Voice Communications over Tandem Wireline IP and WLAN Connections

Voice communication over a tandem connection of a wireline packet switched network and an IEEE 802.11 access point is studied when there are packet losses in the wired IP network and bit errors in the WLAN link. Limited retransmissions are allowed, and packet loss concealment is utilized. We consider several alternative scenarios, including tandem free operation with G.711 in both links, G.711 over UDP in the wired link and G.711 with unequal error protection (UEP) in the WLAN, and G.729 in the wired backbone in tandem with G.711 UEP in the WLAN. To increase the number of calls supported by the WLAN access point, we also examine using AMR codecs at 12.2 kbps and at 5.9 kbps with forward error correction in the wireless link. The standardized PESQ MOS is used to evaluate delivered voice quality.