Retransmission method, transmitter, and communication system

Abstract

An automatic retransmission request control system in an OFDM-MIMO communication system includes a retransmission mode selection part which selects a retransmission mode from among (a) a mode in which to transmit the data, which are to be retransmitted, via the same antenna as in the previous transmission, while transmitting, at the same time, new data by use of an antenna via which no data retransmission is requested; (b) a mode in which to transmit the data, which are to be retransmitted, via an antenna via which no retransmission is requested, while transmitting new data via another antenna at the same time; (c) a mode in which to use STBC to retransmit the data via an antenna via which no retransmission is requested; and (d) a mode in which to use STBC to retransmit the data via all the available antennas.

1 . A retransmission method at a transmitter for communication with a receiver based on an automatic repeat request (ARQ) in a multiple-input multiple-output (MIMO) system using orthogonal frequency division multiplexing (OFDM), the method comprising:
 a reception step of receiving feedback information on an acknowledgment (ACK) or a negative acknowledgement (NACK) based on a result of a cyclic redundancy check of data at the receiver; and   a retransmission mode selection step of selecting a retransmission mode for the data according to the feedback information from among a first mode of transmitting data using an antenna and simultaneously transmitting other data using another antenna and a second mode of transmitting same data with a spatial diversity technique using a plurality of streams.   
     
     
         2 . A transmitter for communicating with a receiver with an automatic repeat request (ARQ) control in a multiple-input multiple-output (MIMO) system using orthogonal frequency division multiplexing (OFDM), the transmitter comprising:
 a reception section that receives feedback information on an acknowledgment (ACK) or a negative acknowledgement (NACK) based on a result of a cyclic redundancy check of data at the receiver; and   a retransmission mode selection section that selects a retransmission mode for the data according to the feedback information from among a first mode of transmitting data using an antenna and simultaneously transmitting another data using another antenna and a second mode of transmitting same data with a spatial diversity technique using a plurality of streams.   
     
     
         3 . The transmitter according to  claim 2 , further comprising an adaptive modulation and coding section that performs a link adaptation based on the feedback information. 
     
     
         4 . The transmitter according to  claim 3 , wherein the link adaptation is performed using an adaptive modulation and coding scheme. 
     
     
         5 . The transmitter according to  claim 3 , wherein the link adaptation is performed according to the number of retransmission of the data. 
     
     
         6 . The transmitter according to  claim 2 , wherein the spatial diversity technique is a space-time block coding (STBC) technique. 
     
     
         7 . The transmitter according to  claim 2 , wherein the antenna used in the transmitting of data using an antenna is an antenna used at a previous transmission in the first mode. 
     
     
         8 . The transmitter according to  claim 2 , wherein the other data is a new data not transmitted at a previous transmission and the another antenna is an antenna not subjected to a request for retransmission of the data in the first mode. 
     
     
         9 . The transmitter according to  claim 2  wherein the data is retransmitted using a higher order of modulation than an order of modulation used at a previous transmission of the data. 
     
     
         10 . The transmitter according to  claim 2 , wherein the data is retransmitted using another interleaving pattern different from an interleaving pattern used at previous transmission of the data 
     
     
         11 . A communication system for employing orthogonal frequency division multiplexing (OFDM) with an automatic repeat request (ARQ) control in a multiple-input multiple-output (MIMO) system, the communication system comprising:
 a receiver and a transmitter,   the receiver comprising:   a CRC processing section that executes a cyclic redundancy check (CRC) for data received from the transmitter; and   an ACK/NACK output section that generates feedback information on an acknowledgement (ACK) or a negative acknowledgment (NACK) based on a result of the cyclic redundancy check, to send to the transmitter, and   the transmitter comprising:   a reception section that receives feedback information on the ACK or the NACK from the receiver; and   a retransmission mode selection section that selects a retransmission mode for the data according to the feedback information from among a first mode of transmitting data using an antenna and simultaneously transmitting other data using another antenna and a second mode of transmitting same data with a spatial diversity technique using a plurality of streams.   
     
     
         12 . A retransmission method based on an automatic repeat request (ARQ) in a multiple-input multiple-output (MIMO) communication system using orthogonal frequency division multiplexing (OFDM), the method being performed by a transmitter having a plurality of antennas and comprising:
 receiving feedback information of acknowledgment (ACK) or negative acknowledgement (NACK) to a data signal based on a result of cyclic redundancy check (CRC) of the data signal at a receiver; and   selecting a retransmission mode for the data signal based on the feedback information,   
       wherein selecting the retransmission mode includes selecting the retransmission mode for the data signal from a plurality of modes that include a mode of transmitting data signal using an antenna of said plurality of antennas and simultaneously transmitting another data signal using another antenna of said plurality of antennas, and a mode of transmitting same data signal with a spatial diversity technique using a plurality of streams. 
     
     
         13 . A transmitter having a plurality of antennas in a multiple-input multiple-output (MIMO) communication system using orthogonal frequency division multiplexing (OFDM), the transmitter comprising:
 a receiving section configured to receive feedback information of acknowledgment (ACK) or negative acknowledgement (NACK) to a data signal based on a result of cyclic redundancy check (CRC) of the data signal at a receiver; and   a retransmission mode selecting section configured to select a retransmission mode for the data signal based on the feedback information,   wherein the retransmission mode selecting section is configured to select the retransmission mode for the data signal from a plurality of modes that include a mode of transmitting data signal using an antenna of said plurality of antennas and simultaneously transmitting another data signal using another antenna of said plurality of antennas, and a mode of transmitting same data signal with a spatial diversity technique using a plurality of streams.