Summary
International Symposium on Antennas and Propagation
2008
Session Number:2C12
Session:
Number:2C12-4
Cooperative MIMO Transmission Based on Multiple Base Station Coordination for OFDM Cellular Systems
Manabu Mikami, Teruya Fujii,
pp.-
Publication Date:2008/10/27
Online ISSN:2188-5079
Summary:
OFDM (Orthogonal Frequency Division Multiplexing) modulation is attracting attention as the wireless transmission technology for the next generation (3.9G/4G) cellular mobile radio systems, due to its many advantages such as high spectral efficiency in multi-path fading channels. For this reason, various mobile radio access systems based on OFDM have been developed such as 3GPP LTE (Long Term Evolution), 3GPP2 UMB (Ultra Mobile Broadband), and Mobile WiMAX. On the other hand, the MIMO (Multi-Input Multi-Output) transmission technique, which uses multiple antennas at the both transmitter and receiver sides, is also attracting attention due to its throughput performance improvement effect. The combination of MIMO and OFDM, MIMO-OFDM, is highly favored to be used as the air interface for the downlink of the next generation mobile radio systems. In MIMO-OFDM cellular systems, it is critical to increase the throughput of cell-edge users because it is difficult for them to obtain sufficient received signal-to-interference-plus-noise power ratio (SINR) to demultiplex the different streams that are spatially multiplexed. Recently, several cooperative downlink transmission schemes, in which multiple BSs (Base Stations) synchronize to each other and coordinate their wireless transmission, have been proposed for cellular mobile radio systems in order to increase the user throughput at the cell edge [1],[2]. This paper focuses on the downlink cooperative MIMO transmission based on multiple BS coordination in order to improve the transmission performance of the celledge users for MIMO-OFDM cellular systems. In this paper, we propose a cooperative MIMO transmission with D-STTD (Double Space Time block coding based Transmit Diversity) [3],[4] and evaluate its performance with consideration of the frequency offset difference between local oscillators in the coordinated BSs by computer simulations. The computer simulations confirm that the proposed cooperative MIMO transmission can improve the user throughput performance at the cell edge. Moreover, we introduce the Per Site Rate Control (PSRC) technique, in which each BS independently controls its modulation level; the computer simulations clarify that the PSRC technique is effective, especially when there is a significant difference in the average received power of the signals transmitted from the coordinated BSs.