Modulation and Spreading Techniques for Burst Transmissions

Novel modulation and spreading techniques are described in this paper. These techniques provide high overall energy efficiency of burst transmissions widely used in communication systems with frequency hopping, time division multiple access (TDMA), transmission of short messages, etc. The techniques can also be useful for other types of data transmission. High overall energy efficiency has been achieved as a combined result of several factors: fast synchronization, high noise immunity of a modulation/demodulation, efficient utilization of transmitter power, high tolerance to drifts of the transmitter and/or receiver frequency references and Doppler, and simplicity of signal processing. The modulation technique has been obtained by developing differential binary phase shift keying (DBPSK) and named alternating quadratures DBPSK (AQ-DBPSK). The spreading technique has been obtained by developing binary phase shift keying (BPSK) and named alternating quadratures BPSK (AQ-BPSK). AQ-DBPSK modulation retains all advantages of DBPSK modulation. Simultaneously, it better utilizes transmitter power and has much higher tolerance to frequency offset between the received and reference signals. AQ-BPSK spreading retains all advantages of BPSK spreading and provides better utilization of transmitter power as well as some other advantages. Initial analysis of these techniques is performed, and recommendations for their implementation are suggested.