An investigation of a DSSS-OFDM-CDMA-FDMA indoor geolocation system

The navigation performance evaluation of a direct sequence spread spectrum (DSSS) orthogonal frequency division multiplexing (OFDM), code division multiple access (CDMA), frequency division multiple access (FDMA) indoor geolocation system is discussed in this paper. This system is an enhancement of a DSSS-CDMA-FDMA indoor geolocation system discussed previously. The OFDM aspect enables the system to achieve high data rate and the FDMA aspect enables the system to achieve higher signal separation; thus, mitigating multipath and eliminating the near-far effect and achieving high data rates. The system theoretical performance and simulations in terms of phase error vs. ideal signal-to-noise ratio (SNR), channel impairments, synchronization time and frequency misalignments are presented in the paper. Based on this preliminary investigation it appears that a DSSS-OFDM-CDMA-FDMA indoor geolocation system can operate with data rate up to 5 MBPS and achieve mm phase errors in an indoor environment with up to 32 transmitters which makes this system very attractive to both indoor communication and navigation applications.