Network Capacity when Some Common Information Theoretic Assumptions Break Down

该研究试图了解多用户信息理论中的两个常见假设对网络容量区域的影响：全球码本知识和全球同步。在这些假设下，复杂的编码方案和协调的传输策略是可能的。在分布式网络以及具有大量节点的网络中，保持同步和跟踪所有用户的码本可能根本不可能；在今天的蜂窝网络中，这会导致严重的开销。拟议研究的目标是从信息论的角度了解放宽这些假设对网络容量区域的性能有何影响。新技术方案的核心在于对离散字母进行编码，而不是使用标准的类高斯编码。从根本上理解，共享码本和保证网络同步的影响与改善现在和未来的异质、分布式、WiFi、蜂窝、自组织军事和急救无线网络中的通信直接相关。在更现实的假设下对网络进行准确的网络容量预测，不仅可以作为工程师构建系统的基准，还可以为获取码本或同步与相应容量区域之间的权衡提供指导。结果可能会证明，如果人们适当地调整传输方案，码本知识或同步可能并不像人们可能怀疑的那样重要，这可能会对无线网络的设计产生巨大影响。这项研究的结果预计将对私营部门和公共部门产生直接和深远的影响。

The proposed research seeks to understand the impact of two common assumptions in multi-user information theory on the capacity region of networks: global codebook knowledge and global synchronism. Under these assumptions, sophisticated coding schemes and coordinated transmission strategies are possible. In distributed networks, as well as networks with a large number of nodes, maintaining synchronicity and keeping track of all users' codebooks may simply not be possible; in today's cellular networks this incurs a severe overhead. The goal of the proposed research is to understand, from an information theoretic perspectiv,e how relaxing these assumptions affects network performance in terms of capacity regions. The core of the proposed new technical approach lies in coding over discrete alphabets rather than by using standard Gaussian-like coding.Understanding from a fundamental perspective the impact of sharing codebooks and guaranteeing synchronism in networks is of direct relevance to improving communications in heterogeneous, distributed, WiFi, cellular, ad hoc military and first responder wireless networks of the present and future. Having accurate network capacity predictions for networks under more realistic assumptions not only acts as a benchmark for engineers building systems, but also provides guidelines on the tradeoffs between acquiring codebooks or synchronism and the corresponding capacity regions. The results may prove that codebook knowledge or synchronism may not be as vital as one might suspect if one tailors transmission schemes properly, which could have dramatic impact on the design of wireless networks. The results of this research are expected to be of immediate as well as far-reaching use to private and public sectors alike.