초록 ▼

An arrangement (apparatus and method) for providing a code division multiple access (CDMA) transmission system in an urban environment using spatially-diverse antennas and time-diversity devices and techniques to provide improved cell coverage without the detrimental effects of multipath (Rayleigh)

An arrangement (apparatus and method) for providing a code division multiple access (CDMA) transmission system in an urban environment using spatially-diverse antennas and time-diversity devices and techniques to provide improved cell coverage without the detrimental effects of multipath (Rayleigh) fading. The spatially-diverse antennas output identical CDMA-modulated signals to a serving area at different times, whereby each CDMA-modulated signal output from a corresponding antenna has a sufficent delay to avoid mutual interference with the identical CDMA-modulated signals output from other antennas. The delay assigned to each antenna is within a range greater than a chip interval, and less than or equal to a base station sequence offset between base stations. As a result, a subscriber station is able to separately demodulate the received CDMA-modulated signals from the different antennas as CDMA signals having adequate multipath delay for demodulation using a rake receiver. The delays may be implemented as delay devices supplying delayed system clock signals from a GPS receiver to corresponding base stations having identical spreading sequences. Alternatively, the delays may be implemented as successively delaying a CDMA-modulated signal output by a single base station before transmission to the antennas along corresponding transmission paths.

대표청구항 ▼

[ What is claimed is:] [47.] In a communications system providing wireless communications services to a plurality of subscriber stations in an urban serving area, the communications system comprising at least one base station and a plurality of antennas spatially distributed around said urban servin

[ What is claimed is:] [47.] In a communications system providing wireless communications services to a plurality of subscriber stations in an urban serving area, the communications system comprising at least one base station and a plurality of antennas spatially distributed around said urban serving area, a method for providing spread spectrum-processed information signals to said urban serving area comprising the steps of:outputting a spread spectrum-processed information signal from said at least one base station;successively supplying said spread spectrum-processed information signal to said antennas at corresponding delay intervals greater than said chip interval and less than a base station sequence offset of said at least one base station; andtransmitting the spread spectrum signals from the respective antennas into the urban serving area to form overlapping coverage regions that minimize shadowing effects.