Access Service Network in WiMAX: The role of ASN-GW--Part III

In some configuration handover decision and control may also reside in the ASN-GW (Profile A of WiMAX NWG Release 1.0). Handover decision module requires populating physical signal readings of mobile subscriber. This is used to decide for handover. This decision module also works in conjunction with load balancing module which has the spare capacity report of each BS. Together they manage handover due to mobility or due to load balancing. Note that if handover controller and radio resource management reside in the base station, ASN-GW may still assist load balancing module residing in the Base station by only utilizing the spare capacity information since BS only has limited neighboring information but ASN-GW on the other hand has the information of all BSs.

ASN-GW data plane may provide backhaul optimization in order to reduce the OPEX. Backhaul between base station and ASN-GW is an IP backbone. Due to the multipath fading environment in the wireless channel, utilization of BS may fluctuate and BS starts to buffer incoming packets. An intelligent ASN-GW may stop forwarding packets during this time in order to minimize the backhaul usage. The same phenomena may occur if backhaul is wireless or error prone in which ASN-GW may kick in and reduce downlink forwarding until the link is up.

ASN-GW data plane may provide deep packet inspection so that it can identify the type of flow such as peer to peer, online gaming, etc. This way operator directly allows or filters certain type of flows. Deep packet inspection capability also provide information about user since URLs requested by user, and keyword based search is possible. This type of information may be used to build up a behavior index for user in order to customize advertisements.

The ASN-GW data plane also assists end-to-end QoS through Diffserv by marking the IP packets with Diffserv codes.

Scalability is fulfilled with additional blades that can be plugged into a chassis to meet more demand as seen in Figure 10. The system can also be customized with this scalable architecture to concurrently address gateway functionality for existing 2G, 3G, and other coming 4G technologies.