DETAILED ACTION
Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Response to Amendment
The amendment filed January 2, 2026 has been accepted and entered. Accordingly, claims 1, 9, 10 and 16 are amended.
Claims 1-16 are pending in this application.
In view of the amendment, the objection to claim 16 has been withdrawn.
In view of the amendment, the previous rejections of claim 9 under 35 U.S.C 112(b) have been withdrawn. However, rejection to claim 9 under 35 U.S.C. 112(b) in the new ground is made as it is not clear what is the equivalent hardware structures of “a removal unit configured to remove” and “selection unit is configured to select”. The previous rejection to claim 10 under 35 U.S.C. 112(b) has not been overcome as it is not clear what are the equivalent hardware structure of “a removal unit configured to remove” and “selection unit is configured to select”.
Response to Arguments
Applicant's arguments filed January 2, 2026 have been fully considered but they are not persuasive.
In response to applicant’s argument regarding the amended claims 1 and 9, “Joung neither recognizes inter-relay interference as a signal component that inevitably arises from the system structure, nor discloses a received signal structure defined on such a premise” (Response filed January 2, 2026, Page 8) and “signal separation cannot be achieved by simple filtering or conventional DSTTD reception schemes, and that application of multiple-input multiple- output (MIMO) signal detection is required” (Response filed January 2, 2026, Page 9), Examiner respectfully disagrees with the Applicant.
According to Joung, “In each time slot in (2=t=T), the S 102 node transmits fresh STBC symbols denoted with {
x
1
(1),
x
2
(1)} to the nodes D 120 and Ra, where Ra ε{R1, R2}. In the same time slot, the STBC symbols retransmitted by the nodes R1 110 or R2 112 are denoted by {
x
^
R
b
,
1
(t−1),
x
^
R
b
,
2
(t−1)} where Rb ε{R1, R2} such that Ra≠Rb. {
x
^
R
b
,
1
(t−1),
x
^
R
b
,
2
(t−1)} are the symbols estimated at Rb in the previous time slot. R1 110 retransmits the estimates
x
^
R
1
,
1
(t−1) and
x
^
R
1
,
2
(t−1) to the nodes D 120 and R2 112” (Joung [Para. 0072]). At time slot t, for example, node D is similar to a relay node regarding the received signal. Both D and R2 112 are situated similarly to receive the same combined signals {
x
1
(1),
x
2
(1)} and {
x
^
R
1
,
1
(t−1),
x
^
R
1
,
2
(t−1)} where {
x
^
R
1
,
1
(t−1),
x
^
R
1
,
2
(t−1)} is the inter-relay interference for R2 112 from R1 110.
Joung provides “x(t)=[
x
^
R
1
,
1
(t−1)
x
^
R
1
,
2
(t−1)
x
1
(1)
x
2
(1)]T is a transmitted symbol vector. Estimates of x(t) may be obtained from the reordered signal from Equation 8 by using a maximum likelihood (ML). This estimation may be done at the D 120. The estimates obtained are denoted
x
^
t
=[
x
^
R
1
,
D
,
1
(t−1)
x
^
R
1
,
D
,
2
(t−1)
x
^
D
,
1
(t)
x
^
D
,
2
(t)]T, the elements of
x
^
t
respectively being estimates of the corresponding elements from x(t)” (Joung [Para. 0076]). Destination node D receives the combined signals {
x
^
R
1
,
1
(t−1),
x
^
R
1
,
2
(t−1)} and
{
x
1
(1),
x
2
(1)} at time slot t where {
x
^
R
1
,
1
(t−1),
x
^
R
1
,
2
(t−1)} is the transmission retransmitted from relay R1 that R1 received at time slot t – 1. At D,
{
x
^
D
,
1
(t),
x
^
D
,
2
(t)} is obtained using a maximum likelihood (ML), the MIMO detection algorithm. {
x
^
R
1
,
1
(t−1),
x
^
R
1
,
2
(t−1)} would be inter-relay interference signal if D were a relay.
Joung teaches “HN 2 N 1 (t) is a 2-by-2 matrix used to denote the MIMO channel from the node N1 to node N2 such that N1 and N2ε{D,R1,R2,S}” (Joung [Para. 0062]), indicating MIMO channels (S, R1), (S, R2), (R1, D) and (R2, D), and “Relay nodes may be located close to each other, in which case the strong interference amongst the relay nodes may deteriorate the relay signals. Inter-relay interference may be removed by employing DSTTD detection at the relay nodes” (Joung [Para. 0108-0109]). Therefore, based on Joung, DSTTD detection used at destination node D can be used at the relay nodes for removal of inter-relay interference from the other relay. The inter-relay interference is combined with the data signal.
Claim Objections
Claim 9 is objected to because of the following informality:
Claim 9 should be amended to read, “a reception unit configured to receive, from at least one relay of the plurality of relays, data signals transmitted during the respective time slots” since the apparatus of claim 9 is receiving.
Appropriate correction is required.
Claim Rejections - 35 USC § 112
The following is a quotation of 35 U.S.C. 112(b):
(b) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention.
The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph:
The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention.
Claims 9-10 are rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor (or for applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention.
Claims 9-10 are directed to an apparatus and recites means plus function elements such as “selection unit is configured to select” and “a removal unit is configured to remove”. The review of the specification does not show any hardware structures that are equivalent to “selection unit” and “removal unit” that perform the recited functions, e.g., “a selection unit is configured to select a plurality of relays” and “a removal unit is configured to remove an inter relay interference (IRI) component”. Therefore, the metes and bounds of claim is not clear as the one of ordinary skill in the art would not know from the claim terms what structure or steps are encompassed by the claim. MPEP 2173.05(g).
Claim Rejections - 35 USC § 103
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
Claims 1 and 8 are rejected under 35 U.S.C. 103 as being unpatentable over Joung et al. (US20120294202A1, hereinafter Joung) in view of Ko et al. (KR101489883B1, hereinafter Ko).
For claim 1. Joung teaches a method for high-speed signal relaying in an MIMO based relay communication system ([Para. 0055] and [FIG. 1], a method 100 of transmission. The transmission uses two-path double space-time transmit diversity (DSTTD) and takes place from a source S 102 to a destination D 120 via relay stations R1 110 and R2 112. [Para. 0062], HN 2 N 1 (t) is a 2-by-2 matrix used to denote the MIMO channel from the node N1 to node N2 such that N1 and N2ε{D,R1,R2,S}[Examiner’s Note: The relay channels are MIMO channels, including (S, R1), (S, R2), (R1, D) and (R2, D)]), the method comprising: receiving, by a plurality of relays, data signals transmitted from a sender during respective time slots according to a sequential relay transmission scheme in which transmission and reception roles of the plurality of relays are alternated ([Para. 0055] and [FIG. 1], The transmission uses two-path double space-time transmit diversity (DSTTD) and takes place from a source S 102 to a destination D 120 via relay stations R1 110 and R2 112. [Para. 0056], the transmission pattern of the nodes for two slots t=2 and t=3 are shown in FIG. 1. In t=2, the S 102 and R1 110 function as transmitters while R2 112 and D 120 function as receivers. In t=3, S 102 and R2 112 function as transmitters while R1 110 and D 120 function as receivers [Examiner’s Note: A sender sends signals to the destination through two relays alternately in two time slots]. [Para. 0073], the relay nodes R1 110 and R2 112 alternatively switch between transmitting and receiving modes from one time slot to the next).
Ko is directed to providing Apparatus and method for transferring using multi relay. More specifically, Ko teaches and removing, by a removal unit, an inter relay interference (IRI) component according to a sequential relay transmission scheme in which transmission and reception roles of the plurality of relays are alternated ([Para. 0074] and [FIG. 4 and 5], data is transmitted by applying an alternate transmission relaying technique. [Para. 0075] the first group relay node 210 receives a signal from the source nodes 100 in the first phase and transmits a signal received from the source node 100 to the destination node 300 in the second phase. In contrast, the second group relay node 230 transmits a signal to the destination node 300 in the first phase and receives a signal from the source node 100 in the second phase. [Para. 0039], in the first phase, the first group relay node 210 receives the preceding data from the plurality of source nodes 100, and the second group relay node 230 transmits the following data to the plurality of destination nodes 300. When the first group relay node 210 receives the preceding data, the following data signal transmitted by the second group relay node 230 may act as an interference signal [Examiner’s Note: The inter-relay interference from relay node 230 is received at relay node 210]. Accordingly, the first group relay node 210 removes the interference signal generated by the second group relay node 230 using the interference cancellation filter. [Para. 0040], In the second phase, the second group relay node 230 receives the following data from the plurality of source nodes 100, and the first group relay node 210 transmits the preceding data to the plurality of destination nodes 300. When the following data is received, the second group relay node 230 may act as an interference signal for the preceding data transmitted by the first group relay node 210 [Examiner’s Note: The inter-relay interference from relay node 210 is received at relay node 230]. Accordingly, the second group relay node 230 removes the interference signal generated by the first group relay node 210 using the interference cancellation filter. [Para. 0059], the relay filter design suitable for removing the inter-relay interference signal generated in the sequential transmission scheme can be performed).
It would have been prima facie obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the method of Joung, so that the interference filters remove the inter relay interference, as taught by Ko. The modification would have provided a relay filter capable of removing inter-relay interference signals without limitation to the number of transmission / reception node pairs and relay nodes and transferring only a desired signal from a source to a destination node (Ko [Para. 0012]).
For claim 8, Joung and Ko teach the method of claim 1. The references further teach selecting, by a selection unit, a plurality of relays (Ko [Para. 0029], the plurality of relay nodes 200 may be divided into a first group relay node 210 and a second group relay node 230. Ko [Para. 0031], the relay node selector 110 included in the plurality of source nodes 100 may select a corresponding relay node. The relay node 210 or the second group relay node 230 may be selected. Ko [Para. 0035], At this time, the relay nodes not selected as the first group relay node 210 become the second group relay node 230 which performs a role of receiving signals from the source nodes 100 again in the next step. In order for the source node 100 to transmit data to the second group relay node 230 in the second phase, the second group relay node 230 is selected again based on the above-described method [Examiner’s Note: Relay 210 is selected in the first phase to receive data and relay 230 is selected in the second phase to receive data alternately]); and transmitting, by a transmission unit, data signals from the sender to the plurality of relays, respectively (Joung [Para. 0025], a multiple antenna source configured to transmit STBC coded signals [Examiner’s Note: The antennas in the source that transmit signals constitute transmission unit]. Joung [Para. 0055] and [FIG. 1], The transmission uses two-path double space-time transmit diversity (DSTTD) and takes place from a source S 102 to a destination D 120 via relay stations R1 110 and R2 112. Joung [Para. 0056], the transmission pattern of the nodes for two slots t=2 and t=3 are shown in FIG. 1. In t=2, the S 102 and R1 110 function as transmitters while R2 112 and D 120 function as receivers. In t=3, S 102 and R2 112 function as transmitters while R1 110 and D 120 function as receivers [Examiner’s Note: A sender sends signals to the destination through two relays alternately in two time slots]. Ko [Para. 0039], in the first phase, the first group relay node 210 receives the preceding data from the plurality of source nodes 100. Ko [Para. 0040], in the second phase, the second group relay node 230 receives the trailing data from the plurality of source nodes 100).
It would have been prima facie obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the method of Joung, so that the selector selects relays and the source nodes send signals to the relays, as taught by Ko. The modification would have provided a relay filter capable of removing inter-relay interference signals without limitation to the number of transmission / reception node pairs and relay nodes and transferring only a desired signal from a source to a destination node (Ko [Para. 0012]).
Claims 2-7 are rejected under 35 U.S.C. 103 as being unpatentable over Joung et al. (US20120294202A1, hereinafter Joung) in view of Ko (KR101489883B1, hereinafter Ko), and further in view of Legnain et al. (MIMO two-way relay communication based on Alamouti code, IEEE CCECE 2011, hereinafter Legnain).
For claim 2, Joung and Ko teaches the method of claim 1. The references further teach wherein the sender transmits data signals X1 and X2 to one relay of the plurality of relays by using an STBC scheme during time slots T1 and T2 (Joung [Para. 0055] and [FIG. 1], The transmission uses two-path double space-time transmit diversity (DSTTD) and takes place from a source S 102 to a destination D 120 via relay stations R1 110 and R2 112. Joung [Para. 0056], the transmission pattern of the nodes for two slots t=2 and t=3 are shown in FIG. 1. In t=2, the S 102 and R1 110 function as transmitters while R2 112 and D 120 function as receivers. In t=3, S 102 and R2 112 function as transmitters while R1 110 and D 120 function as receivers [Examiner’s Note: A sender sends signals to the destination through two relays alternately in two time slots]).
Although teaching transmitting one signal to one relay in one time slot, Joung and Ko do not explicitly disclose wherein the sender transmits data signals X1 and X2 to one relay of the plurality of relays by using an STBC scheme during time slots T1 and T2.
Legnain is directed to providing MIMO two-way relay communication based on Alamouti code. More specifically, Legnain teaches wherein the sender transmits data signals X1 and X2 to one relay of the plurality of relays by using an STBC scheme during time slots T1 and T2 ([Page 000471, Left Col. Third Para.] and [FIG. 1], The communications take place over four time slots. In the first two time slots, nodes A and B transmit their signals to the RN (this stage is called the multiple access stage), and in the third and fourth time slots, the RN relays the received signals to nodes A and B. In multiple access stage, the two nodes, A and B, employ Space-Time Alamouti code to transmit their signals simultaneously in first and second time slots. [Page 000471, Right Col. First Para.], At RN, we assume MR = 2 (two antennas), the received signals during the first and second time slots are given by (1) and (2), where … sj;A and sj;B are the transmitted symbols, from the jth antenna, from node A and B, respectively. [Examiner’s Note: Either Node A or node B can be the sender that sends signals in time slots T1 and T2. For example, in Legnain, s1,A and s2,A (sj,A where j = 1, 2) are the signals from the antennas 1 and 2 of node A sent in the first time slot, and the conjugates of s1,A and s2,A are sent in the second time slot in Space-Time Alamouti code. Legnain teaches transmission of two signals simultaneously and their conjugates simultaneously to one relay in two time slots.).
It would have been prima facie obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the method of Joung and Ko, so that the source transmits two signals simultaneously to one relay in two time slots, as taught by Legnain. The modification would have improved the bit error rate (BER) performance as number of antennas at relay increased (Legnain [Page 000473, Sect. 4 Conclusion]).
For claim 3, Joung, Ko and Legnain teach the method of claim 2. The references further teach wherein the sender transmits data signals X3 and X4 to the other one relay of the plurality of relays by using the STBC scheme during time slots T3 and T4 (Ko [Para. 0074] and [FIG. 4 and 5], data is transmitted by applying an alternate transmission relaying technique. Ko [Para. 0075], the first group relay node 210 receives a signal from the source nodes 100 in the first phase. In contrast, the second group relay node 230 transmits a signal to the destination node 300 in the first phase and receives a signal from the source node 100 in the second phase. Legnain [Page 000471, Left Col. Third Para.] and [FIG. 1], The communications take place over four time slots. In the first two time slots, nodes A and B transmit their signals to the RN (this stage is called the multiple access stage), and in the third and fourth time slots, the RN relays the received signals to nodes A and B. In multiple access stage, the two nodes, A and B, employ Space-Time Alamouti code to transmit their signals simultaneously in first and second time slots [Examiner’s Note: Ko teaches transmission of one signal to one relay in one phase. Legnain teaches transmission of two signals simultaneously and their conjugates simultaneously to one relay in two time slots. It is obvious to combine Ko and Legnain so that the two time slots in Legnain constitute one phase in Ko to transmit the two signals simultaneously to one relay in one phase. X3 and its conjugate, and X4 and its conjugate may be transmitted to the second group relay node 230 in two time slots, the third and fourth time slots, in the second phase by combination of Legnain and Ko]).
It would have been prima facie obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the method of Joung and Ko, so that the source transmits two signals simultaneously to one relay in two time slots, as taught by Legnain. The modification would have improved the bit error rate (BER) performance as number of antennas at relay increased (Legnain [Page 000473, Sect. 4 Conclusion]).
For claim 4, Joung, Ko and Legnain teach the method of claim 3. The references further teach wherein demodulation signals x1 and x2 are transmitted from one relay of the plurality of relays to a receiver by using the STBC scheme during the time slots T3 and T4 (Legnain [Page 000471, Left Col. Third Para.] and [FIG. 1], The communications take place over four time slots. In the first two time slots, nodes A and B transmit their signals to the RN (this stage is called the multiple access stage), and in the third and fourth time slots, the RN relays the received signals to nodes A and B. In multiple access stage, the two nodes, A and B, employ Space-Time Alamouti code (STBC) to transmit their signals simultaneously in first and second time slots. Legnain [Page 000471, Right Col. First Para.], At RN, the received signals during the first and second time slots are given by yR in equation (3). Legnain [Page 000471, Right Col. Last Para.], The signals sA and sB can be estimated ... [Examiner’s Note: Signals sA and sB are the signals received at the relay after interference cancellation estimation during the first two time slots]. Legnain [Page 000471, Left Col. Third Para.], The RN receives both signals from nodes A and B simultaneously. In the broadcast stage, after estimating and demodulating both signals, RN … then retransmit the XORed modulated signal in third and fourth time slots. Legnain [Page 000472, Right Col. First Para.], Upon estimating sA and sB at the RN, they are demodulated to obtain the estimated bits information for them. Legnain [Page 000472, Right Col. Second Para.], The information bits are modulated and transmitted using Alamouti code to the two nodes, A and B. The received signals are then rearranged at both nodes, and they are given by yA and yB in (11) and (12) [Examiner’s Note: yA and yB in Legnain are x1 and x2. They correspond to sA and sB after demodulated at the relay node and are relayed to receivers A and B respectively]).
It would have been prima facie obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the method of Joung and Ko, so that the demodulation signals and their conjugates are transmitted from the relay to a receiver in two time slots, as taught by Legnain. The modification would have improved the bit error rate (BER) performance as number of antennas at relay increased (Legnain [Page 000473, Sect. 4 Conclusion]).
For claim 5, Joung, Ko and Legnain teach the method of claim 4. The references further teach wherein the demodulation signals x1 and x2 are transmitted to the other relay of the plurality of relays to cause the IRI (Ko [Para. 0040], in the second phase, the second group relay node 230 receives trailing data from the plurality of source nodes 100, and the first group relay node 210 transmits the preceding data to the plurality of destination nodes 300. In this case, the second group relay node 230 may act as an interference signal by the preceding data transmitted by the first group relay node 210 when receiving the following data. Legnain [Page 000471, Left Col. Third Para.] and [FIG. 1], The communications take place over four time slots. In the first two time slots, nodes A and B transmit their signals to the RN (this stage is called the multiple access stage), and in the third and fourth time slots, the RN relays the received signals to nodes A and B. In multiple access stage, the two nodes, A and B, employ Space-Time Alamouti code to transmit their signals simultaneously in first and second time slots. The RN receives both signals from nodes A and B simultaneously. In the broadcast stage, after estimating and demodulating both signals, RN … then retransmit the XORed modulated signal in third and fourth time slots [Examiner’s Note: Ko teaches transmission of two signals alternately in two phase. Legnain teaches transmission of two signal simultaneously in two time slots. It is obvious to combine Ko and Legnain so that each phase in Ko includes two time slots to transmit two signals simultaneously in one phase and four signals are transmitted alternately in two phases. In combination of Legnain and Ko, in the second phase, the first group relay node 210 transmits x1 and x2 to the destination, while the second group relay node 230 receives X3 and X4 from the source. Demodulation signals x1 and x2 are also received by the second group relay node 230, causing inter relay interference]).
It would have been prima facie obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the method of Joung and Ko, so that two demodulation signals are transmitted simultaneously in two time slots in one phase, as taught by Legnain. The modification would have improved the bit error rate (BER) performance as number of antennas at relay increased (Legnain [Page 000473, Sect. 4 Conclusion]).
For claim 6, Joung, Ko and Legnain teach the method of claim 5. The references further teach wherein the data signal received by the other relay of the plurality of relays is according to equation: y = [y1,T3 y2,T3 y3,T4 y4,T4]T (Joung [Para. 0072] and [FIG. 1], In each time slot in (2=t=T), the S 102 node transmits fresh STBC symbols denoted with {
x
1
(1),
x
2
(1)} to the nodes D 120 and Ra, where Ra ε{R1, R2}. In the same time slot, the STBC symbols retransmitted by the nodes R1 110 or R2 112 are denoted by {
x
^
R
b
,
1
(t−1),
x
^
R
b
,
2
(t−1)} where Rb ε{R1, R2} such that Ra≠Rb. {
x
^
R
b
,
1
(t−1),
x
^
R
b
,
2
(t−1)} are the symbols estimated at Rb in the previous time slot. R1 110 retransmits the estimates
x
^
R
1
,
1
(t−1) and
x
^
R
1
,
2
(t−1) to the nodes D 120 and R2 112 [Examiner’s Note: Node D receives both transmissions {
x
1
(1),
x
2
(1)} and {
x
^
R
1
,
1
(t−1),
x
^
R
1
,
2
(t−1)}. In this case, node D is similar to a relay node regarding the received signal. Both D and R2 112 are situated similarly to receive the same combined signals {
x
1
(1),
x
2
(1)} and {
x
^
R
1
,
1
(t−1),
x
^
R
1
,
2
(t−1)} where {
x
^
R
1
,
1
(t−1),
x
^
R
1
,
2
(t−1)} is the inter-relay interference for R2 112 from R1 110]. Joung [Para. 0074], At the time slot t, the signal received at the D node, a conventional DSTTD receiver, may thus be interpreted as one DSTTD frame and may be represented as
y
D
(t)=
S
D
(t)x(t) (Equation (8)). Joung [Para. 0076], x(t)=[
x
^
R
1
,
1
(t−1)
x
^
R
1
,
2
(t−1)
x
1
(1)
x
2
(1)]T is a transmitted symbol vector [Examiner’s Note: x(t)=[
x
^
R
1
,
1
(t−1)
x
^
R
1
,
2
(t−1)
x
1
(1)
x
2
(1)]T is also the signal that a relay similarly situated receives]).
For claim 7, Joung, Ko and Legnain teach the method of claim 6. The references further teach wherein the IRI is separated by applying MIMO signal detection to the equation (Joung [Para. 0072] and [FIG. 1], In each time slot in (2=t=T), the S 102 node transmits fresh STBC symbols denoted with {
x
1
(1),
x
2
(1)} to the nodes D 120 and Ra, where Ra ε{R1, R2}. In the same time slot, the STBC symbols retransmitted by the nodes R1 110 or R2 112 are denoted by {
x
^
R
b
,
1
(t−1),
x
^
R
b
,
2
(t−1)} where Rb ε{R1, R2} such that Ra≠Rb. {
x
^
R
b
,
1
(t−1),
x
^
R
b
,
2
(t−1)} are the symbols estimated at Rb in the previous time slot. R1 110 retransmits the estimates
x
^
R
1
,
1
(t−1) and
x
^
R
1
,
2
(t−1) to the nodes D 120 and R2 112 [Examiner’s Note: Node D receives both transmissions {
x
1
(1),
x
2
(1)} and {
x
^
R
1
,
1
(t−1),
x
^
R
1
,
2
(t−1)}. In this case, node D is similar to a relay node regarding the received signal. Both D and R2 112 are situated similarly to receive the same combined signals {
x
1
(1),
x
2
(1)} and {
x
^
R
1
,
1
(t−1),
x
^
R
1
,
2
(t−1)} where {
x
^
R
1
,
1
(t−1),
x
^
R
1
,
2
(t−1)} is the inter-relay interference for R2 112 from R1 110]. Joung [Para. 0074], At the time slot t, the signal received at the D node, a conventional DSTTD receiver, may thus be interpreted as one DSTTD frame and may be represented as
y
D
(t)=
S
D
(t)x(t) (Equation (8)). Joung [Para. 0076], x(t)=[
x
^
R
1
,
1
(t−1)
x
^
R
1
,
2
(t−1)
x
1
(1)
x
2
(1)]T is a transmitted symbol vector. Estimates of x(t) may be obtained from the reordered signal from Equation 8 by using a maximum likelihood (ML). This estimation may be done at the D 120. The estimates obtained are denoted
x
^
t
=[
x
^
R
1
,
D
,
1
(t−1)
x
^
R
1
,
D
,
2
(t−1)
x
^
D
,
1
(t)
x
^
D
,
2
(t)]T, the elements of
x
^
t
respectively being estimates of the corresponding elements from x(t) [Examiner’s Note: D receives the combined signal from a relay and source such that x(t)=[
x
^
R
1
,
1
(t−1)
x
^
R
1
,
2
(t−1)
x
1
(1)
x
2
(1)]T and uses the maximum likelihood (ML) of MIMO detection to obtain the signals as
x
^
D
,
1
(t) and
x
^
D
,
2
(t), the estimate signal from the source]. Joung [Para. 0062], HN 2 N 1 (t) is a 2-by-2 matrix used to denote the MIMO channel from the node N1 to node N2 such that N1 and N2ε{D,R1,R2,S}[Examiner’s Note: The relay channels are MIMO channels, including (S, R1), (S, R2), (R1, D) and (R2, D)]. Joung [Para. 0108-0109], Relay nodes may be located close to each other, in which case the strong interference amongst the relay nodes may deteriorate the relay signals. Inter-relay interference may also be removed by employing DSTTD detection at the relay nodes [Examiner’s Note: The DSTTD detection (MIMO detection for MIMO channels) can be used for inter-relay interference removal at relays]).
Claim 9 is rejected under 35 U.S.C. 103 as being unpatentable over Zhu et al. (WO2021078060A1, hereinafter Zhu) and in view of Joung et al. (US20120294202A1, hereinafter Joung).
For claim 9, Zhu teaches an apparatus for high-speed signal relaying in an MIMO based relay communication system ([Page 3, Summary of the Invention], communication device, and system, so as to be suitable for transmission scenarios that require low transmission delay. [Page 3, second last paragraph before Summary of the Invention], In order to better combat multipath fading, multiple-input multiple-output (MIMO) technology emerged. The core idea of cooperative communication technology is to allow single-antenna mobile users to share each other's antennas in a certain way in a wireless communication environment, thereby communicating in a cooperative and shared manner), a selection unit configured to select a plurality of relays to operate according to a sequential relay transmission scheme in which transmission and reception roles of the plurality of relays are alternated over respective time slots ([Page 29], S1601: Determine the next hop identifier of the current node according to the second routing information. Wherein, S1603 may include the S1601, that is, the relay node may determine the identifier of the next hop according to the second routing information, and then send the third control information indicating the identifier).
Although teaching a relay node including relay selection unit, transmission unit, reception unit and interference removal unit, Zhu does not explicitly disclose the apparatus comprising: a transmission unit transmitting a data signal to the selected plurality of relays according to the sequential relay transmission scheme; a reception unit configured to receive, at at least one relay of the plurality of relays, data signals transmitted during the respective time slots, and a removal unit configured to remove an inter relay interference (IRI) component that is generated as a result of the sequential relay transmission scheme and is included in a received signal at the at least one relay. Joung teaches such limitations.
Joung is directed to providing method of communication. More specifically, Joung teaches the apparatus comprising: a transmission unit transmitting a data signal to the selected plurality of relays according to the sequential relay transmission scheme ([Para. 0055] and [FIG. 1], The transmission uses two-path double space-time transmit diversity (DSTTD) and takes place from a source S 102 to a destination D 120 via relay stations R1 110 and R2 112. [Para. 0056], the transmission pattern of the nodes for two slots t=2 and t=3 are shown in FIG. 1. In t=2, the S 102 and R1 110 function as transmitters while R2 112 and D 120 function as receivers. In t=3, S 102 and R2 112 function as transmitters while R1 110 and D 120 function as receivers [Examiner’s Note: A sender sends signals to the destination through two relays alternately in two time slots]. [Para. 0073], the relay nodes R1 110 and R2 112 alternatively switch between transmitting and receiving modes from one time slot to the next. [Para. 0059], Each node used has two antennae [Examiner’s Note: The two antennas at the sender constitute transmission unit]); a reception unit configured to receive, at at least one relay of the plurality of relays, data signals transmitted during the respective time slots ([Para. 0026], at least two multiple antenna DSTTD relay nodes configured to alternatively decode and forward the STBC coded signals [Examiner’s Note: The antennas in relays constitute receiving unit]. [Para. 0055] and [FIG. 1], The transmission uses two-path double space-time transmit diversity (DSTTD) and takes place from a source S 102 to a destination D 120 via relay stations R1 110 and R2 112. [Para. 0056], the transmission pattern of the nodes for two slots t=2 and t=3 are shown in FIG. 1. In t=2, the S 102 and R1 110 function as transmitters while R2 112 and D 120 function as receivers. In t=3, S 102 and R2 112 function as transmitters while R1 110 and D 120 function as receivers. [Para. 0059], Each node used has two antennae [Examiner’s Note: The two antennas at the sender constitute transmission unit [Examiner’s Note: The two antennas at a relay node constitutes reception unit]); and a removal unit configured to remove an inter relay interference (IRI) component that is generated as a result of the sequential relay transmission scheme and is included in a received signal at the at least one relay ([Para. 0072] and [FIG. 1], In each time slot in (2=t=T), the S 102 node transmits fresh STBC symbols denoted with {
x
1
(1),
x
2
(1)} to the nodes D 120 and Ra, where Ra ε{R1, R2}. In the same time slot, the STBC symbols retransmitted by the nodes R1 110 or R2 112 are denoted by {
x
^
R
b
,
1
(t−1),
x
^
R
b
,
2
(t−1)} where Rb ε{R1, R2} such that Ra≠Rb. {
x
^
R
b
,
1
(t−1),
x
^
R
b
,
2
(t−1)} are the symbols estimated at Rb in the previous time slot. R1 110 retransmits the estimates
x
^
R
1
,
1
(t−1) and
x
^
R
1
,
2
(t−1) to the nodes D 120 and R2 112 [Examiner’s Note: Node D receives both transmissions {
x
1
(1),
x
2
(1)} and {
x
^
R
1
,
1
(t−1),
x
^
R
1
,
2
(t−1)}. In this case, node D is similar to a relay node regarding the received signal. Both D and R2 112 are situated similarly to receive the same combined signals {
x
1
(1),
x
2
(1)} and {
x
^
R
1
,
1
(t−1),
x
^
R
1
,
2
(t−1)} where {
x
^
R
1
,
1
(t−1),
x
^
R
1
,
2
(t−1)} is the inter-relay interference for R2 112 from R1 110]. [Para. 0074], At the time slot t, the signal received at the D node, a conventional DSTTD receiver, may thus be interpreted as one DSTTD frame and may be represented as
y
D
(t)=
S
D
(t)x(t) (Equation (8)). [Para. 0076], x(t)=[
x
^
R
1
,
1
(t−1)
x
^
R
1
,
2
(t−1)
x
1
(1)
x
2
(1)]T is a transmitted symbol vector. Estimates of x(t) may be obtained from the reordered signal from Equation 8 by using a maximum likelihood (ML). This estimation may be done at the D 120. The estimates obtained are denoted
x
^
t
=[
x
^
R
1
,
D
,
1
(t−1)
x
^
R
1
,
D
,
2
(t−1)
x
^
D
,
1
(t)
x
^
D
,
2
(t)]T, the elements of
x
^
t
respectively being estimates of the corresponding elements from x(t) [Examiner’s Note: D receives the combined signal from a relay and source such that x(t)=[
x
^
R
1
,
1
(t−1)
x
^
R
1
,
2
(t−1)
x
1
(1)
x
2
(1)]T and uses the maximum likelihood (ML) of MIMO detection to obtain the signals as
x
^
D
,
1
(t) and
x
^
D
,
2
(t), the estimate signal from the source]. [Para. 0108-0109], Relay nodes may be located close to each other, in which case the strong interference amongst the relay nodes may deteriorate the relay signals. Inter-relay interference may be removed by employing DSTTD detection at the relay nodes [Examiner’s Note: The DSTTD detection can be used for inter-relay interference removal at relays]).
It would have been prima facie obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the apparatus of Zhu, so that the relays receive signals from the sender and the inter-relay interference included in the received signals is removed, as taught by Joung. The modification would have provided multiple transmitters cooperating with low power by reduced co-channel interference (CCI) between the relay nodes (Joung [Para. 0002 and 0003]).
Claim 10 is rejected under 35 U.S.C. 103 as being unpatentable over Zhu et al. (WO2021078060A1, hereinafter Zhu) and in view of Joung et al. (US20120294202A1, hereinafter Joung), and further in view of Ko (KR101489883B1, hereinafter Ko).
For claim 10, Zhu and Joung the apparatus of claim 9. The references further teach and wherein the removal unit is configured to remove the inter relay interference (IRI) by applying multiple-input multiple-output (MIMO) signal detection (Joung [Para. 0072] and [FIG. 1], In each time slot in (2=t=T), the S 102 node transmits fresh STBC symbols denoted with {
x
1
(1),
x
2
(1)} to the nodes D 120 and Ra, where Ra ε{R1, R2}. In the same time slot, the STBC symbols retransmitted by the nodes R1 110 or R2 112 are denoted by {
x
^
R
b
,
1
(t−1),
x
^
R
b
,
2
(t−1)} where Rb ε{R1, R2} such that Ra≠Rb. {
x
^
R
b
,
1
(t−1),
x
^
R
b
,
2
(t−1)} are the symbols estimated at Rb in the previous time slot. R1 110 retransmits the estimates
x
^
R
1
,
1
(t−1) and
x
^
R
1
,
2
(t−1) to the nodes D 120 and R2 112 [Examiner’s Note: Node D receives both transmissions {
x
1
(1),
x
2
(1)} and {
x
^
R
1
,
1
(t−1),
x
^
R
1
,
2
(t−1)}. In this case, node D is similar to a relay node regarding the received signal. Both D and R2 112 are situated similarly to receive the same combined signals {
x
1
(1),
x
2
(1)} and {
x
^
R
1
,
1
(t−1),
x
^
R
1
,
2
(t−1)} where {
x
^
R
1
,
1
(t−1),
x
^
R
1
,
2
(t−1)} is the inter-relay interference for R2 112 from R1 110]. Joung [Para. 0074], At the time slot t, the signal received at the D node, a conventional DSTTD receiver, may thus be interpreted as one DSTTD frame and may be represented as
y
D
(t)=
S
D
(t)x(t) (Equation (8)). [Para. 0076], x(t)=[
x
^
R
1
,
1
(t−1)
x
^
R
1
,
2
(t−1)
x
1
(1)
x
2
(1)]T is a transmitted symbol vector. Estimates of x(t) may be obtained from the reordered signal from Equation 8 by using a maximum likelihood (ML). This estimation may be done at the D 120. The estimates obtained are denoted
x
^
t
=[
x
^
R
1
,
D
,
1
(t−1)
x
^
R
1
,
D
,
2
(t−1)
x
^
D
,
1
(t)
x
^
D
,
2
(t)]T, the elements of
x
^
t
respectively being estimates of the corresponding elements from x(t) [Examiner’s Note: D receives the combined signal from a relay and source such that x(t)=[
x
^
R
1
,
1
(t−1)
x
^
R
1
,
2
(t−1)
x
1
(1)
x
2
(1)]T and uses the maximum likelihood (ML) of MIMO detection to obtain the signals as
x
^
D
,
1
(t) and
x
^
D
,
2
(t), the estimate signal from the source]. Joung [Para. 0062], HN 2 N 1 (t) is a 2-by-2 matrix used to denote the MIMO channel from the node N1 to node N2 such that N1 and N2ε{D,R1,R2,S}[Examiner’s Note: The relay channels are MIMO channels, including (S, R1), (S, R2), (R1, D) and (R2, D)]. Joung [Para. 0108-0109], Relay nodes may be located close to each other, in which case the strong interference amongst the relay nodes may deteriorate the relay signals. Inter-relay interference may be removed by employing DSTTD detection at the relay nodes [Examiner’s Note: The DSTTD detection (MIMO detection for MIMO channels) can be used for inter-relay interference removal at relays]).
It would have been prima facie obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the apparatus of Zhu, so that the inter-relay interference included in the received signals is removed at relays, as taught by Joung. The modification would have provided multiple transmitters cooperating with low power by reduced co-channel interference (CCI) between the relay nodes (Joung [Para. 0002 and 0003]).
Although teaching determination of identifier of next relay, the references do not explicitly disclose wherein the selection unit is configured to select the plurality of relays based on a channel condition.
Ko is directed to providing Apparatus and method for transferring using multi relay. More specifically, Ko teaches wherein the selection unit is configured to select the plurality of relays based on a channel condition (Ko [Para. 0029], the plurality of relay nodes 200 may be divided into a first group relay node 210 and a second group relay node 230. Ko [Para. 0031], the relay node selector 110 included in the plurality of source nodes 100 may select a corresponding relay node, as the first group relay node 210 or the second group relay node 230, a corresponding relay node exceeding a preset channel state threshold value among the channel state estimation values received from the plurality of relay nodes 200. The relay node 210 or the second group relay node 230 may be selected. Ko [Para. 0035], At this time, the relay nodes not selected as the first group relay node 210 become the second group relay node 230 which performs a role of receiving signals from the source nodes 100 again in the next step. [Examiner’s Note: Relay 210 is selected in the first phase to receive data and relay 230 is selected in the second phase to receive data alternately]).
It would have been prima facie obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the apparatus of Zhu and Joung, so that the selector selects relays based on channel state, as taught by Ko. The modification would have avoided reduction in the efficiency of frequency in case of half-duplex relay communication (Ko [Para. 0005]).
Claims 11-16 are rejected under 35 U.S.C. 103 as being unpatentable over Zhu et al. (WO2021078060A1, hereinafter Zhu) in view of Joung et al. (US20120294202A1, hereinafter Joung) and Ko (KR101489883B1, hereinafter Ko), and further in view of Legnain et al. (MIMO two-way relay communication based on Alamouti code, IEEE CCECE 2011, hereinafter Legnain).
For claim 11, Zhu, Joung and Ko teaches the method of claim 10. The references further teach wherein the sender transmits data signals X1 and X2 to one relay of the plurality of relays by using an STBC scheme during time slots T1 and T2 (Joung [Para. 0055] and [FIG. 1], The transmission uses two-path double space-time transmit diversity (DSTTD) and takes place from a source S 102 to a destination D 120 via relay stations R1 110 and R2 112. Joung [Para. 0056], the transmission pattern of the nodes for two slots t=2 and t=3 are shown in FIG. 1. In t=2, the S 102 and R1 110 function as transmitters while R2 112 and D 120 function as receivers. In t=3, S 102 and R2 112 function as transmitters while R1 110 and D 120 function as receivers [Examiner’s Note: A sender sends signals to the destination through two relays alternately in two time slots]).
Although teaching transmitting one signal to one relay in one time slot, Zhu, Joung and Ko do not explicitly disclose wherein the sender transmits data signals X1 and X2 to one relay of the plurality of relays by using an STBC scheme during time slots T1 and T2.
Legnain is directed to providing MIMO two-way relay communication based on Alamouti code. More specifically, Legnain teaches wherein the sender transmits data signals X1 and X2 to one relay of the plurality of relays by using an STBC scheme during time slots T1 and T2 ([Page 000471, Left Col. Third Para.] and [FIG. 1], The communications take place over four time slots. In the first two time slots, nodes A and B transmit their signals to the RN (this stage is called the multiple access stage), and in the third and fourth time slots, the RN relays the received signals to nodes A and B. In multiple access stage, the two nodes, A and B, employ Space-Time Alamouti code to transmit their signals simultaneously in first and second time slots. [Page 000471, Right Col. First Para.], At RN, we assume MR = 2 (two antennas), the received signals during the first and second time slots are given by (1) and (2), where … sj;A and sj;B are the transmitted symbols, from the jth antenna, from node A and B, respectively. [Examiner’s Note: Either Node A or node B can be the sender that sends signals in time slots T1 and T2. For example, in Legnain, s1,A and s2,A (sj,A where j = 1, 2) are the signals from the antennas 1 and 2 of node A sent in the first time slot, and the conjugates of s1,A and s2,A are sent in the second time slot in Space-Time Alamouti code. Legnain teaches transmission of two signals simultaneously and their conjugates simultaneously to one relay in two time slots.).
It would have been prima facie obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the apparatus of Zhu, Joung and Ko, so that the source transmits two signals simultaneously to one relay in two time slots, as taught by Legnain. The modification would have improved the bit error rate (BER) performance as number of antennas at relay increased (Legnain [Page 000473, Sect. 4 Conclusion]).
For claim 12, Zhu, Joung, Ko and Legnain teach the method of claim 11. The references further teach wherein the sender transmits data signals X3 and X4 to the other one relay of the plurality of relays by using the STBC scheme during time slots T3 and T4 (Joung [Para. 0055] and [FIG. 1], The transmission uses two-path double space-time transmit diversity (DSTTD) and takes place from a source S 102 to a destination D 120 via relay stations R1 110 and R2 112. Joung [Para. 0056], the transmission pattern of the nodes for two slots t=2 and t=3 In t=2, the S 102 and R1 110 function as transmitters while R2 112 functions as receiver. In t=3, S 102 and R2 112 function as transmitters while R1 110 functions as receiver. [Examiner’s Note: A signal is transmitted in two phases]. Legnain [Page 000471, Left Col. Third Para.] and [FIG. 1], The communications take place over four time slots. In the first two time slots, nodes A and B transmit their signals to the RN (this stage is called the multiple access stage), and in the third and fourth time slots, the RN relays the received signals to nodes A and B. In multiple access stage, the two nodes, A and B, employ Space-Time Alamouti code to transmit their signals simultaneously in first and second time slots [Examiner’s Note: Joung teaches transmission of two signals alternately in two phase. Legnain teaches transmission of two signal simultaneously in two time slots. It is obvious to combine Joung and Legnain so that each phase in Joung includes two time slots to transmit two signals simultaneously in one phase and four signals are transmitted alternately in two phases. X3 and its conjugate, and X4 and its conjugate may be transmitted to relay R2 112 in two time slots, in the second phase by combination of Legnain and Joung]).
It would have been prima facie obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the apparatus of Zhu, Joung and Ko, so that the source transmits two signals simultaneously to one relay in two time slots, as taught by Legnain. The modification would have improved the bit error rate (BER) performance as number of antennas at relay increased (Legnain [Page 000473, Sect. 4 Conclusion]).
For claim 13, Zhu, Joung, Ko and Legnain teach the method of claim 12. The references further teach wherein demodulation signals x1 and x2 are transmitted from one relay of the plurality of relays to a receiver by using the STBC scheme during the time slots T3 and T4 (Legnain [Page 000471, Left Col. Third Para.] and [FIG. 1], The communications take place over four time slots. In the first two time slots, nodes A and B transmit their signals to the RN (this stage is called the multiple access stage), and in the third and fourth time slots, the RN relays the received signals to nodes A and B. In multiple access stage, the two nodes, A and B, employ Space-Time Alamouti code (STBC) to transmit their signals simultaneously in first and second time slots. Legnain [Page 000471, Right Col. First Para.], At RN, the received signals during the first and second time slots are given by yR in equation (3). Legnain [Page 000471, Right Col. Last Para.], The signals sA and sB can be estimated ... [Examiner’s Note: Signals sA and sB are the signals received at the relay after interference cancellation estimation during the first two time slots]. Legnain [Page 000471, Left Col. Third Para.], The RN receives both signals from nodes A and B simultaneously. In the broadcast stage, after estimating and demodulating both signals, RN then retransmits the XORed modulated signal in third and fourth time slots. Legnain [Page 000472, Right Col. First Para.], Upon estimating sA and sB at the RN, they are demodulated to obtain the estimated bits information for them. Legnain [Page 000472, Right Col. Second Para.], The information bits are modulated and transmitted using Alamouti code to the two nodes, A and B. The received signals are then rearranged at both nodes, and they are given by yA and yB in (11) and (12) [Examiner’s Note: yA and yB in Legnain are x1 and x2. They correspond to sA and sB after demodulated at the relay node and are relayed to receivers A and B respectively]).
It would have been prima facie obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the apparatus of Zhu, Joung and Ko, so that the demodulation signals and their conjugates are transmitted from the relay to a receiver in two time slots, as taught by Legnain. The modification would have improved the bit error rate (BER) performance as number of antennas at relay increased (Legnain [Page 000473, Sect. 4 Conclusion]).
For claim 14, Zhu, Joung, Ko and Legnain teach the method of claim 13. The references further teach wherein the demodulation signals x1 and x2 are transmitted to the other relay of the plurality of relays to cause the IRI (Joung [Para. 0055] and [FIG. 1], The transmission uses two-path double space-time transmit diversity (DSTTD) and takes place from a source S 102 to a destination D 120 via relay stations R1 110 and R2 112. Joung [Para. 0056], the transmission pattern of the nodes for two slots t=2 and t=3 In t=2, the S 102 and R1 110 function as transmitters while R2 112 functions as receiver. In t=3, S 102 and R2 112 function as transmitters while R1 110 functions as receiver. [Examiner’s Note: A signal is transmitted in two phases]. Legnain [Page 000471, Left Col. Third Para.] and [FIG. 1], The communications take place over four time slots. In the first two time slots, nodes A and B transmit their signals to the RN (this stage is called the multiple access stage), and in the third and fourth time slots, the RN relays the received signals to nodes A and B. In multiple access stage, the two nodes, A and B, employ Space-Time Alamouti code to transmit their signals simultaneously in first and second time slots. The RN receives both signals from nodes A and B simultaneously. In the broadcast stage, after estimating and demodulating both signals, RN then retransmits the XORed modulated signal in third and fourth time slots [Examiner’s Note: Joung teaches transmission of two signals alternately in two phase. Legnain teaches transmission of two signal simultaneously in two time slots. It is obvious to combine Joung and Legnain so that each phase in Joung includes two time slots to transmit two signals simultaneously in one phase and four signals are transmitted alternately in two phases. In combination of Legnain and Joung, in the second phase, relay node R1 110 transmits x1 and x2 to the destination, while relay node R2 112 receives X3 and X4 from the source. Demodulation signals x1 and x2 are also received by relay node R2 112, causing inter relay interference]).
It would have been prima facie obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the apparatus of Zhu, Joung and Ko, so that two demodulation signals are transmitted simultaneously in two time slots in one phase, as taught by Legnain. The modification would have improved the bit error rate (BER) performance as number of antennas at relay increased (Legnain [Page 000473, Sect. 4 Conclusion]).
For claim 15, Zhu, Joung, Ko and Legnain teach the method of claim 14. The references further teach wherein the data signal received by the other relay of the plurality of relays is according to equation: y = [y1,T3 y2,T3 y3,T4 y4,T4]T (Joung [Para. 0072] and [FIG. 1], In each time slot in (2=t=T), the S 102 node transmits fresh STBC symbols denoted with {
x
1
(1),
x
2
(1)} to the nodes D 120 and Ra, where Ra ε{R1, R2}. In the same time slot, the STBC symbols retransmitted by the nodes R1 110 or R2 112 are denoted by {
x
^
R
b
,
1
(t−1),
x
^
R
b
,
2
(t−1)} where Rb ε{R1, R2} such that Ra≠Rb. {
x
^
R
b
,
1
(t−1),
x
^
R
b
,
2
(t−1)} are the symbols estimated at Rb in the previous time slot. R1 110 retransmits the estimates
x
^
R
1
,
1
(t−1) and
x
^
R
1
,
2
(t−1) to the nodes D 120 and R2 112 [Examiner’s Note: Node D receives both transmissions {
x
1
(1),
x
2
(1)} and {
x
^
R
1
,
1
(t−1),
x
^
R
1
,
2
(t−1)}. In this case, node D is similar to a relay node regarding the received signal. Both D and R2 112 are situated similarly to receive the same combined signals {
x
1
(1),
x
2
(1)} and {
x
^
R
1
,
1
(t−1),
x
^
R
1
,
2
(t−1)} where {
x
^
R
1
,
1
(t−1),
x
^
R
1
,
2
(t−1)} is the inter-relay interference for R2 112 from R1 110]. Joung [Para. 0074], At the time slot t, the signal received at the D node, a conventional DSTTD receiver, may thus be interpreted as one DSTTD frame and may be represented as
y
D
(t)=
S
D
(t)x(t) (Equation (8)). Joung [Para. 0076], x(t)=[
x
^
R
1
,
1
(t−1)
x
^
R
1
,
2
(t−1)
x
1
(1)
x
2
(1)]T is a transmitted symbol vector [Examiner’s Note: x(t)=[
x
^
R
1
,
1
(t−1)
x
^
R
1
,
2
(t−1)
x
1
(1)
x
2
(1)]T is also the signal that a relay similarly situated receives]).
It would have been prima facie obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the apparatus of Zhu, Ko and Legnain, so that the inter-relay interference is included in the signal received at the other relay, as taught by Joung. The modification would have provided multiple transmitters cooperating with low power by reduced co-channel interference (CCI) between the relay nodes (Joung [Para. 0002 and 0003]).
For claim 16, Zhu, Joung, Ko and Legnain teach the method of claim 15. The references further teach wherein the IRI is separated by applying MIMO signal detection to the equation (Joung [Para. 0072] and [FIG. 1], In each time slot in (2=t=T), the S 102 node transmits fresh STBC symbols denoted with {
x
1
(1),
x
2
(1)} to the nodes D 120 and Ra, where Ra ε{R1, R2}. In the same time slot, the STBC symbols retransmitted by the nodes R1 110 or R2 112 are denoted by {
x
^
R
b
,
1
(t−1),
x
^
R
b
,
2
(t−1)} where Rb ε{R1, R2} such that Ra≠Rb. {
x
^
R
b
,
1
(t−1),
x
^
R
b
,
2
(t−1)} are the symbols estimated at Rb in the previous time slot. R1 110 retransmits the estimates
x
^
R
1
,
1
(t−1) and
x
^
R
1
,
2
(t−1) to the nodes D 120 and R2 112 [Examiner’s Note: Node D receives both transmissions {
x
1
(1),
x
2
(1)} and {
x
^
R
1
,
1
(t−1),
x
^
R
1
,
2
(t−1)}. In this case, node D is similar to a relay node regarding the received signal. Both D and R2 112 are situated similarly to receive the same combined signals {
x
1
(1),
x
2
(1)} and {
x
^
R
1
,
1
(t−1),
x
^
R
1
,
2
(t−1)} where {
x
^
R
1
,
1
(t−1),
x
^
R
1
,
2
(t−1)} is the inter-relay interference for R2 112 from R1 110]. Joung [Para. 0074], At the time slot t, the signal received at the D node, a conventional DSTTD receiver, may thus be interpreted as one DSTTD frame and may be represented as
y
D
(t)=
S
D
(t)x(t) (Equation (8)). Joung [Para. 0076], x(t)=[
x
^
R
1
,
1
(t−1)
x
^
R
1
,
2
(t−1)
x
1
(1)
x
2
(1)]T is a transmitted symbol vector. Estimates of x(t) may be obtained from the reordered signal from Equation 8 by using a maximum likelihood (ML). This estimation may be done at the D 120. The estimates obtained are denoted
x
^
t
=[
x
^
R
1
,
D
,
1
(t−1)
x
^
R
1
,
D
,
2
(t−1)
x
^
D
,
1
(t)
x
^
D
,
2
(t)]T, the elements of
x
^
t
respectively being estimates of the corresponding elements from x(t) [Examiner’s Note: D receives the combined signal from a relay and source such that x(t)=[
x
^
R
1
,
1
(t−1)
x
^
R
1
,
2
(t−1)
x
1
(1)
x
2
(1)]T and uses the maximum likelihood (ML) of MIMO detection to obtain the signals as
x
^
D
,
1
(t) and
x
^
D
,
2
(t), the estimate signal from the source]. Joung [Para. 0062], HN 2 N 1 (t) is a 2-by-2 matrix used to denote the MIMO channel from the node N1 to node N2 such that N1 and N2ε{D,R1,R2,S} [Examiner’s Note: The relay channels are MIMO channels, including (S, R1), (S, R2), (R1, D) and (R2, D)]. Joung [Para. 0108-0109], Relay nodes may be located close to each other, in which case the strong interference amongst the relay nodes may deteriorate the relay signals. Inter-relay interference may also be removed by employing DSTTD detection at the relay nodes [Examiner’s Note: The DSTTD detection (MIMO detection for MIMO channels) can be used for inter-relay interference removal at relays]).
It would have been prima facie obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the apparatus of Zhu, Ko and Legnain, so that the inter-relay interference is separated from the data by applying MIMO detection, as taught by Joung. The modification would have provided multiple transmitters cooperating with low power by reduced co-channel interference (CCI) between the relay nodes (Joung [Para. 0002 and 0003]).
Conclusion
Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
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/S.L./Examiner, Art Unit 2417
/REBECCA E SONG/Supervisory Patent Examiner, Art Unit 2417