MULTI-ACCESS SCHEME AND SIGNAL STRUCTURE FOR D2D COMMUNICATIONS

• US 20130272262A1
• Filed: 12/28/2012
• Published: 10/17/2013
• Est. Priority Date: 04/13/2012
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Intel Corporation
• Inventors: Li, Qinghua, Li, Honggang, Niu, Huaning, Hsuan, Yi, Zhu, Yuan, Chen, Xiaogang, Fwu, Jong-Kae, Davydov, Alexei, Yin, Hujun, Lin, Xintian E., Wong, Wendy C., Zhang, Yujian
• Granted Patent: US 9,661,658 B2
• Time in Patent Office: Days
• US Class Current: 370/330
• CPC Class Codes: H04L 12/189 in combination with wireless systems selective distribution or broadcast in wireless communication networks H04W4/06
• CPC Class Codes: H04L 5/0001 Arrangements for dividing the transmission path duplexing H04L5/14; multiplexing of different sources on one path H04J
• CPC Class Codes: H04L 5/0023 Time-frequency-space
• CPC Class Codes: H04L 5/0037 Inter-user or inter-terminal allocation
• CPC Class Codes: H04L 5/0044 allocation of payload
• CPC Class Codes: H04L 5/0048 Allocation of pilot signals, i.e. of signals known to the receiver
• CPC Class Codes: H04L 5/0053 Allocation of signaling, i.e. of overhead other than pilot signals
• CPC Class Codes: H04L 5/0064 Rate requirement of the data, e.g. scalable bandwidth, data priority
• CPC Class Codes: H04L 5/0094 Indication of how sub-channels of the path are allocated
• CPC Class Codes: H04L 5/14 Two-way operation using the same type of signal, i.e. duplex
• CPC Class Codes: H04W 24/02 Arrangements for optimising operational condition
• CPC Class Codes: H04W 24/10 Scheduling measurement reports ; Arrangements for measurement reports
• CPC Class Codes: H04W 28/02 Traffic management, e.g. flow control or congestion control
• CPC Class Codes: H04W 28/0226 based on location or mobility handoff or reselection H04W36/00; mobile application services making use of the location of users or terminals H04W4/02
• CPC Class Codes: H04W 28/0268 using specific QoS parameters for wireless networks, e.g. QoS class identifier [QCI] or guaranteed bit rate [GBR] negotiating SLA or negotiating QoS H04W28/24
• CPC Class Codes: H04W 36/0016 Hand-off preparation specially adapted for end-to-end data sessions
• CPC Class Codes: H04W 36/08 Reselecting an access point
• CPC Class Codes: H04W 4/06 Selective distribution of broadcast services, e.g. multimedia broadcast multicast service [MBMS]; Services to user groups; One-way selective calling services
• CPC Class Codes: H04W 4/70 Services for machine-to-machine communication [M2M] or machine type communication [MTC]
• CPC Class Codes: H04W 72/04 Wireless resource allocation
• CPC Class Codes: H04W 72/20 : Control channels or signalling for resource management
• CPC Class Codes: H04W 72/23 : in the downlink direction of a wireless link, i.e. towards a terminal
• CPC Class Codes: H04W 72/542 : using measured or perceived quality
• CPC Class Codes: H04W 74/0808 : using carrier sensing, e.g. carrier sense multiple access [CSMA]
• CPC Class Codes: H04W 74/0833 : Random access procedures, e.g. with 4-step access
• CPC Class Codes: H04W 76/10 : Connection setup
• CPC Class Codes: H04W 76/19 : Connection re-establishment
• CPC Class Codes: Y02D 30/70 : in wireless communication networks

Abstract

A signal structure for use in D2D communications is described. In one embodiment, a preamble for automatic gain control at the receiver end is included in the transmitted signal. Techniques for scheduling of D2D transmissions using carrier sensing multiple access (CSMA) and a power control schemes for interference management are also described.

Claims

1. A user equipment (UE) device, comprising:

a radio transceiver to provide an air interface for communicating with an eNB (evolved node B) and for D2D (device-to-device) communications; and

processing circuitry connected to the radio transceiver to;

receive allocations of time-frequency resources for D2 D communications from the eNB;

establish a D2D communications session with a second UE, wherein D2D transmissions to and from the second UE are organized into D2D slots with each D2D slot beginning with a preamble and containing a plurality of OFDM or SC-FDM symbols; and

,

perform automatic gain control (AGC) using the preambles of received D2D slots.

2. The device of claim 1 wherein the preamble is a repeating signal sequence in the time domain.

3. The device of claim 2 wherein the processing circuitry is further to detect the preamble of received D2D slots via autocorrelation.

4. The device of claim 2 wherein each D2D slot includes one or more reference symbols.

5. The device of claim 2 wherein the processing circuitry is further to initiate a communications session with the second UE using carrier sense multiple access (CSMA) with respect to a D2D slot by:

sensing a current D2D slot to determine if transmission activity is present; and

,

if the current D2D slot is not busy, sending a D2D transmission to the second UE at the start of a subsequent D2D slot.

6. The device of claim 5 wherein the processing circuitry is further to initiate a communications session with the second UE by:

if the current D2D slot is not busy, starting a countdown with a selected number;

decrementing the countdown after each non-busy D2D slot is detected and suspending the countdown when a busy D2D slot is detected; and

sending the D2D transmission to the second UE at the start of the next D2D slot after the countdown reaches zero.

7. The device of claim 6 wherein the specified number for the countdown is randomly or pseudo-randomly selected.

8. The device of claim 5 wherein a D2D slot further includes a reservation time encoded in a control channel that specifies how many D2D slots are to be consecutively transmitted by a transmitting device.

9. The device of claim 8 wherein the processing circuitry is further to, when a reservation time is detected in a D2D slot, discontinue sensing of D2D slots until the reservation time expires.

10. The device of claim 9 wherein the processing circuitry is further to, when a reservation time is detected in a D2D slot, enter a sleep state until the reservation time expires.

11. The device of claim 5 wherein D2D slots are numbered consecutively in the time and/or frequency domain.

12. The device of claim 1 wherein the processing circuitry is further to transmit an indication of a transmission power level in each D2D slot.

13. The device of claim 12 wherein the preamble is a repeating signal sequence in the time domain with a periodicity indicative of the transmission power level.

14. The device of claim 13 wherein the processing circuitry further comprises a bank of correlators with different correlation durations for detecting arrival of the preamble and transmission power level.

15. The device of claim 12 wherein the processing circuitry is further to transmit the indication of transmission power level in one or more reference symbols, where a specified reference symbol or specified sequence of reference symbols indicates the transmission power level.

16. The device of claim 12 wherein the processing circuitry is further to transmit and indication of transmission power level as encoded bits in a physical layer header following the preamble.

17. The device of claim 16 wherein the physical layer header further comprises an indication of the number of D2D slots that make up a transport block and are to be consecutively sent.

18. The device of claim 1 wherein the processing circuitry is further to receive allocations of time-frequency resources for D2D communications from the eNB in response to a channel reservation request, and wherein an indication of transmission power level for D2D communications and the duration of the reservation are contained in the channel reservation request.

19. The device of claim 18 wherein the channel reservation request is transmitted at sufficiently high power that other UEs in proximity to the device may learn of the channel reservation and transmission power level.

20. A user equipment (UE) device, comprising:

a radio transceiver to provide an air interface for D2D (device-to-device) communications; and

processing circuitry connected to the radio transceiver to;

initiate a D2D communications session with a second UE, wherein D2D transmissions to and from the second UE are organized into D2D slots with each D2D slot containing a plurality of OFDM or SC-FDM symbols, using carrier sense multiple access (CSMA) with respect to a D2D slot, the processing circuitry being further to;

sense a current D2D slot to determine if transmission activity is present; and

,

if the current D2D slot is not busy, send a D2D transmission to the second UE at the start of a subsequent D2D slot.

21. The device of claim 20 wherein the processing circuitry is farther to initiate a communications session with the second UE by:

if the current D2D slot is not busy, starting a countdown with a selected number;

decrementing the countdown after each non-busy D2D slot is detected and suspending the countdown when a busy D2D slot is detected; and

sending the D2D transmission to the second UE at the start of the next D2D slot after the countdown reaches zero.

22. The device of claim 21 wherein the specified number for the countdown is randomly or pseudo-randomly selected.

23. The device of claim 20 wherein a D2D slot further includes a reservation time encoded in a control channel that specifies how many D2D slots are to be consecutively transmitted by a transmitting device.

24. The device of claim 23 wherein the processing circuitry is further to, when a reservation time is detected in a D2D slot, discontinue sensing of D2D slots until the reservation time expires.

25. The device of claim 24 wherein the processing circuitry is further to, when a reservation time is detected in a D2D slot, enter a sleep state until the reservation time expires.

26. A method for operating a user equipment (UE) device, comprising:

receiving allocations of time-frequency resources for D2D communications from an evolved node B (eNB);

wherein D2D transmissions to and from a second UE are organized into D2D slots with each D2D slot containing a plurality of OFDM or SC-FDM symbols,

sensing a current D2D slot to determine if transmission activity is present; and

,

if the current D2D slot is not busy, sending a D2D transmission to the second UE at the start of a subsequent D2D slot.

27. The method of claim 26 further comprising:

if the current D2D slot is not busy, starting a countdown with a selected number;

decrementing the countdown after each non-busy D2D slot is detected and suspending the countdown when a busy D2D slot is detected; and

sending the D2D transmission to the second UE at the start of the next D2D slot after the countdown reaches zero.

28. The method of claim 26 further comprising including a preamble for use by the second UE in the D2D transmission.

29. The method of claim 26 further comprising including a reservation time encoded in a control channel that specifies how many D2D slots are to be consecutively transmitted.

30. The method of claim 26 wherein further comprising, when a reservation time is detected in a D2D slot, discontinue sensing of D2D slots until the reservation time expires.