IEEE/ACM Transactions on Networking (TON)
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This dissertation addresses the problem of scheduling inelastic and elastic flows in multi-hop wireless networks. Schedulers, by setting the rules for transmission strategies, play a critical role in determining the performance of the network. Thus, a good understanding of schedulers is vital for the design of high performance networks. Towards this goal, we start by studying the problem of stable scheduling for a class of cellular wireless networks. The goal is to stabilize the queues holding information to be transmitted over a fading channel. We prove that, for any mean arrival rate that lies in the capacity region, the queues are stable under the policy we propose. Moreover, we show that it is easy to incorporate imperfect queue length information and other approximations that simplify the implementation of our policy. Next, we focus on the performance of well-known schedulers for serving delay-constrained traffic. In particular, we provide analytical as well as numerical analysis of Opportunistic and Time-Division-Multiplexing schedulers. We demonstrate that the behavior of the throughputs supportable by these schedulers is quite different when delay constraints are imposed. We then consider the problem of fair end-to-end resource allocation in wireless networks. First, we consider the problem of allocating resources (time slots, frequency, power, etc.) at a base station to many competing flows, where each flow is intended for a different receiver. The channel conditions may be time-varying and different for different receivers. It is well-known that appropriately chosen queue-length based policies are throughput-optimal while other policies based on the estimation of channel statistics can be used to allocate resources fairly among competing users. We show that a combination of queue-length-based scheduling at the base station and congestion control implemented either at the base station or at the end users can lead to fair resource allocation and queue-length stability. These results are then generalized to multihop wireless networks. However, for general multihop networks, we require a centralized scheduling policy. For a simple interference model, we study distributed and asynchronous versions of the mechanisms that we proposed, and prove their convergence properties.