A load-aware handoff and cell-site selection scheme in multi-cell packet data systems

Handoff and cell site selection schemes in multi-cell cellular systems are traditionally developed for mobile stations (MS) of dedicated (circuit-switched) channels to/from base stations (BS). The schemes usually only consider physical-layer signal quality in decision making. In high-speed packet access systems, where a downlink channel is being shared by multiple users within each cell, those schemes are subject to local congestion and asymmetric packet call blocking across multiple cells. A way to reduce the hot-spots and alleviate asymmetry loading in such systems is the target of our study. To do so, we formulate the handoff and cell site selection procedures into a problem of iterative optimal channel assignment in multiple cells, and approximately solve the issue by incorporating a distributed load-awareness scheme into the procedures in order to keep the complexity low but practicality high. Extensive experiments show the effectiveness of our scheme and its advantages over the legacy schemes in load balancing and congestion reduction. With our scheme, a multi-cell wireless system in support of high-speed packet data access can accommodate more satisfied users and be more robust to asymmetric load dynamics across the whole system.