Wireless sensor networks are characterized by multihop wireless lossy links and resource constrained nodes. Energy efficiency
is a major concern in such networks. In this paper, we study Geographic Routing with Environmental Energy Supply (GREES) and
propose two protocols, GREES-L and GREES-M, which combine geographic routing and energy efficient routing techniques and take
into account the realistic lossy wireless channel condition and the renewal capability of environmental energy supply when
making routing decisions. Simulation results show that GREESs are more energy efficient than the corresponding residual energy
based protocols and geographic routing protocols without energy awareness. GREESs can maintain higher mean residual energy
on nodes, and achieve better load balancing in terms of having smaller standard deviation of residual energy on nodes. Both
GREES-L and GREES-M exhibit graceful degradation on end-to-end delay, but do not compromise the end-to-end throughput performance.
Keywords Wireless sensor networks - Geographic routing - Energy efficiency - Environmental energy supply
Kai Zeng received his B.E. degree in Communication Engineering and M.E. degree in Communication and Information System both from Huazhong
University of Science and Technology, China, in 2001 and 2004, respectively. He is currently a Ph.D. student in the Electrical
and Computer Engineering department at Worcester Polytechnic Institute. His research interests are in the areas of wireless
ad hoc and sensor networks with emphases on energy-efficient protocol, cross-layer design, routing, and network security.
Kui Ren received his B. Eng. and M. Eng. both from Zhejiang University, China, in 1998 and 2001, respectively. He worked as a research
assistant at Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences from March 2001 to
January 2003, at Institute for Infocomm Research, Singapore from January 2003 to August 2003, and at Information and Communications
University, South Korea from September 2003 to June 2004. Currently he is a PhD candidate in the ECE department at Worcester
Polytechnic Institute. His research interests include ad hoc/sensor network security, wireless mesh network security, Internet
security, and security and privacy in ubiquitous computing environments.
Wenjing Lou is an assistant professor in the Electrical and Computer Engineering department at Worcester Polytechnic Institute. She obtained
her Ph.D. degree in Electrical and Computer Engineering from University of Florida in 2003. She received the M.A.Sc. degree
from Nanyang Technological University, Singapore, in 1998, the M.E. degree and the B.E. degree in Computer Science and Engineering
from Xi’an Jiaotong University, China, in 1996 and 1993 respectively. From December 1997 to July 1999, she worked as a Research
Engineer in Network Technology Research Center, Nanyang Technological University. Her current research interests are in the
areas of ad hoc and sensor networks, with emphases on network and system security and routing.
Patrick J. Moran received his MSEE from Carnegie Mellon University, 1993. He is currently the CTO and Founder of AirSprite Technologies Inc,
and is driving the company to utilize advanced networking protocols for low-power wireless network systems. His interests
include architecture, protocols and high performance implementation of emerging communication technologies. Patrick has been
involved in deployment of communication and signal processing technologies since graduating from the University of Minn. in
1986. He holds several patents and publications relating to storage, medical and data processing information systems. He is
a member of the IEEE.