CIF: Medium: Modeling, Analysis, and Code Design for Portable Wireless Device Transmitters Subject to an Electromagnetic Exposure Constraint

全球销售的便携式无线设备数量达数十亿，它们每天都在使用，因为它们能够通过将处理能力、触摸屏、摄像头和运动传感器与多个无线电集成在一起来提供连接，其中许多无线电可以同时运行。 在人体附近使用的便携式无线设备具有发射机功率限制，这主要取决于对称为“特定吸收率”（SAR）的电磁暴露形式的监管限制。SAR以瓦特每千克为单位测量，是对人体电磁能量吸收率的测量。 今天销售的许多便携式无线设备的工作频率接近公认的人体SAR极限。 本研究探讨如何在便携式无线设备上的多个发射器可以建模，分析和使用，而受到SAR约束。 这项工作着眼于如何建模的约束，以及如何实现可靠性和高数据速率的优势，多个天线的约束。由于便携式设备一般都很小，发射机将物理上接近彼此和电磁耦合。 因此，本研究需要在三个不同的领域进行混合努力：（i）多发射机的电磁学和近场暴露建模，（ii）无线通信系统的远场信息理论性能评估与近场SAR约束，（iii）设计SAR码的最佳性能。 编码性能将通过模拟和实验室评估来确定，这些评估使用了用于近场SAR和远场误差率测量的微波设备。

Portable wireless devices sold around the world number in the billions, andthey are used daily because of their ability to provide connectivity byintegrating processing power, touch screens, cameras, and motion sensorswith multiple radios, many of which can run simultaneously. Portablewireless devices used in close proximity to the human body have transmitterpower constraints that are dictated largely by regulatory limits on a formof electromagnetic exposure called ``specific absorption rate'' (SAR).SAR, measured in Watts per kilogram, is a measure of the rate ofelectromagnetic energy absorption by the body. Many portable wirelessdevices sold today operate near the accepted human SAR limit. Thisresearch examines how multiple transmitters on a portable wireless devicecan be modeled, analyzed, and used while subject to a SAR constraint. Thework looks at how to model the constraint, and how to realize thereliability and high data-rate advantages of multiple antennas subject tothe constraint.Because portable devices are generally small, transmitters will bephysically close to one another and couple electromagnetically. Hence, theresearch requires a blended effort in three distinct areas: (i)electromagnetics and near-field exposure modeling with multipletransmitters, (ii) wireless communication system far-fieldinformation-theoretic performance evaluation with a near-field SARconstraint, (iii) the design of SAR codes for optimum performance. Codeperformance will be determined by simulation and by laboratory evaluationwith microwave equipment for near-field SAR and far-field error-ratemeasurements.