CHANNEL RESERVATION METHOD FOR UNLICENSED BAND COMMUNICATION, BASE STATION, AND USER TERMINAL

• US 20180027418A1
• Filed: 12/28/2015
• Published: 01/25/2018
• Est. Priority Date: 01/09/2015
• Status: Abandoned Application

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: LI, BO, JIANG, QI, LIU, RENMAO
• Application Number:
  US15/541,927
• Publication Number:
  US 20180027418A1
• Time in Patent Office: Days
• CPC Class Codes: H04L 27/0006 Assessment of spectral gaps suitable for allocating digitally modulated signals, e.g. for carrier allocation in cognitive radio for spectrum sharing between different networks H04W16/14
• CPC Class Codes: H04L 5/001 the frequencies being arranged in component carriers
• CPC Class Codes: H04L 5/0048 Allocation of pilot signals, i.e. of signals known to the receiver
• CPC Class Codes: H04W 16/14 Spectrum sharing arrangements between different networks
• CPC Class Codes: H04W 72/04 Wireless resource allocation
• CPC Class Codes: H04W 72/12 Wireless traffic scheduling
• CPC Class Codes: H04W 74/0808 using carrier sensing, e.g. carrier sense multiple access [CSMA]

Abstract

The present invention provides an uplink channel reservation method used in a mobile communication system supporting an unlicensed carrier, as well as a base station and a user terminal that execute the method. The method includes: assessing whether an unlicensed carrier resource is free; and sending a channel reservation signal over the assessed free unlicensed carrier resource. According to embodiments of the present invention, it is ensured that an unlicensed carrier resource remains free during the period from the time when an unlicensed carrier is assessed to be free to the time when an uplink license is issued and comes into effect.

Claims

1. An uplink channel reservation method used in a mobile communication system supporting an unlicensed carrier, comprising the steps of:

assessing whether an unlicensed carrier resource is free; and

sending a channel reservation signal over the assessed free unlicensed carrier resource.

2. The method according to claim 1, wherein the method is executed by a base station or a user terminal.

3. The method according to claim 1, wherein a signal format of the channel reservation signal comprises a signal format of one of the following signals:

an assessment reference signal, a synchronizing signal, and a demodulation reference signal.

4. The method according to claim 1, wherein the mobile communication system comprises a Long Term Evolution (LTE) system and a Long Term Evolution Advanced (LTE-A) system.

5. The method according to claim 1, further comprising:

setting a timer, the timer being indicative of a maximum time of duration for sending the channel reservation signal, wherein the channel reservation signal continues being sent until uplink transmission begins or until the timer expires.

6. The method according to claim 1, wherein the step of assessment is initiated randomly.

7. The method according to claim 1, wherein the step of assessment is initiated according to an uplink scheduling license.

8. The method according to claim 1, wherein the assessment is executed during the period of a Free Channel Assessment (CCA) symbol.

9. The method according to claim 8, wherein the step of sending comprises:

starting to send the channel reservation signal over the assessed free unlicensed carrier resource from a first Orthogonal Frequency Division Multiplexing (OFDM) symbol after the CCA symbol.

10. The method according to claim 1, wherein the assessment is executed during the period of a CCA symbol of a current sub-frame that decides to perform uplink transmission over the unlicensed carrier resource.

11. The method according to claim 1, wherein the assessment is executed during the period of a CCA symbol of an M^th sub-frame after a corresponding sub-frame for sending the uplink scheduling license, M being a positive integer greater than or equal to 1.

12. The method according to claim 7, further comprising:

performing uplink transmission over the assessed free unlicensed carrier resource, wherein a terminal for executing the uplink transmission is a user terminal for executing the step of assessment, or other user terminals accessing the present cell.

13. A base station, comprising:

an assessment module, configured to assess whether an unlicensed carrier resource is free; and

a sending module, configured to send a channel reservation signal over the assessed free unlicensed carrier resource.

14. The base station according to claim 13, wherein the base station supports a Long Term Evolution (LTE) or Long Term Evolution Advanced (LTE-A) standard.

15. The base station according to claim 13, further comprising:

a timer, the timer being indicative of a maximum time of duration for sending the channel reservation signal,

wherein the sending module is further configured to continue sending the channel reservation signal until uplink transmission begins or until the timer expires.

16. The base station according to claim 13, wherein the assessment module is configured to randomly initiate the assessment.

17. The base station according to claim 13, wherein the assessment module is configured to make a decision according to an uplink scheduling license, and initiate the assessment at a specified time before or after a moment when the base station sends the uplink scheduling license.

18. The base station according to claim 13, wherein the assessment module is configured to execute the assessment during the period of a Free Channel Assessment (CCA) symbol.

19. The base station according to claim 18, wherein the sending module is further configured to start to send the channel reservation signal over the assessed free unlicensed carrier resource from a first Orthogonal Frequency Division Multiplexing (OFDM) symbol after the CCA symbol.

20. The base station according to claim 13, wherein the assessment module is further configured to execute the assessment during the period of a CCA symbol of a current sub-frame that decides to perform uplink transmission over the unlicensed carrier resource.

21. The base station according to claim 13, wherein the assessment module is further configured to execute the assessment during the period of a CCA symbol of a next frame with respect to a sub-frame for sending the uplink scheduling license.

22. A user terminal, comprising:

an assessment module, configured to assess whether an unlicensed carrier resource is free; and

a sending module, configured to send a channel reservation signal over the assessed free unlicensed carrier resource.

23. The user terminal according to claim 22, wherein a signal format of the channel reservation signal comprises a signal format of one of the following signals:

an assessment reference signal, a synchronizing signal, and a demodulation reference signal.

24. The user terminal according to claim 22, wherein the user terminal supports a Long Term Evolution (LTE) or Long Term Evolution Advanced (LTE-A) standard.

25. The user terminal according to claim 22, wherein the sending module is further configured to:

set a timer, the timer being indicative of a maximum time of duration for sending the channel reservation signal; and

continue sending the channel reservation signal until uplink transmission begins or until the timer expires.

26. The user terminal according to claim 22, wherein the assessment module is configured to randomly initiate the assessment.

27. The user terminal according to claim 22, wherein the assessment module is configured to initiate, in response to an uplink scheduling license, the assessment.

28. The user terminal according to claim 22, wherein the assessment module is configured to execute the assessment during the period of a Free Channel Assessment (CCA) symbol.

29. The user terminal according to claim 28, wherein the sending module is further configured to start to send the channel reservation signal over the assessed free unlicensed carrier resource from a first Orthogonal Frequency Division Multiplexing (OFDM) symbol after the CCA symbol.

30. The user terminal according to claim 22, wherein the assessment module is further configured to execute the assessment during the period of a CCA symbol of a current sub-frame that decides to perform uplink transmission over the unlicensed carrier resource.

31. The user terminal according to claim 22, wherein the assessment module is further configured to execute the assessment during the period of a CCA symbol of an M^th sub-frame after a corresponding sub-frame for sending the uplink scheduling license, M being a positive integer greater than or equal to 1.

32. The user terminal according to claim 31, further comprising:

a data sending module, configured to start to perform uplink transmission over an unlicensed carrier channel through an M+1^th sub-frame after a corresponding sub-frame for sending the uplink scheduling license.