System and method to perform smooth handoff of mobile terminals between fixed terminals in a network

• US 7,382,740 B2
• Filed: 01/10/2006
• Issued: 06/03/2008
• Est. Priority Date: 01/13/2004
• Status: Expired due to Term

• Current Assignee: Strong Force IoT Portfolio 2016, LLC (Strong Force Intellectual Capital, LLC)
• Original Assignee: MeshNetworks, Inc. (Motorola Solutions, Inc.)
• Inventors: Joshi, Avinash
• Primary Examiner(s): Harper, Kevin C
• Application Number:
  US11/328,623
• Publication Number:
  US 20060114849A1
• Time in Patent Office: 875 Days
• Field of Search: 370/254, 370/328, 370/465, 370/338
• US Class Current: 370/254
• CPC Class Codes: H04W 36/08 Reselecting an access point
• CPC Class Codes: H04W 36/18 for allowing seamless reselection, e.g. soft reselection
• CPC Class Codes: H04W 40/22 using selective relaying for reaching a BTS [Base Transceiver Station] or an access point
• CPC Class Codes: H04W 40/28 for reactive routing
• CPC Class Codes: H04W 48/08 Access restriction or access information delivery, e.g. discovery data delivery signalling during connection H04W76/00
• CPC Class Codes: H04W 84/18 Self-organising networks, e.g. ad-hoc networks or sensor networks

Abstract

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.

Claims

1. A method for performing handoff of a mobile subscriber device between one or more wireless routers in a communication network, the method comprising:

at the mobile subscriber device;

evaluating respective routing metrics associated with the respective wireless routers as the mobile subscriber device is moving; and

sending a routing request message to the wireless router whose respective said routing metrics meet a desired criteria, wherein the routing request message is sent by the mobile subscriber device at a periodic rate, wherein the periodic rate is based on an average number of new neighbors added in a neighbor table of the mobile subscriber device; and

at one of the wireless routers;

receiving the routing request message; and

providing the routing request message to the associated access point to inform the associated access point of a route to the mobile subscriber device.

2. A method as claimed in claim 1, 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.

5. A method as claimed in claim 1, wherein:

the respective routing metrics including information pertaining to factors which affect an ability of the mobile subscriber device to communicate with its associated access point of the network via a respective said wireless router.

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 the mobile subscriber device evaluates respective routing metrics associated with the respective wireless routers as the mobile subscriber device is moving; and

sends a routing request message at a periodic rate to the wireless router whose respective said routing metrics meet a desired criteria, wherein the periodic rate is based on an average number of new neighbors added in a neighbor table of the mobile subscriber device and, further wherein the wireless router provides the routing request message to the associated access point to inform the associated access point of a route to the mobile subscriber device.

4. A wireless communication 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.