Very Low Power Wireless Protocol Performance
Abstract
The IEEE 802.11 standard was established to take advantage of the cost savings and ease of use associated with wireless local area networks. Unfortunately, 802.11 falls short in meeting the low power requirements of many applications not directly associated with typical LAN use. This shortfall is becoming evident with the explosion of a new market for wireless devices such as sensing units, home networks, and portable personal devices. In 1997 the Charles Stark Draper Laboratory began preliminary research into a United States Navy program named Reduced Ships-Crew by Virtual Presence (RSVP). This program calls for numerous battery-powered sensors to wirelessly communicate with a ship's wired backbone. These sensors are considered very low power since they must operate reliably for a period of 10 years without battery replacement. This thesis compares the performance of IEEE 802.11 against a Draper proprietary protocol in an environment characterized by low noise and slow-fat Rayleigh fading. It will be shown that for standard 802.11 devices, configured optimally for the RSVP environment and neglecting sensory power, the best estimate for lifespan when operating on 3 standard AA batteries is only 36 days. Whereas a device using the RSVP protocol can theoretically operate up to 15 years, much longer than the expected life of a standard battery. This problem will further be broken down into individual segments of power consumption, to include transmission, reception, and sleep mode. Unlike previous research that has dealt with the physical layer or medium access layer only, this thesis will bring together all aspects of the system to pinpoint the greatest factors in power consumption. It will be shown that the modulation technique and receiving modes of each protocol are irrelevant in the overall life expectancy of the device and that true power savings come in the form of efficient device design and minimizing the protocol requirements required during sleep mode. c
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 2000
- Accession Number
- ADA384172
Entities
People
- Joshua L. Jabs
Organizations
- Tufts University