EFFICIENT STATUS REPORTING FOR UES IN DUAL CONNECTIVITY DURING MOBILITY

• US 20160212661A1
• Filed: 07/24/2014
• Published: 07/21/2016
• Est. Priority Date: 08/09/2013
• Status: Active Grant

• Current Assignee: Panasonic Intellectual Property Corporation of America (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Intellectual Property Corporation of America (Panasonic Holdings Corporation)
• Inventors: Basu Mallick, Prateek, Loehr, Joachim
• Granted Patent: US 9,860,797 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H04L 1/1614 using bitmaps
• CPC Class Codes: H04L 1/165 Variable formats
• CPC Class Codes: H04L 27/2601 Multicarrier modulation systems
• CPC Class Codes: H04L 5/0023 Time-frequency-space
• CPC Class Codes: H04L 5/003 Arrangements for allocating sub-channels of the transmission path
• CPC Class Codes: H04W 36/0016 Hand-off preparation specially adapted for end-to-end data sessions
• CPC Class Codes: H04W 36/0027 for a plurality of data sessions of end-to-end connections, e.g. multi-call or multi-bearer end-to-end data connections
• CPC Class Codes: H04W 36/023 Buffering or recovering information during reselection
• CPC Class Codes: H04W 36/32 by location or mobility data, e.g. speed data

Abstract

The invention relates to a method for efficiently performing a Se NB change for a UE in dual connectivity. When reconfiguring a data radio bearer going via the Se NB to another target base station, the UE may compile a PDCP status report comprising status information for all of the data radio bearer going via the Se NB, accompanied respectively by a radio bearer ID to identify the radio bearer to which the status report information pertains. Further, the PDCP status report is directly transmitted by the UE to the Me NB to avoid the backhaul delay between the Se NB and the Me NB; this may be done by using a signaling radio bearer (e.g. RRC message), or data radio bearer to the Me NB (e.g. PDCP control PDU), or by using a physical channel transmission to the Me NB (e.g. MAC CE).

Claims

1. A method for transmitting a status report by a mobile station, wherein the mobile station is connected via at least one radio bearer to a master base station and via at least one data radio bearer to a source secondary base station, the method comprising the steps of:

when reconfiguring the at least one data radio bearer of the mobile station from the source secondary base station to a target base station,

transmitting by the mobile station a status report,

comprising information on the reception status of data packets received by the mobile station via all of the at least one data radio bearer connecting the mobile station to the source secondary base station, and

comprising one radio bearer identifier for each of the at least one data radio bearer which information is comprised in the status report.

2. The method according to claim 1, wherein the status report is transmitted by the mobile station to the master base station via one of the at least one radio bearer connecting the mobile station directly to the master base station, preferably via a data radio bearer or signalling radio bearer.

3. The method according to claim 2, wherein the status report is transmitted by the mobile station to the master station as part of a Radio Resource Control, RRC, message via one signalling radio bearer out of the at least one radio bearer connecting the mobile station directly to the master base station, preferably within an RRC connection reconfiguration complete message.

4. The method according to claim 2, wherein the status report is transmitted by the mobile station to the master station as a Packet Data Convergence Protocol, PDCP, control packet data unit via one data radio bearer out of the at least one radio bearer connecting the mobile station directly to the master base station.

5. The method according to claim 2, wherein the status report is transmitted in an Media Access Control, MAC, control element.

6. The method according to claim 1, wherein the target base station is either:

the master base station to which the mobile station is connected, or another master base station, or a target secondary base station.

7. The method according to claim 1, wherein the status report further comprises at least one extension flag after the information on the reception status of data packets received via one of the at least one data radio bearer connecting the mobile station to the source secondary base station, wherein the extension flag indicates the presence of further information on the reception status of data packets received via another one of the at least one data radio bearer.

8. The method according to claim 1, wherein the status report is a PDCP status report, comprising information on the reception status of PDCP service data units received via all of the at least one data radio bearer connecting the mobile station to the source secondary base station.

9. The method according to claim 1, wherein the status report is transmitted in response to the reception of an RRC connection reconfiguration message in the mobile station, the RRC connection reconfiguration message being received as part of the reconfiguring of the at least one data radio bearer of the mobile station from the source secondary base station to the target base station.

10. The method according to claim 1, wherein the status report is a PDCP control packet data unit, PDU, comprising:

a D/C field of 1 bit length to identify the PDCP control PDU as a control or data PDU,

a type field of 3 bit length to identify a type of the PDCP control PDU,

a radio bearer identifier field to identify the radio bearer to which the subsequent first missing information and bitmap field refers,

a field of 12 or 15 bit length to identify a PDCP sequence number of the first missing PDCP service data unit, SDU, regarding the radio bearer identified in the preceding radio bearer identifier field,

optionally, a bitmap field with a variable bit length to identify by use of a bit map the PDCP SDUs starting from the first missing PDCP SDU having been received correctly or not via the radio bearer identified in the preceding radio bearer identifier field,

an extension flag field of 1 bit length to indicate whether further information is comprised in the PDCP control PDU or not,

and in case the extension flag field indicates that further information is comprised, the status report comprises

another radio bearer identifier field to identify the radio bearer to which the subsequent first missing information and bitmap field refers,

another field of 12 or 15 bit length to identify a PDCP sequence number of the first missing PDCP service data unit, SDU, regarding the radio bearer identified in the preceding another radio bearer identifier field,

optionally, another bitmap field with a variable bit length to identify by use of a bit map the PDCP SDUs starting from the first missing PDCP SDU having been received correctly or not via the radio bearer identified in the preceding another radio bearer identifier field,

another extension flag field of 1 bit length to indicate whether further information is comprised in the PDCP control PDU or not.

11. The method according to claim 1, wherein the data packets are forwarded from the master base station via the secondary base station to the mobile station, and wherein a higher layer with the status report function is located at the master base station but not at the secondary base station.

12. A mobile station for transmitting a status report, wherein the mobile station is connected via at least one radio bearer to a master base station and via at least one data radio bearer to a source secondary base station, the mobile station comprising:

a processor and transmitter adapted to transmit a status report, when the at least one data radio bearer of the mobile station is reconfigured from the source secondary base station to a target base station,

the status report comprising information on the reception status of data packets received by the mobile station via all of the at least one data radio bearer connecting the mobile station to the source secondary base station, and comprising one radio bearer identifier for each of the at least one data radio bearer which information is comprised in the status report.

13. The mobile station according to claim 12, wherein the transmitter is adapted to transmit the status report to the master base station via one of the at least one radio bearer connecting the mobile station directly to the master base station, preferably via a data radio bearer or signalling radio bearer.

14. The mobile station according to claim 13, wherein the transmitter is adapted to transmit the status report to the master base station:

as part of a Radio Resource Control, RRC, message via one signalling radio bearer out of the at least one radio bearer connecting the mobile station directly to the master base station, preferably within an RRC connection reconfiguration complete message, or

as a Packet Data Convergence Protocol, PDCP, control packet data unit via one data radio bearer out of the at least one radio bearer connecting the mobile station directly to the master base station, or

in an Media Access Control, MAC, control element.

15. The mobile station according to claim 12, wherein the status report further comprises at least one extension flag after the information on the reception status of data packets received via one of the at least one data radio bearer connecting the mobile station to the source secondary base station, wherein the extension flag indicates the presence of further information on the reception status of data packets received via another one of the at least one data radio bearer.

16. The mobile station according to claim 12, wherein the status report is a PDCP status report, comprising information on the reception status of PDCP service data units, received by a receiver of the mobile station via all of the at least one data radio bearer connecting the mobile station to the source secondary base station.

17. The mobile station according to claim 12, wherein the status report is transmitted in response to the reception of an RRC connection reconfiguration message by a receiver in the mobile station, the RRC connection reconfiguration message being received as part of the reconfiguring of the at least one data radio bearer of the mobile station from the source secondary base station to the target base station.

18. The mobile station according to claim 12, wherein the status report is a PDCP control packet data unit, PDU, comprising:

a D/C field of 1 bit length to identify the PDCP control PDU as a control or data PDU,

a type field of 3 bit length to identify a type of the PDCP control PDU,

a radio bearer identifier field to identify the radio bearer to which the subsequent first missing information and bitmap field refers,

a field of 12 or 15 bit length to identify a PDCP sequence number of the first missing PDCP service data unit, SDU, regarding the radio bearer identified in the preceding radio bearer identifier field,

optionally, a bitmap field with a variable bit length to identify by use of a bit map the PDCP SDUs starting from the first missing PDCP SDU having been received correctly or not via the radio bearer identified in the preceding radio bearer identifier field,

an extension flag field of 1 bit length to indicate whether further information is comprised in the PDCP control PDU or not,

and in case the extension flag field indicates that further information is comprised, the status report comprises

another radio bearer identifier field to identify the radio bearer to which the subsequent first missing information and bitmap field refers,

another field of 12 or 15 bit length to identify a PDCP sequence number of the first missing PDCP service data unit, SDU, regarding the radio bearer identified in the preceding another radio bearer identifier field,

optionally, another bitmap field with a variable bit length to identify by use of a bit map the PDCP SDUs starting from the first missing PDCP SDU having been received correctly or not via the radio bearer identified in the preceding another radio bearer identifier field,

another extension flag field of 1 bit length to indicate whether further information is comprised in the PDCP control PDU or not.

19. The mobile station according to claim 12, further comprising:

a receiver adapted to receive a status report from the master base station, the status report comprising information on the reception status of data packets received by the master base station via all of the at least one data radio bearer connecting the master base station to the source secondary base station, and comprising one radio bearer identifier for each of the at least one data radio bearer which information is comprised in the status report.

20. A master base station for processing a status report transmitted from a mobile station, wherein the mobile station is connected via at least one radio bearer to the master base station and via at least one data radio bearer to a source secondary base station, the base station comprising:

a receiver and processor adapted to receive and process a status report from the mobile station, when reconfiguring the at least one data radio bearer of the mobile station from the source secondary base station to a target base station, the status report comprising information on the reception status of data packets received by the mobile station via all of the at least one data radio bearer connecting the mobile station to the source secondary base station, and comprising one radio bearer identifier for each of the at least one data radio bearer which information is comprised in the status report.