Method for Facilitating Clear Channel Assessment and Radio Unit

• US 20190320462A1
• Filed: 07/11/2016
• Published: 10/17/2019
• Est. Priority Date: 07/11/2016
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Li, Ming, Li, Yanqiang, Liu, Jinhua
• Granted Patent: US 10,757,734 B2
• 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: H04W 16/14 Spectrum sharing arrangements between different networks
• CPC Class Codes: H04W 72/02 Selection of wireless resources by user or terminal
• CPC Class Codes: H04W 74/0808 using carrier sensing, e.g. carrier sense multiple access [CSMA]
• CPC Class Codes: H04W 88/085 Access point devices with remote components

Abstract

The present disclosure provides a method (300) in a Radio Unit (RU) for facilitating Clear Channel Assessment (CCA). The method (300) comprises: detecting (S310), in a first transmission period while the RU is operating in a first channel, whether one or more candidate channels in proximity to the first channel are unoccupied; determining (S320), when the first channel is not clear for transmission in a second transmission period, whether any of the one or more candidate channels that is detected to be unoccupied is clear for transmission in the second transmission period; and selecting (S330) one of the one or more candidate channels that is determined to be clear, for transmission in the second transmission period.

Claims

1-25. -25. (canceled)

26. A method in a Radio Unit (RU) for facilitating Clear Channel Assessment (CCA), comprising:

detecting, in a first transmission period while the RU is operating in a first channel, whether one or more candidate channels in proximity to the first channel are unoccupied;

determining, in response to a determination that the first channel is not clear for transmission in a second transmission period, whether any of the one or more candidate channels detected to be unoccupied are clear for transmission in the second transmission period; and

selecting one of the candidate channels determined to be clear, for transmission in the second transmission period.

27. The method of claim 26, wherein the detecting comprises:

applying a transmitter shutdown to a transmitter in the RU during one or more predetermined symbols in the first transmission period; and

sensing whether an energy level received in each candidate channel during the one or more predetermined symbols is lower than a predetermined threshold and, if so, deeming the candidate channel to be unoccupied.

28. The method of claim 27, wherein, in response to the transmitter shutdown being applied in two or more predetermined symbols, the sensing comprises:

calculating an arithmetic or weighted average of the energy levels received in each candidate channel during the two or more predetermined symbols; and

determining whether the average is lower than the predetermined threshold and, if so, deeming the candidate channel to be unoccupied.

29. The method of claim 27, wherein applying the transmitter shutdown comprises shutting down the transmitter intermittently in each of the one or more predetermined symbols.

30. The method of claim 27, further comprising:

informing a terminal device of the one or more predetermined symbols.

31. The method of claim 27, wherein the one or more predetermined symbols comprise a Guard Period (GP) and an Uplink Pilot Time Slot (UpPTS) in a Time Division Duplex (TDD) special subframe.

32. The method of claim 26, wherein the detecting comprises:

applying an attenuation to a receiver in the RU during one or more predetermined symbols; and

sensing whether an attenuated energy level received by the receiver in each candidate channel during the one or more predetermined symbols is lower than a predetermined threshold and, if so, deeming the candidate channel to be unoccupied.

33. The method of claim 26, further comprising:

transmitting a reservation signal over the selected candidate channel;

reporting the selected candidate channel to a Digital Unit (DU); and

receiving a transmission configuration associated with the selected candidate channel from the DU.

34. The method of claim 26, further comprising:

reporting a CCA failure to a Digital Unit (DU), only in response to a determination that none of the one or more candidate channels is detected to be unoccupied or determined to be clear.

35. The method of claim 26, further comprising:

selecting the first channel for transmission in the second transmission period in response to a determination that the first channel is clear for transmission in the second transmission period.

36. The method of claim 26, further comprising:

monitoring a CCA failure rate at the RU,

wherein the detecting, determining and selecting are performed only in response to a determination that the CCA failure rate is higher than a predetermined level.

37. A Radio Unit (RU) configured for facilitating Clear Channel Assessment (CCA), comprising:

a transceiver;

a processor; and

a memory, the memory containing instructions executable by the processor whereby the RU is operative to;

detect, in a first transmission period while the RU is operating in a first channel, whether one or more candidate channels in proximity to the first channel are unoccupied;

determine, in response to a determination that the first channel is not clear for transmission in a second transmission period, whether any of the one or more candidate channels detected to be unoccupied are clear for transmission in the second transmission period; and

select one of the candidate channels determined to be clear, for transmission in the second transmission period.