Posted: July 30th, 2021
Promptu Systems Corporation V Sky UK Limited and Others, 19 July 2021, Case No.  EWHC 2021 (Pat)
In this judgment, the English High Court held that Promptu’s patent, EP(UK) 1 290 889, lacked inventive step and therefore dismissed Promptu’s claim for infringement against the defendants (together, “Sky”).
Promptu had asserted the patent against Sky Q’s subscription television service. Sky denied infringement on claim construction grounds, and also on the basis that certain steps of the claimed method were performed outside of the UK. Sky also counterclaimed that the patent lacked inventive step over a prior art citation (“Houser”) and was invalid for added matter.
At trial, only method claim 13 as amended was in issue. The invention related to a remote control and set top box connected via a network to a “wireline node”. A user can input voice commands by pressing a talk button on the remote control. When the talk button is pressed, data is transmitted to the wireline node alerting it to the fact that it is about to receive speech data and also identifying the user’s location (the use of a talk button was said by Promptu to be inventive because it reduced latency in returning results to the user). The voice commands are then transmitted along a “backchannel” to the wireline node, where they are processed and separated out based on the user’s location. A speech recognition system recognises the speech, a unique “speech content response” is generated, following which, customised entertainment and/or information from a “content engine” is sent back to the user.
The relevant part of the Sky Q system alleged to infringe consisted of three systems connected via the internet:
a) A VREX voice platform which is hosted on Amazon Web Servers (“AWS”) in the UK.
b) An automatic speech recognition (ASR) function provided by Google which turns voice data into text. This may or may not take place in the UK, and Sky does not know in any individual instance whether it does or does not.
c) Sky Search: a content engine containing searchable metadata for the content available to the user. This is also hosted on AWS, but in Ireland.
When the user presses the talk button on their remote control, a WebSocket (a type of persistent two way connection specific to that user) is opened, which involves sending, among other things, the user’s IP address to the VREX. The VREX is responsible for receiving speech commands from all users, separating them out into each user’s speech using their IP address and sending the response back to the user, once it has received what it needs from the ASR and content engine.
Sky advanced two claim construction arguments at trial in an attempt to escape infringement:
1. Claim 13 was limited to “closed TV cable networks” (i.e. networks owned by a cable TV company, employing coaxial cables and using FDMA or TDMA multiplexing) and did not cover messages sent over the internet.
2. Claim 13 was limited to sending data after an initial connection to the wireline node had been set up (the data transmission relied on by Promptu was part of the WebSocket’s set up).
In both cases, the Court dismissed Sky’s contentions holding there was no basis in the specification for construing the claims so narrowly in either case. With regard to the first argument, the Court considered that the invention was about partitioning of signals at the wireline node, and about sending an alert that speech is potentially on the way from the user. What was in between the set top box and wireline node did not matter, as long as it worked. There was therefore no technical reason to include such a limitation and the specification included examples of other networks to which the invention could be applied.
Sky argued that it did not infringe because the ASR function is sometimes performed outside the UK and the Sky Search function is always performed outside the UK (in Ireland). The Court examined previous case law on this issue (Menashe v. William Hill  EWCA 1702, RIM v. Motorola  EWHC 188 (Pat), and Illumina Inc v Premaitha Health Plc  EWHC 2930 (Pat)) and derived the following principles:
“…that (a) the Court’s task is to identify by whom and where, in substance, the method is being used; and (b) it is relevant to take into account that for some steps it simply may not matter where processing power is located.”
Applying these principles, the Court considered that the method was overall to “a method of using a back channel which takes place at the wireline node…” (i.e. at the “server” end). Whilst user input triggers part of the method (i.e. sending data from the user end identifying the user), it was not the user who put the method into effect. Further, the central part of the processing at the server end was the partitioning of incoming signals on the back channel and subsequent provision of the unique recognised speech content response and customised delivery of services accordingly. These functions were all performed by the VREX server located in the UK. In the Court’s view, the ASR and Sky Search functions were subordinate and essentially sub-contracted functions and it therefore did not matter where those functions took place.
Accordingly, the Court concluded that the method was performed, in substance, by Sky in the UK.
Sky advanced two added matter attacks against amended claim 13, both in the form of alleged intermediate generalisations:
1. The claim feature “individually controlling the delivery of entertainment and information services to each user site (1100) in accordance with said recognized speech” was only disclosed in the context of a closed TV cable system. As the claim was not limited to a closed TV cable system, there was added matter.
2. The “content engine” feature was only disclosed in the context of an “augmented” node or headend (a control centre in a cable TV system where various signals are brought together and monitored before being introduced into the cable network) with the particular characteristics referred to in a cross referenced a co-pending application. As the “content engine” in the claim did not possess such characteristics, there was added matter.
The Court considered that both arguments suffered from the same flaw. Although the claim features were disclosed in a context which also had other features (such as a closed TV cable system or augmented node with particular characteristics), there was no disclosure in the application as a whole that those other features were either a necessary part of the invention, or that they came as part of a package. The Court therefore rejected both added matter attacks.
Obviousness over Houser
Houser disclosed a voice input command system for use in subscription television systems, video on demand, and electronic guides and schedules.
Sky’s inventive step attack focussed on Figure 15, described on the final page of Houser as an optional variation where speech processing is performed at a shared terminal in the network rather than in the subscriber’s equipment.
As a result of a concession made by Promptu limiting its case to claim 13 as amended, the Court considered that only the additional feature of claim 13 needed to be considered for the purposes of steps 3 and 4 of the Pozzoli analysis, i.e., “upon depressing the talk button on the remote control data are sent to the wireline node alerting the system as to the user site and a potential input”.
Promptu advanced a number of arguments as to why Sky’s inventive step attack should fail. The two main arguments were:
1. The skilled person would be interested in the fleshed out embodiments in Houser (which did not implement processing in the network). Figure 15 was an option described near the end of the patent, which was less well developed, and more of an afterthought; and
2. Houser described a “threshold” feature (designed to filter out background noise by only transmitting voice commands above a certain level) which would deter the skilled person from having a talk button at all or using it for the purpose identified in claim 13.
The Court dismissed the first argument on the basis that the experts were in agreement that having processing in the network would be seen as attractive to the skilled person. Furthermore, the explanation that accompanied figure 15 did not require any earlier teaching to be ignored or disregarded, but merely modified.
As for the second argument, the Court concluded that both the threshold and talk button features were presented as options in the specification which could be incorporated in the same system if desired. The fact that the threshold feature was mentioned first in Houser would be of no real significance to the skilled person.
Having weighed up all the evidence, the Court ultimately agreed with Sky that a natural implementation of Houser’s figure 15, when taking into account issues of latency (which, in the Court’s view, the skilled person would have done as part of their common general knowledge), would have been to set up a connection to the network terminal at the point when the talk button was pressed. On that basis, the Court found the claim was obvious and the patent was revoked for lack of inventive step.
A copy of the judgment can be found here.
Headnote by Matthew Raynor, Bristows LLP