The importance of bi-directional monitoring to cellular handoff performance

Handoff control in cellular-based personal communication systems allows a subscriber unit to travel from one cell area to another without service interruption. Previously published handoff studies involve "balanced" system scenarios and focus on only the inbound (subscriber unit to base site) or outbound (base site to subscriber unit) link. We point out the inappropriateness of the balanced system assumption for systems that employ directive antennas. We examine the impact of leaving one link uncontrolled and show that a handoff control monitoring both links adapts better to link imbalances inevitable in different regions of the system.