WiMAX Handbook: Building 802.16 Wireless Networks
Describing how WiMAX affects current telecom technologies including Wi-Fi, fiber optics, and VoIP, this book discusses the business and economic implications of this ground-breaking technology.
TABLE OF CONTENTS WiMAX Handbook: Building 802.16 Wireless Networks
Chapter 4: How WiMAX Works
Like most data communications, WiMAX relies on a process consisting of a session setup and authentication. The RLC manages and monitors the quality of the service flow. With WiMAX, this process is a series of exchanges (DLs and ULs) between the BS and SS. A complex process determines what FDD and TDD settings will be used for the service flow, FEC, sets encryption, bandwidth requests, burst profiles, and so on. The process starts with channel acquisition by the newly installed SS.
Channel Acquisition
The MAC protocol includes an initialization procedure designed to eliminate the need for manual configuration. In other words, the subscriber takes the SS out of the box, plugs in power and Ethernet, and connects almost immediately to the network. The following paragraphs describe how that is possible without laborious user setup or service provider truck roll.
Upon installation, the SS begins scanning its frequency list to find an operating channel. It may be preconfigured by the service provider to register with a specified BS. This feature is useful in dense deployments where the SS might hear a secondary BS due to spurious signals or when the SS picks up a sidelobe of a nearby BS antenna. Moreover, this feature will help service providers avoid expensive installations and subsequent truck rolls.
After selecting a channel or channel pair, the SS synchronizes to the DL transmission from the BS by detecting the periodic frame preambles. Once the PHY is synchronized, the SS will look for the periodically broadcasted DCD...
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