Multi-Hop Network Topology System and Method

Abstract

A wireless communication system and method for a network having a tree topology. An initial path from a base station to an end relay node is selected. The path selection includes an active communication path and a redundant communication path. The path selection is based on at least one policy factor. The at least one policy factor is monitored and the path is updated based on a change to the monitored at least one policy factor.

1 . A wireless communication method for a network having a tree topology, the method comprising:
 selecting an initial path from a base station to an end relay node, the path selection including an active communication path and a redundant communication path, the path selection being based on at least one policy factor;   monitoring the at least one policy factor; and   updating the path based on a change to the monitored at least one policy factor.   
     
     
         2 . The method of  claim 1 , wherein the at least one policy factors include one or more of a number of hops, link quality and path capacity room. 
     
     
         3 . The method of  claim 1 , wherein the network is an IEEE 802.16j network. 
     
     
         4 . The method of  claim 1 , wherein the active communication path and the redundant communication path are defined as an equivalent path from the base station to the end relay node. 
     
     
         5 . The method of  claim 1 , wherein the active communication path and the redundant communication path are defined as a primary path and assistant path, respectively, from the base station to the end relay node. 
     
     
         6 . The method of  claim 1 , further comprising using a relay node preamble to measure at least one of the policy factors. 
     
     
         7 . The method of  claim 6 , wherein measuring at least one of the policy factors includes:
 randomly selecting a monitoring cycle from a monitoring cycle selection base, the monitoring cycle selection base comprising a plurality of preamble cycles;   stopping transmission of the relay node preamble during the selected monitoring cycle; and   transmitting relay node preambles during the remaining preamble cycles   
     
     
         8 . The method of  claim 1 , wherein the path selection is distributed such that path selection is determined at least in part by a relay node. 
     
     
         9 . The method of  claim 1 , wherein the path selection is centralized such that path selection is determined by a base station. 
     
     
         10 . The method of  claim 1 , further comprising:
 storing a topology table corresponding to a local topology;   detecting a change in the local topology; and   requesting a path selection update; the path selection comprising the active communication path and the redundant communication path.   
     
     
         11 . The method of  claim 11 , wherein an architecture of the topology is a hierarchical topology, the hierarchical topology including a master relay node supporting a group of relay nodes. 
     
     
         12 . A method for a relay node to use a relay node preamble to evaluate a wireless communication radio environment, the method comprising:
 randomly selecting a monitoring cycle from a monitoring cycle selection base, the monitoring cycle selection base comprising a plurality of preamble cycles;   stopping transmission of the relay node preamble during the selected monitoring cycle; and   transmitting relay node preambles during the remaining preamble cycles.   
     
     
         13 . The method of  claim 12 , wherein the wireless communication radio environment is an IEEE 802.16j wireless communication network. 
     
     
         14 . A wireless communication system having a tree topology, the system comprising:
 a base station;   a first relay node in communication with the base station; and   a second relay node in direct communication with at least one of the base station and the first relay node, an active communication path being established from the base station to the second relay node and a redundant communication path being established from the base station to the second relay node, the redundant communication path being different than the active communication path and at least one of the active communication path and the redundant communication path including the first relay node.   
     
     
         15 . The system of  claim 14 , wherein the network is an IEEE 802.16j network. 
     
     
         16 . The system of  claim 14 , wherein the active communication path and the redundant communication path are defined as an equivalent path from the base station to the second relay node. 
     
     
         17 . The system of  claim 14 , wherein the active communication path and the redundant communication path are defined as a primary path and assistant path, respectively, from the base station to the second relay node. 
     
     
         18 . The system of  claim 14 , further comprising using a relay node preamble to measure a radio environment, the measured radio environment being used to establish the active and redundant communication paths. 
     
     
         19 . The system of  claim 18 , wherein the first and second relay nodes:
 each randomly select a monitoring cycle from a monitoring cycle selection base, the monitoring cycle selection base comprising a plurality of preamble cycles;   stop transmission of the relay node preamble during their selected monitoring cycle; and   transmit relay node preambles during the remaining preamble cycles.   
     
     
         20 . The system of  claim 14 , wherein the active and redundant communication paths are selected by the second relay node. 
     
     
         21 . The system of  claim 14 , wherein the base station includes a storage device storing a topology table corresponding to a local topology, and wherein the base station operates to detect a change in the local topology and requests a path selection update, the path selection comprising the active communication path and the redundant communication path. 
     
     
         22 . The system of  claim 14 , wherein an architecture of the topology is a hierarchical topology, and wherein at least one of the first relay node and the second relay node is a master relay node supporting a group of relay nodes. 
     
     
         23 . The system according to  claim 14 , wherein the active path selection and the redundant path selection is based on at least one policy factor.