in this action.

The scenario of applicants filing patent applications shortly before or on the same day that a technical document is uploaded to e.g., a server is a familiar one.  Therefore, Birss J’s Judgment that the only frame of reference relevant to novelty under Art 54(2) EPC is that corresponding to the patent office where the first-filing in respect of that invention was made, will be welcomed in the fast-paced world of wireless telecoms standards development.     

This is the first Judgment in a series of six trials before the UK Patents Court.  The first five are technical dealing with patent validity and infringement, with the sixth non-technical trial scheduled for 13 weeks from October 2016 encompassing competition and FRAND (i.e., fair, reasonable and non-discriminatory) issues.  To date, similar actions have settled before the Courts in Europe have had an opportunity to consider FRAND issues substantively.  It will be interesting to see if Unwired Planet will pursue this series of actions to help clarify the meaning of FRAND and how standard-essential patents should be evaluated and licensed in Europe.

This update was prepared by Dr Susan Keston, Patent Director in our Glasgow office and Rachel Fetches, HGF Law Partner in our London office.

If you would like further advice on this or any other matter please contact Susan or Rachel or your usual HGF representative or visit our Contact page to get in touch with your nearest HGF office.