Wimax standards and Security The Wimax

Mesh Network Synchronization

Network configuration (MSH-NCFG) and network entry (MSH-NENT) pack- ets provide a basic level of communication among nodes in different nearby networks, whether from the same or different equipment vendors or wireless operators. These packets are used to synchronize both centralized and distri- buted control mesh networks. This communication is used to support basic configuration activities such as synchronization between nearby networks used (i.e., for multiple, colocated BSs to synchronize their uplink and down- link transmission periods), communication and coordination of channel usage by nearby networks, and discovery and basic network entry of new nodes.
MSH-NCFG, MSH-NENT, and MSH-DSCH can assist a node in synchro- nizing to the start of frames. For these messages, the control subframe, which initiates each frame, is divided into transmit opportunities. The first transmit opportunity in a network control subframe may only contain MSH-NENT messages, while the remainder MSH-CTRL-LEN-1 may only contain MSH- NCFG messages. In scheduling control subframes, the MSH-DSCH-NUM transmit opportunities assigned for MSH-DSCH messages come last in the control subframe. The MSH-NCFG messages also contain the number of its transmit opportunity, which allows nodes to easily calculate the start time of the frame.

2. 
   Summary
   

In this chapter, we have reviewed the functions and features of the core MAC protocol of the WiMAX systems including the PMP topology and mesh topol- ogy. In the standard, the MAC protocol should include another two sublayers, which are convergence sublayer and security sublayer. However, they have not been covered in this chapter. Only the fundamental part of the MAC pro- tocol of the WiMAX systems has been summarized and presented. As a part of communication protocol stack, MAC protocol plays a very important role in the communication procedure. And this is the reason why MAC protocol has been specified in almost every communication standard by the IEEE stan- dard committee. This chapter is expected to be a carrier of the fundamental knowledge of the MAC protocol specified in the IEEE 802.16d and the under- standing of the features and functions of the MAC protocols for the WiMAX systems.



References

1. 
   IEEE 802.16-2004, IEEE Standard for Local and Metropolitan Area Networks—Part 16: Air Interface for Fixed Broadband Wireless Access Systems, October 1, 2004.
   
2. 
   Frank Ohrtman, WiMax Handbook: Building 802.16 Wireless Networks, McGraw-Hill, New York, USA, 2005.
   

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Scheduling and Performance Analysis of QoS for IEEE 802.16 Broadband Wireless Access Network