System and method for achieving continuous connectivity to an access point or gateway in a wireless network following an on-demand routing protocol, and to perform smooth handoff of mobile terminals between fixed terminals in the network
View Patent ↗A system and method for enabling an ad-hoc communication network to maintain connectivity with the mobile nodes in the network in an effective and efficient manner with minimal overhead. The system and method enables an ad-hoc communication network to maintain connectivity between intelligent access points of the network and mobile nodes in the network while performing an on-demand protocol. The system and method further uses an improved distance vector routing algorithm and unicast messages, to thus avoid an increase routing advertisement frequency in the network while keeping network overhead at a minimum. The system and method also modifies the Ad Hoc On-Demand Distance Vector Routing (AODV) protocol to facilitate smooth handoff of subscriber devices in an ad-hoc communication network while also eliminating unidirectional links between nodes in the network.
1. A method for performing a handoff of a mobile subscriber device between a first and a second wireless router in a communication network, the method comprising:
when the subscriber device is moving from a coverage area of the first wireless router to a coverage area of the second wireless router, unicast transmitting a routing advertisement, including information identifying the subscriber device, from the subscriber device to the second wireless router;
updating a routing table of the second wireless router in accordance with the information included in the routing advertisement when the second wireless router receives the routing advertisement;
changing communication routing for the subscriber device from the first wireless router to the second wireless router; and
unicast transmitting another routing advertisement, including information identifying the subscriber device, along a path of communication between the second wireless router and an access point via which the second wireless router gains access to a portion of the network, to inform the access point of the change of communication routing with the subscriber device, wherein said path includes a plurality of wireless routers via which said another routing advertisement travels to reach the access point.
2. A method as claimed in claim 1 , wherein:
the network is a wireless ad-hoc peer-to-peer network, and the first and second wireless routers and the subscriber device communicate in the wireless ad-hoc peer-to-peer network.
3. A wireless communication network, comprising:
a plurality of wireless routers associated with an access point via which the wireless routers gain access to a portion of the network; and
a mobile subscriber device, wherein said mobile subscriber device communicates with any said wireless router within its broadcast range;
wherein when the subscriber device is moving from a coverage area of a first wireless router to a coverage area of a second wireless router, the subscriber device unicast transmits a routing advertisement, including information identifying the subscriber device, to the second wireless router, and when the second wireless router receives the routing advertisement, the second wireless router updates its routing table in accordance with the information included in the routing advertisement, and unicast transmits another routing advertisement, including information identifying the subscriber device, along a path of communication between the second wireless router and the access point, to inform the access point of a change of communication routing for the subscriber device from the first wireless router to the second wireless router, wherein said path includes a plurality of wireless routers via which said another routing advertisement travels to reach the access point.
4. A network as claimed in claim 3 , wherein:
the network is a wireless ad-hoc peer-to-peer network, and the wireless routers, the access point and the subscriber device communicate in the wireless ad-hoc peer-to-peer network.