Radio station, radio terminal, and method therefor

• US 10,575,183 B2
• Filed: 04/17/2015
• Issued: 02/25/2020
• Est. Priority Date: 09/12/2014
• Status: Active Grant

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: Futaki, Hisashi
• Primary Examiner(s): Onamuti, Gbemileke J
• Application Number:
  US15/505,810
• Publication Number:
  US 20180220303A1
• Time in Patent Office: 1,775 Days
• CPC Class Codes: H04W 16/14 Spectrum sharing arrangements between different networks
• CPC Class Codes: H04W 16/32 Hierarchical cell structures
• CPC Class Codes: H04W 48/16 Discovering, processing access restriction or access information
• CPC Class Codes: H04W 48/18 Selecting a network or a communication service
• CPC Class Codes: H04W 72/02 Selection of wireless resources by user or terminal
• CPC Class Codes: H04W 72/20 Control channels or signalling for resource management

Abstract

A radio station (1) is configured to transmit to a radio terminal (3), on a licensed frequency (Cell #1), a notification regarding detection of proximity to a non-serving cell (Cell #2) on an unlicensed frequency (S102) and to receive from the radio terminal (3), on the licensed frequency (Cell #1), a result of the detection performed by the radio terminal (3) in response to the notification. This contributes, for example, to acquisition of information useful for the radio station to determine whether to allow the radio terminal to perform communication on the unlicensed frequency.

Claims

1. A method performed in a radio station, the method comprising:

communicating with a radio terminal performing Licensed Assisted Access (LAA) using a licensed frequency and an unlicensed frequency;

transmitting to the radio terminal, on the licensed frequency, a notification regarding detection or measurement of a non-serving cell on the unlicensed frequency; and

receiving from the radio terminal, on the licensed frequency, a result of measurement of one or more discovery signals transmitted on the non-serving cell, wherein

the detection or the measurement is performed by the radio terminal based on the notification,

the radio station comprises a first radio communication node configured to operate a first cell on the licensed frequency and a second radio communication node configured to operate the non-serving cell on the unlicensed frequency, and

the transmitting comprises transmitting the notification from the first radio communication node in the first cell, in response to reception by the first radio communication node of a control message transmitted from the second radio communication node.

2. The method according to claim 1, wherein the receiving comprises receiving the result of the measurement by the first radio communication node in the first cell.

3. The method according to claim 1, wherein the non-serving cell has been detected in a predetermined period, which is set depending on whether the radio terminal uses Discontinuous Reception (DRX) or not.

4. A radio station comprising:

at least one transceiver configured to communicate with a radio terminal performing Licensed Assisted Access (LAA) using a licensed frequency and an unlicensed frequency;

at least one memory that stores instructions; and

at least one processor configured to execute the instructions to;

transmit to the radio terminal, on the licensed frequency, a notification regarding detection or measurement of a non-serving cell on the unlicensed frequency; and

receive from the radio terminal, on the licensed frequency, a result of measurement of one or more discovery signals transmitted on the non-serving cell,

wherein the detection or the measurement is performed by the radio terminal based on the notification,

the at least one transceiver comprises a first radio communication node configured to operate a first cell on the licensed frequency and a second radio communication node configured to operate the non-serving cell on the unlicensed frequency, and

the instructions cause the at least one processor to transmit the notification from the first radio communication node in the first cell, in response to reception by the first radio communication node of a control message transmitted from the second radio communication node.

5. The radio station according to claim 4, wherein the notification explicitly or implicitly instructs the radio terminal to perform the detection and measurement.

6. The radio station according to claim 4, wherein the notification comprises at least one of information regarding the unlicensed frequency and information regarding a cell on the unlicensed frequency.

7. The radio station according to claim 4, wherein the one or more discovery signals comprises a cell-specific signal containing a symbol or a sequence known to the radio terminal and being transmitted in the non-serving cell.

8. The radio station according to claim 4, wherein the notification is transmitted using system information of a cell on the licensed frequency or using a dedicated control signal dedicatedly transmitted to the radio terminal.

9. The radio station according to claim 8, wherein the instructions further causes the at least one processor to transmit the notification using the dedicated control signal on a condition that capability information has been received from the radio terminal, the capability information indicating that the radio terminal has a function regarding the detection and the measurement on the unlicensed frequency.

10. The radio station according to claim 4, wherein the instructions further causes the at least one processor to determine whether to perform communication with the radio terminal on the unlicensed frequency based on the result of the measurement reported from the radio terminal.

11. The radio station according to claim 4, wherein

the result of the measurement is received by the first radio communication node in the first cell.

12. The radio station according to claim 4, wherein the non-serving cell has been detected in a predetermined period, which is set depending on whether the radio terminal uses Discontinuous Reception (DRX) or not.

13. A radio terminal comprising:

at least one transceiver configured to communicate with a radio station for Licensed Assisted Access (LAA) using a licensed frequency and an unlicensed frequency;

at least one memory that stores instructions; and

at least one processor, wherein

the radio station comprises a first radio communication node configured to operate a first cell on the licensed frequency and a second radio communication node configured to operate the non-serving cell on the unlicensed frequency, and

the at least one processor is configured to execute the instructions to;

receive, from the first radio communication node in the first cell, a notification regarding detection or measurement of a non-serving cell on the unlicensed frequency;

measure, based on the notification, one or more discovery signals transmitted on the non-serving cell; and

report, to the first radio communication node in the first cell on the licensed frequency, a result of the measurement of the one or more discovery signals transmitted on the non-serving cell.

14. The radio terminal according to claim 13, wherein the notification explicitly or implicitly instructs the radio terminal to perform the detection and the measurement.

15. The radio terminal according to claim 13, wherein the notification comprises at least one of information regarding the unlicensed frequency and information regarding a cell on the unlicensed frequency.

16. The radio terminal according to claim 13, wherein the one or more discovery signals comprises a cell-specific signal containing a symbol or a sequence known to the radio terminal and being transmitted in the non-serving cell.

17. The radio terminal according to claim 13, wherein the instructions cause the at least one processor to receive the notification using system information regarding a cell on the licensed frequency or using a dedicated control signal dedicatedly transmitted to the radio terminal.

18. The radio terminal according to claim 17, wherein

the instructions cause the at least one processor to transmit, to the radio station, prior to receiving the notification, capability information indicating that the radio terminal has the function of the detection and the measurement on the unlicensed frequency, and

the notification is transmitted from the radio station using the dedicated control signal on a condition that the capability information has been received by the radio station.

19. The radio terminal according to claim 13, wherein the instructions cause the at least one processor to generate the result of the measurement based on reception quality of the one or more discovery signals transmitted from the radio station on the non-serving cell on the unlicensed frequency, the reception quality being measured only when the unlicensed frequency is satisfying a predetermined condition regarding the detection for the measurement.

20. The radio terminal according to claim 13, wherein the instructions cause the at least one processor to receive the notification transmitted from the first radio communication node in response to reception by the first radio communication node of a control message transmitted from the second radio communication node.

21. The radio terminal according to claim 13, wherein the non-serving cell has been detected in a predetermined period, which is set depending on whether the radio terminal uses Discontinuous Reception (DRX) or not.

22. A method performed in a radio terminal, the method comprising:

communicating with a radio station for Licensed Assisted Access (LAA) using a licensed frequency and an unlicensed frequency, wherein the radio station comprises a first radio communication node configured to operate a first cell on the licensed frequency and a second radio communication node configured to operate the non-serving cell on the unlicensed frequency;

receiving, from the first radio communication node in the first cell, a notification regarding detection or measurement of a non-serving cell on the unlicensed frequency;

measuring, based on the notification, one or more discovery signals transmitted on the non-serving cell; and

reporting, to the first radio communication node in the first cell on the licensed frequency, a result of the measurement of the one or more discovery signals transmitted on the non-serving cell.

23. The method according to claim 22, wherein the receiving comprises receiving the notification transmitted from the first radio communication node in response to reception by the first radio communication node of a control message transmitted from the second radio communication node.

24. The method according to claim 22, wherein the non-serving cell has been detected in a predetermined period, which is set depending on whether the radio terminal uses Discontinuous Reception (DRX) or not.