Battery consumption and handoff examination of a cellular ad-hoc united communication system for operational mobile robots

A hybrid system in which mobile terminals (MTs) themselves select whether to communicate directly or via base stations (BSs) from communication conditions, "cellular ad hoc united communication system", has been proposed by Adachi and Nakagawa (1996). It has been confirmed to have effective channel usage, especially for MTs which tend to communicate with partners which are close together, such as operational mobile robots. In this paper, the hybrid system is examined with respect to battery consumption and handoff rate. In regard to battery consumption, this system showed better performance compared with pure cellular and pure ad-hoc communication systems. Such a system may suffer from frequent handoffs. However, by the addition of a simple hysteresis characteristic, the handoff rate was held down closer to that of a pure cellular system in a multipath environment. When a closer communication condition was assumed, the hybrid system out-performed the pure cellular system.