CDMA line-of-sight data communication system with power control attaining error free condition in presence of inter-sector and inter-cell interference

This paper describes how power control enables one to satisfy the error free condition of a CDMA FDD system for short distance line-of-sight data communication in the presence of inter-sector and inter-cell interference. All sectors and cells are covered by two frequency bands: one for the uplink and the other for the downlink. The data rate is a multiple of 1.5 Mbps. Two 1.5 Mbps channels which are used in synchronization and orthogonal spreading/despreading codes are adopted in both uplink and downlink. The number of actually operating channels in a sector are assumed to be equal to the process gain minus two: this system has a higher spectral efficiency, 21 times that of the conventional TDMA system which uses different frequency bands for all neighboring sectors and cells. Computer simulation is carried out to examine whether the error free condition can be satisfied by power control in the presence of inter-sector, inter-cell interference and thermal noise. Computer simulation has shown that the error free condition can be satisfied when concatenated block and convolutional codes with a code rate 0.44 are adopted.