INTRODUCTION
THE orthogonal frequency division multiplexing (OFDM) is commonly used for high data rate wireless communication due to its inherent error susceptibility in a multipath environment. OFDM-based transmission systems can be extended to a multiple input multiple output (MIMO) architecture using vertical Bell laboratories layered spacetime (V-BLAST) concept, which provides significant capacity gain in wireless channels. In the MIMO-OFDM system, a MIMO signal detection with a low complexity and high performance is a knotty subject. Therefore, a lot of signal detection algorithms have been proposed . Among the detection schemes, a QRD-M scheme achieves very high detection performance. However, since the QRDM is a tree search algorithm, the detection complexity is highly increased, as either the QAM level or the number of transmission antennas increases.
In this project, we propose a simple and efficient detection technique based on QRD-M for MIMO-OFDM systems. In the proposed detection technique, we adopt a new parameter T. If the value of T is high, the system has good detection performance and high complexity. However, if the low value of T is selected, the detection performance is decreased and the complexity is reduced. Therefore, by adjusting the value of the new parameter T , the performance and computational complexity of the system can be controlled. After T -th stage, the decision feedback equalization (DFE) detection based on QR-decomposition is used. The reason why the DFE detection based on QR-decomposition is used is that by using QR-decomposition, both QRD-M and DFE can use the QR-decomposition without additional operation to detect the symbol and among some representative detection schemes, the DFE detection based on QR-decomposition has good performance and low complexity.
THE orthogonal frequency division multiplexing (OFDM) is commonly used for high data rate wireless communication due to its inherent error susceptibility in a multipath environment. OFDM-based transmission systems can be extended to a multiple input multiple output (MIMO) architecture using vertical Bell laboratories layered spacetime (V-BLAST) concept, which provides significant capacity gain in wireless channels. In the MIMO-OFDM system, a MIMO signal detection with a low complexity and high performance is a knotty subject. Therefore, a lot of signal detection algorithms have been proposed . Among the detection schemes, a QRD-M scheme achieves very high detection performance. However, since the QRDM is a tree search algorithm, the detection complexity is highly increased, as either the QAM level or the number of transmission antennas increases.
In this project, we propose a simple and efficient detection technique based on QRD-M for MIMO-OFDM systems. In the proposed detection technique, we adopt a new parameter T. If the value of T is high, the system has good detection performance and high complexity. However, if the low value of T is selected, the detection performance is decreased and the complexity is reduced. Therefore, by adjusting the value of the new parameter T , the performance and computational complexity of the system can be controlled. After T -th stage, the decision feedback equalization (DFE) detection based on QR-decomposition is used. The reason why the DFE detection based on QR-decomposition is used is that by using QR-decomposition, both QRD-M and DFE can use the QR-decomposition without additional operation to detect the symbol and among some representative detection schemes, the DFE detection based on QR-decomposition has good performance and low complexity.
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