Route maintenance and update based on connection identifier in multi-hop relay systems

Abstract

Connection ID (CID) assignment in multi-hop relay system can be used to perform routing. Using CID assignment as routing information in a multi-hop wireless relay system to maintain the routing structure is disclosed. In a CID cache scheme, a base station builds a CID cache based on the upstream packet and broadcasts the CID cache to a relay station. The CID cache comprises CIDs along with routing information. Based on CID cache the spanning tree of the routing can be reconstructed. A hierarchical CID assignment is disclosed wherein a base station assigns a range of CIDs to a relay station. A relay station can recognize its data packets and forward them to corresponding mobile stations. Maintaining routing automatically along with CID assignment is also disclosed.

1 . A method comprising:
 assigning, by a base station, a first set of connection identifiers to a first relay station that is connected to the base station;   assigning a second set of connection identifiers to a second relay station that is connected to the base station, the second set being non-overlapping from the first set;   assigning a third set of connection identifiers to a third relay station that is connected to the second relay station, the third set being a subset of the second set; and   transmitting, within downlink packet transmissions, the assignment of the first set of connection identifiers to the first relay station, the assignment of the second set of connection identifiers to the second relay station, and the assignment of the third set of connection identifiers to the third relay station.   
     
     
         2 . The method of  claim 1 , further comprising identifying a connection between the base station and a mobile station served by the third relay station with a connection identifier from the third set of connection identifiers. 
     
     
         3 . The method of  claim 1 , further comprising:
 receiving, by the second relay station from the base station, a packet, the packet including a connection identifier within the third set; and   routing, by the second relay station, the packet to the third relay station, based on the connection identifier being within the third set.   
     
     
         4 . The method of  claim 1 , further comprising:
 receiving packets from mobile stations via the relay stations, the packets including connection identifiers; and   creating a connection identifier cache indicating the connection identifiers for each of the mobile stations based on the connection identifiers included in the received packets.   
     
     
         5 . The method of  claim 4 , further comprising:
 transmitting the cache to the relay stations; and   setting at least one time-out associated with one of the connection identifiers when the cache is transmitted to the relay stations.   
     
     
         6 . The method of  claim 5 , further comprising deleting a content of the cache after the time-out expires. 
     
     
         7 . The method of  claim 1 , further comprising assigning a fourth set of connection identifiers to a fourth relay station connected to the first relay station, the fourth set of connection identifiers being a subset of the first set. 
     
     
         8 . An base station comprising:
 at least one processor; and   at least one memory comprising instructions stored thereon that, when executed by the at least one processor, are configured to cause the base station to at least:
 assign a first set of connection identifiers to a first relay station that is connected to the base station; 
 assign a second set of connection identifiers to a second relay station that is connected to the base station, the second set being non-overlapping from the first set; 
 assign a third set of connection identifiers to a third relay station that is connected to the second relay station, the third set being a subset of the second set; and 
 transmit, within downlink packet transmissions, the assignment of the first set of connection identifiers to the first relay station, the assignment of the second set of connection identifiers to the second relay station, and the assignment of the third set of connection identifiers to the third relay station. 
   
     
     
         9 . The base station of  claim 8 , wherein the instructions are further configured to cause the base station to identify a connection between the base station and a mobile station served by the third relay station with a connection identifier from the third set of connection identifiers. 
     
     
         10 . The base station of  claim 8 , wherein the instructions are further configured to cause the base station to:
 receive packets from mobile stations via the relay stations, the packets including connection identifiers; and   create a connection identifier cache indicating the connection identifiers for each of the mobile stations based on the connection identifiers included in the received packets.   
     
     
         11 . The base station of  claim 10 , wherein the instructions are further configured to cause the base station to:
 transmit the cache to the relay stations; and   set at least one time-out associated with one of the connection identifiers when the cache is transmitted to the relay stations.   
     
     
         12 . The base station of  claim 11 , wherein the instructions are further configured to cause the base station to delete a content of the cache after the time-out expires. 
     
     
         13 . The base station of  claim 8 , wherein the instructions are further configured to cause the base station to assign a fourth set of connection identifiers to a fourth relay station connected to the first relay station, the fourth set of connection identifiers being a subset of the first set. 
     
     
         14 . A non-transitory computer-readable storage medium comprising instructions stored thereon that, when executed by at least one processor, are configured to cause a base station to at least:
 assign a first set of connection identifiers to a first relay station that is connected to the base station;   assign a second set of connection identifiers to a second relay station that is connected to the base station, the second set being non-overlapping from the first set;   assign a third set of connection identifiers to a third relay station that is connected to the second relay station, the third set being a subset of the second set; and   transmit, within downlink packet transmissions, the assignment of the first set of connection identifiers to the first relay station, the assignment of the second set of connection identifiers to the second relay station, and the assignment of the third set of connection identifiers to the third relay station.   
     
     
         15 . The storage medium of  claim 14 , wherein the instructions are further configured to cause the base station to identify a connection between the base station and a mobile station served by the third relay station with a connection identifier from the third set of connection identifiers. 
     
     
         16 . The storage medium of  claim 14 , wherein the instructions are further configured to cause the base station to:
 receive packets from mobile stations via the relay stations, the packets including connection identifiers; and   create a connection identifier cache indicating the connection identifiers for each of the mobile stations based on the connection identifiers included in the received packets.   
     
     
         17 . The storage medium of  claim 16 , wherein the instructions are further configured to cause the base station to:
 transmit the cache to the relay stations; and   set at least one time-out associated with one of the connection identifiers when the cache is transmitted to the relay stations.   
     
     
         18 . The storage medium of  claim 17 , wherein the instructions are further configured to cause the base station to delete a content of the cache after the time-out expires. 
     
     
         19 . The storage medium of  claim 14 , wherein the instructions are further configured to cause the base station to assign a fourth set of connection identifiers to a fourth relay station connected to the first relay station, the fourth set of connection identifiers being a subset of the first set. 
     
     
         20 . A system comprising:
 a base station configured to:
 assign a first set of connection identifiers to a first relay station that is connected to the base station; 
 assign a second set of connection identifiers to a second relay station that is connected to the base station, the second set being non-overlapping from the first set; 
 assign a third set of connection identifiers to a third relay station that is connected to the second relay station, the third set being a subset of the second set; and 
 transmit, within downlink packet transmissions, the assignment of the first set of connection identifiers to the first relay station, the assignment of the second set of connection identifiers to the second relay station, and the assignment of the third set of connection identifiers to the third relay station; 
   the first relay station configured to:
 receive at least one packet from the base station, the packet including a connection identifier; 
 forward the at least one packet to at least one mobile station connected to the first relay station if the connection identifier is within the first set of connection identifiers; and 
 ignore the at least one packet if the connection identifier is not within the first set of connection identifiers; 
   the second relay station configured to:
 receive at least one packet from the base station, the packet including a connection identifier; 
 forward the at least one packet to the third relay station if the connection identifier is within the third set of connection identifiers; 
 forward the at least one packet to at least one mobile station connected to the second relay station if the connection identifier is within the second set of connection identifiers but is not within the third set of connection identifiers; and 
 ignore the at least one packet if the connection identifier is not within the second set of connection identifiers; and 
   the third relay station configured to:
 receive at least one packet from the second relay station, the packet including a connection identifier; 
 forward the at least one packet to at least one mobile station connected to the third relay station if the connection identifier is within the third set of connection identifiers; and 
 ignore the at least one packet if the connection identifier is not within the third set of connection identifiers.