Bit-loading Algorithm For Adaptive Sc-fde System

Broadband wireless communication technology has been drawing great attention recent years. This thesis focuses on physical layer adaptive transmission techniques, especially the key of adaptive algorithm in SC-FDE system -Bit-loading, which is based on similar algorithms in OFDM system.Firstly, this thesis reviews several classical adaptive algorithms in OFDM and analyzes their advantages as well as flaws. Further, some inherent problems in OFDM are pointed out to be unavoidable in OFDM scheme, which also lead to impractical use of adaptive algorithm in wireless scenarios.Secondly, this thesis gives a detailed introduction of Optimal Signal Subspace theory and the adaptive SC-FDE system based on it. This OSS theory is the cornerstone of SC-FDE adaptive techniques proposed in this thesis. A simple bit-loading and power control algorithm is provided for adaptive SC-FDE using only 1 bit feedback information per subchannel and its computational complexity is analyzed and performance is compared with adaptive OFDM. Simulation results show that although BER performance decrease, depending on its low complexity it is practical for wireless scenarios.Thirdly, this thesis discusses a relatively complex adaptive algorithm based on ordered optimal signal subspace, which needs more feedback information. Also, computational complexity is analyzed and BER performance is compared with adaptive OFDM. Simulation results show that the same BER performance can be achieved as that in adaptive OFDM, while complexity is lower and feedback information less. So the proposed adaptive algorithm in SC-FDE is much better than those in OFDM.