Support of voice services in IEEE 802.11 wireless LANs

The IEEE 802.11 MAC protocol supports two modes of operation, a random access mode for non-real-time data applications, and a polling mode for real-time applications. We design and analyze a system that uses the polling mode for interactive voice traffic. With larger inter-poll periods, more voice calls can be accommodated, but at the expense of increased delay. For example, our analysis shows that with an inter-poll period of 90 ms, a maximum of 26 voice calls can be handled with a worst-case delay of 303 ms, whereas with an inter-poll period of 60 ms, a maximum of 17 voice calls can be handled with a worst-case delay of 213 ms. We also carry out an error analysis that demonstrates the need for error correction of voice packets.