T 1497/15 (Maximum bandwidth/SAMSUNG) of 9.1.2019

Summary of Facts and Submissions

I. The appeal is against the decision of the examining division to refuse the present European patent application for lack of inventive step (Article 56 EPC) with respect to the claims of a main request and first to fifth auxiliary requests, having regard to the disclosure of

D2: Motorola: "Sounding Maximum Bandwidth for UpPTS", Change Request, 3GPP TSG-RAN1 Meeting #53bis, draft R1-082329, pp. 1-2, July 2008

or

D3: CATT et al.: "Sounding maximum bandwidth for UpPTS", 3GPP TSG-RAN1 Meeting #53bis, draft R1-082755, pp. 1-4, July 2008.

Furthermore, the claims of a sixth auxiliary request were not admitted into the examination proceedings on the grounds that they were late-filed and not clearly allowable under Article 84 EPC.

II. With its statement setting out the grounds of appeal, the appellant filed amended sets of claims according to a new main request and two new auxiliary requests. It requested that the examining division's decision be set aside and that a patent be granted on the basis of one of those claim requests.

III. In a communication annexed to the summons to oral proceedings pursuant to Article 15(1) RPBA, the board gave its preliminary opinion on the appeal. In particular, it expressed concerns about the admissibility of the new claim requests under Article 12(4) RPBA, and raised objections under Articles 123(2) and 56 EPC, mainly having regard to prior-art document D3.

IV. With a letter of reply dated 10 December 2018, the appellant submitted amended claims according to an amended main request and new first to third auxiliary requests, replacing the former claim requests on file, along with counter-arguments to the objections raised in the board's communication under Article 15(1) RPBA.

V. Oral proceedings were held on 9 January 2019, during which the appellant filed a fourth auxiliary request. The admissibility and allowability of all the pending claim requests were discussed.

- The appellant's final request was that the decision under appeal be set aside and that a patent be granted on the basis of the claims according to the main request or the first, second or third auxiliary requests, all submitted with the letter dated 10 December 2018, or on the basis of the fourth auxiliary request submitted during the oral proceedings before the board.

At the end of the oral proceedings, the board's decision was announced.

VI. Claim 1 of the main request reads as follows:

"A method for a User Equipment (UE) to transmit a Sounding Reference Signal (SRS) to a network in a communication system, comprising steps of:

identifying a plurality of SRS bandwidth configurations for a given operating bandwidth, wherein each SRS bandwidth configuration comprises a plurality of predetermined SRS bandwidths;

receiving a cell-specific parameter and a

UE-specific parameter, wherein the cell-specific parameter is indicative of an SRS bandwidth configuration of the plurality of SRS bandwidth configurations, and the UE-specific parameter is indicative of an SRS bandwidth of the plurality of SRS bandwidths, wherein a pair of the cell-specific parameter and the UE-specific parameter corresponds to an SRS bandwidth;

reconfiguring the SRS bandwidth to a maximum SRS bandwidth that is equal to or less than a difference between a number of resource blocks for the operating bandwidth and a product of a number of resource blocks in a random access channel and a number of random access channels in case of UpPTS, where the maximum SRS bandwidth is associated with one of the plurality of SRS bandwidth configurations; and

transmitting the SRS (1062) based on the reconfigured SRS bandwidth,

wherein the maximum SRS bandwidth is one of the plurality of predetermined SRS bandwidths corresponding to the SRS bandwidth configuration associated with the maximum SRS bandwidth, and

wherein the maximum SRS bandwidth corresponds to a UE-specific parameter having a lowest index."

Claim 1 of the first auxiliary request reads as follows (amendments compared with claim 1 of the main request highlighted by the board):

"A method for a User Equipment (UE) to transmit a Sounding Reference Signal (SRS) to a network in a communication system, comprising steps of:

identifying a plurality of SRS bandwidth configurations for a given operating bandwidth, wherein each SRS bandwidth configuration comprises a plurality of predetermined SRS bandwidths;

receiving a cell-specific parameter and a

UE-specific parameter, wherein the cell-specific parameter is indicative of an SRS bandwidth configuration of the plurality of SRS bandwidth configurations, and the UE-specific parameter is indicative of an SRS bandwidth of the plurality of SRS bandwidths, wherein a pair of the cell-specific parameter and the UE-specific parameter corresponds to an SRS bandwidth;

reconfiguring the SRS bandwidth to a maximum SRS bandwidth that is equal to or less than a difference between a number of resource blocks for the operating bandwidth and a product of a number of resource blocks in a random access channel and a number of random access channels in case of UpPTS, where the maximum SRS bandwidth is associated with one of the plurality of SRS bandwidth configurations; and

transmitting the SRS (1062) based on the reconfigured SRS bandwidth,

wherein the maximum SRS bandwidth is [deleted: one] a maximum bandwidth of the plurality of predetermined SRS bandwidths corresponding to the SRS bandwidth configuration associated with the maximum SRS bandwidth[deleted: , and]

[deleted: wherein the maximum SRS bandwidth corresponds to a UE-specific parameter having a lowest index]."

Claim 1 of the second auxiliary request comprises all the features of claim 1 of the main request and further adds the following clause at its end:

", and wherein the lowest index is 0."

Claim 1 of the third auxiliary request reads as follows:

"A method for a User Equipment (UE) to transmit a Sounding Reference Signal (SRS) to a network in a communication system, comprising steps of:

identifying a set of predetermined SRS bandwidth configurations;

identifying a number of random access channels;

receiving information regarding an SRS bandwidth configuration;

reconfiguring the SRS bandwidth configuration to obtain a reconfigured SRS bandwidth configuration, wherein the reconfigured SRS bandwidth configuration is an SRS bandwidth configuration among the set of predetermined SRS bandwidth configurations that depends on an uplink bandwidth, such that the reconfigured SRS bandwidth configuration has a maximum bandwidth value that is equal to or less than a value determined as the uplink bandwidth minus a product of a number of resource blocks and the number of random access channels; and

transmitting the SRS (1062) based on the reconfigured SRS bandwidth configuration, and

wherein the maximum bandwidth value corresponds to a lowest index value indicated by a UE-specific parameter on the SRS bandwidth configuration."

Claim 1 of the fourth auxiliary request reads as follows:

"A method for a User Equipment (UE) to transmit a Sounding Reference Signal (SRS) to a network in a Long Term Evolution (LTE) communication system, comprising steps of:

identifying a plurality of SRS bandwidth configurations for a given operating bandwidth, wherein each SRS bandwidth configuration comprises a plurality of predetermined SRS bandwidths;

receiving a cell-specific parameter and a UE-specific parameter, wherein the cell-specific parameter is indicative of an SRS bandwidth configuration of the plurality of SRS bandwidth configurations, and the UE-specific parameter is indicative of an SRS bandwidth of the plurality of SRS bandwidths, wherein a pair of the cell-specific parameter and the UE-specific parameter corresponds to an SRS bandwidth;

reconfiguring the SRS bandwidth to a maximum SRS bandwidth that is equal to or less than a difference between a number of resource blocks for the operating bandwidth and a product of a number of resource blocks in a random access channel and a number of random access channels in case of UpPTS, where the maximum SRS bandwidth is associated with one of the plurality of SRS bandwidth configurations; and

transmitting the SRS (1062) based on the reconfigured SRS bandwidth,

wherein the maximum SRS bandwidth is one of the plurality of predetermined SRS bandwidths corresponding to the SRS bandwidth configuration associated with the maximum SRS bandwidth, and

wherein the maximum SRS bandwidth corresponds to a UE-specific parameter having a lowest index, and

wherein the lowest index is 0,

wherein the maximum bandwidth value of an SRS bandwidth is a maximum of bandwidth values in a set of SRS bandwidth configurations that avoids overlapping with the bandwidth allocated to transmissions of the one or more random access channels (1054),

wherein the maximum SRS bandwidth is denoted by FORMULA/TABLE/GRAPHIC and determined, in terms of resource blocks, as

FORMULA/TABLE/GRAPHIC

where

FORMULA/TABLE/GRAPHIC is an uplink bandwidth in terms of resource blocks,

C is the set of SRS bandwidth configurations,

c is an SRS bandwidth configuration in the set C of SRS bandwidth configurations,

FORMULA/TABLE/GRAPHIC is a possible bandwidth value for SRS bandwidth configuration c; and

NRA is a number of random access channels and Q is a number of resource blocks for each random access channel."

Reasons for the Decision

1. The present invention

1.1 The present application is concerned with transmitting, from a mobile device (UE) to a base station, so-called sounding reference signals (SRS) via Uplink ParT symbols (UpPTS) in the presence of random-access (RA) channels of a 3GPP-based TDD (Time Division Duplexing) communication system.

It describes a first embodiment relating to determining a maximum SRS bandwidth such that overlaps between it and the bandwidth allocated to random-access channels are avoided either by dropping or suspending the SRS transmission bandwidth overlapping with the bandwidth allocated to random-access channels (see e.g. paragraphs [0041] to [0043] and [0049] in conjunction with Figs. 10 and 14 of the application as filed) or by reducing or shifting the SRS transmission bandwidth to the maximum bandwidth supportable in non-UpPTS symbols without extending to the bandwidth allocated to the random-access channels (see paragraphs [0044] to [0048] and [0050] together with Figs. 11 and 15 of the application as filed).

1.2 According to the present description, the main idea of the invention is to set a maximum bandwidth value in terms of resource blocks (RBs) for SRS transmissions in the UpPTS transmission case regardless of the

cell-specific parameter c signalled to the UE by the base station, while in the non-UpPTS transmission case the SRS bandwidth values configured based on the signalled parameter c are still to be respected (see in particular paragraphs [0042] and [0043] as filed). The alleged technical problem to be solved by the present invention is to avoid overlapping between SRS transmissions and the transmission of random-access channels in the UpPTS symbol (see paragraphs [0035] and [0040] as filed).

1.3 Table 1 of the present application shows a typical SRS bandwidth configuration for a certain range of the available uplink (UL) bandwidth FORMULA/TABLE/GRAPHIC and based on the cell-specific parameter c (see rows of Table 1) and the UE-specific parameter b (see columns of Table 1):

FORMULA/TABLE/GRAPHIC

2. FOURTH AUXILIARY REQUEST

Given that claim 1 of the fourth auxiliary request has the largest number of limiting features and is thus more limited in scope compared with claim 1 of the higher-ranking requests, the board considers it appropriate and expedient to discuss its patentability first.

2.1 Novelty and inventive step (Articles 54 and 56 EPC)

2.1.1 The board concurs with the appellant and the impugned decision that prior-art documents D2 and D3 fail to directly and unambiguously disclose that the respective cell-specific and UE-specific parameters (typically sent from the respective base station) are received at the UE. Hence, the subject-matter of claim 1 is considered to be novel (Article 54 EPC).

2.1.2 In view of the substantive amendments made to claim 1, the board finds that document D3 constitutes the most suitable starting point on file for assessing inventive step since it explicitly includes the scenario for determining the maximum SRS bandwidth in the case of "b=0" (i.e. for UEs associated with low uplink

signal-to-noise ratios "UL SINRs"; see e.g. paragraphs [0015] and [0016] of the present application as filed).

2.1.3 More specifically, it is apparent to the board that D3 discloses the following features A) to H) of present claim 1, as labelled by the board:

A method for a user equipment (UE) to transmit a sounding reference signal (SRS) to a network in a Long Term Evolution (LTE) communication system, comprising the steps of:

A) identifying a plurality of SRS bandwidth configurations ("configurations 0, 1,...,7") for a given operating bandwidth ("80 < FORMULA/TABLE/GRAPHIC <= 110"), wherein each SRS bandwidth configuration comprises a plurality of SRS bandwidths ("mSRS,b") (see e.g. page 4, Table 5.5.3.2-4);

B) [deleted: receiving] defining a cell-specific parameter ("SRS bandwidth configuration") and a UE-specific parameter ("UE-specific parameter b"), wherein the cell-specific parameter is indicative of an SRS bandwidth configuration of the plurality of SRS bandwidth configurations, and the UE-specific parameter is indicative of an SRS bandwidth of the plurality of SRS bandwidths, wherein a pair of the cell-specific parameter and the UE-specific parameter corresponds to an SRS bandwidth (see page 2, section 5.5.3.2; page 4, Table 5.5.3.2-4);

C) reconfiguring the SRS bandwidth to a maximum SRS bandwidth (FORMULA/TABLE/GRAPHIC) that is equal to or less than a difference between a number of resource blocks for the operating bandwidth (FORMULA/TABLE/GRAPHIC) and a product of a number of resource blocks in a random-access channel ("6") and a number of random-access channels (NRA) in case of UpPTS (see e.g. page 2, section 5.5.3.2, formula for FORMULA/TABLE/GRAPHIC),

D) where the maximum SRS bandwidth is associated with one of the SRS bandwidth configurations (e.g. "configuration 0") and is one of predetermined SRS bandwidths (e.g. "96") corresponding to the SRS bandwidth configuration associated with the maximum SRS bandwidth (see e.g. page 4, Table 5.5.3.2-4, column corresponding to "b=0");

E) transmitting the SRS based on the reconfigured SRS bandwidth configuration (see e.g. page 3, sentence above Table 5.5.3.2-1: "The sounding reference signal shall be transmitted at the last symbol of the subframe."),

F) wherein the plurality of SRS bandwidths corresponds to a UE-specific parameter having a lowest index (index "0") (see e.g. page 4, Table 5.5.3.2-4, columns for "b=0"),

G) wherein the maximum bandwidth value ("96") of an SRS bandwidth is a maximum of bandwidth values (i.e. values 96, 80, 72, 64, 60, 48) in a set of SRS bandwidth configurations that avoids overlapping with the bandwidth allocated to transmissions of the random-access channels (see e.g. page 4, Table 5.5.3.2-4, columns for "b=0");

H) wherein the maximum SRS bandwidth is denoted by

FORMULA/TABLE/GRAPHIC and determined, in terms of resource blocks, as

FORMULA/TABLE/GRAPHIC

where mSRS,0 is a possible bandwidth value in terms of resource blocks assigned for a certain SRS bandwidth configuration and for "b=0"; FORMULA/TABLE/GRAPHIC is the available uplink operating bandwidth in terms of resource blocks; alpha2, alpha3 and alpha5 are non-negative integers; NRA is the number of random-access channels; and "6" is the number of available resource blocks for each random-access channel (see page 2, section 5.5.3.2, paragraph above the formula: "... the largest entry in Table 5.5.3.2-1 through Table 5.5.3.2-4 should be overridden by the maximum SRS BW FORMULA/TABLE/GRAPHIC ...").

2.1.4 It follows from the above that the sole difference between claim 1 and document D3 resides in feature B), i.e. in that the respective cell-specific and

UE-specific parameters (sent from the base station) are received at the UE.

2.1.5 As regards that distinguishing feature, the board agrees with the finding of the impugned decision that informing the UE regarding the parameters of the SRS bandwidth configuration is an obvious measure in order to indicate by the base station the corresponding parameters, so that the UE is indeed able to determine the maximum bandwidth which may subsequently be used for SRS transmissions (see also appealed decision, Reasons 3 and 4, penultimate paragraphs). This was not contested by the appellant. Hence, the board concludes that the skilled person would come up with this straightforward implementation detail without the need of inventive skills.

2.1.6 As to the above features G) and H), the appellant persistently argued at the oral proceedings before the board that the determination of the maximum SRS bandwidth value according to present claim 1 was significantly different from that of D3. The approach according to claim 1, based on the formula

FORMULA/TABLE/GRAPHIC

relied on reconfiguring the maximum SRS bandwidth FORMULA/TABLE/GRAPHIC to the maximum of the maximum SRS transmission bandwidths FORMULA/TABLE/GRAPHIC across the set C of all supportable configurations (i.e. across all possible values of the cell-specific parameter c) that is equal to or smaller than the difference between the number of resource blocks available for the uplink operating bandwidth FORMULA/TABLE/GRAPHIC and a product of the number of resource blocks comprised in a random-access channel, Q, and the total number of random-access channels in the case of UpPTS symbols, NRA. By applying this approach, the maximum SRS bandwidth value obtained in the case of Table 1 of the present application (see point 1.3 above) was e.g. "96", provided that it remained below the upper limit FORMULA/TABLE/GRAPHIC.

Conversely, the approach of D3, which was the conventional approach at the application's priority date, determined the maximum value among those SRS bandwidth values that are both even and a multiple of 2, 3 and 5 according to the mathematical expression 2**(1+alpha2)·3**(alpha3)·5**(alpha5), while that value is also equal to or smaller than the above upper limit (with Q = 6 in D3). As a consequence, according to the appellant, in the scheme of D3 "unsupported" bandwidth values such as 50, 54 or 90 (i.e. multiples of 2 rather than 4 resource blocks) could also be obtained as maximum values. Therefore, the maximum value was not selected from the set of bandwidth values configured in the respective configuration table but only overridden by potentially unsupported bandwidth values that were not included in an SRS bandwidth configuration table such as Table 1 above.

2.1.7 The board is not convinced by this line of argument for various reasons.

- Firstly, it is noted that D3 teaches that, for the uplink bandwidth range of 80 < FORMULA/TABLE/GRAPHIC <= 110, the respective SRS bandwidth values are in fact 96, 80, 72, 64, 60 and 48 (see page 4, Table 5.5.3.2-4), in full accordance with e.g. Table 1 of the present application (see point 1.3 above).

- Secondly, it is apparent to the board that the very generation of specific SRS bandwidth values is not defined in the claims at all and that, in particular, present claim 1 is not restricted to SRS bandwidth values that are multiples of 4 resource blocks (generally obtainable through 22**(+alpha2)·3**(alpha3)· 5**(alpha5), emphasis added).

- Lastly, and most importantly, the board holds that the skilled person would be well aware that the formula given in D3 for the determination of the maximum SRS bandwidth value, i.e.

FORMULA/TABLE/GRAPHIC ,

is to be understood as selecting that maximum value of the SRS bandwidth values derivable from the mathematical expression 2**(1+alpha2)·3**(alpha3)·5**(alpha5)(e.g. 96 by setting alpha2=4, alpha3=1, alpha5=0 or 80 by setting alpha2=3, alpha3=0, alpha5=1, etc.) and pre-configured in the respective configuration table, with the additional property that this maximum value must be smaller than or equal to the respective upper limit. Thus, selecting a bandwidth value as a maximum value which is not included in the set of bandwidth values would be at odds with the formula, all the more so when considering that the fact that the formula of D3 relies on mSRS,0 (emphasis added), i.e. corresponding to the specific set of bandwidth values associated with the column "b=0", would otherwise be completely meaningless.

2.1.8 In view of the above, the board concludes that the subject-matter of claim 1 of the fourth auxiliary request does not involve an inventive step having regard to document D3.

2.2 In conclusion, the fourth auxiliary request is not allowable under Article 56 EPC.

3. MAIN REQUEST, FIRST AND SECOND AUXILIARY REQUESTS

Claim 1 of the present main request as well as the first and second auxiliary requests has fewer limiting features (in particular, it lacks the specific formula recited in claim 1 of the fourth auxiliary request) and thus is broader in scope than claim 1 of the fourth auxiliary request. Given, moreover, that the board has already read the appellant's interpretation of the particular formula onto the determination step of claim 1 of the above claim requests, the board must naturally conclude that a fortiori its subject-matter lacks an inventive step, based on the reasoning set out in point 2.1 above.

3.1 Consequently, the main request and the first and second auxiliary requests are likewise not allowable under Article 56 EPC.

4. THIRD AUXILIARY REQUEST

Claim 1 of the third auxiliary request differs from claim 1 of the fourth auxiliary request essentially in that it no longer includes features B), G) and H), and further specifies that (amendments compared with claim 1 of the fourth auxiliary request highlighted by the board)

I) the UE identifies a number of random-access channels;

J) the UE receives [deleted: a cell-specific and a UE-specific parameter] information regarding an SRS bandwidth configuration;

K) the maximum [deleted: SRS] bandwidth value is equal to or less than a value determined as the uplink bandwidth minus a product of a number of resource blocks [deleted: in a random-access channel] and a number of random-access channels [deleted: in case of UpPTS].

4.1 Admission into the proceedings (Article 13(1) RPBA)

4.1.1 The claims of the third auxiliary request were filed with the appellant's letter of reply dated 10 December 2018 (see point IV above), i.e. after the appellant had filed its statement of grounds of appeal. The appellant argued that they were submitted in reaction to the board's remarks made in its communication under Article 15(1) RPBA on the admissibility of the claim requests on file under Article 12(4) RPBA.

4.1.2 In appeal proceedings, the admissibility of claim requests filed after a party has submitted its statement setting out the grounds of appeal, which "shall contain a party's complete case" (Article 12(2) RPBA), is mainly governed by Article 13(1) and (3) RPBA. By virtue of Article 13(1) RPBA, a board's discretion in admitting any amendment to a party's case "shall be exercised in view of inter alia the complexity of the new subject-matter submitted, the current state of the proceedings and the need for procedural economy".

4.1.3 In the present case, the board notes that the instant subject-matter of claim 1 of the third auxiliary request includes significant amendments and virtually constitutes a substantial broadening of the scope of the subject-matter of the higher-ranking claim requests. In particular, the new subject-matter relates to any generic "information" received by the UE (rather than cell-specific and UE-specific parameters) and is no longer restricted to the UpPTS case. As a consequence, the subject-matter in question does not converge as regards the other higher-ranking claim requests and amounts to a "fresh case", contrary to procedural economy.

4.2 In view of the foregoing, the board has decided not to admit the third auxiliary request into the appeal proceedings under Article 13(1) RPBA.

5. In conclusion, the main request and first, second and fourth auxiliary requests not being allowable, and the third auxiliary request not being admissible, the present appeal must be dismissed.

Order

For these reasons it is decided that:

The appeal is dismissed.