Smart antenna CDMA wireless communication system

A TDD antenna array S-CDMA communications method for communicating message data between a base station and a plurality of terminals, comprising

• receiving, using multichannel receivers, combinations of uplink S-CDMA signals during an uplink frame at said base station;
• despreading, using terminals' PN code sequences, to obtain despread multichannel results for each of said terminals;
• estimating a spatial signature associated with each of said terminals from said despread multichannel results, thereby producing spatial signature estimates for each of said terminals,
• generating receive and transmit beamforming vectors or matrices based on said terminals' spatial signature estimates;
• uplink beamforming said despread multichannel results using said receive beamforming vectors or matrices to obtain enhanced signals for each of said terminals;
• demodulating said enhanced signals to recover message data from each of said terminals;
• modulating message data to obtain S-CDMA signals for each of said terminals;
• downlink beamforming said S-CDMA signals using said transmit beamforming matrices to obtain beamformed S-CDMA signals for each of said terminals;
• combining all of said beamformed S-CDMA signals to obtain downlink multichannel S-CDMA signals;
• transmitting, in a downlink frame following said uplink frame, said combinations of downlink S-CDMA signals.

A time division duplex (TDD) antenna array synchronous code division multiple access (S-CDMA) communications system for communicating message data to/from a plurality of terminals, comprising:

• a multichannel transceiver array comprising a plurality of antennas and a plurality of transceivers, wherein said multichannel transceiver array is adapted for receiving combinations of multichannel uplink S-CDMA signals from said terminals and transmitting multichannel downlink S-CDMA signals towards said terminals, wherein said multichannel transceiver array is adapted for receiving said combinations of multichannel uplink S-CDMA signals from said terminals during a first time frame and is adapted for transmitting multichannel downlink S-CDMA signals towards said terminals during a second time frame in a time division duplex manner;
• spatial signature estimation means coupled to said multichannel transceiver array for determining spatial signature estimates associated with said terminals from said combinations of multichannel uplink S-CDMA signals, wherein said spatial signature estimation means is also operable to calculate uplink and downlink beamforming matrices based on the spatial signature estimates;
• demodulator means coupled to said spatial signature estimation means and said
• multichannel transceiver array for determining estimates of uplink messages from said terminals from said combinations of multichannel uplink S-CDMA signals, and modulator means coupled to said multichannel transceiver array for generating said multichannel downlink S-CDMA signals to transmit messages destined for said terminals.

A smart antenna base station comprising:

• a spatial signature estimator means for estimating a plurality of spatial signatures associated with a plurality of uplink signals received from a corresponding plurality of remote terminals wirelessly coupled to the base station, the plurality of uplink signals simultaneously received on a common carrier frequency during an uplink time slot;
• a downlink beamformer means coupled to said spatial signature estimator means and responsive to the plurality of spatial signatures for beamforming a plurality of downlink beamforms correspondingly unique to each of the plurality of remote terminals and for simultaneously transmitting a plurality of downlink signals to the plurality of remote terminals on the common carrier frequency during a downlink time slot subsequent to the uplink time slot;
• and
• a code division multiple access modulator means coupled to said downlink beamformer means for code modulating each of the plurality of downlink signals on a corresponding plurality code channels whereby each of the plurality of downlink signals has a unique downlink beamform and a unique code channel on the common carrier frequency;
• a parameter estimator means coupled to said spatial signature estimator means for further processing at least one of the plurality of spatial signatures for determining a corresponding direction of arrival vector associated with a remote terminal of the plurality of remote terminals, wherein said downlink beamformer means is not dependent upon the direction of arrival vector for beamforming a downlink beamform associated with the remote terminal.

A method in a smart antenna base station comprising the steps of:

• simultaneously receiving a plurality of uplink signals on a common carrier frequency during an uplink time slot from a plurality of remote terminals wirelessly coupled to the base station;
• estimating a plurality of spatial signatures associated with the plurality of uplink signals;
• processing at least one of the plurality of spatial signatures for determining a corresponding direction of arrival vector associated with a remote terminal of the plurality of remote terminals;
• beamforming a plurality of downlink beamforms correspondingly unique to each of the plurality of remote terminals, wherein said step of beamforming is not dependent upon the direction of arrival vector for beamforming a downlink beamform associated with the remote terminal;
• and
• simultaneously transmitting a plurality of downlink signals to the plurality of remote terminals on the common carrier frequency during a downlink time slot subsequent to the uplink time slot.

A smart antenna base station comprising:

• a spatial signature estimator for estimating a plurality of spatial signatures associated with a plurality of uplink signals received from a corresponding plurality of remote terminals wirelessly coupled to the base station, the plurality of uplink signals simultaneously received on a common carrier frequency during an uplink time slot;
• a downlink beamformer coupled to said spatial signature estimator and responsive to the plurality of spatial signatures for beamforming a plurality of downlink beamforms correspondingly unique to each of the plurality of remote terminals and for simultaneously transmitting a plurality of downlink signals to the plurality of remote terminals on the common carrier frequency during a downlink time slot subsequent to the uplink time slot;
• and
• a code division multiple access modulator coupled to said downlink beamformer for code modulating each of the plurality of downlink signals on a corresponding plurality code channels whereby each of the plurality of downlink signals has a unique downlink beamform and a unique code channel on the common carrier frequency;
• a demodulator for demodulating each of the plurality of uplink signals received by an array of antenna elements to produce a multiplicity of demodulated uplink signals having the plurality of uplink signals received by each element of the array of antenna elements;
• wherein said spatial signature estimator is coupled to said demodulator and estimates the plurality of spatial signatures in response to the multiplicity of demodulated uplink signals.

A method in a smart antenna base station, comprising the steps of:

• simultaneously receiving a plurality of uplink signals on a common carrier frequency during an uplink time slot from a plurality of remote terminals wirelessly coupled to the base station, wherein the plurality of uplink signals are received by an array of antenna elements;
• demodulating each of the plurality of uplink signals to produce a multiplicity of demodulated uplink signals having the plurality of uplink signals received by each element of the array of antenna elements;
• estimating a plurality of spatial signatures associated with the plurality of uplink signals, wherein said step of estimating estimates the plurality of spatial signatures in response to the multiplicity of demodulated uplink signals;
• beamforming a plurality of downlink beamforms correspondingly unique to each of the plurality of remote terminals, wherein said step of beamforming includes producing a plurality of modulated downlink signals having components associated with each element of the array of antenna elements by uniquely modulating each of the plurality of downlink signals for each element of the array of antenna elements to beamform the plurality of downlink beamforms;
• and
• simultaneously transmitting the plurality of modulated downlink signals to the plurality of remote terminals on the common carrier frequency during a downlink time slot subsequent to the uplink time slot.