Method and system for intra base station carrier handover

• US 8,520,635 B2
• Filed: 12/22/2008
• Issued: 08/27/2013
• Est. Priority Date: 09/03/2008
• Status: Active Grant

• Current Assignee: ZTE Corporation
• Original Assignee: ZTE Corporation
• Inventors: Zhang, Ruixia, Wang, Wenhuan, Liu, Min, Lv, Kaiying, Li, Nan, Fang, Huiying
• Primary Examiner(s): PARK, JUNG H
• Application Number:
  US13/061,778
• Publication Number:
  US 20110170519A1
• Time in Patent Office: 1,709 Days
• US Class Current: 370/331
• CPC Class Codes: H04W 36/0083 Determination of parameters used for hand-off, e.g. generation or modification of neighbour cell lists
• CPC Class Codes: H04W 36/06 Reselecting a communication resource in the serving access point
• CPC Class Codes: H04W 36/18 for allowing seamless reselection, e.g. soft reselection
• CPC Class Codes: H04W 36/30 by measured or perceived connection quality data

Abstract

A method and a system for intra-BS carrier handover are provided. The method comprises: a mobile station scanning predetermined carriers within the base station based on predetermined rules; obtaining a scanning report comprising channel quality information of part of or all of the predetermined carriers; and sending the scanning report to the base station; the base station obtaining the channel quality information in the scanning report; selecting a target carrier from the predetermined carriers; and informing the mobile station of the selected target carrier via a message; and the mobile station handing over to the target carrier in a predetermined manner in response to the message. By using the method, seamless handover of intra-BS carriers can be performed in a multi-carrier system for ensuring the service continuity of the mobile station to eliminate carrier handover time delay.

Claims

1. A method for intra-BS carrier handover, used for the handover of carriers within a base station in a multi-carrier system, the method comprising:

a mobile station scanning predetermined carriers within the base station based on predetermined rules, wherein the predetermined carriers comprises fully-configured carriers and partially-configured carriers supported by the mobile station and configured by the base station, except a primary carrier and a secondary carrier of the mobile station;

obtaining a scanning report comprising channel quality information of part of or all of the predetermined carriers; and

sending the scanning report to the base station;

the base station obtaining the channel quality information in the scanning report;

selecting a target carrier from the predetermined carriers; and

informing the mobile station of the selected target carrier via a message; and

the mobile station handing over to the target carrier in a predetermined manner in response to the message.

2. The method according to claim 1, wherein before the step of the mobile station scanning the predetermined carriers based on the predetermined rules, the method further comprises:

the mobile station obtaining, via its primary carrier, broadcast information related to multi-carrier operations and configuration information of other carriers except the current primary carrier, which are configured in the base station, and obtaining information related to multi-carrier scanning according to the configuration information and the broadcast information related to multi-carrier operations.

3. The method according to claim 2, wherein the predetermined rules comprise at least one of the followings:

the mobile station periodically scanning the predetermined carriers according to the information related to multi-carrier scanning;

the mobile station scanning the predetermined carriers in an event triggering manner based on the information related to multi-carrier scanning; and

the mobile station receiving a notifying message sent by the base station, and scanning the predetermined carriers based on scanning information carried in the notifying message, wherein the scanning information comprises at least one of the followings;

a list of carriers to be scanned, a start time for scanning and a scanning interval.

4. The method according to claim 1, wherein the predetermined rules comprise at least one of the followings:

the mobile station periodically scanning the predetermined carriers according to the information related to multi-carrier scanning;

the mobile station scanning the predetermined carriers in an event triggering manner based on the information related to multi-carrier scanning; and

the mobile station receiving a notifying message sent by the base station, and scanning the predetermined carriers based on scanning information carried in the notifying message, wherein the scanning information comprises at least one of the followings;

a list of carriers to be scanned, a start time for scanning and a scanning interval.

5. The method according to claim 4, wherein in the case that the source carrier is a primary carrier of the mobile station, the predetermined manner comprises:

the mobile station maintaining a connection with the base station on the current main carrier, before predetermined time arrives; and

when the predetermined time arrives, the mobile station handing over to the target carrier, parsing the obtained control information on the target carrier, and taking the target carrier as a primary carrier of the mobile station.

6. The method according to claim 4, wherein in the case that the source carrier is a primary carrier of the mobile station, the predetermined manner comprises:

the mobile station receiving, via the source carrier, a notification of assigning resource for the mobile station on the target carrier by the base station;

the mobile station receiving or sending data at the indicated position of the target carrier according to the notification of assigning resource; and

the mobile station parsing the control information obtained by the mobile station from the target carrier and taking the target carrier as a primary carrier of the mobile station when the next superframe arrives.

7. The method according to claim 4, wherein in the case that the source carrier is a secondary carrier of the mobile station, the predetermined manner comprises:

the mobile station receiving, via the primary carrier, a notification of assigning resource for the mobile station on the target carrier by the base station; and

in response to the notification of assigning resource, the mobile station terminating a connection with the source carrier, handing over to the target carrier, and receiving or sending data at the indicated position of the target carrier.

8. The method according to claim 1, wherein the step of the base station selecting a target carrier comprises:

the base station selecting the target carrier based on the channel quality information and carrier load conditions obtained in advance by the base station, moreover if a source carrier of the mobile station is a primary carrier of the mobile station, the target carrier is a fully-configured carrier; and

if the source carrier is a secondary carrier of the mobile station, the target carrier is the fully-configured carrier or the partially-configured carrier.

9. The method according to claim 1, wherein the message is a carrier handover notifying message.

10. The method according to claim 9, wherein the carrier handover notifying message carries source carrier information of the mobile station and indication information indicating whether to perform synchronization on the target carrier, moreover, in the case that the target carrier and the source carrier meet a predetermined condition, the carrier handover notification also carries at least one of the followings:

a specified ranging code and specified ranging resource information on the target carrier.

11. The method according to claim 10, wherein the predetermined condition is:

the center frequency difference between the target carrier and the source carrier is greater than a predetermined frequency difference f.

12. The method according to claim 11, wherein after the predetermined condition is met and the base station sends the carrier handover notification, the method further comprises:

the base station storing a mapping relationship among a mobile station identifier, the specified ranging code, and the specified ranging resource.

13. The method according to claim 12, wherein in the case that the carrier handover notifying message carries the indication information and the indication information indicates that synchronization is needed, the step of handing over the mobile station to the target carrier in a predetermined manner comprises:

the mobile station sending the specified ranging code on the specified ranging resource of the target carrier in response to the carrier handover notifying message; and

the mobile station receiving on its primary carrier a ranging response message sent by the base station based on the mapping relationship and handing over in the predetermined manner from the source carrier to the target carrier.

14. The method according to claim 1, wherein in the case that the source carrier is a primary carrier of the mobile station, the predetermined manner comprises:

the mobile station maintaining a connection with the base station on the current main carrier, before predetermined time arrives; and

when the predetermined time arrives, the mobile station handing over to the target carrier, parsing the obtained control information on the target carrier, and taking the target carrier as a primary carrier of the mobile station.

15. The method according to claim 1, wherein in the case that the source carrier is a primary carrier of the mobile station, the predetermined manner comprises:

the mobile station receiving, via the source carrier, a notification of assigning resource for the mobile station on the target carrier by the base station;

the mobile station receiving or sending data at the indicated position of the target carrier according to the notification of assigning resource; and

the mobile station parsing the control information obtained by the mobile station from the target carrier and taking the target carrier as a primary carrier of the mobile station when the next superframe arrives.

16. The method according to claim 1, wherein in the case that the source carrier is a secondary carrier of the mobile station, the predetermined manner comprises:

the mobile station receiving, via the primary carrier, a notification of assigning resource for the mobile station on the target carrier by the base station; and

in response to the notification of assigning resource, the mobile station terminating a connection with the source carrier, handing over to the target carrier, and receiving or sending data at the indicated position of the target carrier.

17. A system for intra-BS carrier handover, used for the handover of carriers within a base station in a multi-carrier system, the system comprising:

a mobile station, configured to scan predetermined carriers within the base station based on predetermined rules, wherein the predetermined carriers comprises fully-configured carriers and partially-configured carriers supported by the mobile station and configured by the base station, except a primary carrier and a secondary carrier of the mobile station, obtain a scanning report comprising channel quality information of part of or all of the predetermined carriers, and send the scanning report to the base station;

the base station, configured to obtain the channel quality information in the scanning report, select a target carrier from the predetermined carriers, and inform the mobile station of the selected target carrier via a carrier handover notifying message; and

the mobile station, further configured to hand over to the target carrier in a predetermined manner based on a predetermined message of the base station.

18. The system according to claim 17, wherein

in the case that the source carrier is a primary carrier of the mobile station, the predetermined manner comprises:

presetting a handover time, and before the handover time arrives, maintaining, by the mobile station, a connection with the base station on the current primary carrier;

when the handover time arrives, the mobile station hands over to the target carrier, parses the obtained control information on the target carrier, and takes the target carrier as a primary carrier of the mobile station;

or

the mobile station receives via the source carrier a notification of assigning resource for the mobile station on the target carrier by the base station;

the mobile station receives or sends data at the indicated position of the target carrier according to the notification of assigning resource;

when the next superframe arrives, the mobile station parses the control information obtained by the mobile station from the target carrier and takes the target carrier as a primary carrier of the mobile station;

or

in the case that the source carrier is a secondary carrier of the mobile station, the predetermined manner comprises;

the mobile station receiving, via the primary carrier, a notification of assigning resource for the mobile station on the target carrier by the base station; and

in response to the notification of assigning resource, the mobile station terminates a connection with the source carrier, hands over to the target carrier, and receives or sends data at the indicated position of the target carrier.