Multiple Description Coding with Correlating Transforms for Multiple Antenna Wireless Systems

多描述编码（MDC）是一种有效的方法，它假定在发送端和接收端之间存在多个独立的信道，每个信道都可能是暂时中断的，也可能会出现突发错误，从而在传输效率降低相对较小的情况下为多媒体传输提供抗误码能力。 利用MDC，生成多个编码流，称为描述，并在不同的信道上传输。 在目的地，如果所有的数据流都是无差错接收的，那么信号就可以以最高的保真度重建。然而，如果只有一个或几个描述以可用的形式被接收，接收机仍然可以重构可接受的信号。 到目前为止，所有的多描述编码方法都假设发射机和接收机之间的信道模型是开-关的;每个链路要么是断开的，在这种情况下，发送的符号或数据包完全丢失，要么是正常工作的，在这种情况下，接收的数据包没有错误。 该模型适用于Internet传输，但不适用于无线信道，本研究将并行独立on-off信道模型替换为无线信道模型，如瑞利衰落模型。 通信是使用多个发射和接收天线在信道上执行。 在这些模型下，任何一根接收天线上的信号都是来自每个发射天线的独立衰落的发射信号的叠加，因此，即使在接收端的描述是完全独立的，每个天线上的接收信号也将包含来自每个描述的一些信息. 这项研究涉及到为这些信道寻找最佳的多描述编码策略，这种方案的理论限制，以及它可以实现的效率。

An effective way of providing error resilience for multimedia transmission in acommunication system with a relatively small reduction in efficiency is multipledescription coding (MDC), which assumes the existence of multiple independentchannels between the transmitter and receiver, each of which can be temporarilydown or can experience burst errors. With MDC several coded streams, calleddescriptions, are generated and transmitted over different channels. At thedestination, if all of the streams are received error free, than the signal canbe reconstructed at its highest level of fidelity. However, if only one or a fewdescriptions are received in a usable form, the receiver can still reconstructan acceptable signal. All multiple description coding methods to date assume anon-off channel model between the transmitter and the receiver; each link iseither broken, in which case the transmitted symbols, or packets, are lostcompletely, or it functions properly, in which case the packets are receivedfree of errors. This model is appropriate for Internet transmission, but it isnot appropriate for wireless channels.This study replaces the parallel independent on-off channel model with awireless channel model, such as a Rayleigh fading model. Communication isperformed using multiple transmit and receive antennas over the channel. Withthese models the signal at any of the receive antennas is the superposition ofthe transmitted signals from each transmit antenna independently faded.Therefore, even if the descriptions at the receiver side are completelyindependent, the received signal at each antenna will include some informationfrom each description. This research involves finding the best multipledescription coding strategy for these channels, the theoretical limits of such ascheme, and the efficiency with which it can be implemented.