MIMO LAYERED SPACE-TIME SYSTEM WITH VIRTUAL RECEIVE ANTENNAS

无线通信技术正成为普通大众的日常必需品。随着互联网使用和多媒体业务的爆炸式增长，对高数据速率无线通信系统的需求正在飙升。然而，传统的单天线系统已经达到了极限，无法满足这种需求。MIMO分层空时（LST）系统通过使用多个发射和接收天线，利用了额外的空间资源，可以达到远远超出单天线系统限制的效果。然而，这种技术要求接收天线的数量至少与发射天线的数量一样多。由于移动设备的尺寸有限，这样的要求不容易满足，并且阻碍了这项有前途的技术的成熟。本项目旨在通过探索虚拟接收天线的新思想来降低这种严格的要求。这些虚拟天线的信号是利用一些信号处理技术对实际接收到的信号进行处理而产生的。这项研究的结果将使MIMO LST技术的可行实施和更广泛的传播成为可能。这个想法将在不同的渠道环境中进行彻底的研究。研究了接收机的结构，并对其性能进行了计算机仿真。此外，我们亦会进行初步的实际执行研究，以便日后进一步推广这一新意念。

Wireless communication technology is becoming a daily necessity for the general public. With the explosive growth of internet usage and multimedia services, the demand for higher data rate wireless communication systems is soaring. However, conventional single antenna systems are reaching the limit and cannot satisfy this need. By using multiple transmit and receive antennas, MIMO Layered Space-Time (LST) systems exploit the additional spatial resource and can reach far beyond the limit of single antenna system. This technology, however, requires the number of receive antennas at least as many as the number of transmit antennas. Being limited in size at the mobile unit, such a requirement cannot be met easily and hinders the maturity of this promising technology. This project aims at reducing this stringent requirement by exploring the novel idea of virtual receive antennas. The signals from these virtual antennas are created by using some signal processing techniques on the actual received signals. The result of this research will allow feasible implementation and wider dissemination of the MIMO LST technology. This idea will be thoroughly investigated for different channel environments. The receiver architecture will be developed and its performance will be obtained by computer simulation. Preliminary study on practical implementation will also be conducted to allow further exploitation of this new idea in the future.