Waveform Diversity for Wireless Communications with Joint Transceiver Multipath Exploitation and Interference Avoidance

多输入多输出(MIMO)无线通信系统配备了多个发射和接收天线，提供了显著改善的误码性能和增强的容量。然而，实现MIMO系统的潜力会受到衰落、移动性、干扰和低功率要求的影响。无线自组织网络和超宽带通信的出现加剧了干扰问题。现有的MIMO无线收发信机设计方法要么假设发射机完全了解信道，要么假设发射机没有信道知识。后者产生悲观的设计，而前者是不切实际的，并且在严重的通道失配的情况下会导致大量的性能损失。因此，研究人员正在研究MIMO无线系统在不同程度的部分信道知识下的基本容量和误码性能极限。相应地，他们正在开发基于部分信道知识的信道自适应MIMO收发器，以最大限度地减少发射功率，并在规定的差错概率容限下最大化数据速率。人们正在研究将空时分组编码和空时波束形成结合在一起的混合方案，以实现干扰避免和对不完美的信道知识的稳健性。正在开发的先进算法将深刻地改变MIMO技术，并直接影响无线多天线通信的稳健性和带宽效率。

Multi-input multi-output (MIMO) wireless communication systems, equipped with multiple transmit and receive antennas, offer dramatically improved error performance and enhanced capacity. However, realizing the potential of MIMO systems is countered by the effects of fading, mobility, interference, and low-power requirements. The problem of interference is exacerbated by the proliferation of ad-hoc networks and the emergence of ultra-wideband communications.Existing approaches to MIMO wireless transceiver design assume either perfect channel knowledge or no channel knowledge at the transmitter. The latter yields pessimistic designs, while the former is unrealistic and can result in substantial performance losses in cases of severe channel mismatch. Thus, the researchers are investigating the fundamental capacity and error performance limits of MIMO wireless systems for varying degrees degrees of PARTIAL channel knowledge. Correspondingly, they are developing channel-adaptive MIMO transceivers based on partial channel knowledge that minimize transmit-power and maximize data rates at a prescribed error probability margin. Hybrid schemes are being researched that incorporate both space-time block coding and space-time beam forming to effect interference avoidance and robustness to imperfect channel knowledge. The advanced algorithms under development will profoundly alter MIMO technology and directly impact the robustness and bandwidth efficiency of wireless multi-antenna communications.