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IEEE Std 802.16-2001

LOCAL AND METROPOLITAN AREA NETWORKS—PART 16:

PHSI=0

IP Packet (including header)

 

 

Figure 15—IP CS PDU format IEEE 802.3/Ethernet CS

PDU format without header suppression

PHSI≠0

Header-Suppressed IP Packet

 

 

Figure 16—IP CS PDU format IEEE 802.3/Ethernet CS

PDU format with header suppression

5.2.7.2 IP classifiers

IP classifiers operate on the fields of the IP header and the transport protocol. The parameters (11.4.9.3.6.2—11.4.9.3.6.7) may be used in IP classifiers.

6. MAC common part sublayer (CPS)

A network that utilizes a shared medium requires a mechanism to efficiently share it. A two-way point-to-multipoint wireless network is a good example of a shared medium; here the medium is the space through which the radio waves propagate.

The downlink, from the base station (BS) to the user, operates on a point-to-multipoint basis. The IEEE Std 802.16-2001 wireless link operates with a central BS and a sectorized antenna which is capable of handling multiple independent sectors simultaneously. Within a given frequency channel and antenna sector, all stations receive the same transmission, or parts thereof. The base station is the only transmitter operating in this direction, so it transmits without having to coordinate with other stations, except for the overall time division duplexing that may divide time into uplink and downlink transmission periods. It broadcasts to all stations in the sector (and frequency); stations check the address in the received messages and retain only those addressed to them.

In the other direction, the user stations share the uplink to the BS on a demand basis. Depending on the class of service utilized, the SS may be issued continuing rights to transmit, or the right to transmit may be granted by the BS after receipt of a request from the user.

In addition to individually addressed messages, messages may also be sent on multicast connections (control messages and video distribution are examples of multicast applications) as well as broadcast to all stations.

Within each sector, users adhere to a transmission protocol that controls contention between users and enables the service to be tailored to the delay and bandwidth requirements of each user application. This is accomplished through five different types of uplink scheduling mechanisms. These are implemented using unsolicited bandwidth grants, polling, and contention procedures. Mechanisms are defined in the protocol to allow vendors to optimize system performance using different combinations of these bandwidth allocation techniques while maintaining consistent inter-operability definitions. For example, contention may be used to avoid the individual polling of SSs which have been inactive for a long period of time.

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Copyright © 2002 IEEE. All rights reserved.

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