Evolution of mean opinion Score due to handover events in IEEE 802.11 WLAN networks

Although networks based on IEEE 802.11 was originally intended to transport best-effort data traffic, the appearance of IEEE 802.11e has brought about the opportunity of supplying real time voice communications with strict requirements of quality of service. In WLAN IEEE 802.11 networks, the handover process follow a ldquobreak-before-makerdquo mechanism, provoking discontinuities in the communication, which have associated a variation of the packet loss rate, and, therefore, changes in the subjective quality of voice perceived by the user along the communication. It will be necessary to take into account this effect in the planning and sizing process of WLAN networks which have to deal with conversational services. With this purpose, in this paper is illustrated the influence of the horizontal handover events on the evolution of the MOS value for different VoIP codecs and several handover decision algorithms and durations.