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UK – Adaptive Spectrum and Signal Alignment v British Telecommunications

16 Dec 2013

Adaptive Spectrum and Signal Alignment Inc. v British Telecommunications PLC Patents Court, London, UK, 3 December 2013, [2013] EWHC 3768 (Pat) Birss J

In his judgment, Mr Justice Birss upheld the validity of two patents (“EP’495” and “EP’790”), rejecting BT’s novelty and obviousness attacks.  He found EP’790 to be infringed by one of BT’s systems.  Both patents relate to methods for controlling the way in which a digital subscriber line (“DSL”) operates.  ASSAI contended that the BT Dynamic Line Management System (the “DLM System”), which is responsible for controlling the operation of the DSL lines that make up BT’s broadband access network, infringed claims 1, 6, 8 and 15 of EP’495 and claims 1, 10 and 13 of EP’790.   BT counter-claimed that EP’495 was invalid for lack of novelty (claim 1) and/or obviousness (claims 1, 6, 8 and 15) and that EP’790 was invalid for obviousness (claims 1, 10 and 13). 



None of BT’s three DLM Systems (20CN, 21CN and NGA) were found to infringe EP’495.  This turned on the construction of the term “generating a parameter set” in claim 1.  ASSAI argued for a wide construction to encompass both creating a parameter set and selecting a set of parameters from a group of pre-stored parameter sets.  Birss J rejected this construction and accepted BT’s narrower construction that the set of parameters had to be created anew, based on the natural meaning of “generating”, because he found the word to have no technical meaning. 

As such, BT’s systems, which selected an existing set of parameters from a group of pre-stored parameter sets, did not infringe.  Claims 6 and 8, being dependent on claim 1, could not be infringed because claim 1 was not infringed.  Notwithstanding this finding of non-infringement, the Judge went on to consider infringement of these claims in the event that claim 1 were (e.g. on appeal) found to be infringed.  In that case, Birss J found that BT’s NGA system (but not the other two systems) would infringe claim 6 because it uses a safe rate calculation system that meets the claim 6 requirement of actually determining what value will meet a given threshold, rather than simply coming to a conclusion that a parameter should be increased or decreased by a pre-set amount.

Furthermore, although it was not disputed that if claim 1 was infringed all three systems would also infringe claims 8 and 15, Birss J noted that he did not accept that claim 15 would be infringed by the NGA system if (as BT contented) the required functionality of claim 15 is switched off in the NGA network because in those circumstances the system is not able to perform the relevant task (and indirect infringement had not been alleged by ASSAI). Claim 1 was novel because the cited prior art (“Hendrichs”) did not satisfy the claim’s requirement of collecting both current and historical data.  Claim 1 was also found to be inventive over Hendrichs and two other pieces of prior art, “Rahamim” and “Kerpez”.

Although the Judge found that claim 1, as well as claims 8 and 15, would have been obvious over Kerpez on the wide construction of the term “generating”, he noted that claim 6 would not be, such that on the wide construction of EP’495, BT’s NGA system would infringe a valid claim (i.e. claim 6, for the reasons set out above). 


EP’790 is concerned with managing line profiles in a DSL system.  Only BT’s NGA system was alleged to infringe EP’790 and two infringement cases were advanced by ASSAI. The first was based on evidence from ASSAI that the whole of the NGA process could be represented by a profile state transition matrix which had been reverse engineered from the logic disclosed in EP’790. 

Birss J held that this argument failed in any event on his narrow construction of the claim, and would fail also even if the ASSAI’s wider construction were followed.  The second infringement argument was based on the profile cap level table which is used as part of the NGA processing in certain circumstances.  This table was found to satisfy all the requirements of the profile state transition matrix in claim 1.  All other features of claims 1, 10 and 13 were also satisfied by the NGA system, which therefore infringed each of these claims. None of the claims of EP’790 were found to be obvious over either of the two pieces of cited prior art, “Hendrichs” or “Gross”.   As a result, EP’790 was found to be valid and infringed by BT’s NGA system.

Read the decision (in English) here.

Head note: Amy Crouch and Sara de Sousa