Multi-user direction of arrival and channel estimation for time-slotted CDMA with joint detection

In cellular mobile radio systems, the directional inhomogeneity of the radio channel can be exploited to increase the spectral efficiency via the implementation of smart antennas. In this paper, we investigate the optimum and a simplified smart antenna concept for a time-slotted CDMA mobile radio system termed joint detection CDMA (JD-CDMA). These new combined direction of arrival and channel estimation algorithms and the conventional detection scheme are evaluated via Monte Carlo simulations. They reveal that significant performance improvements can be achieved by exploiting relationships between the estimated directions of arrival and the channel impulse response vectors. Compared to the optimum solution, the new suboptimum approach offers a considerable reduction of the signal processing complexity without severe degradations of the system´s performance