Evaluation of Joint Admission Control and VoIP Codec Selection Policies in Generic Multirate Wireless Networks

  • B. Bellalta
  • C. Macian
  • A. Sfairopoulou
  • C. Cano
Part of the Lecture Notes in Computer Science book series (LNCS, volume 4712)


Multirate wireless networks in general share a common problem for the transmission of VoIP traffic, since the rate changes of some of the flows affect the transmission of all others, which causes an unacceptable voice quality degradation. In this work, an admission control algorithm is combined with a codec selection block to mitigate this negative effect. This centralized admission control is able to block or drop calls in order to maintain the system stability despite rate changes. Moreover, the integrated codec selection block is able to select the most adequate VoIP codec for each incoming or already active call based on the channel rate used and according to a number of optimization policies. Several such policies are designed and evaluated in this paper. Results show that this combined adaptive solution provides a beneficial trade-off among the performances of the different codecs in terms of MOS, blocking and dropping probability and cell resource usage. Furthermore, a number of interesting singularities deriving from the multirate nature of the network are identified.


VoIP codecs Mobile Networks Multiple channel transmission rates WLANs 


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  1. 1.
    Lacage, M., Manshaei, M.H., Turletti, T.: IEEE 802.11 Rate Adaptation: A Practical Approach. In: ACM International Symposium on Modeling, Analysis, and Simulation of Wireless and Mobile Systems (MSWiM), Venice, Italy, ACM Press, New York (2004)Google Scholar
  2. 2.
    IEEE Std 802.11. Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications. ANSI/IEEE Std 802.11 (1999 edn.) (Revised 2003) Google Scholar
  3. 3.
    Heusse, M., Rousseau, F., Berger-Sabbatel, G., Duda, A.: Performance Anomaly of 802.11b. In: IEEE INFOCOM 2003, San Francisco, USA, IEEE Computer Society Press, Los Alamitos (2003)Google Scholar
  4. 4.
    Leng Ng, S., Hoh, S., Singh, D.: Effectiveness of Adaptive Codec Switching VoIP Application over Heterogeneous Networks. In: 2nd Int. Mobility Conference, Guangzhou, China (2005)Google Scholar
  5. 5.
    Toshihiko, T., Tadashi, I.: Wireless LAN Resource Management Mechanism Guaranteeing Minimum Available Bandwidth for Real-time Communication. In: IEEE WCNC 2005, New Orleans, USA, IEEE Computer Society Press, Los Alamitos (2005)Google Scholar
  6. 6.
    Sfairopoulou, A., Macian, C., Bellalta, B.: QoS adaptation in SIP-based VoIP calls in multi-rate 802.11 environments. In: ISWCS 2006, Valencia (2006)Google Scholar
  7. 7.
    Servetti, A., Martin, J.C.D.: Adaptive interactive speech transmission over 802.11 wireless LANs. In: Proc. IEEE Int. Workshop on DSP in Mobile and Vehicular Systems, Nagoya, Japan, April 2003, IEEE Computer Society Press, Los Alamitos (2003)Google Scholar
  8. 8.
    Matta, J., Pépin, C., Lashkari, K., Jain, R.: A Source and Channel Rate Adaptation Algorithm for AMR in VoIP Using the Emodel. In: 13th NOSSDAV, Monterey, CA, USA (2003)Google Scholar
  9. 9.
    McGovern, P., Murphy, S., Murphy, L.: Addressing the Link Adaptation Problem for VoWLAN using Codec Adaptation. In: IEEE Globecom 2006 - Wireless Communications and Networking, San Francisco, CA, IEEE Computer Society Press, Los Alamitos (2006)Google Scholar
  10. 10.
    Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston, A., Peterson, J., Sparks, R., Handley, M., Schooler, E.: RFC3261: SIP: Session Initiation Protocol. Internet RFCs  (2002)Google Scholar
  11. 11.
    Gilbert (Gang) Chen.: Component Oriented Simulation Toolkit (2004), http://www.cs.rpi.edu/~cheng3/
  12. 12.
    Schulzrinne, H., Casner, S., Frederick, R., Jacobson, V.: RFC1889: RTP: A Transport Protocol for Real-Time Applications. Internet RFCs  (1996)Google Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2007

Authors and Affiliations

  • B. Bellalta
    • 1
  • C. Macian
    • 1
  • A. Sfairopoulou
    • 1
  • C. Cano
    • 1
  1. 1.Network Technologies and Strategies (NeTS) Research Group, Departament de Tecnologies de la Informació i Comunicació, Universitat Pompeu Fabra, Passeig de Circumval.lació, 8, 08003 BarcelonaSpain

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