Wimax standards and Security The Wimax

Thomas Schwengler
CONTENTS

1. 
   Introduction 78
   
   1. 
      Fixed and Mobile 78
      
   2. 
      Frequency 79
      
2. 
   Propagation Environment 81
   
   1. 
      Propagation Modeling 81
      
   2. 
      Fixed Broadband Access 83
      
   3. 
      Link Budgets 84
      
   4. 
      Propagation Characteristics 84
      
   5. 
      In-Building Penetration 87
      
3. 
   System Performance 90
   
   1. 
      Data Rates 90
      
   2. 
      Experimental Data 92
      
   3. 
      Other Trial Considerations 92
      
   4. 
      Radio Parameters Analysis and Modeling 93
      
   5. 
      Throughput Measurements 97
      
4. 
   Conclusion 99
   

References 100
Modern wireless communication systems deliver reliable high-speed data services. Consumer expectations have become very high: cheaper rates, higher data throughput, flexible applications, better service integration, and almost ubiquitous availability are expected from wireless service providers. Radio technologies and standards have been successful in delivering many of these expectations: CDMA-based third-generation systems such as EV- DO (IS-858) and HSDPA provide affordable multimegabit services, and are available in major cities. IEEE standard 802.16 and the WiMAX Forum are pursuing similar goals and present another high-speed access alterna- tive. WiMAX offers both fixed and mobile systems, efficient and adaptive


77

coding and modulation techniques, scalable channel sizes, subchannelization schemes, MIMO antenna systems, quality of service (QoS), and more.

High-speed wireless services have already achieved great success in local area networks (LAN) with the IEEE 802.11 standard and Wi-Fi certified prod- ucts. The goal is now to broaden wireless access to metropolitan area networks (MAN) and complement current wired services such as ADSL and cable modem.
This chapter presents carriers’ perspectives for wireless services like fixed WiMAX access. Of course, fundamentals of wave propagation are still of the utmost importance, and the nature of wireless channels (including their relative unpredictability and fading characteristics) must be well under- stood. Before deploying new wireless services on a large scale, service providers need a good estimate of capacity and coverage of these sys- tems. To this end, this chapter presents various aspects of propagation and performance for WiMAX radio systems: it reviews WiMAX radio system parameters such as link budgets; it presents relevant propagation models; and it analyzes system throughput and performance for a typical subur- ban area.

1. 
   Introduction
   

IEEE 802.16 is a standard for wide area wirelss networks. It includes important service providers requirements such as QoS, security, flexible and scal- able operations in different RF bands. WiMAX goes one step further and narrows down some implementation choices of 802.16 to achieve interop- eration between equipment manufacturers. WiMAX standardizes several air interfaces and several profiles in different frequency bands. Of course, performance varies with frequency, channel bandwidth, and other profile characteristics; and conformance between products and suppliers exist only in a given profile.

1.