Conversant Wireless Licensing SARL v Huawei Technologies Co. Ltd & Ors

Factual and Procedural Background

The appeal concerns the validity of European Patent (UK) No 1 797 659 relating to a method for autonomous transmission in high-speed uplink packet access (HSUPA). The patent proprietor, the Appellant, challenges the High Court's decision that the patent is invalid on the ground of added matter, resulting in its revocation. The original decision was made by the High Court of Justice, Business and Property Courts of England and Wales, Intellectual Property List (ChD), with the judgment delivered by the then Mr Justice Arnold. The appeal focuses solely on the added matter ground, as other issues previously raised have fallen away.

The patent relates to technical concepts in the Universal Mobile Telecommunications Standard (UMTS) network, specifically dealing with transmission scheduling and power control in mobile communications. The technical background includes concepts such as Code Division Multiple Access (CDMA), Rise over Thermal (RoT), Transmission Time Interval (TTI), Hybrid Automated Repeat Request (HARQ), and the architecture of the Medium Access Control (MAC) layer, including MAC-e and MAC-d components.

The patent's invention aims to improve efficiency by slowing down the transmission rate of autonomous, non-scheduled data to reduce control overhead and better manage power allocation within the cell. The patent specification describes mechanisms involving a virtual transmission time interval (vTTI) and checks on whether the MAC entity is transmitting data or able to empty the radio link control (RLC) buffer within a TTI.

Legal Issues Presented

1. Whether the patent is invalid on the ground of added matter, specifically concerning amendments to claim 1 involving a "transmitting check" and an "able-to-empty check" related to the MAC entity's transmission during a current air interface TTI.
2. Whether the amended claims disclose subject matter that was not clearly and unambiguously disclosed in the original application as filed.
3. The proper construction of the terms "transmitting" and "able to empty the RLC buffer" within the claims and their relationship to the specification.
4. Whether the introduction of the transmitting check and its link to the able-to-empty check constitutes an impermissible intermediate generalisation or added matter.
5. Whether a new construction of the term "transmitting" as "able to transmit" rather than "actually transmitting" can be introduced on appeal.

Arguments of the Parties

Appellant's Arguments

• The amended claim restores the disclosure to that which the skilled person would understand from the specification, linking the transmitting check to the able-to-empty check.
• The term "transmitting" in the claim should be understood as the MAC entity being in an active or able-to-transmit state, not necessarily actually transmitting at every moment within the TTI.
• The check disclosed in the specification ([0052]) is a way of determining the MAC's active state, identifying transitions between transmitting and non-transmitting states.
• The claim should be read as detecting the transition from active to non-active states, with the prohibition on transmission until the next vTTI if not transmitting.
• The claim construction advanced is consistent with the patent's embodiments, including those illustrated in the figures, and the skilled person would understand it accordingly.
• The new construction of "transmitting" was substantially before the court below and supported by expert evidence.

Respondents' Arguments

• The transmitting check and its link to the able-to-empty check represent new matter not disclosed in the original application.
• The application as filed discloses only an able-to-empty check, not a transmitting check or a link between the two.
• The claim requires a binary determination of whether the MAC is transmitting at the end of the TTI, which is not derivable from the original specification.
• The skilled person would not understand that the able-to-empty check determines actual transmission, due to factors such as higher priority data blocking transmission.
• The new construction of "transmitting" as "able to transmit" was not ventilated below and would require new evidence and re-examination of expert testimony.
• Allowing the new construction on appeal would be unfair and procedurally improper.

Table of Precedents Cited

Court's Reasoning and Analysis

The court began by examining the technical background and the patent's disclosure, particularly focusing on the amended claim 1 and its integers [C] and [D], which involve a "transmitting check" and an "able-to-empty check" of the MAC entity in relation to the RLC buffer during a TTI.

The court noted that the original application disclosed an able-to-empty check but did not explicitly or implicitly disclose a transmitting check or a link between the two. The amended claim introduced this link, which the court found to add new information about the invention not derivable from the original application.

The court considered the construction of "transmitting" in the claim. The Appellant argued for a broader meaning related to the MAC entity being "active" or "able to transmit" rather than actually transmitting. However, this construction was not properly ventilated below, would require new evidence, and was not supported by the trial record or expert evidence.

The court emphasized the strict approach to added matter, requiring that any amendment must be clearly and unambiguously disclosed in the original application. The introduction of the transmitting check and its link to the able-to-empty check was not disclosed, constituting added matter.

The court further held that the claim discloses a binary test of whether the MAC is transmitting at the end of the TTI, which is not supported by the original disclosure, where supervening factors might prevent transmission even if the buffer is not emptied.

Procedurally, the court refused to admit the new construction argument on appeal due to lack of ventilation below, potential unfairness to the Respondents, and the need for additional evidence.

Accordingly, the court upheld the finding of invalidity on the ground of added matter.

Holding and Implications

The Court of Appeal DISMISSED the Appellant's appeal and upheld the High Court's decision that the patent is invalid due to added matter.

The direct consequence is that the patent remains revoked, and the Appellant cannot enforce the patent claims as amended. The decision confirms the strict application of the added matter rule, emphasizing the necessity for amendments to be clearly and unambiguously disclosed in the original application to avoid extending the monopoly beyond what was originally filed.

No new precedent was established beyond reaffirming established principles and their application to the facts of this case.