Abstract: A radio communication system comprises a communication channel between a transmitter (106) comprising a plurality of antennas (108) and a receiver (112) comprising at least one antenna. The communication channel is wideband and comprises a plurality of paths, and the transmitter comprises means for splitting data for transmission into a plurality of sub-streams. The receiver comprises fewer antennas than the number of transmitted sub-streams and sampling means for determining at least as many substantially uncorrelated received signal samples as the number of sub-streams. In one embodiment, transmissions on the channel employ code division techniques and the sampling means comprises a Rake receiver. In another embodiment a maximum likelihood technique is used to generate sufficient samples. By means of the present invention a receiver for use in a Multiple Input Multiple Output (MIMO) communication system may comprise fewer antennas than the number of sub-streams, thereby enabling smaller terminals.

Abstract: A radio communication system has a communication channel with many paths between two terminals having many antennas. One of the terminals has a receiver and a transmitter, where the receiver is configured to determine the directions from which the strongest signals arrive from the other terminal, corresponding to particular paths. The transmitter separates a signal for transmission into sub-streams and transmits each sub-stream in the respective directions determined by the receiver.

Abstract: A method of selecting a combination of transmit antennas (TA1 to TA4) and receive antennas (RA1 to RA4) in a MIMO antenna system to give the best isolation from adjacent parallel signal streams comprises transmitting a first signal from one of the transmit antennas and measuring a quality metric, for example signal strength of the received signal at each of the receive antennas. The process is repeated using signals transmitted in turn by each the remaining transmit antennas. A channel matrix is compiled of the transmit antennas versus the receive antennas and a selection is made of a combination of transmit and receive antennas receiving acceptably a first signal and unacceptably a second signal and vice versa. The selected combination is used to send and receive MIMO signals. Switches (SW1, SW2) are provided for coupling the selected antennas to the respective transmitters (TX1, TX2) and receivers (RX1, RX2).

Abstract: A method of selecting a combination of transmit antennas (TA1 to TA4) and receive antennas (RA1 to RA4) in a MIMO antenna system to give the best isolation from adjacent parallel signal streams comprises transmitting a first signal from one of the transmit antennas and measuring a quality metric, for example signal strength, of the received signal at each of the receive antennas. The process is repeated using signals transmitted in turn by each the remaining transmit antennas. A channel matrix is compiled of the transmit antennas versus the receive antennas and a selection is made of a combination of transmit and receive antennas receiving acceptably a first signal and unacceptably a second signal and vice versa. The selected combination is used to send and receive MIMO signals.

Abstract: A radio communication system comprises a communication channel between a transmitter (106) comprising a plurality of antennas (108) and a receiver (112) comprising at least one antenna. The communication channel is wideband and comprises a plurality of paths, and the transmitter comprises means for splitting data for transmission into a plurality of sub-streams. The receiver comprises fewer antennas than the number of transmitted sub-streams and sampling means for determining at least as many substantially uncorrelated received signal samples as the number of sub-streams.

Abstract: A radio communication system comprises a communication channel between two terminals each comprising a plurality of antennas (108). The communication channel comprises a plurality of paths, and at least one of the terminals comprises a receiver having means (306, 308) for determining the directions from which the strongest signals are received, corresponding to paths between the terminals. The terminal may also include a transmitter having means (302) for separating a signal into a plurality of parts, each having a reduced bit rate, and transmitting the parts in respective directions corresponding to those from which the strongest signals are received.