Method and devices for signaling transmission in unlicensed band

1. A method for signal transmission in a wireless communication network performed by a base station, the method comprising:

sending, to a user terminal (UE), via a licensed frequency band, information indicating a signal transmission pattern, wherein:

the signal transmission pattern defines time resources for transmitting at least one signal in an unlicensed frequency band,

the signal transmission pattern indicates (1) a transmission periodicity of first subframes and (2) a subframe offset for transmitting at least one of a reference signal or a synchronization signal, and

the signal pattern includes simultaneous transmission of the at least one signal and a control signal occurring in subframes 0 and 5 only; and

performing channel detection before transmitting the at least one of a reference signal or a synchronization signal in any of the first subframes.

2. The method of claim 1 , further comprising:

if a channel of the unlicensed frequency band is detected to be busy, transmitting the at least one signal via the unlicensed frequency band to the UE after the channel is detected to be idle.

3. The method of claim 1 , further comprising:

detecting whether a channel of the unlicensed frequency band is idle in a next time duration

if the channel is not detected to be idle in a time duration after transmission of the at least one signal is ready, or

if the channel is not detected to be idle in any of time durations within a time period immediately before the transmission of the at least one signal.

4. The method of claim 3 ,

wherein the time period includes consecutive time durations.

5. The method of claim 1 , further comprising:

signaling to the UE a channel state information reference signal (CSI-RS) offset applicable to a CSI-RS resource.

6. The method of claim 1 ,

wherein the signal transmission pattern defines time resources for one of a periodic transmission, an opportunistic transmission, or a combination thereof.

7. The method of claim 1 ,

wherein the at least one signal includes at least one of:

a cell-specific reference signal (CRS);

a channel state information reference signal (CSI-RS);

a primary synchronization signal (PSS); or

a secondary synchronization signal (SSS).

8. A method for signal reception in a wireless communication network performed by a user equipment (UE), the method comprising:

receiving a signal transmission pattern from a base station via a licensed frequency band, wherein:

the signal transmission pattern defines time resources for transmitting at least one signal in an unlicensed frequency band,

the signal transmission pattern indicates (1) a transmission periodicity of first subframes and (2) a subframe offset for transmitting at least one of a reference signal or a synchronization signal,

the signal transmission pattern includes simultaneous transmission of the at least one signal and a control signal occurring in subframes 0 and 5 only, and

wherein channel detection is performed by the base station before transmitting the at least one of a reference signal or a synchronization signal in any of the first subframes.

9. The method of claim 8 , further comprising:

if a channel of the unlicensed frequency band is detected to be busy, receiving the at least one signal via the unlicensed frequency band after the channel is detected to be idle.

10. A method of claim 8 , further comprising:

detecting whether the channel of the unlicensed frequency band is idle in a next time duration

if the channel is not detected to be idle in a time duration after transmission of the at least one signal is ready, or

if the channel is not detected be idle in any of time durations within a time period immediately before transmission of the at least one signal.

11. The method of claim 8 ,

wherein the time period includes consecutive time durations.

12. The method of claim 8 , further comprising:

receiving a channel state information reference signal (CSI-RS) offset applicable to a CSI-RS resource.

13. A base station in a wireless communication network, comprising:

a transceiver configured to send, to a user equipment (UE), information indicating a signal transmission pattern via a licensed frequency band, wherein:

the signal transmission pattern defines time resources for transmitting at least one signal in an unlicensed frequency band,

the signal transmission pattern indicates (1) a transmission periodicity of first subframes and (2) a subframe offset for transmitting at least one of: a reference signal or a synchronization signal, and

the signal transmission pattern includes simultaneous transmission of the at least one signal and a control signal occurring in subframes 0 and 5 only; and

a controller configured to perform channel detection before transmitting the at least one of a reference signal or a synchronization signal in any of the first subframes.

14. The base station of claim 13 , wherein the transceiver is further configured to:

if a channel of the unlicensed frequency band is detected to be busy, transmit the at least one signal via the unlicensed frequency band to the UE after the channel is detected to be idle.

15. The base station of claim 13 , wherein the controller is further configured to:

detect whether a channel of the unlicensed frequency band is idle in a next time duration

if the channel is not detected to be idle in a time duration after transmission of the at least one signal is ready, or

if the channel is not detected to be idle in any of time durations within a time period immediately before the transmission of the at least one signal.

16. The base station of claim 15 ,

wherein the time period includes consecutive time durations.

17. The base station of claim 13 , wherein the controller is further configured to:

detect the channel of the unlicensed frequency band before transmitting each of the at least one signal; and

determine whether to transmit each of the at least one signal based on detected results.

18. The method of claim 1 ,

wherein a channel of the unlicensed frequency band is detected to be busy when received signal power on a same frequency resource is above a threshold, the threshold being configurable or fixed.

19. The method of claim 1 , wherein signaling the signal transmission pattern to the UE includes:

signaling only when a listen before talk mode is determined to be adopted in the unlicensed frequency band.

20. The method of claim 1 ,

wherein at least one of the unlicensed frequency band or the licensed frequency band includes multiple carriers.

21. The method of claim 1 ,

wherein at least one carrier in the unlicensed frequency band and at least one carrier in the licensed frequency band are configured for the UE for carrier aggregation or dual connectivity.

22. The method of claim 1 , wherein the base station is a first base station, and wherein:

signaling the signal transmission pattern to the UE includes signaling by the first base station, and

the at least one signal is transmitted to the UE by a second base station that is different from the first base station.

23. The method of claim 8 ,

wherein at least one of the unlicensed frequency band or the licensed frequency band includes multiple carriers.

24. The method of claim 8 ,

wherein at least one carrier in the unlicensed frequency band and at least one carrier in the licensed frequency band are configured for a device for carrier aggregation or dual connectivity.

25. The method of claim 8 , wherein the base station is a first base station, and wherein:

the signal transmission pattern is received from the first base station, and

the at least one signal is received from a second base station that is different from the first base station.