Download (direct link):
Benchmark wireless network Cell radius, km cost, USSk per km2
Figure 1.3 Wireless network: coverage vs cost
Wireless technologies are used for tasks as simple as switching off the television or as complex as supplying the sales force with information from an automated enterprise application while in the field. For businesses, wireless technologies mean new ways to stay in touch with customers, suppliers and employees (Figure 1.3).
The most notable factors that have contributed to this exponential growth are the Internet boom, the need for mobility in an ever-changing environment, low costs (flat rate), increased data rates, increased battery life, application friendliness and innovativeness. In many countries there are now more wireless phone, lines than fixed lines. There are a number of reasons for this unexpected boom in wireless networks, the foremost being the use of wireless or mobile phones, which is more convenient and requires less investment than a fixed infrastructure.
In addition, a wireless infrastructure has more ‘flexibility’ than a fixed infrastructure, in which at least the part of the access network closest to the user is dedicated to a specific locations and its profitability depends on the use made of this access by that household or business. Wireless networks do not suffer from this limitation; their use can be shared and reassigned much more easily, and they can become profitable more rapidly.
Some analysts of the telecommunications industry believe that, within a few years, most telephone calls in the residential market will be placed over wireless networks.
Drivers for wireless networks
It is by improving business processes that wireless access will find a place in many enterprises. Several internal and external factors are converging to drive a sense of urgency among businesses to find these process efficiencies, for example increased customer expectations, need for effective time utilization and employee empowerment, cost reduction and cost avoidance, advancing enterprise connectivity, legislation and government requirements.
Issues for wireless networks
As with any relatively new technology, there are many issues that affect the implementation and utilization of wireless networks. These are both common and specific, depending on the type of wireless network. Some of the common factors include electromagnetic interference and physical obstacles that limit coverage of wireless networks, while others are more specific, such as standards, data security, throughput and ease of use, (Figure 1.4).
There are basically three ways to connect a wireless network. Point-to-point bridge
A bridge connects two networks. A point-to-point bridge would interconnect two buildings. Access points connect a network to multiple users. For example, a wireless LAN bridge can interface with an Ethernet network directly to a particular access point. This may be necessary if you have several devices in a distant part of the facility that are interconnected using Ethernet.
CDMA2000 1x EV DO
High-speed downlink Racket access
RFID Warehouse management systems
technology ^802.11n (next-
Bluetooth peer-to-peer ^Enhanced data for 'global evolution
As of June 2004
Peak of inflated expectations
Trough of disillusionment Maturity
Slope of enlightment
Plateau of productivity
Figure 1.4 Wireless hype cycle. Reproduced from P. Redmant et ah, Hype Cycle for Wireless Networking, 2004 by permission of Gartner Inc.
Figure 1.5 Wireless network standards
When connecting three or more LANs that may be located on different floors in a building or across buildings, the point-to-multipoint wireless bridge is utilized. The multipoint wireless bridge configuration is similar to a point-to-point bridge in many ways.
Mesh or ad hoc network
An ad hoc (peer-to-peer) network is an independent local area network that is not connected to a wired infrastructure and in which all stations are connected directly to one another (called a mesh topology). Configuration of a WLAN in ad hoc mode is used to establish a network where wireless infrastructure does not exist or where services are not required, such as a trade show or collaboration by co-workers at a remote location (Figure 1.5).