A cognitive PHY-MAC cooperative protocol for low-power short-range wireless ad-hoc networks using UWB PPM radios.

摘要

Nowadays low-power short-range wireless ad-hoc networks are becoming more popular as the demand for wireless applications such as sensor and personal area networks continue to grow. Recently, in particular since the Federal Communications Commission approval in 2002, ultra-wideband (UWB) communications have been proposed as a viable and efficient alternative to implement short-range wireless applications. For the past decade, numerous investigations and research works have been done in order to employ UWB technology in wireless applications that have been traditionally implemented with conventional narrowband technologies. The vast range of benefits offered by UWB makes it, in many cases, an ideal solution when implementing wireless radios and networks. Low-power operation, low-complexity and low-cost radio architectures, and high data rates are among the many advantages of UWB. In most short-range wireless ad-hoc networks, low-power operation as well as multiple access control (MAC) is crucial in the network design.;Pulse-position modulation (PPM) is a well-known digital modulation scheme that when used in UWB radios can achieve simple low-cost architectures and more importantly a very low-power operation while offering relatively good data rates and bit-error rate (BER) performance. The DCF function described by the IEEE 802.11 WLAN standard is used quite often as the MAC protocol when implementing wireless networks in general and has proven to be efficient for many applications. This doctoral dissertation presents a new cognitive and cooperative protocol between the physical (PHY) layer and the MAC sublayer for wireless ad-hoc networks using PPM UWB radios. By a cognitive estimation of the wireless channel and the cooperation between the MAC and PHY layers, the cognitive protocol can dynamically adjust the transmission data rate between two nodes optimizing their communication. Simulations show that the protocol improves the overall network performance in terms of message delivery ratio and average transmission delay.