Downlink scheduling in a cellular network for quality of service assurance

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We consider the problem of scheduling data in the downlink of a cellular network, over parallel time-varying channels, while providing quality of service (QoS) guarantees, to multiple users in the network. We design simple and efficient admission control, resource allocation, and scheduling algorithms for guaranteeing requested QoS. Our scheduling algorithms consists of two sets, namely, (what we call) joint K&H/RR scheduling and reference channel (RC) scheduling. The joint K&H/RR scheduling, composed of K&H scheduling and round robin (RR) scheduling, utilizes both multiuser diversity and frequency diversity to achieve capacity gain, and the RC scheduling minimizes the channel usage while satisfying users' QoS constraints. The relation between the joint K&H/RR scheduling and the RC scheduling is that 1) if the admission control allocates channel resources to the RR scheduling due to tight delay requirements, then the RC scheduler can be used to minimize channel usage; 2) if the admission control allocates channel resources to the K&H scheduling only, due to loose delay requirements, then there is no need to use the RC scheduler. In designing the RC scheduler, we propose a reference channel approach and formulate the scheduler as a linear program, dispensing with complex dynamic programming approaches, by the use of a resource allocation scheme. An advantage of this formulation is that the desired QoS constraints can be explicitly enforced, by allotting sufficient channel resources to users, during call admission.