A location-adaptive signal detection scheme for dual-antenna terminals using maximal ratio combining and spatial demultiplexing

In typical cellular mobile radio systems, the intercell interference degrades the signal detection performance of mobiles due to the low signal-to-interference ratio (SIR) near coverage boundaries. Such performance impairment can be mitigated by the usage of the terminals equipped with dual antennas, as suggested in 3GPP-LTE contributions, e.g., Rl-050829. Standardization and related usages of systems utilizing dual-antenna terminals is expected to keep increasing due to the anticipated performance gain. In this paper, we propose an adaptive signal detection strategy of dual-antenna terminals which can enhance the reception quality and the system bandwidth efficiency, and investigate the performance gain of the proposed scheme. The scheme either uses maximal ratio combining (MRC) between two antennas or performs spatial demultiplexing (SD) under the 2-by-2 MIMO channel model, based on the received SIR value. We first analyze the probability density function (pdf) and the effective SIR for the MRC and SD detection respectively, using the 4-cell and 7-cell configurations. Based on the analysis, we derive the location range within a cell at which the switching location of the adaptive detection mode is applied to the dual-antenna terminals. It is demonstrated that the proposed scheme significantly improves the effective SIR and spectral efficiency near the cell boundaries.