Study on the spectral efficiency of SFH-GMSK in land mobiletelephone communication by direct simulation

摘要

A spread spectrum system, slow frequency hopping with GMSK(Gaussian minimum shift keying) modulation (SFH-GMSK), is proposed formobile telephone communications. The system performance is evaluatedusing computer simulation and is compared with an unspread system.Results show that under multipath fading conditions, when thesignal-to-noise ratio (SNR) is greater than 15 dB, slow frequencyhopping gives some bit error rate improvement over the unspread system.Theoretical predictions indicate that a system efficiency of 20-65 usersper cell can be achieved in the cellular configuration. Joint use ofSFH-GMSK and FM is also investigated. It is shown that FM interferencecan cause serious degradation to the SFH-GMSK performance