Channel Estimation Technology Of MB-OFDM-UWB Wireless Communication System

Ultra-wideband wireless communication technology with high data transfer rate, low cost, low power consumption and strong anti-interference ability is considered the physical layer standard of the next generation wireless personal area network, and it has gained great attention of the industry, the media and academia of paramount. Relative to Direct-sequence code division multiple access ultra-wideband(DS-CDMA-UWB)program, Multi-band orthogonal frequency division multiplexing ultra-wideband(MB-OFDM-UWB)program has absolute advantages in bandwidth efficiency, multipath energy harvesting and high-speed wireless data transmission and gains more and more support. at present, MB-OFDM-UWB program is considered the most promising UWB technology.In MB-OFDM-UWB communication system, we often use coherent demodulation method in order to improve the receiver sensitivity with higher data rate and spectrum efficiency and ensure that the system performance is unaffected by multi-path channel and the fading effect. Because the coherent demodulation depends on knowning about changes of the carrier signal phase and amplitude information, which is used to restore the original data bits, we should require the correct channel estimation to track the changes of channel response to obtain accurate channel parameters. This paper introduces the concept and characteristics of the UWB technology, as well as future development trends, studies the basic principles and a variety of channel models of the MB-OFDM-UWB system and analyzes the channel estimate technology emphatically. The paper first studies common channel estimation methods in-depth, including LS, improved LS, MMSE, SVD-based MMSE, DFT transform domain, ML, improved ML,etc. Then based on these methods, this paper has realized a kind of LS-DFT-pilot joint channel estimation algorithm through comprehensive analysis and learning from each other, which has two characteristics: 1) Based on the principle of the LS algorithm and the idea of the DFT-domain algorithm, we use the adaptive method to estimate the channel length, which can effectively distinguish between different channel types according to the channel characteristics and add different lengths of rectangular windows, so we not only can remove noise but also can effectively improve the channel estimation performance; 2) It carries on the estimation jointly with the pilot signal of the data symbols, so that it can track the changes of the channel to further enhances the channel estimation performance. Finally, this paper gives bit error rate and mean-square error performance simulation curves of a variety of estimation methods and analyses the advantages and disadvantages of the performance, the order of complexity height and different application environments of various algorithms. Through the theoretical analysis and the simulation research, this algorithm obtains the very good performance improvement with low computation load and has some practical engineering value.