Capacity of orthogonal space-time block coded system under adaptive transmission

For the independent and identically distributed (i.i.d.) Rayleigh fading channel with the number of receive antennas is more than one, orthogonal space-time block codes (OSTBC) incur a capacity loss which is related to the code rate, the rank of channel matrix as well as the number of receive antennas. To improve the channel capacity of OSTBC, in this paper we apply the adaptive transmission technique to the space-time block coded system. In this scheme the transmitter adapt its power to the equivalent channel fading factor of the space-lime coded system by the method of power control. Numerical results show that by using the policy of adaptive transmission the space-time block coded system is improved obviously in channel capacity, and even can achieve higher capacity than MMO system when the number of receive antenna is one.