Characteristics of CMA adaptive array for selective fading compensation in digital land mobile radio communications

This paper considers CMA adaptive array for the high-speed TDMA transmission system using GMSK, which is the most ordinary constant-envelope modulation system in the digital mobile land communication. A computer simulation is executed for the case where a four-element adaptive array is applied to cope with the selective fading. CMA is employed as the array control algorithm, which is suited to the compensation of the constant-envelope modulated signal. Assuming a model with two arriving waves, the convergence and the BER performances of CMA are evaluated. It is shown that the BER is improved greatly up to the limit that no more error can be reduced, compared to the case without an adaptive array. It is seen also that the error rate is improved better when the delay difference between the two arriving waves is large. Thus, the proposed method is shown to be an effective technique to cope with selective fading.