Base station, signal synthesis method, and signal forwarding method

• US 10,194,449 B2
• Filed: 12/24/2015
• Issued: 01/29/2019
• Est. Priority Date: 01/13/2015
• Status: Active Grant

• Current Assignee: Panasonic Intellectual Property Management Co., Ltd. (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Intellectual Property Management Co., Ltd. (Panasonic Holdings Corporation)
• Inventors: Ku, Richol, Seki, Yuta, Nakao, Seigo
• Primary Examiner(s): Moutaouakil, Mounir
• Application Number:
  US15/503,178
• Publication Number:
  US 20170238327A1
• Time in Patent Office: 1,132 Days
• CPC Class Codes: H04B 7/024 Co-operative use of antennas of several sites, e.g. in co-ordinated multipoint or co-operative multiple-input multiple-output [MIMO] systems
• CPC Class Codes: H04B 7/026 Co-operative diversity, e.g. using fixed or mobile stations as relays
• CPC Class Codes: H04B 7/0885 with combination
• CPC Class Codes: H04L 1/0045 Arrangements at the receiver end
• CPC Class Codes: H04L 1/06 using space diversity
• CPC Class Codes: H04L 1/08 by repeating transmission, e.g. Verdan system H04L1/1858 and H04L1/189 take precedence
• CPC Class Codes: H04L 1/1829 Arrangements specially adapted for the receiver end
• CPC Class Codes: H04L 1/1845 Combining techniques, e.g. code combining
• CPC Class Codes: H04L 2001/0093 Point-to-multipoint
• CPC Class Codes: H04L 2001/0097 Relays
• CPC Class Codes: H04L 5/0035 Resource allocation in a cooperative multipoint environment
• CPC Class Codes: H04W 16/28 using beam steering
• CPC Class Codes: H04W 28/04 Error control
• CPC Class Codes: H04W 72/0446 Resources in time domain, e.g. slots or frames
• CPC Class Codes: H04W 72/21 in the uplink direction of a wireless link, i.e. towards the network
• CPC Class Codes: H04W 72/541 using the level of interference
• CPC Class Codes: H04W 88/08 Access point devices

Abstract

A base station receives signals transmitted from one terminal in cooperation with another base station and performs synthesis processing of the received signals of the other base station and the received signals of the local base station. In the base station, a determination circuit determines necessity of synthesis processing using the received signals of the local base station at the time of the first transmission of the terminal. A base station-to-base station communication circuit transmits a message requesting forwarding of the received signals to the other base station in a case where the synthesis processing is determined to be necessary and receives the forwarded signals that are forwarded from the other base station at the time of retransmission of the terminal. A synthesis circuit synthesizes the forwarded signals from the other base station and the received signals of the local base station in a case where the synthesis processing is determined to be necessary.

Claims

1. A first base station that receives signals transmitted from one terminal in cooperation with a second base station and performs synthesis processing of the received signals of the second base station and the received signals of the first base station, the first base station comprising:

a determination circuit that determines that the synthesis processing is necessary in a case where there is an error in a result of decoding of the received signals of the first base station at the time of the first transmission of the terminal;

a communication circuit that transmits to the terminal a Negative Acknowledgement (NACK) indicating that there is the error in the result of decoding, and transmits to the second base station a message requesting forwarding of the received signals in a case where the synthesis processing is determined to be necessary, and receives the forwarded signals that are forwarded from the second base station at the time of retransmission of the terminal; and

a synthesis circuit that synthesizes the forwarded signals from the second base station and the received signals of the first base station in a case where the synthesis processing is determined to be necessary,

wherein the forwarded signals are obtained by synthesizing signals that have been received at the second base station from the first transmission until the current retransmission.

2. The base station of claim 1, wherein the forwarded signal is a logarithm likelihood ratio that is calculated from the signal received at the second base station.

3. A base station that receives signals transmitted from one terminal in cooperation with a plurality of base stations and forwards the received signals of the base station to a synthesizing base station that performs synthesis processing of the received signals among the plurality of base stations, the base station comprising:

a demodulation circuit that demodulates the signals transmitted from the terminal; and

a communication circuit that forwards the demodulated signals to the synthesizing base station in a case where a message requesting forwarding of the received signals is received from the synthesizing base station,

wherein the message requesting forwarding of the received signals is transmitted from the synthesizing base station in a case where there is an error in a result of decoding of the received signals of the synthesizing base station at the time of the first transmission of the terminal, and

wherein the communication circuit forwards signals obtained by synthesizing signals that have been received at the base station from the first transmission until the current retransmission.

4. A signal synthesis method of a first base station that receives signals transmitted from one terminal in cooperation with the first base station and a second base station, and performs synthesis processing of the received signals of the second base station and the received signals of the first base station, the method comprising:

determining that the synthesis processing is necessary in a case where there is an error in a result of decoding of the received signals of the first base station at the time of the first transmission of the terminal;

transmitting to the terminal a NACK indicating that there is the error in the result of decoding, transmitting a message requesting forwarding of the received signals to the second base station in a case where the synthesis processing is determined to be necessary, and receiving the forwarded signals that are forwarded from the second base station at the time of retransmission; and

synthesizing the forwarded signals from the second base station and the received signals of the first base station in a case where the synthesis processing is determined to be necessary,

wherein the forwarded signals are obtained by synthesizing signals that have been received at the second base station from the first transmission until the current retransmission.

5. A signal forwarding method of a base station that receives signals transmitted from one terminal in cooperation with a plurality of base stations, and forwards the received signals of the base station to a synthesizing base station that performs synthesis processing of the received signals among the plurality of base stations, the method comprising:

demodulating the signals transmitted from the terminal; and

forwarding the demodulated signals to the synthesizing base station in a case where a message requesting forwarding of the received signals is received from the synthesizing base station,

wherein the message requesting forwarding of the received signals is transmitted from the synthesizing base station in a case where there is an error in a result of decoding of the received signals of the synthesizing base station at the time of the first transmission of the terminal, and

in the forwarding, signals obtained by synthesizing signals that have been received at the base station from the first transmission until the current retransmission are forwarded.