Collision avoidance scheme for wireless communications over unlicensed spectrum

• US 10,420,143 B2
• Filed: 06/20/2017
• Issued: 09/17/2019
• Est. Priority Date: 05/20/2013
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Bhushan, Naga, Malladi, Durga Prasad, Wei, Yongbin, Gaal, Peter, Luo, Tao, Ji, Tingfang, Horn, Gavin Bernard, Chen, Wanshi, Damnjanovic, Aleksandar
• Primary Examiner(s): Mattis, Jason E
• Application Number:
  US15/628,401
• Publication Number:
  US 20170288823A1
• Time in Patent Office: 819 Days
• CPC Class Codes: H04J 11/00 Orthogonal multiplex systems, e.g. using WALSH codesH04J13/00 takes precedence
• CPC Class Codes: H04L 1/00 Arrangements for detecting or preventing errors in the information received correcting synchronisation H04L7/00
• CPC Class Codes: H04L 1/0003 by switching between different modulation schemes
• CPC Class Codes: H04L 1/0009 by adapting the channel coding H04L1/1812 takes precedence
• CPC Class Codes: H04L 1/0026 Transmission of channel quality indication
• CPC Class Codes: H04L 1/003 Adaptive formatting arrangements particular to signalling, e.g. variable amount of bits
• CPC Class Codes: H04L 1/009 arrangements specific to transmitters
• CPC Class Codes: H04L 1/0612 Space-time modulation
• 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 27/2602 Signal structure
• CPC Class Codes: H04L 27/2603 Signal structure ensuring backward compatibility with legacy system
• CPC Class Codes: H04L 5/001 the frequencies being arranged in component carriers
• CPC Class Codes: H04L 5/0044 allocation of payload
• 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 5/14 Two-way operation using the same type of signal, i.e. duplex
• CPC Class Codes: H04L 5/1469 using time-sharing
• CPC Class Codes: H04W 16/14 Spectrum sharing arrangements between different networks
• CPC Class Codes: H04W 24/02 Arrangements for optimising operational condition
• CPC Class Codes: H04W 28/0252 per individual bearer or channel dynamic wireless traffic scheduling H04W72/12
• CPC Class Codes: H04W 28/0289 : Congestion control load shedding arrangements in network planning H04W16/08; performing reselection for handling the traffic H04W36/22; wireless traffic scheduling H04W72/12
• CPC Class Codes: H04W 28/08 : Load balancing or load distribution transferring a connection for handling the traffic H04W36/22; wireless traffic scheduling H04W72/12
• CPC Class Codes: H04W 28/16 : Central resource management; Negotiation of resources or communication parameters, e.g. negotiating bandwidth or QoS [Quality of Service]
• CPC Class Codes: H04W 48/10 : using broadcasted information
• CPC Class Codes: H04W 56/001 : Synchronization between nodes
• CPC Class Codes: H04W 56/0015 : one node acting as a reference for the others
• CPC Class Codes: H04W 56/002 : Mutual synchronization
• CPC Class Codes: H04W 72/04 : Wireless resource allocation
• CPC Class Codes: H04W 72/12 : Wireless traffic scheduling
• CPC Class Codes: H04W 72/21 : in the uplink direction of a wireless link, i.e. towards the network
• CPC Class Codes: H04W 72/541 : using the level of interference
• CPC Class Codes: H04W 74/006 : in the downlink, i.e. towards the terminal
• CPC Class Codes: H04W 74/04 : Scheduled access hybrid access H04W74/02
• CPC Class Codes: H04W 74/0808 : using carrier sensing, e.g. carrier sense multiple access [CSMA]
• CPC Class Codes: H04W 74/0816 : with collision avoidance
• CPC Class Codes: H04W 74/0833 : Random access procedures, e.g. with 4-step access
• CPC Class Codes: H04W 76/15 : Setup of multiple wireless link connections
• CPC Class Codes: H04W 84/12 : WLAN [Wireless Local Area Networks]
• CPC Class Codes: H04W 88/02 : Terminal devices
• CPC Class Codes: H04W 88/06 : adapted for operation in multiple networks or having at least two operational modes, e.g. multi-mode terminals
• CPC Class Codes: H04W 88/08 : Access point devices

Abstract

Methods and apparatuses are described in which an unlicensed spectrum is used for Long Term Evolution (LTE) communications. A first method includes performing clear channel assessment (CCA) to determine availability of an unlicensed spectrum, transmitting a request-to-send (RTS) signal to a set of user equipments (UEs) using the unlicensed spectrum when a determination is made that the unlicensed spectrum is available, and receiving, in the unlicensed spectrum, a common clear-to-send (CTS) signal and an individual CTS signal from one or more of the UEs in response to the RTS signal. A second method includes transmitting an RTS signal in an unlicensed spectrum or a V-RTS signal in a licensed spectrum, addressed to a set of UEs, and transmitting a CTS-to-self signal in the unlicensed spectrum along with the transmission of the V-RTS signal.

Claims

1. A method for wireless communications, comprising:

transmitting a virtual RTS (V-RTS) signal in a licensed spectrum, addressed to a set of user equipments (UEs); and

transmitting a clear-to-send (CTS)-to-self signal in the unlicensed spectrum along with the transmission of the V-RTS signal in the licensed spectrum.

2. The method of claim 1, further comprising:

receiving, in the licensed spectrum, a virtual CTS (V-CTS) signal from each UE in the set of UEs in response to a request-to-send (RTS) signal or to the V-RTS signal.

3. The method of claim 2, wherein the V-CTS signal comprises measurements made by the respective UE for use in future scheduling.

4. The method of claim 2, further comprising:

scheduling, after receiving the V-CTS signal, traffic based on current channel knowledge for a remainder of a subframe.

5. The method of claim 1, further comprising:

transmitting a request-to-send (RTS) signal in an unlicensed spectrum, wherein the RTS signal is transmitted in a downlink primary component carrier for each UE in the set of UEs.

6. An apparatus for wireless communications, comprising:

a processor;

memory in electronic communication with the processor; and

instructions stored in the memory, the instructions being executable by the processor to;

transmit a virtual RTS (V-RTS) signal in a licensed spectrum, addressed to a set of user equipments (UEs); and

transmit a clear-to-send (CTS)-to-self signal in the unlicensed spectrum along with the transmission of the V-RTS signal in the licensed spectrum.

7. The apparatus of claim 6, wherein the instructions are executable by the processor to:

receive in the licensed spectrum a virtual CTS (V-CTS) signal from each UE in the set of UEs in response to a request-to-send (RTS) signal or to the V-RTS signal.

8. The apparatus of claim 7, wherein the V-CTS signal comprises measurements made by the respective UE for use in future scheduling.

9. The apparatus of claim 7, wherein the instructions are executable by the processor to:

schedule, after receiving the V-CTS signal, traffic based on current channel knowledge for a remainder of a subframe.

10. A method for wireless communications, comprising:

receiving, at a user equipment (UE), a request-to-send (RTS) signal in an unlicensed spectrum or a virtual RTS (V-RTS) in a licensed spectrum, the RTS signal or the V-RTS signal being addressed to a set of UEs; and

transmitting, in the licensed spectrum, a virtual CTS (V-CTS) signal from the UE in response to the RTS signal or to the V-RTS signal.

11. The method of claim 10, wherein the V-CTS signal comprises measurements made by the UE for use in future scheduling.

12. The method of claim 10, wherein the RTS signal is received in a downlink primary component carrier of the UE.

13. An apparatus for wireless communications, comprising:

a processor;

memory in electronic communication with the processor; and

instructions stored in the memory, the instructions being executable by the processor to;

receive, at a user equipment (UE), a request-to-send (RTS) signal in an unlicensed spectrum or a virtual RTS (V-RTS) in a licensed spectrum, the RTS signal or the V-RTS signal being addressed to a set of UEs; and

transmit, in the licensed spectrum, a virtual CTS (V-CTS) signal from the UE in response to the RTS signal or to the V-RTS signal.

14. The apparatus of claim 13, wherein the V-CTS signal comprises measurements made by the UE for use in future scheduling.

15. The apparatus of claim 13, wherein the RTS signal is received in a downlink primary component carrier of the UE.