Minimizing the Effects of Multi-rate WLANs by Adapting Link Adaptation and Call Admission Interfaces

  • M. Fatih Tüysüz
  • Hacı A. Mantar
Part of the Communications in Computer and Information Science book series (CCIS, volume 88)


Link Adaptation (LA) is a term used in wireless communications to adjust the physical transmission rate of nodes according to the channel conditions it senses and optimize the bit transmission by using multi-rate transmissions. It has a direct impact on the transmissions of all active calls and can cause a general degradation on the quality of service (QoS). Besides, Call admission control (CAC) is used in the call set-up phase and it determines whether it has sufficient resources to accept a new call. However, CAC also does not work efficiently on the existence of transmission rate changes. Since IEEE 802.11 standard was not created for voice communications in first place, it brings a lot of new limitations for successfully deploying VoIP. In this paper, we propose a fast and efficient, algorithm which integrates LA interface, codec-frame size adaptation and CAC interface to minimize the impact of multi-rate transmission and optimize the maximum throughput and voice quality over multi-rate WLANs.


Voice over IP Link adaptation Call admission control multi-rate WLANs QoS IEEE 802.11e 


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  1. 1.
    Tüysüz, M.F., Mantar, H.A.: An Adaptive Codec and Frame Size Modification Based QoS Algorithm over Multi-rate WLANs. In: WIMO 2010, Ankara (June 2010) (to appear)Google Scholar
  2. 2.
    Tüysüz, M.F., Mantar, H.A.: A Cross Layer QoS Algorithm to Improve Wireless Link Throughput and Voice Quality over Multi-rate WLANs. In: IWCMC 2010, Caen (June 2010) (to appear)Google Scholar
  3. 3.
    Yin, J., Wang, X., Agrawal, D.P.: Optimal Packet Size in Error-prone Channel for IEEE 802.11 Distributed Coordination Function. In: WCNC 2004. IEEE Communications Society, Los Alamitos (2004)Google Scholar
  4. 4.
    Huang, C.W., Chindapol, A., Ritcey, J.A., Hwang, J.N.: Link Layer Packet Loss Classification for Link Adaptation in WLAN. In: 4th Annual Conference on Information Sciences and Systems, Princeton (March 2006)Google Scholar
  5. 5.
    Sfairopoulou, A.: A cross-layer mechanism for QoS improvements in VoIP over Multi-rate WLAN networks. PhD thesis, Pompeu Fabra University (April 2008)Google Scholar
  6. 6.
    Sfairopoulou, A., Macián, C., Bellalta, B.: QoS adaptation in SIP-based VoIP Calls in Multi-rate IEEE 802.11 Environments. In: ISWCS 2006, Valencia (2006)Google Scholar
  7. 7.
    Sfairopoulou, A., Macián, C., Bellalta, B.: How to Tune VoIP Codec Selection in WLANs? IEEE Communications Letters 12(8) (August 2008)Google Scholar
  8. 8.
    Servetti, A., De Martin, J.C.: Interactive Speech Transmission Over 802.11 Wireless Lans. Cercom, Torino, Italy (2003)Google Scholar
  9. 9.
    Hirannaiah, R.M., Jasti, A., Pendse, R.: Influence of Codecs on Adaptive Jitter Buffer Algorithm. In: GRASP Symposium. Wichita State University (2007)Google Scholar
  10. 10.
    Kawata, T., Yamada, H.: Adaptive Multi-Rate VoIP for IEEE 802.11 Wireless Networks with Link Adaptation Function. In: GLOBECOM 2006, San Francisco (2006)Google Scholar
  11. 11.
    Kawata, T., Yamada, H.: Impact of Multi-Rate VoIP on Quality of Service in IEEE 802.11e EDCA with Link Adaptation. In: ICC 2007, Glascow, June 24-28 (2007)Google Scholar
  12. 12.
    Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specification, IEEE Std. 802.11 (1997)Google Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2010

Authors and Affiliations

  • M. Fatih Tüysüz
    • 1
  • Hacı A. Mantar
    • 1
  1. 1.Computer Science DepartmentGebze Institute of TechnologyGebzeTurkey

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