Evaluating of Capacities in TD-SCDMA Systems When Employing Smart Antenna and Multi-User Detection Techniques

Abstract

In TD-SCDMA systems, the multi-user detection (MUD) and adaptive smart antenna techniques are adopted in both uplink and downlink. Considering the complexity of cancelling inter-cell interference, the technique of MUD in this paper mainly focuses on the interference suppression of intra- cells. The adaptive smart antenna technique is adopted to suppress the interference from both intra- and inter-cells. Since these two motioned techniques are not adopted in WCDMA and cdma2000 systems, the corresponding capacity and load evaluating models for TD-SCDMA systems must be reinvestigated. In this paper, a theoretical analysis model for CDMA capacity constraints is presented firstly when employing the adaptive smart antenna and MUD techniques in both uplink and downlink, in which the factors of average beamforming interference and intra-cell MUD factors are proposed for evaluating the impacts of adopting these key techniques. Based on the theoretical model, the pole capacity and load estimation models are deduced. The simulation results demonstrate the theoretical analytical models specified for TD-SCDMA systems available. According to our proposals, the TD-SCDMA network planning and optimization can be processed efficiently.