Stations in IEEE 802.11 ad-hoc WLAN protocol exchange frames by contending for the channel and follow the binary exponential
backoff for retransmitting the frames on collisions. This contention and collisions lead to low throughput and high power
consumption. Although the stations can enter sleep mode, however they are forced to keep awake for full Beacon interval period
if there are frames buffered for them. This long awake period leads to high power consumption. We have devised improved mechanisms
that facilitate transmissions with reduced contention. We have defined a reservation period in which the senders reserve the
channel by announcing the data frames to be transmitted to the Power Save (PS) stations. These announced frames are then transmitted
collision-free in the following transmission period, leading to high throughput. The PS stations keep awake for short duration to receive
these frames at predetermined periods, leading to high power saving. The mechanisms involve only software changes to the existing
802.11 protocol and can be
implemented on the existing 802.11 WLAN cards. The average power consumption in our mechanisms is only 1/6th of the power consumed in the 802.11b protocol, with the
stations consuming 84% lesser power. Our maximum throughput improved to 25% higher than the throughput of the 802.11b protocol. Our work also shows significant
performance improvement over some related work in this area. Under conditions of optimal throughput, our improved protocol
consumes 55% to 70% lesser power than SPAN protocol and has 3 to 5.8 times better Throughput/Energy consumption characteristics
than DPSM protocol.
Vimal K. Khanna (vimal_k@ieee.org) has nearly 21 years experience in the Communications Software industry. He has conducted research to develop
innovative networking protocols and products in a range of domains, like TCP/IP suite, Dynamic Source Routing, IEEE 802.11
WLAN, ATM, Frame Relay, ISO/OSI protocols suite, SNMP, Ethernet, X.25/PAD, etc. His independently written papers have appeared
in leading international archival networking journals. He has also developed innovative high performance techniques in the
Operating Systems domain. His work on performance enhancements to Unix/Linux STREAMS kernel mechanisms has won wide acceptance
in the industry and is cited on the Linux STREAMS (LiS) Open Source Community Website. He is on the Technical Editorial Board
of “IEEE Communications” magazine (pub. New York) since 1999. He has acted as a reviewer for “IEEE Multimedia” magazine and
multiple IEEE international conferences, like Globecom, ICC, etc. He has been an All India rank holder in the Indian Engineering
Services Examinations and Silver Medallist in the All India Senior Secondary School Examinations (Class XII). He has been
recipient of Ministry of Education All India Merit Scholarship and the National Talent Search Scholarship.
Hari M. Gupta received the B.E. degree from the University of Roorkee, now the Indian Institute of Technology (IIT), Roorkee, in 1967,
the M.Tech. degree from IIT, Kharagpur in 1969, and the Ph.D. degree from IIT Kanpur in 1974. He joined the faculty of Department
of Electrical Engineering at IIT, Delhi in 1973 where he has been a professor since 1986. He has been the Dean of Undergraduate
Studies, the Head of the Department of Electrical Engineering, and the Coordinator of Bharti School of Telecommunication Technology
and Management at IIT, Delhi. He has held faculty appointments at McGill University, Montreal, Canada and Drexel University,
Philadelphia, PA, USA. He has been an academic visitor to University of Maryland, College Park, MD, USA, the Media Lab, at
Massachusetts Institute of Technology, Cambridge, MA, USA, the Swiss Federal Institute of Technology, Lausanne, Switzerland,
Helsinki University of Technology, Helsinki, Finland, and several British Universities. His academic and professional interests
are in communication systems, computer communication networks, multimedia systems and photonic information systems. Dr. Gupta
has been India’s representative on the International Federation for Information processing (IFIP) Communications Committee.
He is a Fellow of The Institution of Electronics and Telecommunication Engineers (IETE), The Institution of Engineers (India),
and a Senior Member of Computer Society of India (CSI). He has been the Vice-President of the Systems Society of India, a
Council Member of IETE, the Chairman of the Data Communication Division of CSI, and a Founder Member of the Association for
Security of Information Systems (ASIS).
Satyavardhan Maheshwari was born in Indore, India. He received M.S. degree from the Department of Electrical Engineering, IIT Delhi in 2003. He received
B.E degree from the Department of Electrical Engineering, Devi Ahilya University, Indore. He joined Reliance Infocomm, India
in 2003 as an R&D Engineer working on CDMA2000 system design. He is working on CDMA Base Station and planning in RF Engineering.
His research area is IEEE 802.11 Ad-hoc Networks.