Network-assisted cell selection at connection re-establishment

• US 9,961,607 B2
• Filed: 05/28/2014
• Issued: 05/01/2018
• Est. Priority Date: 08/09/2013
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Cui, Tao, Mller, Walter, Xuan, Zhiyi
• Primary Examiner(s): Sheikh, Ayaz
• Assistant Examiner(s): Asefa, Debebe
• Application Number:
  US14/372,666
• Publication Number:
  US 20150092686A1
• Time in Patent Office: 1,434 Days
• CPC Class Codes: H04W 36/305 Handover due to radio link failure control signalling for hand-off failure H04W36/0079
• CPC Class Codes: H04W 36/36 by user or terminal equipment
• CPC Class Codes: H04W 48/16 Discovering, processing access restriction or access information
• CPC Class Codes: H04W 76/19 Connection re-establishment

Abstract

According to several disclosed techniques, a wireless network provides assistance information to a mobile terminal for cell selection at re-establishment of a connection after a radio link failure. An example method is implemented in a mobile terminal served in a first cell of a wireless network, and includes receiving (510) a configuration message from the network, the configuration message identifying at least one carrier frequency. Upon subsequently losing connection with the first cell without receiving a handover command, the mobile terminal initiates (520) a cell search using the identified at least one carrier frequency, based on the configuration message.

Claims

1. A method in a mobile terminal for controlling connection re-establishment between said mobile terminal and a wireless communication network, said mobile terminal being served in a first cell of said network, the method comprising:

receiving a configuration message from the network, the configuration message comprising assistance information for radio resource control (RRC) connection re-establishment including at least one carrier frequency; and

,

responsive to subsequently losing connection with the first cell due to radio link failure, initiating a cell search using the assistance information including the at least one carrier frequency.

2. The method of claim 1, wherein the configuration message indicates one or more first carrier frequencies that are to be searched, and wherein initiating the cell search comprises searching for the indicated one or more first carrier frequencies, based upon the configuration message.

3. The method of claim 1, wherein the configuration message indicates one or more second carrier frequencies that are not to be searched, and wherein initiating the cell search comprises searching only for carrier frequencies other than the indicated one or more second carrier frequencies, based on the configuration message.

4. The method of claim 1, wherein the configuration message is received via a first radio access technology (RAT) and further includes an indication that the cell search should begin with an alternative RAT, and wherein initiating the cell search comprises beginning the cell search by searching for one or more carrier frequencies of the alternative RAT, based upon the indication.

5. The method of claim 4, wherein the configuration message further includes one or more third carrier frequencies corresponding to the alternative RAT, and wherein initiating the cell search comprises beginning the cell search by searching for one or more of the third carrier frequencies, based on the configuration message.

6. The method of claim 4, wherein the configuration message further includes an identifier of the alternative RAT, and wherein initiating the cell search comprises beginning the cell search by searching for a carrier frequency of the identified alternative RAT.

7. A method, in a wireless network node, for controlling radio resource control (RRC) connection re-establishment between a mobile terminal and a wireless communication network, the method comprising:

establishing a connection with the mobile terminal; and

sending a configuration message to the mobile terminal, the configuration message comprising assistance information for RRC connection re-establishment including at least one carrier frequency for use by the mobile terminal in initiating a cell search responsive to losing connection with the wireless communication network due to radio link failure.

8. The method of claim 7, wherein the configuration message indicates one or more first carrier frequencies that are to be searched in the cell search initiated upon losing connection with the wireless communication network.

9. The method of claim 7, wherein the configuration message indicates one or more second carrier frequencies that are not to be searched in the cell search initiated upon losing connection with the wireless communication network.

10. The method of claim 7, wherein the configuration message is received via a first radio access technology (RAT) and further includes an indication that the cell search initiated upon losing connection with the wireless communication network should begin with an alternative RAT.

11. The method of claim 10, wherein the configuration message further includes one or more third carrier frequencies corresponding to the alternative RAT.

12. The method of claim 10, wherein the configuration message further includes an identifier of the alternative RAT.

13. The method of claim 7, wherein the method further comprises first preparing at least one list of carrier frequencies for each of one or more cells, based on frequency relations for each cell obtained from statistical records or configuration information, wherein the configuration message is based on the at least one list corresponding to the cell serving the mobile terminal.

14. A mobile terminal comprising a radio transceiver circuit configured to communicate with a wireless communication network and a processing circuit configured to control the radio transceiver circuit, wherein the processing circuit is further configured to:

receive a configuration message from the network, via the radio transceiver circuit, the configuration message comprising assistance information for radio resource control (RRC) connection re-establishment including at least one carrier frequency; and

,

responsive to subsequently losing connection with the first cell due to radio link failure, initiate a cell search using the assistance information including the at least one carrier frequency.

15. The mobile terminal of claim 14, wherein the configuration message indicates one or more first carrier frequencies that are to be searched, and wherein the processing circuit is configured to initiate the cell search by searching for the indicated one or more first carrier frequencies, based on the configuration message.

16. The mobile terminal of claim 14, wherein the configuration message indicates one or more second carrier frequencies that are not to be searched, and wherein the processing circuit is configured to search only for carrier frequencies other than the indicated one or more second carrier frequencies, based on the configuration message.

17. The mobile terminal of claim 14, wherein the processing circuit is configured to receive the configuration message via a first radio access technology (RAT) wherein the configuration message further includes an indication that the cell search should begin with an alternative RAT, and wherein the processing circuit is configured to begin the cell search by searching for one or more carrier frequencies of the alternative RAT, based on the indication.

18. The mobile terminal of claim 17, wherein the configuration message further includes one or more third carrier frequencies corresponding to the alternative RAT, and wherein the processing circuit is configured to begin the cell search by searching for one or more of the third carrier frequencies, based on the configuration message.

19. The mobile terminal of claim 18, wherein the configuration message further includes an identifier of the alternative RAT, and wherein the processing circuit is configured to begin the cell search by searching for a carrier frequency of the identified alternative RAT, based on the configuration message.

20. A wireless network node, comprising a radio transceiver circuit configured to communicate with a mobile terminal, a communications interface circuit configured for communication with one or more other wireless network nodes, and a processing circuit configured to control the radio transceiver circuit and the communications interface circuit, wherein the processing circuit is further configured to:

establish a connection with the mobile terminal, using the radio transceiver circuit; and

send a configuration message to the mobile terminal via the radio transceiver circuit, the configuration message comprising assistance information for radio resource control (RRC) connection re-establishment including at least one carrier frequency for use by the mobile terminal in initiating a cell search responsive to losing connection with the wireless communication network due to radio link failure.

21. The wireless network node of claim 20, wherein the configuration message indicates one or more first carrier frequencies that are to be searched in the cell search initiated upon losing connection with the wireless communication network.

22. The wireless network node of claim 20, wherein the configuration message indicates one or more second carrier frequencies that are not to be searched in the cell search initiated upon losing connection with the wireless communication network.

23. The wireless network node of claim 20, wherein the processing circuit is configured to send the configuration message via a first radio access technology (RAT) and wherein the configuration message further includes an indication that the cell search initiated upon losing connection with the wireless communication network should begin with the alternative RAT.

24. The wireless network node of claim 23, wherein the configuration message further includes one or more third carrier frequencies corresponding to the alternative RAT.

25. The wireless network node of claim 23, wherein the configuration message further includes an identifier of the alternative RAT.

26. The wireless network node of claim 20, wherein the processing circuit is further configured to first prepare at least one list of carrier frequencies for each of one or more cells, based on frequency relations for each cell obtained from statistical records or configuration information, and to form the configuration message based on the at least one list corresponding to the cell serving the mobile terminal.