Quality-of-Service Driven Power and Rate Control in Mobile Wireless Networks

We propose a Quality-of-Service (QoS) driven power- and rate-control scheme in mobile wireless networks. Specifically, the proposed scheme aims at maximizing the system throughput subject to a given delay QoS constraint. Over the block fading channel, we derive the optimal adaptation policy by integrating information theory with the concept of effective capacity. The analyses demonstrate that there exists a fundamental tradeoff between spectral efficiency and QoS provisioning. When the QoS constraint is loose, the optimal power control policy converges to the well-known water-filling scheme, where the Shannon capacity can be achieved. On the other hand, when the QoS constraint is stringent, the optimal policy converges to the total channel inversion such that the system operates with a constant service rate.