Multicast and Broadcast Service (MBS) is defined as an interoperability feature (IO-MBS) by WiMAX Forum and will be tested in Wave 2. MAC and Physical layer related to MBS already defined in IEEE802.16e. Hence, the implementation between MS and BS is more clear. Currently, WiMAX forum not yet define the interface between MBS server and ASN GW but some common industry implementation methodology can be done by vendor.
ASN GW can be a proxy for multicast and broadcast just like an multicast router in IP world. When the MS need to receive multicast service, an IGMP join message for a specific multicast channel will be sent to ASN GW. After some authorization procedure, ASN GW will notify BS to setup multicast channel with the requesting MS through DSA messages which is defined in 802.16. After DSA procedure, MS can receive the multicast channel information from MBS_MAP. Before MS terminate the multicast reception, an IGMP leave message will be sent to AGW. Broadcast service can also be acquired through DSA process and MBS_MAP but bypass the IGMP process.
Mobility function of MBS service can be supported through MBS zone. When the MS moving in the BS culster within the same MBS zone, there is no need to setup new connection ID.
read more ...
沒有留言:
張貼留言