An evaluation of a sideband diversity technique for data transmission on the forward path in a mobile radio area coverage scheme

The technique of sideband diversity has been applied to a quasi-synchronous amplitude modulated area coverage scheme for mobile radio, primarily to improve the error performance ofmedium-speed data transmissions to vehicles. Results are presented for commercial voice frequency modems using f.s.k. modulation at 1200 baud. Improvements in error performance of between one and two orders of magnitude have been measured. The residual errors after sideband diversity had been applied were heavily dependent upon ignition interference.