Among recent internet applications, Voice-over-IP (VoIP) is one of appealing ones due to its advantages over traditional telephony, such as low communication cost, high bandwidth and easy creation of new services. However, when it is applied to wireless local area networks (WLANs), power consumption becomes a critical issue for voice stations (handsets) in the network. In this chapter, we propose an efficient power saving MAC mechanism for VoIP applications (PSM-V) based on the IEEE 802.11e EDCA. The basic idea of PSM-V is adding a contention-free period for voice traffic in the EDCA mechanism. We utilize a beacon frame to periodically announce a TDMA access schedule for voice stations to follow. The access schedule can allow voice stations to avoid voice packet collisions and to reduce station idle time. Simulation results show that the proposed PSM-V improves the energy efficiency of voice stations over the U-APSD approach, which has been included in the IEEE 802.11e standard , and the U-APSD-M approach , by 51% and 17% in terms of average duty cycle, respectively. The simulation results also show that PSM-V improves the aggregate throughput of voice traffic over U-APSD and U-APSD-M on average by 63% and 8%, and it reduces the average delay of voice packets over U-APSD and U-APSD-M by 34% and 20%, respectively. In summary, PSM-V can guarantee that while improving the energy efficiency of voice stations, the throughput and packet delay performance of the voice traffic will not be degraded within system capacity.
|主出版物標題||Mobile Computing Research and Applications|
|發行者||Nova Science Publishers, Inc.|
|出版狀態||Published - 1 一月 2009|