An Investigaton of the Interaction Between Codes and Decoding Machines

摘要：NCR-9415685，约翰霍普金斯大学，“码与译码机相互作用的研究”，PI-Collins：这项研究的基本概念是将译码本身作为一个通信问题来研究。电子学已经发展到这样一个阶段：许多芯片，每个芯片包含数万甚至数十万个门，可以交换卫星终端天线孔径的减小或远程浮标或蜂窝电话中较低的发射机功率。由于两个通信方向的成本不对称，这些后一种应用程序能够很好地使用极其强大的编码。以移动电话为例，从移动设备连接到移动设备的节电比连接到移动设备的节电重要得多。基站中的复杂解码器从交流电源获取电力，可以节省移动发射机的电池电力。同样，一个大规模的环境数据收集网络只需要在发射机中加入简单和廉价的编码器；卫星或地面站的单个解码器可以服务所有这些编码器。不幸的是，单片硅片处理能力的一小部分都很难开发，更不用说包含许多芯片的模块了。难点在于如何在译码机的不同部分之间提供足够的内部通信。今天，布线连接而不是门数限制了信号处理的复杂性。这项研究提出了在解码引擎的不同部分被分割成单独的部分时，必须流入和流出的信息量的界限。目前，这些边界仅限于基于移位寄存器的代码的维特比解码。本研究将这些界限扩展到其他编码和解码算法，更重要的是，探索允许以最小信息流解码的编码（包括卷积和基于一般有限状态机的编码）。用于分析解码器信息流的相同技术也将应用于其他情况，其中划分是重要的，例如，非常大的电路开关。剖析解码器信息流可能会产生具有实际用途的新一代代码，并且肯定会产生对当前使用的代码类型的最终限制的见解。***************************************************************************** 奥布里·m·BushProgram导演,代理副分工和DirectorDivision网络和通信研究和InfrastructureNational科学基金会

ABSTRACT: NCR-9415685, Johns Hopkins University, "An Investigation of the Interaction Between Codes and Decoding Machines", PI-Collins: The essential concept of this research is to study decoding, itself, as a communications problem. Electronics has advanced to the stage where many chips, each containing tens or even hundreds of thousands of gates, can advantageously be exchanged for a decrease in antenna aperture in a satellite terminal or for a lower transmitter power in a remote buoy or cellular telephone. These latter applications are well able to use extremely powerful coding because of the asymmetry of cost in the two directions of communication. In the case of cellular telephones, for example, power savings are much more important in the link from the mobile unit than in the link to the mobile unit. A sophisticated decoder in the base station drawing power from the AC mains can save battery power in the mobile transmitter. Similarly, a large scale environmental data collection network need incorporate only simple and cheap encoders in the transmitters; a single decoder in a satellite or ground station can service all of these encoders. Unfortunately, exploiting even a small fraction of the processing power of a single piece of silicon is hard, let alone that of a module containing many chips. The difficulty is providing sufficient internal communication among the different parts of the decoding machine. Today, wiring connectivity rather than gate count limits the sophistication of signal processing. This research presents bounds on the amount of information which has to flow in and out of the different sections of a decoding engine when it is partitioned into separate parts. At the moment, these bounds are confined to the Viterbi decoding of shift register based codes. This research will extend these bounds to other codes and decoding algorithms and, more importantly, explore codes (both convolutional and general finite state machine based) which allow decoding with minimum information flow. The same techniques used in analyzing decoder information flow will also be applied to other situations where partitioning is important, e.g., very large circuit switches. Dissecting decoder information flow may result in a new generation of codes of great practical use and will certainly yield insights into the ultimate limits of the type of codes in use today.*****************************************************************************Aubrey M. BushProgram Director, Acting Deputy Divison DirectorDivision of Networking and Communications Research and InfrastructureNational Science Foundation