Space-time coding using MSK

Recent papers have shown that space-time (ST) coding using continuous phase modulation has a number of advantages relative to linear modulation, among which is its constant envelope, which allows transmission with inexpensive and power-efficient Class C amplifiers. The present paper presents a particularly simple variant, ST coding based on minimum shift keying (MSK), an offset format. ST codes with offset modulation give much better performance than quadrature phase shift-keying (QPSK), for the same number of states, and the MSK ST decoding computational load is smaller than that of QPSK by a ratio that improves exponentially with the number of transmitter antennas. The relationship between offset and nonoffset modulation formats is explored and the effect of pulse shape is shown explicitly.