The Algorithm And Performance Analysis Of Unitary Space-time Cooperative Diversity

Using the multiple-input multiple-output (MIMO) systems, we can improve the performance of the system without incurring the expenditure of transmission time or bandwidth. However, such as cellular mobile communication system, many wireless devices (mobile phone) can not practically adopt multiple-antenna techniques, due to their size, weight, power, cost limitations.In order to solve this limitation, cooperative diversity has been proposed, which allow single-antenna mobiles to reap some of the benefits of MIMO systems. The basic idea is that single-antenna mobiles in a multi-user scenario can "share" their antennas in a manner that creates a virtual MIMO system.Unitary space-time code is well-tailored for flat-fading channels where neither the transmitter nor the receiver knows the fading coefficients, it will be promising in the multiple antennas and the high-data-rate wireless communication. The space-time coded cooperative diversity which has been suggested in references all know the fading coefficients at the receiver, for cooperative diversity, if we need the terminal to estimate the channel coefficient, it will lead to increase the complexity, time delay, and power consumption. This will bring difficulties for the practical application of cooperative communication. If we use unitary space-time code, the problem can be easily solved.A unitary space-time cooperative diversity is proposed in this paper. First of all, this thesis researches the system model and channel model of cooperative diversity, and analyses the performance of coded cooperation. Second, Unitary space-time code is proposed, various generation matrices of USTC are searched out, the main factors which affected the USTC system's performance are fingered out. At last a unitary space-time cooperative diversity based on detect and forward method is proposed in this paper. From the computer simulation, we know the algorithm can improve the performance of system.