Voice over Wireless: The Challenge

Wireless communications systems that are "fixed" in place have historically been divided into two different categories based on the application. The first application, delivering Plain Old Telephone Service (POTS) to underserved or infrastructure-challenged customers primarily in developing nations, was served by products classified as wireless local loop (WLL). The second application, Internet access, has to date been delivered by broadband wireless systems primarily in the enterprise market.

Because they were designed for voice with a capacity of 64 Kbps at most, the WLLs were inefficient in delivering high-speed data. Broadband wireless access (BWA) systems have been designed to deliver high-speed IP access first to the enterprise and, ultimately, to the residential customer.^[1] They, in turn, were not designed to deliver voice. Neither of these systems is widely deployed. A wireless broadband Internet technology that also delivers good-quality voice has the potential to bypass and potentially replace the PSTN as we know it.

The emerging popularity of VoIP in the enterprise market coupled with 802.11 LANs raises the following questions: Can voice be transported over an 802.11 network? Is 802.11 not simply a wireless IP technology? If voice can travel over a wired IP network, why could it not travel over a wireless network? If transporting voice over an 802.11 network has limitations, what are they? How can they be overcome? This chapter will cover the objections to transmitting voice over 802.11 (Vo802.11) networks and will offer solutions to those objections.

^[1]"Fixed Wireless Networks and Voice," a 2002 white paper from Malibu Networks, available at www.malibu.com.