Tandem voice communications: digital cellular, VoIP, and voice over Wi-Fi

We consider the problems of voice over wireless LANs and voice communications over heterogeneous asynchronous tandem networks, including digital cellular, VoIP, and voice over Wi-Fi. For voice over Wi-Fi, we minimize retransmissions by combining new packetization methods and packet loss concealment approaches. We demonstrate that tandem network connections can suffer significant loss in voice quality, even with ideal channels. We present a particular example of a VoIP network in tandem with voice over Wi-Fi and study end-to-end performance for different voice codecs, bit error rates, packet loss rates, and packet loss concealment methods.