RADIO COMMUNICATION SYSTEM, RADIO STATION, RADIO TERMINAL, COMMUNICATION CONTROL METHOD, AND COMPUTER-READABLE MEDIUM

• US 20200137640A1
• Filed: 12/30/2019
• Published: 04/30/2020
• Est. Priority Date: 12/28/2012
• Status: Active Grant

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: FUTAKI, Hisashi, AMINAKA, Hiroaki
• Granted Patent: US 11,382,002 B2
• Time in Patent Office: Days
• CPC Class Codes: H04B 7/024 Co-operative use of antennas of several sites, e.g. in co-ordinated multipoint or co-operative multiple-input multiple-output [MIMO] systems
• CPC Class Codes: H04W 24/10 Scheduling measurement reports ; Arrangements for measurement reports
• CPC Class Codes: H04W 36/0016 Hand-off preparation specially adapted for end-to-end data sessions
• CPC Class Codes: H04W 36/00692 using simultaneous multiple data streams, e.g. cooperative multipoint [CoMP], carrier aggregation [CA] or multiple input multiple output [MIMO] allocation of physical resources in CoMP or in CA H04L5/0035
• CPC Class Codes: H04W 36/00695 using split of the control plane or user plane
• CPC Class Codes: H04W 36/02 Buffering or recovering information during reselection ; Modification of the traffic flow during hand-off
• CPC Class Codes: H04W 36/0235 by transmitting sequence numbers, e.g. SN status transfer
• CPC Class Codes: H04W 36/087 between radio units of access points
• CPC Class Codes: H04W 36/28 involving a plurality of connections, e.g. multi-call or multi-bearer connections
• CPC Class Codes: H04W 36/30 by measured or perceived connection quality data
• CPC Class Codes: H04W 48/20 Selecting an access point
• CPC Class Codes: H04W 74/004 in the uplink, i.e. towards network
• CPC Class Codes: H04W 76/10 Connection setup
• CPC Class Codes: H04W 76/15 Setup of multiple wireless link connections
• CPC Class Codes: H04W 76/28 Discontinuous transmission [DTX]; Discontinuous reception [DRX]
• CPC Class Codes: H04W 84/045 using private Base Stations, e.g. femto Base Stations, home Node B
• CPC Class Codes: H04W 88/06 adapted for operation in multiple networks or having at least two operational modes, e.g. multi-mode terminals
• CPC Class Codes: H04W 88/08 Access point devices

Abstract

A radio network (6) and a radio terminal (4) are configured to, when the radio terminal (4) is using a first cell (10) served by a first radio station (1) as a primary cell and a second cell (20) served by a second radio station (2) as a secondary cell, change the secondary cell form the second cell (20) to a third cell (30) while keeping communication status information regarding the radio terminal (4) on the second cell (20). It is thus, for example, possible to enable a communication service in the secondary cell to be continued after the secondary cell is changed when the radio terminal which is simultaneously using a plurality of cells served by different radio stations changes the secondary cell from a cell of one radio station to a cell of another radio station.

Claims

1-41. -41. (canceled)

42. A first radio station comprising:

a memory storing instructions; and

at least one processor configured to process the instructions to;

operate a first cell,

communicate with a radio terminal configured to perform Dual Connectivity using the first cell as a Primary Cell and either a second cell operated by a second radio station or a third cell operated by a third radio station as a Secondary Cell,

initiate a secondary bearer establishment on the Secondary Cell for the radio terminal, wherein the secondary bearer is mapped to a network bearer used for data transfer between a core network and the radio terminal via a radio station operating the Secondary Cell,

send, to the core network, a request to change a radio station, where the network bearer of the radio terminal is established, from the second radio station to the third radio station, and

send, to the radio terminal, a request to change the Secondary Cell from the second cell to the third cell by releasing the secondary bearer from the second cell with keeping a bearer information of the secondary bearer.

43. A method of a first radio station comprising:

operating a first cell;

communicating with a radio terminal configured to perform Dual Connectivity using the first cell as a Primary Cell and either a second cell operated by a second radio station or a third cell operated by a third radio station as a Secondary Cell;

initiating a secondary bearer establishment on the Secondary Cell for the radio terminal, wherein the secondary bearer is mapped to a network bearer used for data transfer between a core network and the radio terminal via a radio station operating the Secondary Cell;

sending, to the core network, a request to change a radio station, where the network bearer of the radio terminal is established, from the second radio station to the third radio station; and

sending, to the radio terminal, a request to change the Secondary Cell from the second cell to the third cell by releasing the secondary bearer from the second cell with keeping a bearer information of the secondary bearer.

44. A radio terminal comprising:

a memory storing instructions; and

at least one processor configured to process the instructions to;

perform Dual Connectivity which is configured with a first cell operated by a first radio station as a Primary Cell and either a second cell operated by a second radio station or a third cell operated by a third radio station as a Secondary Cell,

release a secondary bearer from the second cell, wherein the secondary bearer is mapped to a network bearer used for data transfer between a core network and the radio terminal via a radio station operating the Secondary Cell, with keeping a bearer information of the secondary bearer, in response to a request, from the first radio station, to change the Secondary Cell from the second cell to the third cell, and

continue performing data transmission and reception in the first cell during change of the Secondary Cell.

45. The radio terminal according to claim 44, wherein the at least one processor is configured to process the instructions to allow data communication which has been performed in the second cell as the Secondary Cell to be resumed in the third cell after the Secondary Cell is changed from the second cell to the third cell.

46. A communication control method in a radio terminal, the method comprising:

performing Dual Connectivity which is configured with a first cell operated by a first radio station as a Primary Cell and either a second cell operated by a second radio station or a third cell operated by a third radio station as a Secondary Cell;

releasing a secondary bearer from the second cell, wherein the secondary bearer is mapped to a network bearer used for data transfer between a core network and the radio terminal via a radio station operating the Secondary Cell, with keeping a bearer information of the secondary bearer, in response to a request, from the first radio station, to change the Secondary Cell from the second cell to the third cell; and

continuing performing data transmission and reception in the first cell during change of the Secondary Cell.

47. The communication control method according to claim 46, further comprising allowing data communication which has been performed in the second cell as the Secondary Cell to be resumed in the third cell after the Secondary Cell is changed from the second cell to the third cell.