A MC-CDMA indoor geolocation system

A direct sequence spread spectrum (DSSS), orthogonal frequency division multiple access (OFDM), code division multiple access (CDMA) and frequency division multiple access (FDMA) (or MC-CDMA) indoor geolocation system is presented and discussed in this paper. The data sequence on the transmitter is spread in time using two spreading sequences and then is modulated employing a quadrature phase shift keying (QPSK) scheme. The channel is modeled as a slowly varying frequency-selective, Rayleigh fading channel typical of an indoor office building or factory. The receiver utilizes a non-coherent data demodulator to minimize the sensitivity of the receiver to the Rayleigh fading channel. The bit-error-probability (BEP) performance of this system is compared to that of a DSSS-CDMA-FDMA (or C-CDMA) system when operating in a Rayleigh fading channel with additive white Gaussian noise, range and Doppler shift. Performance results indicate superior performance of the coded MC-CDMA systems of roughly equal transmitter and post RF receiver complexity