Development & Analysis of Multi-user Receivers for Multi-rate Wireless Communication

为了使未来的无线通信网络能够适应各种潜在的不同来源（语音、数据和视频信号），必须开发多速率通信方案。可能的来源，如语音、视频和数据通信，具有本质上不同的服务质量（QoS）需求。当前无线网络中存在的恒定比特率范式将无法服务于未来的这种多等级服务。本研究的主要目的是对不同信息速率的多用户扩频通信接收机进行分析和开发。研究了直接序列扩频码分多址通信中几种多速率多用户接入方案。初步研究计划开展三项活动。首先，将研究现有的单比特率接收器，以确定它们是否易于扩展到多速率通信。其次，将创建多用户接收器，以明确地利用窄带和宽带用户信号混合中的冗余。第三，将开发成本函数来比较创建的各种接收器。由于所考虑的信号的性质，位检测错误的概率不能完全捕获给定接收器的性能。初步研究的最终目标是使申请人能够进行真正可变比特率通信（例如视频传输）的设计和分析研究；每个用户的比特率都在变化的通信。在多速率通信中，每个用户以恒定速率传输，该速率可能因用户而异。认为这种接收机必须具有自适应特性，才能适当地支持可变额定通信量。

9505881 Urbashi Mitra In order for future wireless communications networks to accommodate a variety of potentially disparate sources (voice, data and video signals), multi-rate communication schemes must be developed. Possible sources such as voice, video, and data communications have inherently different quality of service (QoS) requirements. A constant bit-rate paradigm as exists in the current wireless network will not serve such multi-rated services of the future. The principal aim of this research is to begin the analysis and development of communication receivers for multi-user spread-spectrum communications with different information rates. Several multi-rate multi-user access schemes will be considered for Direct-Sequence Spread Spectrum Code-Division Multiple-Access communications. Three activities are planned for the preliminary study. First, existing single bit rate receivers will be investigated to determine whether they are easily extensible to multi-rate communications. Second, multi-user receivers will be created to explicitly exploit the redundancy in the mixture of narrowband and wideband user signals. Third, a cost function will be developed to compare the various receivers created. Due to the nature of the signals being considered, the probability of bit detection error does not fully capture the performance of a given receiver. The ultimate goal of the proposed preliminary research is to position the applicant to perform research on the design and analysis of true variable bit rate communications (e.g. video transmissions); communications where the bit rate is changing for each individual user. In multi-rate communications each user transmits at a constant rate which may differ from user to user. It is believed that such receivers must be adaptive in nature to properly support the variable rated traffic.