T 0529/20 26-01-2023

Reasons for the Decision

1. The appeal is admissible.

All requests - added subject-matter (Article 123(2) EPC)

2. The board concurs with the appellant that the amendments made to the independent claims of the main request and of the first and second auxiliary requests overcome the objection under Article 123(2) EPC raised under section IV.a of the reasons for the decision.

Main request - inventive step (Articles 52(1) and 56 EPC)

3. Closest prior art

3.1 The first step of the problem-and-solution approach is to determine the closest prior art, i.e. the item of prior art which appears to be the most promising starting point for arriving at the claimed subject-matter in an obvious manner. The case law of the boards of appeal has established criteria for objectively identifying the closest prior art. When applied properly, these should normally prevent unrealistic starting points being used. The case law has emphasised the following two main criteria (see Case Law of the Boards of Appeal of the European Patent Office ("Case Law"), 10th edition 2022, I.D.3, decision T 698/10, point 3 of the Reasons and T 1148/15, points 4.1 and 4.2 of the Reasons):

(a) As a first criterion, the closest prior art should be related to the claimed invention, in the sense that it should disclose subject-matter conceived for the same purpose or aiming at the same objective, corresponding to a similar use, or relating to the same or a similar technical problem or, at least to the same or a closely related technical field.

(b) As a second criterion, the closest prior art should disclose subject-matter having the greatest number of technical features in common with the claimed invention, i.e. requiring the minimum of structural and functional modifications.

3.2 Document D8 relates to detecting, prioritising and scheduling packets in a communication network (see paragraph [001]). It explicitly refers to 4G long-term evolution (LTE) wireless communication systems (see, for instance, paragraph [041]). It deals with the problem that existing scheduling techniques for packets do not take the underlying application under consideration and thus cannot address their unique packet delivery requirements (see paragraphs [047],[087],[088] and [095]), i.e. a problem similar to that addressed by the present invention (see paragraphs [0002] and [0070] of the application as filed).

3.3 Hence, regarding the above first criterion, document D1 and D8 both essentially address the same problem as the claimed invention.

3.4 In the board's view, document D8 discloses the following features of claim 1 of the main request:

An evolved node (eNodeB) base station for coordinating communication of data packets between a user device and an application server, [see figure 3 and paragraphs [049],[097] and [0226]] the base station comprising:

a memory; [storage module 283 in figure 3] and

a computer processor operatively coupled to the memory, to a radio transmitter, and to a radio receiver [processor module 281 in figure 3, "one or more antennae for transmission and reception of radio signals" in paragraph [049]], the computer processor of the eNodeB base station being configured to:

inspect the data packet; [paragraph [004] and packet inspection modules 410' and 1500 in figures 13 and 21]

determine, based on the inspection, an application type of the data packet ["application class", first sentence of paragraph [0101] and figure 11], a priority value of the data packet ["application factor (AF)" assigned to each scheduling queue: paragraphs [0131], [0132] and [0135]], a delay sensitivity of the data packet [implicit from the determination of the application class or specific application: see penultimate sentence of paragraph [047], last sentence of paragraph [0144] and paragraph [058]], and a sensitivity to the loss of the data packet [implicit from the determination of the application class or specific application: see penultimate sentence of paragraph [047] and last sentence of paragraph [0144]];

determine, based on the inspection, an application state corresponding to the data packet, wherein the application state comprises one of a TCP data establishment state and a TCP data transfer state; [see paragraph [0228]: "Subsequently, the connection detection module 1530 may inspect packets to identify the setup of a TCP connection via detection of the packets used for TCP establishment (e.g., SYN, SYN-ACK, ACK) between a TCP client and a TCP server", paragraph [0229] and 1615 in figure 22]

[deleted: mark the data packet for a higher priority scheduling and a higher reliability modulation coding scheme (MCS) coding upon determination that the application state is the TCP data establishment state;]

[deleted: mark the data packet for a lower priority scheduling and a lower reliability MCS coding upon determination that the application state is the TCP data transfer state;]

assign radio resource blocks for transmitting the data packet based on the inspection of the data packet [deleted: and the marking]; [see assignment of data packets to different scheduling queues based on application class or specific application in figures 6 and 9] and

transmit the data packet utilizing the assigned radio resource blocks [see figures 6 and 9].

3.5 Hence, regarding the above second criterion, the base station in document D8 has a greater number of technical features in common with the claimed invention than that in document D1, i.e. it requires fewer structural and functional modifications. In addition, importantly, contrary to document D1, document D8 discloses an evolved node (eNodeB) base station (see, for instance, figure 3 and paragraphs [049], [097] and [0226]).

3.6 For the above reasons, the board considers that, based on the above two criteria, the closest prior art to the subject-matter of claim 1 is not document D1, but document D8.

3.7 The appellant argued that document D8 disclosed fewer of the features of claim 1 as alleged by the board, but it did not dispute that document D8 could be regarded as the closest prior art. The appellant's arguments regarding features of claim 1 allegedly not disclosed in document D8 are addressed by the board in section 4 below.

4. Distinguishing features

4.1 Based on the analysis under point 3.4 above, the board considers that the base station in claim 1 differs from that in document D8 on account of the following distinguishing features:

(a) marking the data packet for a higher priority scheduling and a higher reliability modulation coding scheme (MCS) coding upon determination that the application state is the TCP data establishment state;

(b) marking the data packet for a lower priority scheduling and a lower reliability MCS coding upon determination that the application state is the TCP data transfer state; and

(c) taking into account the above marking for assigning radio resource blocks.

4.2 The appellant argued that, in addition to the above distinguishing features (a) to (c), the following features (emphasis in bold added by the board) of claim 1 were not disclosed in document D8 either:

(d) determining, based on the inspection, a priority value of the data packet, a delay sensitivity of the data packet and a sensitivity to the loss of the data packet, and

(e) determining, based on the inspection, an application state corresponding to the data packet, wherein the application state comprises the TCP data transfer state.

With regard to the features under point (d), the appellant's arguments may be summarised as follows.

In document D8, the data packets are, upon inspection, assigned an "application factor (AF)" and a corresponding scheduling queue. This is equivalent to, but not the same as, assigning the data packets a priority value. Moreover, there is no explicit disclosure in document D8 that a delay sensitivity or a sensitivity to the loss of data packets are determined, nor are they implicitly disclosed.

With regard to the features under point (e), the appellant's arguments may be summarised as follows.

Document D8 discloses determining a TCP data establishment state (in paragraphs [0228] and [0229]) but not a TCP data transfer state.

4.3 The board does not find these arguments persuasive for the following reasons.

With regard to the features under point (d)

According to paragraph [0135] of D8, "the enhanced policy information 350 can include the assignment of a quantitative level of importance and relative priority based upon application class and specific application. This factor is referred to herein as the application factor (AF) and the purpose of the AF is to provide the operator with a means to adjust the relative importance, and ultimately the scheduling parameters, of queues following enhanced classification and enhanced queuing" (emphasis added by the board).

In the board's view, it is clear from the above quotation that the application factor (AF) assigned to a data packet represents a priority value of that data packet.

Moreover, document D8 discloses that the delay sensitivity and the sensitivity to loss of the data packets depend on the application type or specific application; see, in paragraph [0047], "This first-in-first-out (FIFO) method has the disadvantage of treating all packets with equal fairness, regardless of user, application, or urgency. This is an undesirable response as it ignores that each data stream can have unique packet delivery requirements, based upon the applications generating the traffic (e.g. voice, video, email, internet browsing, etc.). Different applications degrade in different manners and with differing severity due to packet delay and/or discard." (emphasis added by the board) and, in paragraph [0144], "This is undesirable during times of network congestion, due to the fact that a video chat session is more sensitive, in terms of user QoE, to packet delay or discard than a Facebook update." (emphasis added by the board).

The board thus considers that it is implicit in the disclosure of document D8 that by determining the application type or the specific application of a data packet, the delay sensitivity and the sensitivity to the loss of that packet is also determined.

With regard to the features under point (e)

The "Transmission Control Protocol (TCP)" is one of the core protocols of the Internet protocol suite (see D10, page 1, first sentence). It is used, for instance, by applications for transmitting data packets over the World Wide Web. The protocol operations are divided into three successive phases: connection establishment, data transfer and connection termination (see "Protocol operation" section in D10).

Paragraphs [0228] to [0232] of document D8 disclose that it is determined by packet inspection to which of the three TCP phases a data packet belongs.

The determination of the TCP connection establishment phase is disclosed, for instance, in paragraph [0228], "Subsequently, the connection detection module 1530 may inspect packets to identify the setup of a TCP connection via detection of the packets used for TCP establishment (e.g., SYN, SYN-ACK, ACK) between a TCP client and a TCP server" and in paragraph [0229], "the connection detection module 1530 retains the state of the connection establishment protocol (e.g., TCP SYN, SYN-ACK, ACK messages) and identifies a new connection based upon a successful result from that protocol".

The determination of the TCP data transfer phase is disclosed, for instance, in paragraph [0229], "If the connection identification information (e.g., logical link, IP addresses, UDP socket) matches an existing, active connection in the context stored by the status module 1550, then the connection information is deemed to be for an existing connection rather than a new connection ... The process then continues ... monitoring ... the connection status and any streams, sessions, and applications associated with traffic transported on the connection" (emphasis added by the board).

The determination of the TCP connection termination phase is disclosed, for instance, in paragraph [0232], "In step 1640, the connection detection module 1530 inspects packets to determine if the connection being monitored has been terminated".

Hence, it is determined in document D8, by packet inspection, that an application state corresponding to a data packet is the TCP data transfer state.

5. Technical effect and objective technical problem

5.1 The board notes that, according to the application as filed (see paragraph [0078]), the technical effect of the above distinguishing features is that of reducing the time required to transition a TCP (Transmission Control Protocol) communication session from a connection establishment state to a data transfer state.

The board therefore considers that the objective technical problem should be formulated, without pointers to the solution, as "how to improve the establishment of a communication session".

5.2 The appellant argued that the objective technical problem should be formulated as "how to provide an improved apparatus/method for allocating radio resource blocks to a data packet"; see letter of 19 December 2022, page 3, second full paragraph.

5.3 For the reasons given under point 5.1 above, the technical effect of the distinguishing features relates to improving aspects of a communication session rather than to allocating radio resource blocks. The board thus regards the appellant's formulation as too general and too unrelated to the technical effect of the distinguishing features.

6. Obviousness

6.1 As evidence of common general knowledge regarding the TCP connection establishment and TCP data transfer states, the examining division referred to the following web link:

https://en.wikipedia.org/wiki/Transmission_Control_Protocol#Connection_establishment

6.2 The appellant did not dispute that TCP connection establishment and TCP data transfer phases were common general knowledge (see statement of grounds of appeal, page 8, first sentence); however, the appellant disputed that it was common general knowledge that the TCP connection establishment phase was more delay sensitive than the TCP data transfer phase (see statement of grounds of appeal, page 8, second paragraph) and submitted that evidence of common general knowledge should be provided if this allegation was maintained (see statement of grounds of appeal, from page 8, penultimate paragraph, to page 9, first paragraph).

6.3 The board notes that the link cited in the decision under appeal (see point 6.1 above) corresponds to a Wikipedia article which is constantly updated, not to a prior-art version of this Wikipedia article. Hence, the board considered it appropriate to introduce document D10, which is a version of this Wikipedia article published shortly before the priority date, into the appeal proceedings as evidence of common general knowledge.

6.4 It is undisputed that the Transmission Control Protocol (TCP) belongs to common general knowledge. As already mentioned above, it was well known that the TCP protocol operations were divided into three successive phases: connection establishment, data transfer and connection termination (see "Protocol operation" section in D10). The connection establishment phase comprised a three-step handshake between client and server using SYN, SYN-ACK and ACK messages (see "Connection establishment" section in D10) and was followed by the data transfer phase.

6.5 In document D8, the packet inspection module 1500 inspects packets to identify those which belong to a TCP connection establishment phase and those which belong to the subsequent TCP data transfer phase (see paragraph [0228] and the first ten lines of paragraph [0229]).

The board notes that there are usually far fewer packets transferred in the TCP connection establishment phase than in the TCP data transfer phase. Moreover, the TCP data transfer phase can only start when the TCP connection establishment phase is complete. In the board's view, the skilled person would therefore have been well aware that fast and reliable delivery was significantly more important for the TCP connection establishment phase than for the TCP data transfer phase. This awareness would have obviously made it desirable in the system in document D8 to give the packets in the connection establishment phase higher priority than the packets in the data transfer phase in order to achieve faster delivery and a higher reliability modulation coding scheme in order to achieve higher reliability. The implementation of such a change in the system in document D8 would have been straightforward because it would have been easy to assign the packets in the connection establishment phase and the packets in the data transfer phase to two different scheduling queues corresponding to different priorities and modulation coding schemes.

Regarding the expression to "mark the data packet" in claim 1, the board regards it as meaning that the processor internally marks it for certain processing, not that the processor adds additional information to the data packet itself. This interpretation is consistent with the use of the terms "mark" and "marking" in the description of the application as filed (see "the DPI function will apply a particular process as indicated by the rule set, e.g., mark the packet for priority treatment for scheduling by the base station" in paragraph [0069]). Such marking must necessarily exist in the processor in document D8 in order to indicate which scheduling queue to select.

6.6 The appellant's arguments in the statement of grounds of appeal focused on the examining division's assertion that the TCP connection establishment packets were more "delay sensitive" than the TCP transfer phase packets, but the appellant does not consider it to be proven that this belongs to common general knowledge.

6.7 In the board's view, when using the term "delay sensitive" the examining division actually meant that fast and reliable delivery was more important for the TCP connection establishment packets than for the TCP transfer phase packets, which the board regards as well known, and obvious in any case, for the reasons given under point 6.5 above.

6.8 The appellant also argued that document D8 taught assigning all the data packets of a given application to the same scheduling queue. Hence, the teaching of document D8 led away from assigning data packets of the same application to different scheduling queues in the TCP connection establishment phase and in the data transfer phase.

6.9 The board does not find this argument persuasive for the following reasons.

In the TCP connection establishment phase, the data packets correspond to the SYN, SYN-ACK and ACK messages (see "Connection establishment" section in D10). These messages are not yet part of the application to be transmitted in the subsequent data transfer phase and do not contain information allowing the base station to identify the application by packet inspection. The teaching of document D8 therefore does not lead away from assigning these packets to a different scheduling queue.

7. Conclusion on inventive step for the main request

For the above reasons, the subject-matter of claim 1 does not involve an inventive step in view of document D8 and the common general knowledge of the skilled person.

First auxiliary request - inventive step (Articles 52(1) and 56 EPC)

8. Claim 1 of the first auxiliary request differs from claim 1 of the main request in that "a provider of the data packet" is also determined based on the data packet inspection.

9. The board notes that this additional feature is known from document D8; see, for instance, the references to the service providers YouTube, Netflix, Skype and iChat in paragraph [0100].

10. The appellant did not present an argument that was specific to the first auxiliary request. Instead, it referred to its arguments regarding the main request.

11. For the above reasons, the subject-matter of claim 1 of the first auxiliary request lacks an inventive step, essentially for the same reasons as for the main request.

Second auxiliary request - inventive step (Articles 52(1) and 56 EPC)

12. Claim 1 of the second auxiliary request differs from claim 1 of the first auxiliary request on account of the additional step to "select a modulation coding scheme (MCS) index based on the inspection".

13. For the reasons given under point 6.5 above, the board regards this feature as obvious.

14. The appellant argued that document D8 did not suggest selecting a modulation coding scheme based on data packet inspection.

15. The board does not find this argument persuasive because, as pointed out by the examining division under point Vll.c.ii of the decision, paragraph [0200] of document D8 discloses changing the modulation coding scheme under certain circumstances. Moreover, it is common general knowledge in the technical field of data transmission to change the modulation coding scheme depending on the level of quality of service required.

Conclusion

16. Since none of the appellant's requests is allowable, the appeal must be dismissed.

Reimbursement of the appeal fee under Rule 103(1)(a) EPC

17. According to Rule 103(1)(a) EPC, which entered into force on 1 April 2020 (see OJ EPO 2020, A5), the reimbursement of the appeal fee has to be ordered in full where the board of appeal deems an appeal allowable, if such reimbursement is equitable by reason of a substantial procedural violation. The board may, even when reimbursement has not been requested (as is the case here), examine this issue ex officio (see, for example, J 7/82, OJ EPO 1982, 391).

In the case at hand, the precondition for reimbursement of the appeal fee in full under Rule 103(1)(a) EPC is not met because the appeal is not allowable. Since a substantial procedural violation was not alleged by the appellant and a request for reimbursement of the appeal fee was not submitted, the board sees no need in the case at hand to examine ex officio whether a substantial procedural violation occurred during the first-instance proceedings.