Fair Bandwidth Sharing Algorithms Based on Game Theory Frameworks for Wireless Ad-hoc Networks

This paper examines the theoretical aspects of bandwidth sharing in wireless, possibly mobile, ad-hoc networks (MANETs) through a game theoretic framework. It presents some applications to show how such a framework can be invoked to design efficient media access control protocols in a noncooperative, self-organized, topology-blind environment as well as in environments where the competing nodes share some basic information to guide their choice of channel access policies. For this purpose, contentions between concurrent links in a MANET are represented by a conflict graph, and each maximal clique in the graph defines a contention context which in turn imposes a constraint on the share of bandwidth that the links in the clique can obtain. Using this approach the fair bandwidth allocation problem is modeled as a general utility based constrained maximization problem, called the system problem, which is shown to admit a unique solution that can only be obtained when global coordination between all links is possible. By using Lagrange relaxation and duality theory, both a non-cooperative and a cooperative game formulation of the problem are derived. The corresponding mathematical algorithms to solve the two games are also provided where there is no need for global information. Implementation issues of the algorithms are also considered. Finally, simulation results are presented to illustrate the effectiveness of the algorithms

A Novel Decentralized Asynchronous Scheduler for Hadoop

In cloud computing systems, such as Hadoop, system performance is a significant target for improvement. In classic master node-central schedulers, decision is made in the heartbeat time scale, and idle slots during a heartbeat, remain idle until allocated a task by the master node. In this paper, we propose a novel scheduler named multiple queues scheduler (MQS) that improves the throughput of the system by increasing data locality rate of map tasks, reducing thereby the average completion time of jobs. To achieve this, we associate slave nodes with individual queues, and distribute the tasks of a job at arrival to those nodes that contain the associated input data, based on data locality. To reduce the load on overloaded slave nodes, task migration is performed asynchronously between nodes within a rack, without the intervention of the master node. Our results demonstrate the effectiveness of the proposed algorithm. The benefits of MQS are three-fold: first, it decreases the probability of allocating map tasks to non data-local nodes; second, it decreases the time wasted between heartbeats; these two aspects immediately improve the system performance; and third, it mitigates the stress on the master node by assigning part of the scheduler's functions to slave nodes

Priority-based Multiple Access for Service Differentiation in Wireless Ad-hoc Networks

This article describes the Priority Based Multiple Access (PriMA) protocol, a new medium access control (MAC) protocol for single-channel ad-hoc networks. Unlike previously proposed protocols, PriMA takes into account the QoS requirements of the packets queued in stations to provide each station with a priority-based access to the channel. The direct support of PriMA for ad-hoc routing is that when some stations act as hubs in the routing structure and route packets for other stations besides their own, they can have high priorities and obtain larger share of bandwidth. Simulation results show the potential benefits that PriMA brings about to ad-hoc networks, and confirm PriMA as an initial step towards QoS provision in ad-hoc networks

Core-PC: A class of correlative, power control algorithms for single channel mobile ad hoc networks

In this paper we study the correlations that exist between the required transmission power of RTS, CTS, DATA and ACK frames to guarantee a successful 4-way handshake in wireless ad hoe networks based on the IEEE 802.11 distributed coordination function (DCF). From these correlations, and starting from a set of different initial conditions, we can derive a class of power controlled media access control (MAC) algorithms for single channel ad hoc networks based on the existing IEEE 802.11 DCF. From substantial simulations of the different algorithms and comparison to some prominent alternatives, we come to a conclusion that contradicts the intuitively sound, commonly held belief which states that sending control frames at maximum power - to reduce interference on the long data frames - then, the ensuing long data frames at a lower, yet sufficient power level decreases power consumption per carried bit

Balancing download throughput in densely deployed IEEE802.11 multi-cell WLANs

Multi-cell wireless LANs (WLANs) are often densely deployed in order to achieve full coverage of a given area, in particular in indoor environments. In such scenarios, it is widely believed that the co-existence of hidden and exposed APs simultaneously results in a dramatic download throughput degradation for the clients. Indeed, in such environment, intutively, each AP while competing for channel access with neighbouring exposed APs may suffer collisions from hidden APs each time it wins such competition. In this paper we study the problem of fairly allocating download bandwidth to clients in such dense multi-cell WLANs. To this end, we design algorithms that adapt client association, airtime sharing among clients and rate control to achieve optimal fairness in bandwidth access. We model this problem as a non-linear programming problem, and propose a distributed algorithm to solve such an NP-hard problem via transformation into a convex problem as well as approximations. Our numerical and simulation results show that, the proposed algorithm significantly improves the performance compared to existing solutions, and leads to the counter intuitive conclusion that intelligently adding exposed APs will lead to better system performance.1 © 2013 IEEE

Achieving Fairness in IEEE 802.11 DFWMAC with Variables Packet Lengths

Abstract—The Medium Access Control (MAC) protocol through which mobile stations can share a common broadcast channel is essential in an ad-hoc network. Due to the existence of hidden terminals and partiallyconnected network topology, contention among stations in an ad-hoc network is not homogeneous. Some stations are at a disadvantage in access to the shared channel and can suffer severe throughput degradation when load to channel is high. This is known as the “fairness problem”. Existing MAC protocols like IEEE 802.11 Distributed Foundation Wireless Medium Access Control (DFWMAC) may exacerbate this problem as it uses the binary exponential backoff (BEB) algorithm in contention resolution, which always favors the last succeeding station. This paper reviews the “fairness index”, which is a metric to quantify fairness, and proposes a new estimation based backoff algorithm for the IEEE 802.11 DFWMAC protocol. The new algorithm can support the case when packet lengths are variable, which is a typical scenario of IEEE 802.11 compliant implementations that include both the basic CSMA/CA access method and the RTS/CTS access method. Simulation results show that the fairness problem can be very severe with the original BEB algorithm when packet length is variable and our new backoff algorithm can achieve far better fairness without adding much in complexity. I

Minimum energy probabilistic reliable data delivery in wireless sensor networks

Many sensor network applications only require probabilistic data delivery, as they can tolerate some missing data samples. For example, in environmental monitoring, missing temperature, pressure and humidity level samples can often be inferred by spatial and/or temporal interpolations. In this paper we propose and study an adaptive p-persistent CSMA-based media access control protocol that supports end-to-end probabilistic reliability for sensor networks on a hop-by-hop basis. In an effort to reduce the probability of packet collisions, first we tune the carrier sensing range of the nodes; then given an end-to-end reliability requirement, we determine the optimal allocation of per-hop reliability requirements on each route to minimize the expected total number of transmissions needed; finally, our adaptive p-persistent CSMA protocol tunes its link persistence probability to further reduce the expected total number of transmissions, and thereby minimizes the energy consumption in the network. We formulate this latter problem as a constrained optimization problem, and then derive an algorithm to adapt the link persistence probabilities using the Lagrangian dual decomposition method. Copyright 2008 ACM