Implementation of K-Best method for MIMO decoder in WLAN 802.11n

WLAN IEEE 802.11n is recent wireless data communication technology which provides high throughput and high performance. These features are definitely determined by the strength of MIMO decoder. The existing MIMO decoder of WLAN 802.11n is based on linear method, i.e Zero Forcing (ZF) and Minimum Mean Square Error (MMSE). Both of them are low in complexity but poor in performance. In the other hand Maximum Likelihood Detection method demonstrates optimal performance but with very high in complexity. This paper presents our research in developing a high performance low complexity MIMO decoder for WlAN 802.11n by implementing K-Best method. Simulation of WLAN 802.11n 2×2 with QPSK, 16QAM, and 64QAM modulation order is conducted under channel model B of TGn. By target BER of 10-4, the performance and complexity of each decoder are analyzed. The results show that K-Best detector achieves near-MLD performance, only degrade 1 dB, and has much better performance compared to ZF and MMSE with average 12 dB to 8 dB. The complexity ratio of the K-Best to MLD will significantly decrease as the increasement of transmitter antena (Ntx) and modulation order, i.e 46,9 % for QPSK to 5,27 % for 64QAM in Ntx=2.