There are good reasons why nodes in a mobile ad hoc network, that lacks the networking infrastructure which has been deployed through the investment of a telecommunications corporation, would prefer not to cooperate within the network. When nodes do cooperate, they form the necessary ad hoc infrastructure

This paper introduces a novel feedback arrangement, termed re-feedback. It ensures metrics in data headers such as time to live and congestion notification will arrive at each relay carrying a truthful prediction of the remainder of their path. We propose mechanisms at the network edge that ensure the dominant selfish strategy of both network domains and endpoints will be to set these headers honestly and to respond correctly to path congestion and delay, despite conflicting interests. Although these mechanisms influence incentives, they don’t involve tampering with end-user pricing. We describe a TCP rate policer as a specific example of this new capability. We show it can be generalised to police various qualities of service. We also sketch how a limited form of re-feedback could be deployed incrementally around unmodified routers without changing IP.

We present a power control scheme based on noncooperative game theory, using a fairly broad class of convex cost functions. The multicell CDMA wireless data network is modeled as a switched hybrid system where handoffs of mobiles between different cells correspond to discrete switching events between different subsystems. Under a set of sufficient conditions, we prove the existence of a unique Nash equilibrium for each subsystem, and prove global exponential stability of an update algorithm. We also establish the global convergence of the dynamics of the multicell power control game to a convex superset of Nash equilibria for any switching (handoff) scheme satisfying a mild condition on average dwell-time. Robustness of these results to feedback delays as well as to quantization is investigated. In addition, we consider a quantization scheme to reduce the communication overhead between mobiles and the base stations. Finally, we illustrate the power control scheme developed through simulations.

We present and analyse an approach to service di#erentiation in third generation mobile networks based on Wideband CDMA, that exposes a new weight parameter designed to reflect allocation of the congestible resource. The approach naturally takes into account the di#erence in resource scarcity for the uplink and downlink, because it is grounded on fundamental economic models for e#cient utilization of resources in WCDMA. Discrete values of the weight parameter can be presented as di#erent service classes. Finally, we present numerical experiments demonstrating the e#ectiveness of our approach, and investigate its performance and transient behaviour under power control and signal quality estimation errors.

We investigate the problem of efficient resource control for loss-sensitive traffic in CDMA networks, using an economic modelling framework that takes into account the joint control of the transmission rate and the signal quality. Although the corresponding global optimization problem has a non-trivial structure, and we cannot in general guarantee that a solution can be found using the Lagrangian method, we have strong experimental evidence that this is possible for a wide range of user utilities. In this case the global optimum can be achieved in a decentralized manner, using shadow prices to influence the individual user resource requests. Based on this evidence, the main contribution of the paper is to discuss how existing rate control and outer-loop power control procedures can obtain a simple and attractive form that takes into account, through shadow prices, the level of demand and supply in order to achieve efficient resource utilization. Moreover, we describe and evaluate approximations of the proposed resource control model that can simplify its application, and we present extensions of the model for the case where the packet success ratio depends on the transmission rate in addition to the signal quality, and for network paths containing multiple wireless links.

Properly characterising paths is an important foundation for resource sharing and routing in packet networks. We realign metrics so that fields in packet headers characterise the path downstream of any point, rather than upstream. Then closed loop control is possible for either end-points or network nodes. We show how incentives can be arranged to ensure that honest reporting and responsible behaviour will be the dominant strategies of selfish parties, even for short flows. This opens the way for solutions to a number of problems we encounter in data networking, such as congestion control, routing and denial of service. 1

We present a new approach for seamless congestion control over heterogeneous networks containing wired and wireless IEEE 802.11 links. The approach uses ECN (Explicit Congestion Notification) as a common signalling mechanism for conveying congestion information from both wired and wireless links. Two additional novel aspects of the approach are that ECN marking for a wireless link, due to the way resources are shared, is performed for both the uplink and the downlink based on measurements of the aggregate traffic in both directions, and the marking mechanism dynamically adapts to different traffic and load conditions. Simulation results demonstrate that our approach achieves higher fairness compared to drop-tail queueing, while achieving the same utilization, and can effectively control the average packet delay over the wireless link.

We present a model for efficient and robust power control in the downlink of Wideband CDMA wireless systems. The model is based on microeconomics, and takes into account both the congestion, in terms of increased interference, that a mobile user imposes to other users, and the downlink resource constraint, which involves the total transmission power at the base station. We discuss the application of the model for supporting service differentiation, and investigate various alternatives and their corresponding tradeoffs. Our approach involves adjusting the target signal quality based on weights declared by mobile users.

Noncooperative game theory is used as a basis for analyzing, developing, and implementing decision, control, and resource allocation schemes to address various network control problems such as congestion control, code division multiple access (CDMA) power control, and network intrusion detection and response. In the cases of CDMA power control and congestion control, a fairly general, distributed, market-based resource allocation framework is developed and analyzed. The applicability of the underlying noncooperative network game's principles to both network control problems can be considered as an indicator of the generality and usefulness of this approach. Based on this general framework, various algorithms customized according to the specific nature of the network at hand are developed. Making use of a variety of control theoretic tools such as Lyapunov and hybrid system theories, stability and robustness properties of these algorithms are studied rigorously. An analysis of robustness with respect to feedback delays, which is of particular importance, is provided for most of the algorithms considered. In the case of network intrusion detection, dynamic noncooperative games are utilized to model the decision and analysis processes in an IDS. Again, both generic and system-specific schemes and models are considered. In addition to the theoretical analysis of the network control problems addressed, implementation related aspects of the schemes developed are investigated. For each algorithm, theoretical results obtained are supported and demonstrated either via high-level MATLAB simulations or using the NS-2 packet level network simulator. Through extensive simulations, applicability and underlying assumptions of the theoretical models are verified.

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