Smart Antenna Technology in High-Speed Wireless Access Communications Using the OFDM Scheme

本课题研究基于数字波束形成的高性能智能天线系统在高速无线通信中的应用。研究的主要目的是为了减少衰落和干扰在下一代无线通信系统中的影响。2001年至2002年的研究成果摘要如下：1.讨论了多载波KMA(MC-KMA)自适应阵列在正交频分复用系统中的性能。对于FFT处理后的频域数据，该算法在抑制其他波形的同时，接收期望的波(同步信号)和保护间隔内的延迟波。仿真结果表明，由于提高了期望信号的接收功率，所提出的系统具有更好的性能。提出了一种基于递归ESPRIT算法的自适应均衡器。计算机仿真结果表明，该算法在静态环境和…环境下均能获得理想的性能更多的瑞利衰落环境，结果表明，本文提出的方法是非常有效的。当接收到超过保护间隔的长延时多径波时，Ofem谱的正交性被破坏。从这一角度出发，提出了无数据传输的零载波优化方法，并通过计算机仿真观察到了其有趣的性能。本文研究了MMSE自适应阵列在OFDM传输中的应用。本文提出的自适应阵列在FFT处理后逐个子载波地控制阵列权重。当导频码元被以相等间隔插入到指定的子载波处时，内插技术可以在没有导频码元的子载波处生成接收信号，然后将这些接收信号和导频码元一起使用来为所有子载波产生最佳的阵列权重。计算机仿真结果表明，该算法在输出信干噪比和误码率方面与在所有子载波中插入导频符号的算法性能相当。较少

This research project deals with high-function DBF-based smart antenna systems in high-speed wireless communications using the OFDM scheme. The main objective of the research is to reduce the effects of fading and interference in the OFDM systems for the next generation wireless communication systems. The research results obtained from 2001 to 2002 are summarized below.1. The performance of Multi-Carrier KMA (MC-KMA) adaptive array for the OFDM system has been discussed. With the frequency-domain data after FFT processing, this algorithm operates to receive the desired wave (synchronized signal) and delayed waves within a guard interval while suppressing other waves. It is confirmed that the proposed system has better performance because of increased received power of the desired signal.2. We proposed the adaptive equalizer with the recursive ESPRIT algorithm for the OFDM system. Via computer simulation, it is shown that the ideal performance is obtained in the static environments and … More Rayleigh fading environments, and as a result the proposed method is found to be much effective.3. When the multipath waves with long delay time beyond the guard interval are received, the orthogonality of the OFEM spectrum is destroyed. From the viewpoint, we proposed the optimization method using zero carriers which transmits no data, and the interesting performance has been observed through computer simulation.4. The MMSE adaptive array for OFDM transmission has been considered. The adaptive array proposed herein controls array weights subcarrier by subcarrier after FFT processing. When pilot symbols are inserted at specified subcarriers with equal spacing, an interpolation technique can generate received signals at subcarriers with no pilot symbols and then using these received signals and pilot symbols together produces optimum array weights for all subcarriers. Computer simulation results show that performance of the proposed algorithm is nearly equal in the output SINR and BER to that of the algorithm in which pilot symbols are inserted into all subcarriers. Less