A new access point selection policy for multi-rate IEEE 802.11 WLANs

International Journal of Parallel Emergent and Distributed Systems 05/2008; 23(4):291-307. DOI: 10.1080/17445760801930914
Source: DBLP


In wireless local area networks often a station can potentially associate with more than one access point. Therefore, a relevant question is which access point to select \best" from a list of candidate ones. In IEEE 802.11, the user simply associates to the access point with the strongest received signal strength. However, this may result in a signican t load imbalance between several access points. Moreover, the multi-rate exibilit y provided by several IEEE 802.11 variants can cause low bit rate stations to negatively aect high bit rate ones and consequently degrade the overall network throughput. This paper investigates the various aspects of \best" access point selection for IEEE 802.11 systems. In detail, we rst derive a new decision metric which can be used for AP selection. Using this metric we propose two new selection mechanisms which are decentralized in the sense that the decision is performed by each station, given appropriate status information of each access point. In fact, only few bytes of status information have to be added to the beacon and probe response frames which does not impose signican t overhead. We show that our mechanism improves mean quality of service of all stations and better utilizes network resources compared to the conventional one implemented today in IEEE 802.11 devices. Also, the schemes are appealing in terms of stability and provide their performance improvement even for denser or lighter network congurations.

Download full-text


Available from: James Gross, Sep 29, 2015
46 Reads
  • Source
    • "Additionally, there are number of industrial standards of AP defined for WLANs where each AP can maintain a restricted number of parallel voice nodes [38] [39] [40] [41] [42] [43] [44] [45] [46]. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Transmission of VoIP over packet switching networks is one of the rapidly emerging real-time Internet Protocol. The real-time application of the Voice over Internet Protocol (VoIP) is growing rapidly for it is more flexible than the traditional Public Switched Telephone Networks systems (PSTN). Meanwhile, the VoIP deployment on Wireless Local Area Networks (WLANs), which is based on IEEE 802.11 standards, is increasing. Currently, many schedulers have been introduced such as Weighted Fair Queueing (WFQ), Strict Priority (SP) General processor sharing (GPS), Deficit Round Robin (DRR), andContention-Aware Temporally fair Scheduling (CATS). Unfortunately, the current scheduling techniques have some drawbacks on real-time applications and therefore will not be able to handle the VoIP packetsin a proper way. The objective of this research is to propose a new scheduler system model for the VoIP application named Voice Priority Queue (VPQ) scheduler. The scheduler system model is to ensureefficiency by producing a higher throughput and fairness for VoIP packets. In this paper, only the First Stage of the VPQ packet scheduler and its algorithm are presented. Simulation topologies for VoIP traffic were implemented and analyzed using the Network Simulator (NS-2). The results show that this method can achieve a better and more accurate VoIP quality throughput and fairness index.
  • Source
    • "In the second group, we have association policies that start from the throughputs that individual STAs are getting at present [10], [12], [14], [15] and [18]. For each STA associated with an AP, the ratio of throughput to the physical rate of association is obtained, and this fraction is added over all the STAs. "
    [Show abstract] [Hide abstract]
    ABSTRACT: We obtain an association policy for STAs in an IEEE 802.11 WLAN by taking into account explicitly two aspects of practical importance: (a) TCP-controlled short file downloads interspersed with read times (motivated by web browsing), and (b) different STAs associated with an AP at possibly different rates (depending on distance from the AP). Our approach is based on two steps. First, we consider an analytical model to obtain the aggregate AP throughput for long TCP-controlled file downloads when STAs are associated at k different rates r1, r2, : : :, rk; this extends earlier work in the literature. Second, we present a 2-node closed queueing network model to approximate the expected average-sized file download time for a user who shares the AP with other users associated at a multiplicity of rates. These analytical results motivate the proposed association policy, called the Estimated Delay based Association (EDA) policy: Associate with the AP at which the expected file download time is the least. Simulations indicate that for a web-browsing type traffic scenario, EDA outperforms other policies that have been proposed earlier; the extent of improvement ranges from 12.8% to 46.4% for a 9-AP network. To the best of our knowledge, this is the first work that proposes an association policy tailored specifically for web browsing. Apart from this, our analytical results could be of independent interest Comment: 9 pages, 13 figures
  • [Show abstract] [Hide abstract]
    ABSTRACT: Network performance monitor has now become a central issue in network application and operation optimization. This article describes an integrated network performance monitor system using a combination of active and passive measurement techniques. Active probing technique is used for overall network performance monitor, and passive monitoring technique is used for local network performance information collection and analysis. The integrated network performance monitor system combing two measurement techniques is a brand-new idea. Experiment results indicate this system is effective and of a definite practicability.
    Third International Symposium on Intelligent Information Technology and Security Informatics, IITSI 2010, Jinggangshan, China, April 2-4, 2010; 01/2010
Show more