Method and apparatus for handover in a wireless communication system
A method and apparatus for handover in a wireless communication system. A handover indication can be received from a source base station ( 120 ) that is connected with a mobile station ( 110 ). The handover indication can include a random access channel preamble. The random access channel preamble can include a temporary mobile equipment identifier. The random access channel preamble can be received from the mobile station. A timing advance message can be sent in response to receiving random access channel preamble. The timing advance message can be addressed by the random access channel preamble and a source base station identifier. The connection with the mobile station can be switched from the source base station to a target base station ( 130 ).
1. A method in a source base station that is connected with a mobile station for handover of the mobile station, the method comprising:
sending a handover request to a target base station, the handover request including a random access channel preamble generated at the source base station, the random access channel preamble comprising a temporary mobile equipment identifier;
receiving, from the target base station, a timing advance message including timing advance information for the mobile station;
forwarding the timing advance message to the mobile station prior to performing the handover by switching a connection of the mobile station from the source base station to the target base station.
2. The method of claim 1 , further comprising:
receiving, from the target base station, a medium access control identifier; and
forwarding the medium access control identifier to the mobile station.
3. The method of claim 1 , further comprising:
sending a persistent resource assignment message to the mobile station, the persistent resource assignment message indicating resources reserved for handover communications.
4. The method of claim 3 , further comprising:
sending the random access channel preamble to the mobile station by sending a handover preparation message over at least one of the resources reserved for handover communications to the mobile station.
5. The method of claim 1 , wherein the random access channel preamble is selected from a set of a plurality of random access channel preambles reserved for the handover.
6. The method of claim 5 , wherein the set of the plurality of random access channel preambles are shared between a plurality of base stations in adjacent cells and wherein a base station of the plurality of base stations selects the random access channel preamble from the plurality of random access channel preambles based on a starting random access channel preamble that is different than a starting random access channel preamble for at least one other base station of the plurality of base stations.
7. The method of claim 1 , wherein the handover request is sent to the target base station in response to the source base station receiving a measurement report from the mobile station and making a handover determination based on the measurement report.
8. A source base station comprising:
a controller;
a transceiver, coupled to the controller, configured to:
send a handover request to a target base station, the handover request including a random access channel preamble generated at the source base station, the random access channel preamble comprising a temporary mobile equipment identifier;
receive, from the target base station, a timing advance message including timing advance information for the mobile station; and
forward the timing advance message to the mobile station prior to the controller performing the handover by switching a connection of the mobile station from the source base station to the target base station.
9. The source base station of claim 8 , wherein the transceiver is further configured to:
receive, from the target base station, a medium access control identifier; and
forward the medium access control identifier to the mobile station.
10. The source base station of claim 8 , wherein the transceiver is further configured to:
send a persistent resource assignment message to the mobile station, the persistent resource assignment message indicating resources reserved for handover communications.
11. The source base station of claim 10 , wherein the transceiver is further configured to:
send the random access channel preamble to the mobile station by sending a handover preparation message over at least one of the resources reserved for handover communications to the mobile station.
12. The source base station of claim 8 , further comprising:
a random access channel preamble generation module, coupled to the controller, configured to generate the random access channel preamble by selecting the random access channel preamble from a set of a plurality of random access channel preambles reserved for the handover.
13. The source base station of claim 12 , wherein the set of the plurality of random access channel preambles are shared between a plurality of base stations in adjacent cells and wherein a base station of the plurality of base stations selects the random access channel preamble from the plurality of random access channel preambles based on a starting random access channel preamble that is different than a starting random access channel preamble for at least one other base station of the plurality of base stations.
14. The source base station of claim 8 , wherein the transceiver sends the handover request to the target base station in response to the source base station receiving a measurement report from the mobile station and making a handover determination based on the measurement report.