METHOD AND EQUIPMENT FOR CHANNEL SENSING AND SIGNAL TRANSMISSION

• US 20170019924A1
• Filed: 07/07/2016
• Published: 01/19/2017
• Est. Priority Date: 07/16/2015
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: WANG, Yi, ZHANG, Shichang, LI, Yingyang
• Granted Patent: US 10,873,972 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H04L 5/001 the frequencies being arranged in component carriers
• CPC Class Codes: H04L 5/005 of common pilots, i.e. pilots destined for multiple users or terminals
• CPC Class Codes: H04L 5/0053 Allocation of signaling, i.e. of overhead other than pilot signals
• CPC Class Codes: H04L 5/0092 Indication of how the channel is divided
• CPC Class Codes: H04W 74/0808 using carrier sensing, e.g. carrier sense multiple access [CSMA]

Abstract

A method for channel sensing and signal transmission is provided. The method includes that a signal transmission mode of a communication node in a predefined time window is different from a signal transmission mode of the communication node outside the predefined time window, which includes at least one of a channel sensing mode and a data transmission mode. By performing the method, a frequency domain multiplexing coefficient among nodes adopting the same access technology can be improved, and the coexistence of the access technology and others can be ensured.

Claims

1. A method for channel sensing and signal transmission on a cell in an unlicensed frequency band, the method comprising:

performing, by a sending node, channel sensing before sending at least one of data signals and reference signals;

determining whether to send the at least one of the data signals and the reference signals according to a result of the channel sensing; and

after the determining of whether to send the at least one of the data signals and the reference signals and when sending the at least one of the data signals and the reference signals in a predefined time window, not sending, by the sending node, any signal or sending predefined signals on first time-frequency resources,

wherein the first time-frequency resources are at least one of in the time window and immediately adjacent to a beginning of the time window.

2. The method of claim 1, wherein the predefined time window is a time window of reference signals that are sent for performing radio resource management (RRM) measurement, a time window of reference signals that are sent for performing channel state information (CSI) measurement, or a time window of reference signals that are sent for performing synchronization.

3. The method of claim 1,

wherein the first time-frequency resources at least one of appear periodically or a-periodically in the time window for a plurality of times, and are immediately adjacent to the beginning of the time window,

wherein in a time dimension, each first time-frequency resources occupy X orthogonal frequency division multiplexing (OFDM) symbols, and in a frequency dimension, each first time-frequency resources contain at least one of all sub-carriers, all sub-carriers in a system bandwidth, all sub-carriers in a predefined bandwidth, part of sub-carriers in a system bandwidth, or a predefined bandwidth,

wherein the sending node does not send any signal or sends predefined signals on the first time-frequency resources, and

wherein X is a positive real number.

4. The method of claim 3,

wherein the time window is a discovery signal (DRS) measurement timing configuration (DMTC) window, and

wherein the first time-frequency resources are at least one of X OFDM symbols at a beginning or end of a possible location of a DRS that appears in the DMTC time window periodically, and located prior to the beginning of the first possible location of the DRS that is immediately adjacent to the beginning of the DMTC time window.

5. The method of claim 4,

wherein, if the sending node sends the data signals and the reference signals in the time window or sends the data signals in the time window, the sending node not sending any signal on the first time-frequency resources comprises avoiding, by the sending node, mapping the sent data signals and reference signals or the sent data signals to the first time-frequency resources through rate matching or puncturing, and

wherein, if the at least one of the first time-frequency resources are located in the DMTC time window and are not prior to the beginning of resources for sending the DRS by the sending node, the first time-frequency resources are located at the end of a subframe, the last subframe in the DMTC time window does not contain the first time-frequency resources, and the first time-frequency resources and the location of a conventional reference signal overlap, the conventional reference signal is sent on resources other than the first time-frequency resources.

6. The method of claim 4,

wherein, if only the reference signals are sent in the time window and the reference signals are reference signals in the DRS, all or part of resources located between the last OFDM symbol of the last possible location of the DRS and the first OFDM symbol of the next possible location of the DRS are the first time-frequency resources, and

wherein the sending of the reference signals comprises at least one of:

sending the reference signals in the DRS on the location of conventional resources, wherein the location of the first time-frequency resources is not filled when padding signals are sent;

if a subframe where the first time-frequency resources are located supports a sending mode based on a demodulation reference signal (DM-RS), mapping the DM-RS to the location of resources other than the first time-frequency resources; and

sending the reference signals in the DRS according to a new mapping mode, and reserving at least X1 OFDM symbols between the last OFDM symbol of the reference signals in the DRS and the first OFDM symbol at the next location of the DRS.

7. The method of claim 1, wherein, when the channel sensing is performed in the time window, the channel sensing comprises performing type 2 channel sensing on second time-frequency resources in the time window.

8. The method of claim 7,

wherein the second time-frequency resources are a subset or universal set of the first time-frequency resources, or

wherein the second time-frequency resources and the first time-frequency resources intersect partially.

9. The method of claim 7,

wherein the second time-frequency resources appear periodically or a-periodically in the time window for a plurality of times, and

wherein the performing of the type 2 channel sensing on the second time-frequency resources comprises:

performing initial clear channel assessment (CCA) detection on each second time-frequency resources,

if the initial CCA detection is passed, sending the at least one of the data signals and the reference signals on other resources except the first time-frequency resources until the next second time-frequency resources, otherwise, not sending the at least one of the data signals and the reference signals until the next second time-frequency resources;

performing initial CCA detection on each second time-frequency resources,

if the initial CCA detection is passed, sending the at least one of the data signals and the reference signals on other resources except the first time-frequency resources until the next second time-frequency resources, otherwise, performing eCCA detection,

if the eCCA detection is passed before at least one of the beginning of the next second time-frequency resources and the beginning of predefined partial subframes, sending the at least one of the data signals and the reference signals on other resources except the first time-frequency resources until the next second time-frequency resources, and

if the eCCA detection is not passed before the beginning of the next second time-frequency resources, not sending the at least one of the data signals and the reference signals until the next second time-frequency resources;

performing initial CCA detection on each second time-frequency resources,

if the initial CCA detection is passed, sending the at least one of the data signals and the reference signals on other resources except the first time-frequency resources until the next second time-frequency resources, otherwise, performing eCCA detection,

if the eCCA detection is passed before the beginning of the next second time-frequency resources, sending the at least one of the data signals and the reference signals on other resources except the first time-frequency resources until the next second time-frequency resources, and performing the initial CCA detection,

if the eCCA detection is not passed before the beginning of the next second time-frequency resources, not sending the at least one of the data signals and the reference signals until the next second time-frequency resources, and continuing the eCCA detection;

when the sending node is in an idle state, performing initial CCA detection on current second time-frequency resources,

if the initial CCA detection is passed, sending the at least one of the data signals and the reference signals on other resources except the first time-frequency resources until the next second time-frequency resources, and performing the initial CCA detection, otherwise, performing eCCA detection,

if the eCCA detection is passed before the beginning of the next second time-frequency resources, sending the data signals and/or the reference signals on other resources except the first time-frequency resources until the next second time-frequency resources, and performing the initial CCA detection,

if the eCCA detection is not passed before the beginning of the next second time-frequency resources, not sending the at least one of the data signals and the reference signals until the next second time-frequency resources, continuing the eCCA detection or performing the eCCA detection again; and

when the sending node is not in an idle state, performing eCCA detection on each second time-frequency resources,

if the eCCA detection is passed, sending the at least one of the data signals and the reference signals on other resources except the first time-frequency resources until the next second time-frequency resources, and performing the eCCA detection again, otherwise, not sending the at least one of the data signals and the reference signals until the next second time-frequency resources, and continuing the eCCA detection or performing the eCCA detection again.

10. The method of claim 7, wherein the second time-frequency resources appear periodically or a-periodically in the time window for a plurality of times, and signals are directly sent on other resources except the first time-frequency resources without performing initial clear channel assessment (CCA) detection on the second time-frequency resources.

11. The method of claim 9, wherein the eCCA detection is performed by adopting zero defer, or adopting a defer shorter than or equal to slot length of channel sensing performed outside the time window.

12. The method of any of claim 7, wherein the length of an initial clear channel assessment (CCA) detection slot in the type 2 channel sensing is larger than, smaller than or equal to the length of an initial CCA detection slot in the type 2 channel sensing performed outside the time window.

13. The method of claim 7, wherein data transmission before the last first time-frequency resources in the time window is determined whether to be performed according to a result of the type 2 channel sensing.

14. The method of claim 7,

wherein the type 2 channel sensing is performed when there is data to be sent in the time window, or

wherein in a scenario that a channel has been occupied before the time window through channel sensing to send signals, performing the type 2 channel sensing in the time window, if the channel has not been occupied before the time window through channel sensing and the sending node has data to be sent but has no discovery signal (DRS) to be sent, performing the type 1 channel sensing in the time window, or performing the type 2 channel sensing in the time window.

15. The method of claim 7,

wherein, in a scenario that the channel has been occupied before the time window through channel sensing, a scenario that the channel has not been occupied before the time window through channel sensing, and a scenario that the duration of occupying the channel through the type 2 channel sensing exceeds a defined threshold, modes for performing the type 2 channel sensing in the time windows are the same or different.

16. The method of claim 1, wherein, when data is not sent but the discovery signal (DRS) is sent and the channel sensing is performed in the time window, the channel sensing comprises:

performing, by the sending node, type 3 channel sensing on third time-frequency resources, and

determining whether to send the DRS in the time window according to the result of the type 3 channel sensing,

wherein the third time-frequency resources and the first time-frequency resources overlap, and the type 3 channel sensing is energy detection or sequence detection in time domain or in frequency domain.

17. The method of claim 16,

wherein the first time-frequency resources at least one of appear periodically or a-periodically in the time window for a plurality of times, and are immediately adjacent to the beginning of the time window,

wherein in a time dimension, each first time-frequency resources occupy X orthogonal frequency division multiplexing (OFDM) symbols, and in a frequency dimension, each first time-frequency resources contain at least one of all sub-carriers, or all sub-carriers in a system bandwidth or all sub-carriers in a predefined bandwidth or part of sub-carriers in a system bandwidth or a predefined bandwidth,

wherein the sending node does not send any signal or sends predefined signals on the first time-frequency resources,

wherein X is a positive real number, and

wherein the channel sensing performed by the sending node on the third time-frequency resources is the energy detection in time domain or in frequency domain.

18. The method of claim 16,

wherein the third time-frequency resources appear periodically in the time window, and

wherein, after performing the type 3 channel sensing every time, if the type 3 channel sensing is passed, the sending node sends the DRS at the closest sending location of the DRS, otherwise, when there is no data to be sent, performing the type 3 channel sensing on the next third time-frequency resources.

19. The method of claim 18,

wherein, if the type 3 channel sensing is passed on the first time-frequency resources, the sending node does not send signals or sends predefined signals on the first time-frequency resources until the closest sending location of the DRS, and sends the DRS, or

wherein the sending node sends reservation signals on the first time-frequency resources until the closest sending location of the DRS, and sends the DRS.

20. An equipment for channel sensing and signal transmission on a cell in an unlicensed frequency band, the equipment comprising:

a channel sensing unit, and

a signal sending unit;

wherein the channel sensing unit is configured to;

perform channel sensing before sending at least one of data signals and reference signals, and

determine whether to send the at least one of the data signals and the reference signals according to a result of the channel sensing,

wherein the signal sending unit is configured to;

send signals when the channel sensing unit determines to send the at least one of the data signals and the reference signals, and

when sending the at least one of the data signals and the reference signals in a predefined time window, not send signals or send predefined signals on first time-frequency resources, and

wherein the first time-frequency resources are at least one of in the time window and immediately adjacent to a beginning of the time window.