| Wireless sensor networks (WSNs) are well suited to solve numerous real-world data collection and estimation problems. While the wireless nodes used for these applications share many similarities with classical wireless terminals, they are also unique in many ways. In particular, WSNs are typically deployed with little or no existing infrastructure and thus must set-up and operate autonomously. In addition, these wireless nodes are often severely constrained in terms of operational resources. For these reasons, there has been a great deal of research and development for medium access control (MAC) and network layers that are designed to meet these unique operational parameters. Here, we introduce a dynamic channel allocation (DCA) algorithm that is designed to operate in a fully distributed ad hoc manner. This DCA-MAC algorithm employs a common channel for link setup as well as multiple additional frequency channels that are used for data transmission. Benefits for ad hoc networks, in general, include the ability to provide reduced contention and higher aggregate network throughput. In addition, the algorithm is able to provide increased Quality of Service (QoS) through cross-layer optimizations between the network and MAC layer. Specifically for WSNs, the algorithm provides the ability to operate in heavily contented spectrum by avoiding interference. Deemed essential for long-term operation, sleep synchronization is popular for WSNs; DCA-MAC has been designed to incorporate this mechanism. |
| Richard Cagley, Senior Analyst, Toyon, received the B.S. degree in engineering from
Harvey Mudd College in Claremont, CA in 1997 and the M.S. and Ph.D. degrees in electrical engineering from University of California, Santa Barbara in 1999 and 2003 respectively. Dr. Cagley's general research interests are in the areas of physical and MAC layer design for wireless communication. This includes multiuser detection, interference cancellation, space-time processing, spectrum management, and digital receiver design.
Dr. Cagley has worked on multiuser detectors for direct-sequence code-division multiple-access (DS/CDMA) communication systems. The bulk of this work has pertained to a specific detection technique, termed successive interference cancellation (SIC), as it applies to the IS-95 downlink. While with Toyon, Dr. Cagley has been involved in a variety of programs relating to wireless communication and sensor networks. Dr. Cagley has served or is currently functioning as the Principal Investigator on eight SBIR/STTR programs. These primarily focus on MAC layer algorithm design and multiple-input multiple-output (MIMO) antenna systems. Dr. Cagley has practical design experience with algorithm implementation on a variety of embedded systems including MCU/DSP/FPGA platforms. Prior to joining Toyon Research Corporation, Dr. Cagley held positions with Fujant Incorporated, Jet Propulsion Laboratories, and Qualcomm Corporation.
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