关键词：传感器；无线传感器网络；无线衰落信道；环境监测
摘 要：Wireless Sensor Networks (WSNs) are widely used in applications such as event detection, environment monitoring, target tracking, and home automation. Typically, manually deployed sensors measure environmental information, e.g., temperature, image, and wind speed, etc., and transmit noisy versions of these measurements over wireless fading channels to the local intelligent control center (ICC), in which an estimation of these state measurements is obtained and thus related control operations are conducted. This chapter investigates physical layer communications of WSNs in two parts:(1) Impulse Radio Ultra-Wideband (IR-UWB) capacity optimization under the coexistence with the OFDM-based wireless communication system-IEEE 802.11n. The optimal power allocation scheme is presented by using the water-filling algorithm with Karush-Kuhn-Tucker (KKT) conditions, which is also compared with a traditional equal power allocation scheme;(2) sensor selection schemes for the parameter estimation in energy-constrained WSNs. To prolong the network lifetime and optimize the power consumption, only sensors experiencing favorable conditions will participate in the estimation process. And two sensor selection schemes are proposed to improve the estimation performance.