T 1664/18 (Reconnecting a device to a group call/BLACKBERRY) 20-04-2021

1. MAIN REQUEST

1.1 Claim 1 - Novelty in view of D5 (Article 54 EPC)

1.1.1 Using the wording of claim 1 of the main request, prior-art document D5 discloses (board's outline):

(a) A method, for execution on a group call server ("server 602"), for re-establishing a voice communications session moderated by the group call server between telephony devices (see e.g. [0036]), the method comprising:

(b) storing, in a memory ("buffer 612") accessible by a processor monitoring participation of a telephony device in a group communications session between a plurality of participating telephony devices, one or more data records ("participant list 608"; "disconnected participant list DPL 610") representing group call information (see e.g. [0035]),

(c) the group call information including information ("DPL 610") useable for re-establishing participation by the telephony device in the group communications session (see e.g. [0035]);

(d) receiving a presence signal ("periodic heartbeat" or "I am alive" signal) from the telephony device at fixed time intervals (see e.g. [0018]) ;

(e) automatically detecting disconnection of the participating telephony device from the group communications session, and automatically determining that the disconnection was not intentionally initiated ([0022]: "If the participant has been involuntarily disconnected ..."; Fig. 1, blocks 118 and 120), the determination being based on the stored group call information ([0019]: "... An identification for any new participants may be added to a participant list ..."; Fig. 1, blocks 104 and 112) and based on a failure to receive the presence signal from the at least one telephony device (e.g. [0018]);

(f) accessing the stored group call information data ("DPL") and, using such accessed group call information data, causing signals ("re-invite signal or message") adapted to invite

re-establishment of participation by the disconnected telephony device in the group communications session to be sent from the group call server to the disconnected telephony device if the presence signal is received from the disconnected telephony device (e.g. [0023]; Fig. 2, blocks 202, 204 and 206);

(g) upon receipt by the group call server from the at least one disconnected telephony device of signals representing a request to reconnect ([0024]: "... participant accepted the re-invitation ..."; [0031]: "... sent a request to rejoin ...") the disconnected telephony device with the group communications session, outputting command signals (i.e. internal DPL commands or "re-invite signals") adapted for re-establishing a communications session between the disconnected participating device and at least one other device participating in the group communications session, using the accessed group call information ([0024]: "... If the participant is determined to have rejoined the conference ... the rejoining participant may be removed from the disconnected participant list ..."; Fig. 2, blocks 208 and 210 or Fig. 4, blocks 410 and 412 together with [0031]).

Given that D5 anticipates all the features of present claim 1, the subject-matter of claim 1 is not new (Article 54 EPC).

1.1.2 The appellant submitted that, in D5, the re-invitation had to be manually processed in order to establish the reconnection, as described in paragraph [0024] ff. of D5. In block 114 of D5 (as described e.g. in paragraphs [0020] and [0021]), a determination might be made whether a participant has exited or left the meeting. For this determination, an intentional or unintentional disconnection was not determined. If the participant had not voluntarily exited or left the meeting or conference, a further determination might be made if the participant had been involuntarily disconnected in block 118. For such a determination, the group call information was disregarded. If the participant had not been involuntarily disconnected in block 118, the method 100 might advance to block 116 and the participant might be removed from the participant list. The use of the group call information combined with the presence signal was not suggested in D5. Accordingly, in the appellant's opinion, the processing using both, namely the group call information combined with the presence signal as required by feature (e) was not suggested.

1.1.3 The board holds that the "participant list" and the "disconnected participant list" constitute "group call information" in the claimed sense. Furthermore, the determination that a disconnection was not intentionally initiated is based in D5 on both the "participant list", since, according to block 104 (see paragraphs [0018] and [0019]), the participant list determines for which terminal disconnection will be monitored, and on the failure to receive e.g. a "heartbeat signal" from any of the members of the participant list, according to block 118 (see paragraphs [0018] and [0022]). Hence, D5 discloses feature (e).

1.1.4 The appellant further argued that, according to the claimed invention, the server stored call group information data, which implicitly and necessarily comprised authorisation and authentication information. This stored group call information data was subsequently used to re-establish the session with the disconnected device. The server would output command signals, e.g. the server would dial the disconnected device's number in order to reconnect it to the conference bridge, with the result that the disconnected device was not bothered with having to

re-enter any such authorisation and authentication information. D5 only taught in paragraph [0023] and Fig. 2, step 206, that "a re-invite signal or message may be sent to the participant" and that the participant might accept or decline the re-invitation. The participant rejoined the conference by re-entering the necessary authorisation codes to re-authorise itself, which rather led away from the claimed solution.

Furthermore, in D5, the group call server did not output "command signals" adapted for re-establishing the communications session with the disconnected device. Instead, it only determined that the participant had completed the activities for rejoining the conference, and in response, took the rejoined participant off the disconnected participant list, as explained in paragraph [0024] together with Fig. 2, blocks 208 and 210. The appellant concluded that D5 did not disclose feature (g) either.

1.1.5 This is not convincing. First, "stored call group information" in claim 1 of the main request may certainly - in theory - encompass the presence of authorisation codes, but neither the general wording used nor the context of claim 1 as a whole necessarily imply such specific interpretation. Besides, the limitation to the group communication session comprising at least one of authorisation and authentication information is undeniably presented as a mere preferred implementation in dependent claim 4 of the main request. In consequence, it is irrelevant whether D5 requires the user to re-enter authorisation codes to re-authorise itself or not when rejoining a conference.

Second, concerning the limitation implied by the claimed "command signals", the board considers that this feature must not be narrowly construed as implying an outgoing call from the server. The fact that the conferencing server of D5 is supposed to determine whether "the participant accepted the re-invitation and rejoined the conference" and to subsequently remove the participant from the "disconnected participant list" necessarily requires the same server to output at least some kind of internal "command signals" (see feature analysis of point 1.1.1 above). In summary, the board concludes that D5 likewise discloses feature (g).

1.2 It follows that the main request is not allowable under Article 54 EPC.

2. FIRST AUXILIARY REQUEST

Claim 1 of the first auxiliary request comprises all the limiting features of claim 1 of the main request and the following additional features (board's outline and underlining):

(h) the group call information comprises call leg information associated with at least one participating telephony device;

the determining that the disconnection was not intentionally initiated comprises:

(i) comparing said call leg information to active call legs in the group communication session; and

(j) determining that a number of current active call legs is less than a previously determined number of active call legs.

2.1 Claim 1 - Clarity (Article 84 EPC).

2.1.1 Present claim 1 is not clear, contrary to the requirements of Article 84 EPC.

2.1.2 Claim 1 establishes no clear relationship between the claimed "call leg information", being part of the "group call information" according to feature (h), and the "previously determined number of the active call legs" according to feature (j). It is therefore not apparent whether in step (i) the "call leg information", as an object of comparison with "active call legs in the group communication session", should be understood as the "previously determined number of the active call legs", or whether in step (i) the comparison involves other, not further defined parameters related to the call legs.

2.1.3 Furthermore, it is unclear to a skilled reader how an unintended disconnection of a participant could be detected only by determining that a number of current active call legs is less than a previous number of active call legs according to feature (j), without any further information on the association of the respective call legs and a more precise definition of "previous number". While a change in the count of "active call legs" may arguably suffice to detect a disconnection, this information alone does not indicate that the "disconnection was not intentionally initiated", as required by the claim. For example, in the embodiments of the underlying description, an additional indication of whether the call was regularly terminated is always required (see e.g. paragraph [0060]: "... the absence of an END OF CALL indicator that would indicate that the disconnect was intentional ...").

2.1.4 The appellant argued that "call leg information" was clear and that there existed several disclosed possibilities other than an "END OF CALL indicator" for determining that a call leg was not intentionally disconnected, such as the "call termination command" of paragraph [0060] or the flag of paragraph [0055] of the description as filed. In general, an applicant was allowed to broadly claim all options.

2.1.5 The board disagrees. The "END OF CALL indicator" is a specific instance of a "call termination command". Furthermore, the "flag" of paragraph [0060] is set depending on the reception of such a "call termination command". It is therefore possible to define the invention more precisely without unduly restricting the scope of the claims.

An applicant is indeed allowed to broadly claim all options, if necessary, by filing more than one independent claim in the same category (cf. Rule 43(2) EPC), but the fact that more than one alternative embodiment of a given feature is presented in the description does not mean that the actual implementation of a feature can be dispensed with and replaced by the respective result to be achieved.

2.2 In conclusion, the first auxiliary request is not allowable under Article 84 EPC.

3. SECOND AUXILIARY REQUEST

3.1 Claim 1 - Clarity (Article 84 EPC)

Features (h) to (j) in claim 1 of the second auxiliary request are the same as in claim 1 of the first auxiliary request. It follows that the same reasons as set out in point 2.1 above apply mutatis mutandis and that also claim 1 of the second auxiliary request lacks clarity (Article 84 EPC).

3.2 The second auxiliary request is thus not allowable under Article 84 EPC either.

4. THIRD AND FOURTH AUXILIARY REQUESTS

Claim 1 of the third auxiliary request comprises all the limiting features of claim 1 of the main request and the following additional features (board's outline and underlining):

(k) the information useable for re-establishing participation by the at least one telephony device in the group communications session comprises at least one of authorisation information and authentication information;

(l) re-establishing participation by the at least one telephony device in the group communications session comprises authorising or authenticating the device using the at least one of authorisation information and authentication information.

Claim 1 of the fourth auxiliary request comprises all the limiting features of claim 1 of the first auxiliary request. Additionally, it further comprises features (k) and (l), and the step relating to determining that the disconnection was not intentionally initiated further comprises (board's outline and underlining):

(m) determining the absence of an intentional end of call indicator.

4.1 Admission into the appeal proceedings (Article 13(2) RPBA 2020)

4.1.1 The claims of the third and fourth auxiliary requests were filed after notification of the summons to oral proceedings before the board.

4.1.2 Hence, the matter of admission of the third and fourth auxiliary requests is governed by Article 13(2) RPBA 2020, according to which any amendment to a party's appeal case is, in principle, not taken into account unless there are exceptional circumstances, which have been justified with cogent reasons by the party concerned. Additionally, at the stage of appeal proceedings when Article 13(2) RPBA 2020 applies, the board may, in its exercise of discretion, also rely on criteria mentioned in Article 13(1) RPBA 2020, such as prima facie allowability.

4.1.3 As to the third auxiliary request, the appellant submitted that dependent claims 4 and 5 (i.e. features (k) and (l)) had been added to claim 1 of both the main request and the first auxiliary request in response to the board's narrow understanding of the claimed term "group call information" as excluding authorisation and/or authentication information. The board's interpretation of this term became apparent in its novelty analysis in view of D5, which was not part of the appealed decision. No new aspect was added to the appeal proceedings with these claims since the amendments were completely based on dependent claims that had always been the subject of the examination proceedings. The appealed decision referred to claims 4 and 5 in item 15 of an obiter dictum, by referring to paragraphs [0021] and [0028] of D5. These paragraphs did not relate in any way to the subject-matter of the above dependent claims. On the contrary, in the appellant's view, D5 was silent as to authorisation and authentication information stored by the server and used for rejoining a disconnected participant.

As to the fourth auxiliary request, the appellant submitted that the introduction of feature (m) was a direct reaction to the clarity objection raised by the board in its preliminary opinion. As regards inventive step, starting from D5, which was based on

packet-switching, the skilled person did not receive any hints towards considering call legs, even less towards comparing and counting active call legs. Furthermore, the usage of this information for distinguishing between intentional versus unintentional call disconnection was a very specific and uncommon application thereof and could not be seen as being common general knowledge. No pertinent prior art had been cited. In addition, the application of the internet-based system of D5 to a circuit-switched TDM context would have required further significant system modifications (such as the usage of PBX, conference bridge, etc.), which would have prevented the skilled person from going in this direction.

4.1.4 In that regard, the board notes that even if it were, in the appellant's favour, accepted that there are cogent reasons justifying presence of "exceptional circumstances", claim 1 of both auxiliary requests are not clearly allowable.

As regards features (k) and (l), paragraph [0019] of D5 discloses that "an identification for any new participants may be added to a participant list", from which list a participant may be removed to enter into a "disconnected participant list" according to paragraphs [0021] and [0022]. This "identification" is actively used by the server for rejoining a disconnected participant (see e.g. paragraph [0023]; see also paragraph [0028]) and may therefore well constitute "at least one of authorisation information and authentication information" in the claimed sense.

As regards feature (m), D5 teaches in paragraph [0037]:

"The network or medium 614 may be the Internet or a private network, such as an intranet or the like. The communication network or medium 614 may be any communication system including by way of example, dedicated communication lines, telephone networks, and wireless data transmission systems, two-way cable systems, and customized computer networks, interactive kiosk networks, the Internet and the like."

In view of this explicit teaching, the board sees, prima facie, no reason to limit the understanding of D5 to packet-switched networks. When applying the teachings of D5 to a circuit-switched TDM network, call termination commands such as "END OF CALL" would have been customarily used to signal a regular, i.e. intentional, call termination, whereas counting legs in a TDM conference bridge constitutes a straightforward manner to determine disconnections in a conference.

For these reasons, features (k) to (m) cannot contribute, prima facie, to the presence of an inventive step starting from D5. Thus, the third and fourth auxiliary requests are not clearly allowable.

4.2 Accordingly, neither the third auxiliary request nor the fourth auxiliary request were admitted into the appeal proceedings (Article 13(2) RPBA 2020).

5. As there is no allowable claim request, it follows that the appeal must be dismissed.