Working Toward Capacity in Multiple Antenna Radio

在过去的几年里，已经有大量的研究通过利用发射机和/或接收机的分集和空间复用来提高衰落环境下的无线通信的性能。Telata、Foschini和Gans的开创性工作表明，无线通信系统中的多天线无线电(MAR)可以极大地提高性能。MAR成为经济上可行的无线通信选择的主要障碍是无线电模拟部分的成本。采用复杂信令和信号处理算法的点对点MAR系统已经被设计和建造，并且已经获得了非常接近停机能力的性能。在MAR中可以实现的剩余收益只能通过考虑MAR信令和信号处理中的模拟电路的成本和复杂性、考虑更复杂的无线传播模型以及将MAR放在网络环境中来利用。这项工作的重点是通过在这些更复杂的模型和网络场景中利用结构来推动MAR技术。努力的目标可以简单地表述为：1)通信理论通常对固定平均功率的性能标准化感兴趣，但在无线实施中，峰值功率是比平均功率更关键的驱动因素。这项研究正在研究在多天线无线电中具有峰值功率约束的性能和吞吐量的优化。2)反馈通信可能在联网场景中实现吞吐量和解调器复杂性的显著改进，特别是在低移动性的环境中(例如，无线计算机网络)。本研究采用一种经典的科学方法来探讨反馈通信，即在真实信道上的实验和基于实验结果的更现实的理论问题公式之间迭代。3)目前无线通信中的成本驱动因素是模拟电路。这项研究正在研究在多天线无线电中将模拟系统的复杂性降至最低的技术。目标是通过以下研究任务来实现：a)改进用于多天线无线电的远程预测的信道参数，b)设计和现场测试各种MAR自动重发请求算法，c)试验所提出的用于MAR的反馈算法，d)用于恒定包络调制的MAR的反馈算法，e)用于具有有限模拟能力的MAR的反馈算法，

Over the past several years, there has been a great deal of research to improve performance of wireless communications in fading environments by exploiting transmitter and/or receiver diversity and spatial multiplexing. The pioneering work by Telatar, Foschini and Gans showed that multiple antenna radios (MAR) in a wireless communication system can greatly improve the performance. The major roadblock to MAR being a financially viable option for wireless communications is the cost of the analog portions of the radio. Point--to--point MAR systems employing complex signaling and signal processing algorithms have been designed and built and have achieved performance very close to the outage capacity. The remaining gains that are achievable in MAR will only be exploited by considering the cost and complexity of analog circuitry in MAR signalling and signal processing, by considering more complex models for wireless propagation, and by putting MAR in networking context. The focus of this effort is to push MAR technology by exploiting the structure in these more complex models and networking scenarios.The objectives of the effort can be succinctly stated as:1) Communication theory is often interested in normalizing performance for a fixed average power but in wireless implementations the peak power is a more critical driver than the average power. The research is examining optimization of performance and throughput with a peak power constraint in multiple antenna radio.2) Feedback communication is likely going to enable a significant improvement in throughput and demodulator complexity in a networked scenario especially in environments with low mobility (e.g., wireless computer networks). This research is approaching feedback communication with a classic scientific method of iterating between experimentation on real channels and more realistic theoretical problem formulations based on the results derived in experimentation.3) The cost driver in wireless communication currently is the analog circuitry. This research is examining techniques that would minimize the complexity of the analog systems in a multiple antenna radio. The objectives are to being met by the following research tasksa) Improved channel parameterization for long range prediction for multiple antenna radio,b) Design and field testing of a variety of MAR automatic repeat request algorithms,c) Experimentation with the proposed feedback algorithms for MAR,d) Feedback algorithms for MAR with constant envelop modulations,e) Feedback algorithms for MAR with limited analog capabilities,