Abstract: This invention provides a CDMA (IS-95) cellular communication system, in which a base station transmits a common broadcast pilot signal through a sector wide beam and traffic signals through narrower adaptive spatial beams by way of an adaptive antenna array. The present invention further provides methods of recovering the phase mismatch between the pilot and traffic signals received at a mobile station, thereby providing for coherent demodulation. By implementing the phase-recovery process at individual mobile stations, the present invention enables the base station to transmit the traffic signals with optimal power gain and minimal interference.

Abstract: The invention provides systems and methods for providing improved wireless data communication. Preferred embodiments of the present invention utilize multiple antenna beams in the forward link to provide increased forward link capacity and/or improved forward link signal quality. Multiple orthogonal sub-pilots are transmitted from a plurality of antenna elements for use in determining forward link channel characteristics according to a preferred embodiment. Forward link channel estimates may then be made by the preferred embodiment subscriber units and provided in a reverse link control channel to the corresponding base station. Multiple beams may also be utilized in the reverse link to provide increased reverse link capacity, such as for use in providing feedback of forward link channel estimates.

Abstract: A system and method is provided for adaptive downlink beamforming in a wireless communication system. The technique involves using an antenna array to transmit downlink control signals from the base station to the subscribers in the cell. Rather than transmitting the control signals in a given direction continuously, the control signals in the present system are transmitted for only a short time interval using one of a sequence of specified directional beams. After a predetermined sweep cycle period, the control signal beam is then retransmitted again in the same direction. Typically, during this cycle period control signal beams are also transmitted in other specified directions. In one embodiment, for example, the control signal beams sweep around the base station once during each cycle. A subscriber located in the cell will receive a repeating pattern of signal pulses corresponding to the periodic beams directed toward the subscriber.

Abstract: A practical way to enhance signal quality (carrier to interference. C/I) in both up and downlink of wireless point to multi-point CDMA service implements basic radio direction finding techniques to allow for optimal diversity combining in an antenna array employing large number of elements. This approach is facilitated through the use of very small bit counts arithmetic and capitalizing on finite alphabet signal structure (Walsh symbols, for example in IS-95 CDMA) or a known training sequence. Alternate implementations can use floating point data representations. The method facilitates ASIC implementation, thereby enabling distributed processing to achieve the required computation practicality. The method utilizes the uplink channel data to determine the downlink spatial structure (array beams) to enhance downlink C/I and hence, increase downlink capacity.