From Wireless Communications

Infrastructure-based wireless networks have base stations, also called access points, deployed throughout a given area. These base stations provide access for mobile terminals to a back-bone wired network. Network control functions are performed by the base stations, and often the base stations are connected together to facilitate coordinated control. This infrastructure is in contrast to ad hoc wireless networks, described in Chapter 16, which have no backbone infrastructure. Examples of infrastructure-based wireless networks include cellular phone systems, wireless LANs, and paging systems. Base station coordination in infrastructure-based networks provides a centralized control mechanism for transmission scheduling, dynamic resource allocation, power control, and handoff. As such, it can more efficiently utilize network resources to meet the performance requirements of individual users. Moreover, most networks with infrastructure are designed so that mobile terminals transmit directly to a base station, with no multihop routing through intermediate wireless nodes. In general these single-hop routes have lower delay and loss, higher data rates, and more flexibility than multihop routes. For these reasons, the performance of infrastructure-based wireless networks tends to be much better than in networks without infrastructure. However, it is sometimes more expensive or simply not feasible or practical to deploy infrastructure, in which case ad hoc wireless networks are the best option despite their typically inferior performance.

Cellular systems are a type of infrastructure-based network that make efficient use of spectrum by reusing it at spatially separated locations. The focus of this chapter is on cellular system design and analysis, although many of...

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Wireless communications services provide cellular phone service, SMS, WAP and GPRS services to mobile phones.
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Specialty communications infrastructure service provide specialty or proprietary services related to the development and maintenance of communications infrastructures.
GPRS Chips
GPRS chips use general packet radio service (GPRS), a standard for wireless communication with a throughput rate of 115 kilobits per second.
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Telecommunications infrastructure services provide setup, maintenance and consulting for all data and voice communications technologies.
Auto Dialers
Auto dialers are alarms that send signals when equipment malfunctions, a process variable exceeds a predefined limit, or another alarm-triggering event occurs.

Topics of Interest

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