Power Aware Routing in Mobile Ad Hoc Networks

International Joint Conference on Neural Networks

Link adaptation to dynamically select the data transmission rate at a given time has been recognized as an effective way to improve the goodput performance of the IEEE 802.11 wireless local-area networks (WLANs). Recently, with the introduction of the new high-speed 802.11a physical layer (PHY), it is even more important to have a well-designed link adaptation scheme work with the 802.11a PHY such that its multiple transmission rates can be exploited. In this paper, we first present a generic method to analyze the goodput performance of an 802.11a system under the distributed coordination function (DCF) and express the expected effective goodput as a closed-form function of the data payload length, the frame retry count, the wireless channel condition, and the selected data transmission rate. Then, based on the theoretical analysis, we propose a novel MPDU (MAC protocol data unit)-based link adaptation scheme for the 802.11a systems. It is a simple table-driven approach and the basic idea is to preestablish a best PHY mode table by applying the dynamic programming technique. The best PHY mode table is indexed by the system status triplet that consists of the data payload length, the wireless channel condition, and the frame retry count. At runtime, a wireless station determines the most appropriate PHY mode for the next transmission attempt by a simple table lookup, using the most up-to-date system status as the index. Our in-depth simulation shows that the proposed MPDU-based link adaptation scheme outperforms the single-mode schemes and the autorate fallback (ARF) scheme-which is used in Lucent Technologies' WaveLAN-II networking devices-significantly in terms of the average goodput, the frame drop rate, and the average number of transmission attempts per data frame delivery.

http://home.eng.iastate.edu/~daji/papers/tmc02.pdf

Goodput analysis and link adaptation for IEEE 802.11a wireless LANs

We introduce a game-theoretic setting for routing in a mobile ad hoc network that consists of greedy, selfish agents who accept payments for forwarding data for other agents if the payments cover their individual costs incurred by forwarding data. In this setting, we propose Ad hoc-VCG, a reactive routing protocol that achieves the design objectives of truthfulness (i.e., it is in the agents' best interest to reveal their true costs for forwarding data) and cost-efficiency (i.e., it guarantees that routing is done along the most cost-efficient path) in a game-theoretic sense by paying to the intermediate nodes a premium over their actual costs for forwarding data packets. We show that the total overpayment (i.e., the sum of all premiums paid) is relatively small by giving a theoretical upper bound and by providing experimental evidence. Our routing protocol implements a variation of the well-known mechanism by Vickrey, Clarke, and Groves in a mobile network setting. Finally, we analyze a very natural routing protocol that is an adaptation of the Packet Purse Model [8] with auctions in our setting and show that, unfortunately, it does not achieve cost-efficiency or truthfulness.

https://web2.utc.edu/~djy471/CNS-reading/anderegg03.pdf

Ad hoc-VCG: a truthful and cost-efficient routing protocol for mobile ad hoc networks with selfish agents

Reducing the energy consumption by wireless communication devices is perhaps the most important issue in the widely-deployed and exponentially-growing IEEE 802.11 Wireless LANs (WLANs). TPC (Transmit Power Control) and PHY (physical layer) rate adaptation have been recognized as two most effective ways to achieve this goal. The emerging 802.11h standard, which is an extension to the current 802.11 MAC and the high-speed 802.11a PHY, will provide a structured means to support intelligent TPC.In this paper, we propose a novel scheme, called MiSer, that minimizes the communication energy consumption in 802.11a/h systems by combining TPC with PHY rate adaptation. The key idea is to compute offline an optimal rate-power combination table, and then at runtime, a wireless station determines the most energy-efficient transmission strategy for each data frame by a simple table lookup. Another key contribution of this paper is to provide a rigorous analysis of the relation among different radio ranges and TPC's effect on the interference in 802.11a/h systems, which justifies MiSer's approach to ameliorating the TPC-caused interference by transmitting the CTS frames at a stronger power level. Our simulation results show that MiSer delivers about 20% more data per unit of energy consumption than the PHY rate adaptation scheme without TPC, while outperforming single-rate TPC schemes significantly thanks to the excellent energy-saving capability of PHY rate adaptation.

/pdf/miser-an-optimal-low-energy-transmission-strategy-for-ieee-3zcs847zof.pdf

MiSer: an optimal low-energy transmission strategy for IEEE 802.11a/h

In this paper, distributed power control is proposed as a means to improve the energy efficiency of routing algorithms in ad hoc networks. Each node in the network estimates the power necessary to reach its own neighbors, and this power estimate is used both for tuning the transmit power (thereby reducing interference and energy consumption) and as the link cost for minimum energy routing. With reference to classic routing algorithms, such as Dijkstra and Link State, as well as more recently proposed ad hoc routing schemes, such as AODV, we demonstrate by extensive simulations that in many cases of interest our scheme provides substantial transmit energy savings while introducing limited degradation in terms of throughput and delay.

Distributed power control for energy efficient routing in ad hoc networks

With the aim of explaining the formal development behind the chaos-based modeling of network traffic and other similar phenomena, we generalize the tools presented in the paper of Setti et al. (see ibid., vol.90, p.662-90, May 2002) to the case of piecewise-affine Markov maps with a possibly infinite, but countable number of Markov intervals. Since, in doing so, we keep the dimensionality of the space of the observables finite, we still obtain a finite tensor-based framework. Nevertheless, the increased complexity of the model forces the use of tensors of functions whose handling is greatly simplified by extensive z transformation. With this, a systematic procedure is devised to write analytical expressions for the tensors that take into account the joint probability assignments needed to compute any-order expectations. As an example of use, this machinery is finally applied to the study of self-similarity of quantized processes both in the analysis of higher order phenomena as well as in the analysis and design of second-order self-similar sources suitable for artificial network traffic generation.

Statistical modeling and design of discrete-time chaotic processes: advanced finite-dimensional tools and applications

In this paper, a distributed power control mechanism for ad hoc networks is proposed and investigated. This mechanism, acting at different layers, reduces the power consumption maintaining similar behavior, in terms of delay and throughput, as classic schemes. In the proposed strategy, the generic sender uses an appropriate power level to transmit its packets by reducing channel interference and energy consumption, and the final path is selected by minimizing the overall power spent in the end-to-end transmission. Two classic routing schemes are revisited in order to apply to them this power consumption policy, by appropriately redefining the cost functions associated to each link. The effectiveness of this proposed distributed power control, which combines two power saving strategies working at two different levels, is shown by means of extensive simulation results.

Distributed Power Control for Power-Ware Energy-Efficient Routing in Ad Hoc Networks

An improved Markov model for Rayleigh fading is proposed. Such a system considers both the amplitude and the speed of the fading envelope which jointly represent the Markov state. By properly selecting the state space size, proper fitting between the proposed system and Jakes' Rayleigh fading simulator has been obtained. Further simulations, using a simple Go back N protocol, confirm the good throughput match between Jakes' and the proposed Markov generators, not obtainable with classic one-dimensional models.

Improved Markov model for Rayleigh fading envelope

The TCP/IP header compression (HC) problem on wireless channels is investigated. After a brief review of the existing HC algorithms, two novel HC schemes are proposed, discussed and tested by means of simulations. The proposed schemes outperform the well-known approaches for all possible channel conditions, and the results are very close to the ideal case of HC without loss of synchronisation.

A. Giovanardi

Papers

Distributed power control for energy efficient routing in ad hoc networks

Statistical modeling and design of discrete-time chaotic processes: advanced finite-dimensional tools and applications

Distributed Power Control for Power-Ware Energy-Efficient Routing in Ad Hoc Networks

Improved Markov model for Rayleigh fading envelope

Improved header compression for TCP/IP over wireless links