Research at the Frontier of the Physical Layer

网络协议栈的物理层是指通过物理介质传输和接收的信号，这些物理介质包括电线（例如双绞线或同轴电缆）、电磁波（例如卫星转发器、蜂窝/PCS塔或无线局域网（WLAN）基站）或记录介质（例如磁碟或光盘）。从物理介质的角度来看，该研究具有广阔的视角，而由于所解决的问题都涉及一种形式的前向误差控制（FEC），因此该研究具有狭窄的焦点。本论文的研究方向包括三个方面：编码的数学方法与分析算法；代数编码中的Turbo码错误控制；交叉编码的理论与实践；一种计算二元卷积码权重分布的新方法；第二个主题领域涉及代数几何（AG）编码领域的基本理解和进展。这些AG码显示了在输电系统中的应用潜力。进一步的理解需要发展，使实际实施AG规范。在最后的主题中，“涡轮编码”的新应用被确定，包括具有存储器和涡轮编码调制的系统。

The physical layer of the network protocol stack refers to the signals transmitted, and received, over a physical medium, such as a wire (e.g. a twisted pair of wires or a coaxial cable), an electromagnetic wave (e.g. a satellite transponder, a cellular/PCS tower or a wireless local area network (WLAN) base station), or a recording medium (e.g. magnetic or optical disks). The research has a broad perspective, from the viewpoint of the physical medium, and a narrow focus in that the problems addressed all involve a form of forward error control (FEC). The research is directed in three areas: Mathematical methods and analysis algorithms for coding Problems in algebraic coding Turbo code error control In the first topic area, the following are considered: theory and practice of interleaving, a novel method for computing the weight distribution of a binary convolutional code, and problems concerning the capacity of wireless channels with and without side information on channel state. The second topic area concerns basic understanding and advances in the area of algebraic geometry (AG) coding. These AG codes show potential for application in transmission systems. Further understanding needs to be developed to enable the practical implementation of AG codes. In the final topic, new applications of "turbo coding" are identified, including systems with memory and turbo coded modulation.