Co-operative downlink scheduling for cell edge and handoff users

We present a new co-operative scheduling approach which provides not only more reliability but also higher effective capacity. Cooperation region is defined for active handoff users between two base stations (BSs) based on the user quality-of-service (QoS) requirements. A proper definition of co-operation or handoff region, where the user can be scheduled in a cooperative manner from more than one BS, is also given based on per-BS load and user QoS. Numerical results are presented showing reliability, user QoS performance, handoff region and capacity gain due to co-operative scheduling. Our analysis indicates that, when the QoS requirement is loose, co-operation provides relatively less gain and the handoff window size is also less. On the other hand, when the QoS requirement becomes more stringent, the gain in the effective capacity increases by using co-operation and the co-operation or handoff window size is also large, which can go up to 25% of the total area.