Tuesday, March 30, 2010

communication technologies

Ultra-Wideband is a new type of wireless communication technologies in recent years. It has the advantages of high data rate, low-power, anti-multipath capability, easy and low-cost structure, etc, opening up new opportunities for the development of ralph lauren polo shirts wireless communications. In the Ultra-wideband wireless communications systems, the receiver must understand the transmission channel characteristics, in order to ensure the reliability and effectiveness of communications. Therefore, channel estimation is one of the key technologies in the Ultra-wideband wireless communication systems.First the paper introduces the concept of ultra-wideband wireless communication systems, characteristics and signal waveforms, focusing on channel cheap Wholesale nike shoes models for UWB system; then we study UWB based on OFDM. On this Lacoste Polo basis, the paper focuses on the channel estimation algorithms for UWB based on OFDM, including the LS, MMSE, the chi flat iron estimation algorithm based on DFT. And in the channel conditions of the cheap wedding gown dresses UWB, we use the Matlab to simulate and analyze a variety of the channel estimation algorithms. Through the analysis of the traditional channel estimation algorithms, the algorithm based on DFT estimation in terms of performance and the achievement has a clear advantage, but the algorithm will encounter the problem of data length, which will affect the accuracy of channel estimation, so we need to modify this algorithm. For the characteristics of channels in UWB, the paper presents an algorithm for the UWB system based on DFT estimation. The algorithm can adaptively select the filter length of the best properties, improving the performance of channel estimation, effectively allowing the system to achieve optimal performance of the receiver , having some practical value in engineering.
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