Since the advent of the telephone system, copper wire has traditionally provided the link in the local loop between the telephone subscriber and the local exchange. But copper's heyday in the local loop is coming to an end. Economic imperatives and emerging technologies are opening the door for WLL solutions. Sometimes called RITL or FRA, WLL uses wireless technology coupled with line interfaces and other circuitry to complete the last mile between the customer premise and the exchange equipment.

Bill Frezza, president of Wireless Computing Associates, calls WLL "the hot telecom growth industry of the next decade." According to the research firm MTA-EMCI, the worldwide WLL market will reach 202 million subscribers by the year 2005. Herschel Shosteck Associates estimates there will be a demand for WLL service for 172 million to 307 million subscribers but that actual service will be provided for 50 million to 60 million subscribers by the year 2000 (see Figure 1).

Figure 1. Projected WLL Subscribers by Region

In developed economies, wireless technology's relatively low deployment and maintenance costs and learning-curve advantages make WLL a competitive bypass solution and a viable alternative to wireline networks for POTS and data access. Two issues will determine how quickly WLL will be deployed in developed markets: cost and bandwidth.

• Today's exorbitant access rates, coupled with regulatory changes, have created a competitive environment that gives new operators the incentive to invest in their own WLL networks. However, WLL deployment costs (expected to drop to $200 per subscriber installation) must be balanced with the potential for lower access fees.
• The growing demand for high-bandwidth transmission capable of supporting rich-data types places additional requirements on a WLL system. Operators must evaluate the various technologies based on their ability to support data rates up to integrated services digital network (ISDN) speeds.