T 2833/18 (Handling of a "Timer_Status_Periodic" timer for an RLC of a UMTS wireless communications system) 19-08-2021

Reasons for the Decision

1. The application concerns the handling of a "Timer_Status_Periodic" timer for a Radio Link Control Acknowledge Mode (RLC AM) entity of a UMTS wireless communications system.

2. Admissibility (Article 13(1) RPBA)

The set of claims according to the sole request differs from that of the main request considered in the impugned decision in that claims 2 and 4 have been deleted.

Since deleting entire claims furthers procedural economy, the board decided to admit the sole request into the proceedings.

3. Clarity (Article 84 EPC)

In the impugned decision, the examining division concluded that former dependent claim 3 (which is identical to present claim 2) lacked clarity due to the contradicting features it mentioned. In particular, "maintaining a value of the ... timer" had to be interpreted as "not stopping". Since "not stopping" was already mentioned in claim 1 (on which former claim 3 was dependent), this feature was redundant. The claims and the description did not provide any other meaning.

In the statement setting out the grounds of appeal, the appellant essentially argued that the step of "maintaining" was equivalent to "not stopping the timer" but was more specific as it stated that the "value and operation" were to be maintained.

The board considers that, in the context of document D2, a timer is set by assigning it an absolute time in the future, i.e. the time at which it will expire, as evident from page 104, 3rd SDL block:

"Set(NOW+timer_durations!status_periodic,

Timer_Status_Periodic)"

Hence, "maintaining a value of a timer" and "maintaining operation of the timer" claimed in current claim 2 may be understood as constituting sub-steps of the "not stopping a timer" claimed in claim 1. The board thus finds that claim 2 is clear.

4. Added subject-matter (Article 76(1) EPC)

An objection regarding added subject-matter was raised with respect to claim 2 during the appeal proceedings. As the current set of claims does not include this claim, the objection no longer applies.

5. Novelty (Article 54(1) EPC)

In line with the impugned decision and as argued by the appellant, the board holds that document D2 fails to disclose feature (1.5) of claim 1, which thus constitutes the distinguishing feature. The board finds that document D2 explicitly discloses that the "RESET PDU is used ... to reset all ... protocol timers" (see item b) in section 9.1.2 on page 18), which is clearly different from "not stopping" the timer.

The subject-matter of claim 1 is therefore novel.

6. Inventive step (Article 56 EPC)

6.1 Closest prior art

In the statement setting out the grounds of appeal, the appellant argued that document D1 should be regarded as the closest prior art rather than document D2, adding that document D1 superseded the preceding versions of the same standard, including document D2. It argued that the skilled person would not start from an older version since doing so would put them at risk of not complying with the standard.

In the impugned decision, the examining division adhered to the reasoning provided by the board of appeal in section 9.2.5 of decision T 2330/10 concerning the grandparent application.

This board is not convinced by the appellant's argument and confirms the reasoning provided on the same point in decision T 2330/10. In particular, this board considers that the skilled person would assume that any standard document issued by ETSI on the subject at issue would be a promising starting point. The board notes that standardisation bodies might revert to a superseded version of a standard if later developments turn out to be disadvantageous. Furthermore, the board notes that "the state of the art shall be held to comprise everything made available to the public ... before the date of filing of the European patent application" (Article 54(2) EPC). Therefore, what is claimed may also be examined for inventive step on the basis of an earlier prior-art document, such as document D2 (in line with decision T 0113/00, item 3.7).

As a consequence, the board considers that what remains to be established is whether the claimed subject-matter would have been obvious to the skilled person in view of either of documents D1 and D2.

6.2 Technical effect and objective technical problem

In the impugned decision, the examining division formulated the technical problem to be solved starting from document D2 as "how to effectively operate the Timer_Status_Periodic timer during and following a reset procedure".

The appellant argued that the cited prior art disclosed that this timer was reset during a reset procedure (see document D2, item b) in section 9.1.2 on page 18) and thus stopped. The appellant added that other mechanisms for implementing a transmission of a status report were also disclosed (see document D2, section 9.7.2 on page 35). Therefore, compared with the solution in document D2, in which the timers are reset, the technical effect achieved by the distinguishing feature was that the status report is transmitted earlier. The resulting objective technical problem was "how to modify the known reset procedure such that status reports are transmitted earlier".

The board notes that document D2 indeed discloses that, during a reset procedure, all timers are reset (see document D2, item b) in section 9.1.2 on page 18), which implies stopping them, i.e. terminating their operation. Even if the timer were restarted immediately after the reset, it would in any case expire later than if it had not been stopped, in accordance with the claimed solution. Essentially, in line with what the appellant has argued, the board considers that the objective technical problem may be formulated as "avoiding an undue status report transmission delay in the context of a reset procedure".

6.3 Obviousness

The appellant argued that since document D2 disclosed causing a transmission of a status report without using a timer at all, the skilled person was not prompted to act against the teaching of document D2 whereby all timers are to be reset/stopped during a reset procedure. Therefore, the skilled person would not arrive at the distinguishing feature without exercising inventive skill.

The board considers that the skilled person could have recognised that, when performing the reset procedure, it was only necessary to reset specific timers in order to synchronise the RLC entities, which is described as being the purpose of the RLC reset procedure. Moreover, the skilled person could have realised the existence of the above problem and considered solving it by not stopping the "Timer_Status_Periodic" timer, either in addition or as an alternative to the other ways of effecting a poll disclosed in document D2. However, document D2 does not give the skilled person any pointer towards this problem or towards the claimed solution. On the contrary, document D2 discloses resetting the timer, which implies stopping it, i.e. the opposite of distinguishing feature (1.5). In view of the above, the skilled person would not arrive at the distinguishing feature without exercising inventive skill. Therefore, the subject-matter of claim 1 involves an inventive step over what is known from document D2.

6.4 Since the feature distinguishing the subject-matter of claim 1 from document D2 also distinguishes it from document D1, and D1 likewise fails to mention any pointer towards the claimed solution, the board finds that the subject-matter of claim 1 involves an inventive step over what is known from document D1 as well.

6.5 In view of the above, the sole request is allowable.

7. Consequently, the appeal is allowable.