Research And Implementation Of Precoding Technology In Ultra High Throughput Wlan

As WLAN (Wireless Local Area Network) rapidly develops, the ultrahigh throughput WLAN technology attracts much attention in WLANresearch. In IEEE802.11ac ultra high troughput WLAN, the SingularValue Decomposition (SVD)-based MIMO (Multiple-inputMultiple-output) precoding technology could eliminate the interferencesbetween different data streams and improve the MIMO channel capacity.Then it can improve the throughput and data reliability of the wirelesscommunication system. So the SVD-based precoding has become one ofthe key technologies in the ultra high troughput WLAN.Taking performance, hardware cost and computation complexity intoaccount, this thesis proposes a hermitian matrix Eigen ValueDecomposition (EVD)-based SVD precoding algorithm. The proposedalgorithm applies the property of hermitian matrix and employs the TPR(Two Plane Rotation) method to reduce computation complexity in eachiteration. In addition, comparison operation of the off-diagonal entries hasalso reduced the number of iterations by a quarter. By matrix expansion,the proposed algorithm could support all antenna modes (up to4transmitantennas and4receive antennas) in the802.11ac ultra high troughputWLAN.Simulation shows that the proposed SVD precoding algorithm couldachieve almost the same system BER (Bit Error Rate) performance as theideal SVD precoding in all the antenna modes (up to4transmit antennasand4receive antennas). In VLSI design of the proposed algorithm, we usethe SMIC0.13um CMOS process to complete logic synthesis and static timing analysis. The results represent that our SVD precoding moduleconsumes174K gates with the maximum clock frequency of179MHz, andthe throughput is1429K predocing matrices per second. With lower designcomplexity, our design also achieves higher throughput than most otherimplementations of SVD precoding. Therefore, it’s very suitable for theapplication in the802.11ac ultra high troughput WLAN.