International Journal of Networking and Computing – www.ijnc.org ISSN 2185-2839 (print) ISSN 2185-2847 (online) Volume 1, Number 1, pages 63–81, January 2011 Cross-layer Design for Cooperative Wireless Sensor Networks with Multiple Optimizations Wei Chen, Heh Miao Department of Computer Science, Tennessee State University 3500 John A. Merritt Blvd, Nashville, TN 37209, U.S.A. Liang Hong Department of Electrical and Computer Engineering, Tennessee State University 3500 John A. Merritt Blvd, Nashville, TN 37209, U.S.A. Received: July 1, 2010 Revised: October 26, 2010 Accepted: December 11, 2010 Communicated by Akihiro Fujiwara Abstract In virtual MIMO technology, distributed single-antenna radio systems cooperate on infor- mation transmission and reception as a multiple-antenna MIMO radio system. In this paper, a cooperative transmission scheme, virtual MIMO network formation and reconfiguration al- gorithms, and a cooperative routing backbone are cross-layered designed for wireless sensor networks (WSNs) to jointly achieve required reliability, energy efficiency and delay reduction. The proposed cooperative transmission scheme minimizes the number of intra communications among cooperative nodes. It can save energy and reduces latency at transmission links even when the distance between cooperative nodes is large. In the proposed routing backbone, en- ergy consumption and latency are optimized simultaneously along the route which leverages the MIMO advantages from local transmission links into the whole network. In order to apply the virtual MIMO technology to a general WSN, the number of the cooperative nodes and the length of transmission links are allowed to have heterogeneity. The proposed virtual MIMO radio network can be formed for any underlying WSN with low reconfiguration cost. The per- formance evaluation shows that the proposed design can fully realize the potential of the virtual MIMO technology and largely improve reliability, latency and energy consumption in a WSN. Keywords: wireless sensor networks, MIMO radio systems, cooperative wireless communication, cross-layer design, reconfigurable routing 1 Introduction A multi-hop network of wireless micro sensor devices has been used for many real time applications such as environment monitoring and vehicle tracking [1]. Since a wireless micro sensor device is usu- ally equipped with computational-capability constrained processor, single-antenna radio and limited battery power, high network performance and low energy consumption have been very challenging issues in the design of wireless sensor networks (WSNs). Multiple Input Multiple Output (MIMO) radio transceivers employ multiple digital adaptive transmission and reception antennas which can 63