Joint Transmit and Receive Procedure

A method, in a user equipment (UE), for a joint transmit and receive procedure with a radio base station (RBS), the method comprising:

• receiving a first transmission from the RBS at a time slot n, the transmission comprising a first pre-coded symbol;
• estimating a real channel and an effective channel, the real channel referring to a transfer function of the channel estimated by the UE by means of reference signals, the effective channel referring to the real channel adjusted by transmission weights for the received first transmission;
• determining a combining vector based on the effective channel;
• determining a feedback vector based on the combining vector and the real channel;
• transmitting the feedback vector to the RBS, to be used by the RBS for determining a Signal-to-Leakage-and-Noise-Ratio (SLNR) pre-coding vector for a second transmission to the UE in a subsequent time slot.

A method, in a radio base station (RBS), for a joint transmit and receive procedure with K numbers of user equipments (UEs), where K≧1, the method comprising:

• transmitting a first respective transmission to the K UEs at a time slot n−1, each transmission comprising an individual first pre-coded symbol;
• receiving individual feedback vectors, at time slot n, from at least a part of the UEs having determined their respective feedback vectors based on the respective first transmission;
• determining individual Signal-to-Leakage-and-Noise-Ratio (SLNR) pre-coding vectors for the UEs based on the received feedback vectors;
• pre-coding, for respective UEs, a second individual symbol using the respective individual determined SLNR pre-coding vector;
• transmitting, at time slot n+1, the respective pre-coded second symbol in a second transmission to the UEs.

A user equipment (UE) adapted for a joint transmit and receive procedure with a radio base station (RBS), the UE comprising:

• one or more processing circuits configured to function as:
• a receiving circuit configured to receive a first transmission from the RBS at a time slot n, the transmission comprising a first pre-coded symbol;
• an estimating circuit configured to estimate a real channel and an effective channel, the real channel referring to a transfer function of the channel estimated by the UE by means of reference signals, the effective channel referring to the real channel adjusted by transmission weights for the received first transmission;
• a determining circuit configured to determine a combining vector based on the effective channel, and to determine a feedback vector based on the combining vector and the real channel;
• a transmitting circuit configured to transmit the feedback vector to the RBS, to be used by the RBS for determining a Signal-to-Leakage-and-Noise-Ratio (SLNR) pre-coding vector for a second transmission to the UE in a subsequent time slot.

A radio base station (RBS) adapted for a joint transmit and receive procedure with K numbers of user equipments (UEs), where K≧1, the RBS comprising:

• one or more processing circuits configured to function as:
• a transmitting circuit configured to transmit, a first respective transmission to the K UEs at a time slot n−1, each transmission comprising an individual first pre-coded symbol;
• a receiving circuit configured to receive individual feedback vectors from at least a part of the UEs having determined their respective feedback vectors based on the respective first transmission;
• a determining circuit configured to determine individual Signal-to-Leakage-and-Noise-Ratio (SLNR) pre-coding vectors for the UEs based on the received feedback vectors;
• a pre-coding circuit configured to pre-code, for respective UEs, a second individual symbol using the respective individual determined SLNR pre-coding vector;
• wherein the transmitting circuit further is configured to transmit the respective pre-coded second symbol in a second transmission to the UEs at time slot n+1.