Abstract
In this paper the problem of channel-aware opportunistic resource allocation for the downlink in CDMA wireless networks supporting simultaneously real-time multimedia and non-real-time data services is addressed. In order to treat different types of services with diverse QoS prerequisites through common optimization formulation a utility-based power and rate allocation framework is adopted. Emphasis is placed on real-time services' strict short-term QoS prerequisites, the fulfillment of which requires a significantly different treatment than the use of static utility functions, traditionally used to address long-term QoS or fairness prerequisites of delay-tolerant data services. To that end, we introduce a novel framework that enables the dynamic adaptation of real-time multimedia users' utilities as the system evolves, with respect to the corresponding short-term throughput service performance variations. The corresponding non-convex network utility maximization (NUM) problem is then formulated and solved, to obtain optimal power and rate allocation. Via simulation and analysis it is demonstrated that significant performance improvements are achieved in terms of real-time user's short-term throughput requirement satisfaction, without any considerable loss in total system throughput. Finally, essential tradeoffs between fulfilling real-time services' short-term QoS prerequisites and maximizing system performance, under an opportunistic scheduling wireless environment, are revealed and quantified.
Highlights
With the growing demand for high data rate and support of multiple services with various quality of service (QoS) requirements, the scheduling policy plays a key role in the efficient resource allocation process in future wireless networks
In order to better illustrate the performance and the efficacy of the proposed scheme, in terms of average achieved actual downlink throughput and RT users’ short-term throughput constraints satisfaction, we compare it against the performance of a fundamental utility-based power and rate allocation scheme [24] which only aims at optimizing users’ actual throughput performance, without considering RT users’ QoS prerequisites; serving the purpose of system’s performance benchmark
In the second and the third scenarios (SC2 and Scenario 3 (SC3)), we evaluate the performance of our proposed scheduler when users with different average channel conditions are served, considering, respectively, only RT users (SC2) and both non-real-time users (NRT) and RT users (SC3) at the system in order to demonstrate our schemes’ flexibility in adapting the resource allocation process according to users’ various QoS requirements and to their average channel conditions, aiming at reducing the drawbacks emerging from the users’ “near-far” effect
Summary
With the growing demand for high data rate and support of multiple services with various quality of service (QoS) requirements, the scheduling policy plays a key role in the efficient resource allocation process in future wireless networks. The second one, residing at the mobile node, dynamically adapts a real-time user’s utility by realizing a control loop which: (a) constantly monitors a user’s service performance, (b) analyzes its current status with respect to QoS requirements, and (c) reacts to QoS triggering events via the dynamic alteration of the user’s utility It is demonstrated via modeling and simulation that our proposed scheme achieves to the fulfillment of real-time users’ short-term prerequisites without any considerable loss in the system’s total achieved throughput.
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