Real-time deployment of multihop relays for range extension

摘要

When the range of single-hop wireless communication is limited by distance or harsh radio propagation conditions, relays can be used to extend the communication range through multihop relaying. This paper targets the need in certain scenarios for rapid deployment of these relays when little or nothing is known in advance about a given environment and its propagation characteristics. Applications include first responders entering a large building during an emergency, search and rescue robots maneuvering a disaster sight, and coal miners working underground. The common element motivatingthis work is the need to maintain communications in an environment where single-hop communication is typically inadequate. This paper investigates the feasibility of the automated deployment of a multihop network. A deployment procedure is proposed that employs real-time link measurements and takes into account the physical layer characteristics of a mobile multipath fading environment and the radio in use. A prototype system is implemented based on 900 MHz TinyOS motes supporting low-speed data applications including text messaging, sensor data and RFID-assisted localization. Results of deployments in a hi-rise office building are presented.