WIRELESS COMMUNICATION METHOD IN MULTIANTENNA COMMUNICATION SYSTEM
A wireless communication method in which use of the HERQ technique brings about an improved throughput of data transmission. In this method, if the number of retransmissions n is equal or below an upper limit value (ST 404 : NO), a transmission mode k is computed for k=n mod 4 at the transmission side (ST 405 ), sub-streams are grouped into combinations of sub-streams according to the channel status fed back from the transmission side if k=1 (ST 407 ), time-space block coding of the data of each group is performed (ST 408 ), the coded data is allocated to the corresponding antenna and retransmitted (ST 409 ), and the retransmitted data is combined with the previously transmitted data and time-space block decoding is performed (ST 410 ).
1 . A radio communication method comprising:
on a transmitting side of a multi-antenna communication system:
grouping a plurality of antennas into a plurality of groups according to a retransmission request from a receiving side based on a channel condition;
carrying out space-time encoding on data for each of the plurality of groups; and
retransmitting the encoded data through the plurality of antennas to the receiving side.
2 . The radio communication method according to claim 1 , wherein antennas having a maximum signal-to-noise ratio are combined with antennas having a minimum signal-to-noise ratio in the grouping.
3 . The radio communication method according to claim 1 , wherein an order of data is changed according to another retransmission request from the receiving side based on a channel condition.
4 . The radio communication method according to claim 3 , wherein an order of data is changed by assigning data having a minimum signal-to-noise ratio to an antenna having a maximum signal-to-noise ratio.
5 . The radio communication method according to claim 1 , wherein a number of retransmissions is limited to a preset maximum number.
6 . The radio communication method according to claim 1 , wherein a number of antennas of each group is determined according to a space-time encoding scheme in the grouping.
7 . The radio communication method according to claim 1 , wherein the space-time encoding is space-time block encoding or space-time trellis encoding.
8 . The radio communication method according to claim 1 , wherein the receiving side carries out space-time decoding using initial transmission data and retransmission data.
9 . The radio communication method according to claim 8 , wherein the receiving side combines a plurality of space-time decoding results.
10 . A radio communication apparatus in a multi-antenna communication system, the apparatus comprising:
a grouping section that groups a plurality of antennas into a plurality of groups according to a retransmission request based on a channel condition;
a encoding section that carries out space-time encoding on data for each of the plurality of groups; and
a modulation section that modulates the encoded data and retransmits the encoded data to the receiving side through the plurality of antennas.