Optimization of Efficiency and Energy Consumption in p-persistent CSMA-based Wireless LANs

Wireless technologies in the LAN environment are becoming increasingly important. The IEEE 802.11 is the most mature technology for Wireless Local Area Networks (WLANs). The limited bandwidth and the finite battery power of mobile computers represent one of the greatest limitations of current WLANs. In this paper we deeply investigate the efficiency and the energy consumption of MAC protocols that can be described with a p-persistent CSMA model. As already shown in the literature, the IEEE 802.11 protocol performance can be studied using a p-persistent CSMA model [Cal00]. For this class of protocols, in the paper we define an analytical framework to study the theoretical performance bounds from the throughput and the energy consumption standpoint. Specifically, we derive the p values (i.e., the average size of the contention window in the IEEE 802.11 protocol) that maximizes the throughput, $p^C_{opt}$, and minimizes the energy consumption, $p^E_{opt}$. By providing analytical closed formulas for the optimal values, we discuss the trade-off between efficiency and energy consumption. Specifically, we show that power saving and throughput maximization can be jointly achieved. Our analytical formulas indicate that the optimal $p$ values depend on the network configuration, i.e., number of active stations and length of the messages transmitted on the channel

Throughput and energy efficiency in IEEE 802.11 WLANs: friends or foes?

Proceedings of: 6th International ICST Conference on Heterogeneous Networking for Quality, Reliability, Security and Robustness, QShine 2009 and 3rd International Workshop on Advanced Architectures and Algorithms for Internet Delivery and Applications, AAA-IDEA 2009, Las Palmas, Gran Canaria, November 23-25, 2009Understanding and optimizing the energy consumption of wireless devices is critical to maximize network lifetime and to provide guidelines for the design of new protocols and interfaces. In this work we first provide an accurate analysis of the energy performance of an IEEE 802.11 WLAN, and then we derive the configuration to maximize it. We also analyze the impact of the energy configuration of the device on the throughput performance, and discuss in which circumstances throughput and energy efficiency can be both maximized and where they constitute different challenges.European Community's Seventh Framework ProgramPublicad

A Game Theory based Contention Window Adjustment for IEEE 802.11 under Heavy Load

The 802.11 families are considered as the most applicable set of standards for Wireless Local Area Networks (WLANs) where nodes make access to the wireless media using random access techniques. In such networks, each node adjusts its contention window to the minimum size irrespective of the number of competing nodes, so in saturated mode and excessive number of nodes available, the network performance is reduced due to severe collision probability. A cooperative game is being proposed to adjust the users’ contention windows in improving the network throughput, delay and packet drop ratio under heavy traffic load circumstances. The system’s performance evaluated by simulations indicate some superiorities of the proposed method over 802.11-DCF (Distribute Coordinate Function)

On the energy efficiency of IEEE 802.11 WLANs

Proceedings of: 2010 European Wireless Conference (EW2010), (April 12-15, 2010), Lucca, ItalyUnderstanding the energy consumption of wireless interfaces is critical to provide guidelines for the design and implementation of new protocols or interfaces. In this work we analyze the energy performance of an IEEE 802.11 WLAN. Our contributions are as follows: i) we present an accurate analytical model that is able to predict the energy consumption, ii) we present an approximate model that sacrifices accuracy for the sake of analytical tractability, iii) based on this simplified analysis, we derive the optimal configuration to maximize energy efficiency of a WLAN, and iv) finally, we also analyze the tradeoff between throughput and energy efficiency that IEEE 802.11 imposes. While most of these results consider a homogeneous WLAN scenario where all stations share the same energy features, we also discuss the case of heterogeneous environments, where different devices show different power consumption characteristics.European Community's Seventh Framework ProgramPartly funded by the Ministry of Science and Innovation of Spain, under the QUARTET project (TIN2009-13992-C02-01)Publicad

Improving the Performance of Wireless LANs

This book quantifies the key factors of WLAN performance and describes methods for improvement. It provides theoretical background and empirical results for the optimum planning and deployment of indoor WLAN systems, explaining the fundamentals while supplying guidelines for design, modeling, and performance evaluation. It discusses environmental effects on WLAN systems, protocol redesign for routing and MAC, and traffic distribution; examines emerging and future network technologies; and includes radio propagation and site measurements, simulations for various network design scenarios, numerous illustrations, practical examples, and learning aids