Encoded diversity transmission for slow-frequency-hopped multiple access communication

In slow-frequency-hopped multiple access communication systems using M-ary FSK modulation, multiple access interference may lead to erroneous reception of symbols. An encoded diversity transmission scheme is proposed for reducing the probability of symbol error due to multiple access interference. Using this scheme, a transmitter encodes each symbol into a sequence of L symbols (L is called diversity degree), chooses a sequence of L frequency bins and transmits the L encoded symbols in the L chosen bins, respectively. In this manner, the transmitter can encode more information about each symbol for diversity transmission. The receiver can use this information to increase the chance of decoding the correct symbol in the presence of multiple access interference. It is demonstrated that the proposed scheme can significantly reduce the probability of symbol error caused by multiple access interference.