A Diversity-Embedding Approach for High-Rate Reliable Multimedia Wireless Communications

在多天线无线通信中，速率和可靠性(分集)之间存在根本的权衡。本研究将多样性视为一种系统资源，并探讨在多媒体无线通信中如何分配这种资源以达到可接受的速率分集折衷。多媒体数据通常是复杂的，由具有不同速率/可靠性要求的各种分量组成。例如，实时数据流可以接收比非实时数据更多的分集(保护)。其他例子包括复杂的数据流，如压缩视频，其各种分量需要不同级别的差错保护。将分集过度分配给一个数据分量将意味着对该数据分量和其他数据分量的速率损失，这是对系统资源的浪费。本研究的重点是创建灵活的空时资源池，而不是设计固定的最大分集方案。研究人员设计了高速率的空时码，其中嵌入了高分集代码。这允许一种形式的无线通信，其中高速率码机会主义地利用良好的信道实现，而嵌入的高分集码确保至少部分信息被可靠地解码。所提出的分集嵌入码在传输端不需要信道知识，且性能优于分时方案。使用所提出的编码方案，每个业务类型构成在合适的速率分集折衷点处操作的传输层。研究人员从设计问题、特定的代码结构以及多媒体通信的应用等方面探讨了这一观点。

There is a fundamental tradeoff between rate and reliability (diversity)in multiple-antenna wireless communications. This research views diversityas a systems resource and explores allocation of this resource to achieve adesirable rate-diversity tradeoff in multimedia wireless communications.Multimedia data is often complex and consists of various components withdifferent rate/reliability requirements. For example, a real-time datastream is a candidate to receive more diversity (protection) thannon-real-time data. Other examples include complex data streams such ascompressed video, whose various components require different levels oferror protection. Over-provisioning of diversity to one data componentwill mean the loss of rate to that and other data components, a waste ofsystem resources.The focus of this research is on the creation of a flexible poolof space-time resources rather than the design of fixedmaximum-diversity schemes. The investigators design high-rate space-time codes that have a high-diversity code embedded within them. This allows a form of wireless communications where the high-rate codeopportunistically takes advantage of good channel realizationswhile the embedded high-diversity code ensures that at least partof the information is decoded reliably. The proposeddiversity-embedding codes do not require channel knowledge at thetransmitter and outperform time-sharing schemes. Using the proposed coding scheme, each traffictype constitutes a transmission layer that operates at a suitablerate-diversity tradeoff point. The investigators explore this point of view withdesignissues, specific code constructions, and application to multimediacommunications.