Medium Access Control in LTE-U

• US 20160073344A1
• Filed: 09/09/2014
• Published: 03/10/2016
• Est. Priority Date: 09/09/2014
• Status: Active Grant

• Current Assignee: Malikie Innovations Limited (Key Patent Innovations Limited)
• Original Assignee: Blackberry Limited
• Inventors: Vutukuri, Eswar, Suzuki, Takashi, Anderson, Nicholas William, Cai, Zhijun
• Granted Patent: US 10,560,891 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 5/0091 Signaling for the administration of the divided path
• CPC Class Codes: H04W 16/14 Spectrum sharing arrangements between different networks
• CPC Class Codes: H04W 52/0216 using a pre-established activity schedule, e.g. traffic indication frame
• CPC Class Codes: H04W 52/0229 where the received signal is a wanted signal
• CPC Class Codes: H04W 72/23 in the downlink direction of a wireless link, i.e. towards a terminal
• CPC Class Codes: H04W 74/0816 with collision avoidance
• CPC Class Codes: H04W 76/28 Discontinuous transmission [DTX]; Discontinuous reception [DRX]
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

In some implementations, a Medium Access Control (MAC) method for LTE in Unlicensed (LTE-U) includes transmitting at least one of a Clear to Send (CTS) message or a Request to Send (RTS) message on an LTE-U Secondary Cell (SCell) carrier. The at least one of the CTS message or the RTS message may include a duration field. The duration field may indicate a transmission time of a transmission on a packet data shared channel on the LTE-U SCell carrier. An evolved NodeB (eNB) transmits a scheduling grant for the transmission on the packet data shared channel on the LTE-U SCell carrier.

Claims

1. A method, comprising:

transmitting at least one of a Clear to Send (CTS) message or a Request to Send (RTS) message on a LTE-U SCell carrier, wherein the at least one of the CTS message or the RTS message includes a duration field, the duration field indicating a transmission time of a transmission on a packet data shared channel on the LTE in Unlicensed (LTE-U) Secondary Cell (SCell) carrier; and

transmitting a scheduling grant for the transmission on the packet data shared channel on the LTE-U SCell carrier.

2. The method of claim 1, wherein the scheduling grant indicates a Physical Downlink Shared Channel (PDSCH) transmission, further comprising transmitting a PDSCH subframe during the transmission time.

3. The method of claim 1, wherein the scheduling grant indicates a Physical Uplink Shared Channel (PUSCH) transmission by a UE, further comprising:

receiving, from the UE, an Uplink (UL) transmission request prior to the transmission of the at least one of the CTS or RTS message; and

receiving, from the UE, a PUSCH subframe during the transmission time.

4. A method, comprising:

receiving, from an eNB, an UL grant that indicates a permission for a PUSCH transmission on a LTE-U SCell carrier during one or more subframes;

determining whether the LTE-U SCell carrier is available for transmission during the one or more subframes;

if the LTE-U SCell carrier is available for transmission, transmitting a PUSCH subframe on the LTE-U SCell carrier; and

if the LTE-U SCell carrier is not available for transmission, refraining from transmitting on the LTE-U SCell carrier.

5. The method of claim 4, wherein the UL grant is received on a Physical Downlink Control Channel (PDCCH).

6. The method of claim 4, wherein the UL grant is a semi-static UL grant received in an RRC message.

7. The method of claim 4, wherein the UL grant is received on a Long Term Evolution (LTE) Primary Cell (PCell) carrier.

8. The method of claim 5, further comprising:

transmitting at least one of a CTS message or an RTS message on the LTE-U SCell carrier, wherein the at least one of the CTS message or the RTS message includes a duration field, the duration field indicating a transmission time; and

transmitting a PUSCH subframe during the transmission time.

9. The method of claim 4, wherein determining whether the LTE-U SCell carrier is available for transmission comprises measuring a signal level on the LTE-U SCell carrier.

10. The method of claim 9, further comprising determining that the LTE-U SCell carrier is available for transmission upon measuring a signal level lower than a threshold.

11. The method of claim 9, further comprising determining that the LTE-U SCell carrier is not available for transmission upon measuring a signal level higher than a threshold.

12. The method of claim 4, wherein LTE Transmission Time Interval (TTI) bundling is used when transmitting more than one subframes.

13. A method, comprising:

receiving, from an evolved NodeB (eNB), a first Discontinuous Reception (DRX) configuration;

while operating in the first DRX configuration, receiving, from the eNB, a DRX Configuration Switch indication that indicates a switch to a second DRX configuration, wherein the DRX configuration switch indication is received after a load change in an LTE in Unlicensed (LTE-U) Secondary Cell (SCell) carrier; and

in response to the DRX Configuration Switch indication, switching from the first DRX configuration to the second DRX configuration.

14. The method of claim 13, wherein the DRX Configuration Switch indication is received in a Medium Access Control (MAC) Control Element (CE).

15. The method of claim 13, wherein the load change in the LTE-U SCell carrier is detected based on a change in at least one of a collision rate on the LTE-U SCell carrier, a mean energy level detected on the LTE-U SCell carrier, a mean data rate achieved over the LTE-U SCell carrier, or a medium occupancy factor.

16. The method of claim 13, wherein the DRX Configuration Switch indication is received in a Radio Resource Control (RRC) Connection Reconfiguration message.

17. The method of claim 16, wherein the RRC Connection Reconfiguration message includes parameters associated with the second DRX configuration.

18. The method of claim 13, wherein the first and the second DRX configurations are preconfigured at a User Equipment (UE).

19. The method of claim 18 wherein the first and second DRX configurations are preconfigured at the UE using an RRC Connection Reconfiguration message.

20. A method, comprising:

transmitting, from an eNB, a first DRX configuration, causing a UE to operate in a first DRX configuration mode;

determining a load change in an LTE-U SCell carrier; and

based on the determining, transmitting, from the eNB, a DRX Configuration Switch indication that indicates a switch to a second DRX configuration, causing the UE to operate in a second DRX configuration mode.

21. A base station, comprising:

one or more processors configured to;

transmit at least one of a Clear to Send (CTS) message or a Request to Send (RTS) message on an LTE-U SCell carrier, wherein the at least one of the CTS message or the RTS message includes a duration field, the duration field indicating a transmission time of a transmission on a packet data shared channel on the LTE-U SCell carrier; and

transmit a scheduling grant for the transmission on the packet data shared channel on the LTE-U SCell carrier.

22. The base station of claim 21, wherein the scheduling grant indicates a Physical Downlink Shared Channel (PDSCH) transmission, and the one or more processors are further configured to transmit a PDSCH subframe during the transmission time.

23. The base station of claim 21, wherein the scheduling grant indicates a Physical Uplink Shared Channel (PUSCH) transmission by a UE, and the one or more processors are further configured to:

receive, from the UE, an Uplink (UL) transmission request prior to the transmission of the at least one of the CTS or RTS message; and

receive, from the UE, a PUSCH subframe during the transmission time.

24. A user equipment (UE), comprising:

one or more processors configured to;

receive, from an eNB, an UL grant that indicates a permission for a PUSCH transmission on an LTE-U SCell carrier during one or more subframes;

determine whether the LTE-U SCell carrier is available for transmission during the one or more subframes;

if the LTE-U SCell carrier is available for transmission, transmit a PUSCH subframe on the LTE-U SCell carrier; and

if the LTE-U SCell carrier is not available for transmission, refrain from transmitting on the LTE-U SCell carrier.

25. The UE of claim 24, wherein the UL grant is received on a Physical Downlink Control Channel (PDCCH).

26. The UE of claim 24, wherein the UL grant is a semi-static UL grant received in an RRC message.

27. The UE of claim 24, wherein the UL grant is received on a Long Term Evolution (LTE) Primary Cell (PCell) carrier.

28. The UE of claim 25, wherein the one or more processors are further configured to:

transmitting at least one of a CTS message or an RTS message on the LTE-U SCell carrier, wherein the at least one of the CTS message or the RTS message includes a duration field, the duration field indicating a transmission time; and

transmitting a PUSCH subframe during the transmission time.

29. The UE of claim 24, wherein determining whether the LTE-U SCell carrier is available for transmission comprises measuring a signal level on the LTE-U SCell carrier.

30. The UE of claim 29, wherein the one or more processors are further configured to determining that the LTE-U SCell carrier is available for transmission upon measuring a signal level lower than a threshold.

31. The UE of claim 29, wherein the one or more processors are further configured to determining that the LTE-U SCell carrier is not available for transmission upon measuring a signal level higher than a threshold.

32. The UE of claim 24, wherein LTE Transmission Time Interval (TTI) bundling is used when transmitting more than one subframes.

33. A user equipment (UE), comprising:

one or more processors configured to;

receive, from an evolved NodeB (eNB), a first Discontinuous Reception (DRX) configuration;

while operating in the first DRX configuration, receive, from the eNB, a DRX Configuration Switch indication that indicates a switch to a second DRX configuration, wherein the DRX configuration switch indication is received after a load change in an LTE in Unlicensed (LTE-U) Secondary Cell (SCell) carrier; and

in response to the DRX Configuration Switch indication, switch from the first DRX configuration to the second DRX configuration.

34. The UE of claim 33, wherein the DRX Configuration Switch indication is received in a Medium Access Control (MAC) Control Element (CE).

35. The UE of claim 33, wherein the load change in the LTE-U SCell carrier is detected based on a change in at least one of a collision rate on the LTE-U SCell carrier, a mean energy level detected on the LTE-U SCell carrier, a mean data rate achieved over the LTE-U SCell carrier, or a medium occupancy factor.

36. The UE of claim 33, wherein the DRX Configuration Switch indication is received in a Radio Resource Control (RRC) Connection Reconfiguration message.

37. The UE of claim 36, wherein the RRC Connection Reconfiguration message includes parameters associated with the second DRX configuration.

38. The UE of claim 33, wherein the first and the second DRX configurations are preconfigured at the UE.

39. The UE of claim 38 wherein the first and second DRX configurations are preconfigured at the UE using an RRC Connection Reconfiguration message.

40. A base station, comprising:

one or more processors configured to;

transmit, from the base station, a first DRX configuration, causing a UE to operate in a first DRX configuration mode;

determine a load change in an LTE-U SCell carrier; and

based on the determining, transmit, from the base station, a DRX Configuration Switch indication that indicates a switch to a second DRX configuration, causing the UE to operate in a second DRX configuration mode.