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Wireless Data Networks: Reaching the Extra Mile


The demand for high-speed links has been continuing relentlessly over the past decade. While wireless networks have been evolving rapidly to meet this demand, they have been lagging behind the accelerated evolution common to wire-based networks. Meanwhile, as evolving technologies make wireless computing more attractive, the availability of bandwidth will become more and more of an issue. While spectrum is getting less expensive, it is also getting more crowded, particularly at times of peak use. Currently, alternative carriers make their off-peak capacity available for reduced cost, or even for free, while the rates at peak time for these carriers are relatively expensive. As spectrum becomes more limited, users will be increasingly driven to use off-peak capacity, ultimately making it as saturated as the same spectrum at peak times. The net result of this trend is to push users to higher frequencies with higher device costs. These higher frequencies suffer from reduced signal propagation and penetration, which means higher overall system costs. Another consideration in assessing bandwidth-bottleneck solutions is the requirement for real-time data services for many of the telemetry and control applications that will consume an increasing percentage of this bandwidth in the future. While voice applications are forgiving of noisy media, and non-real-time data transfer applications can wait for bandwidth to appear, realtime applications must have access on demand, which puts further pressure on the existing pool of spectrum. The ultimate objective of wireless data communication is, of course, to use radio waves to interconnect end users in areas ranging in size from a few feet for desk area networks and to hundreds of feet for local area networks, and up to several miles for campuswide and regional networks. The best solution to the spectrum saturation and bandwidth availability problem is to adopt technologies that make the most efficient use of existing spectrum through frequency reuse schemes, optimized signaling mechanisms, and scalable network architectures. But if wireless networks are to be a truly viable technology they’ll need to be • ubiquitous, to support enough geographic coverage to provide seamless integration with existing wired networks; • robust, to transfer multimedia information requiring data rates in the range of 10 to 20 Mbps; • scalable, to accommodate the potentially high level of demand within the same geographic area of coverage; • secure, to ensure confident use of the networks; and • open, to facilitate competition among vendors for the benefit of the consumer. In order to achieve these goals quickly, we’ll need to accelerate the development and implementation of a number of key technologies—such as spread spectrum multihopping—especially because wire users have grown accustomed to near-instantaneous response and the background noise level for wireless communications is already high.

Paper: PDF file of paper

Information & Date

IEEE Computer, , December. 1997


Hasan S. Alkhatib
Chase Bailey
Mario Gerla
James McCrae