CIF: Small: Fundamental limits and coding for massive wireless random-access

下一代无线电接入网络（诸如蜂窝）的关键预期创新是它们服务于如在所谓的“物联网”中设想的大量有源设备的能力。不幸的是，目前的网络设计考虑到了人类类型的通信，这导致了对（相对）少数同时活跃用户的操作机制的关注。更具体地，本系统采用集中式资源分配，从而使来自不同用户的接入正交化。这种解决方案对于机器类型的通信是不可接受的，因为它依赖于显著的控制层开销，从而导致延迟和能量效率的显著损失。因此，无论是在非授权频谱（所谓的低功率广域网）还是在授权频谱（5G）中，都存在对新的解决方案的强烈的经济需求，本文的目标是为下一代无线网络的多址接入层设计提供理论指导。关于这个主题的经典工作缺乏一些具体的细节，使其不足：忽略网络分析文献中的控制层开销，以及忽略信息论中的延迟。因此，这项工作的目的是提供必要的当代修改：（a）一个巨大的数量的空闲（不活跃）用户;（B）仍然大量的活跃用户;（c）短数据包;（d）高能源效率（低能量每比特）。该项目介绍了一种新的随机接入编码的范例，将数据通信与用户识别分离，将导出基本限制并研究低复杂度的实用解决方案。目前可用的解决方案的性能将与非渐近的基本限制和新的解决方案开发。除了信息理论和通信理论的部分，工作涉及的组合理论的组成部分，在构造西顿集，B2序列和叠加码的形式。

The key expected innovation of the next generation of radio-access networks (such as cellular) is their ability to service vast numbers of active devices as envisioned in the so-called "Internet-of-Things". Unfortunately, current networks were designed with the human-type communication in mind, and this led to a focus on the operating regime of a (relatively) few simultaneously active users. More specifically, present systems employ centralized resource allocation, thus orthogonalizing the access from different users. This solution is not acceptable for machine-type communication, as it relies on a significant control-layer overhead thereby incurring a significant penalty in latency and energy efficiency. Consequently, there is a strong economical demand for a new solution in both the unlicensed spectrum (so called, low-power wide-area networks) and the licensed spectrum (5G).The goal of this work is to provide theoretical guidance for the design of the multiple-access layer in the next generation of wireless networks. Classical work on the topic lacks several specific details, making it inadequate: ignoring the control-layer overhead in network analytic literature, and ignoring delay in information theory. Consequently, this work aims to provide necessary contemporary modifications: (a) a gigantic number of idle (inactive) users; (b) a still large number of active users; (c) short packets; (d) high energy-efficiency (low energy-per-bit). This project introduces a new paradigm of random-access coding that separates data communication from user identification, for which fundamental limits are going to be derived and the low-complexity practical solutions studied. Performance of the currently available solutions will be contrasted with the non-asymptotic fundamental limits and new solutions developed. In addition to information-theoretic and communication-theoretic parts, the work involves a combinatorial-theoretic component in the form of constructing Sidon sets, B2-sequences and superimposed codes.