Differential spatial multiplexing techniques for high spectrum efficiency on very fast fading MIMO links

空间多路复用(有时被称为BLAST)是一种通过利用发射机和接收机(MIMO)处的多个天线来增加无线系统吞吐量的方法-它潜在地可以将容量增加等于最小数量的系数或发送和接收天线。然而，它需要接收器估计信道的准确特性，当信道变化(衰落)非常快时，这是困难的，例如在高速移动通信中。已经为单天线系统和空时编码MIMO系统(其不增加容量)开发了差分技术，其避免了通过发送信息作为一个发射码元与下一个发射码元之间的差来估计信道的需要。然而，这在以前对于空间多路复用是不可能的。提出者已经开发了一种允许这一点的技术，但当前的方案存在分集差，导致通信健壮性较差，并且需要在接收器处的高复杂性。所提出的研究旨在作为一项可行性研究，以确定是否可以通过在发射端使用适当的映射方案以及在接收端使用诸如球形译码或SGA之类的技术，或者使用带有迭代译码的FEC编码来缓解这些问题。它还将研究潜在的应用，包括码分多址和正交频分复用等技术，使其能够在多用户宽带信道上使用。

Spatial multiplexing (sometimes referred to as 'BLAST') is a way to increase the throughput of a wireless system by exploiting multiple antennas at both transmitter and receiver (MIMO) - potentially it can increase capacity by a factor equal to the minimum of the number or transmit and receive antennas. However it requires the receiver to estimate the exact characteristics of the channel, which is difficult when the channel varies (fades) very rapidly, as in mobile communcation at high speeds. Differential techniques have been developed for single antenna systems and for space-time coded MIMO systems (which do not increase capacity), which avoid the need to estimate the channel by sending information as the difference between one transmitted symbol and the next. However this has not previously been possible for spatial multiplexing. The proposers have developed a technique which allows this, but the current scheme suffers from poor diversity, resulting in less robust communication, and requires high complexity at the receiver. The proposed research is intended as a feasibility study to determine whether these problems can be mitigated, using appropriate mapping schemes at the transmitter and techniques such as sphere decoding or SGA at the receiver, or using FEC coding with iterative decoding. It will also examine potential applications, including techniques like CDMA and OFDM to enable its use on a multi-user wideband channel.