DEVICE-TO-DEVICE COMMUNICATIONS APPARATUS AND METHODS

• US 20150271720A1
• Filed: 03/17/2015
• Published: 09/24/2015
• Est. Priority Date: 03/18/2014
• Status: Active Grant

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Laboratories of America Incorporated (Hon Hai Precision Industry Co., Ltd.)
• Inventors: YAMADA, Shohei, Sheng, Jia
• Granted Patent: US 10,257,871 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H04W 48/20 Selecting an access point
• CPC Class Codes: H04W 72/02 Selection of wireless resources by user or terminal
• CPC Class Codes: H04W 72/0453 Resources in frequency domain, e.g. a carrier in FDMA
• CPC Class Codes: H04W 76/14 Direct-mode setup

Abstract

As a result of the selection/reselection operation, a wireless terminal (26) selects the high priority candidate frequency for use in the device-to-device (D2D) communications. During the cell selection/reselection operation, the wireless terminal (26) is required to consider selection/reselection candidate frequencies at which the wireless terminal (26) cannot receive or transmit device-to-device (D2D) signals to be of low priority candidate frequencies when the wireless terminal (26) is capable of device-to-device (D2D) communications and is receiving or transmitting, or anticipating receiving or transmitting, device-to-device (D2D) signals on device-to-device (D2D) supported frequencies. In another basic mode predefined RRC Idle Mode state transition(s) are used to determine when a wireless terminal (26) encounters an out-of-coverage situation for device-to-device (D2D) communications purposes; and when the out-of-coverage situation is determined, the wireless terminal (26) uses pre-configured device-to-device (D2D) radio resources for the device-to-device (D2D) communications.

Claims

1. A method in a wireless terminal which is in wireless communications with a radio access node over a radio interface, the method comprising:

when the wireless terminal is configured to perform device-to-device (D2D) communications while camping on a frequency, during a cell selection/reselection operation the wireless terminal considering the camped-on frequency to be a high priority candidate frequency.

2. The method of claim 1, further comprising as a result of the selection/reselection operation the wireless terminal selecting a candidate frequency for use in the device-to-device (D2D) communications.

3. The method of claim 2, further comprising as a result of the selection/reselection operation the wireless terminal selecting the high priority candidate frequency for use in the device-to-device (D2D) communications.

4. The method of claim 1, further comprising during the cell selection/reselection operation, requiring the wireless terminal to consider selection/reselection candidate frequencies at which the wireless terminal cannot receive or transmit device-to-device (D2D) signals to be of low priority candidate frequencies when the wireless terminal is capable of device-to-device (D2D) communications and is receiving or transmitting, or anticipating receiving or transmitting, device-to-device (D2D) signals on device-to-device (D2D) supported frequencies.

5. The method of claim 1, further comprising during the cell selection/reselection operation, requiring the wireless terminal to consider only cell selection/reselection candidate frequencies which are device-to-device (D2D)-supported frequencies when the wireless terminal is capable of device-to-device (D2D) communications and is receiving or transmitting, or anticipating receiving or transmitting, the device-to-device (D2D) signals on the device-to-device (D2D) supported frequencies.

6. The method of claim 1, further comprising:

determining whether the wireless terminal when engaged in device-to-device (D2D) communications encounters a wireless terminal selected resource mode; and

the wireless terminal determining whether to transmit the device-to-device (D2D) signals using resources selected by the wireless terminal from pre-configured device-to-device (D2D) radio resources or using network-allocated radio resources scheduled by the node based on determining whether the wireless terminal encounters the wireless terminal selected resource mode.

7. The method of claim 1, further comprising the wireless terminal transmitting device-to-device (D2D) signals using device-to-device (D2D) radio resources selected in accordance with the cell selection/reselection operation.

8. A wireless terminal of a communications network which communicates over a radio interface with a radio access node, the wireless terminal comprising:

a processor configured, during a cell selection/reselection operation when the wireless terminal is performing the device-to-device (D2D) communications while camping on frequency, to consider the camped-on frequency to be a high priority candidate frequency for the cell selection/reselection operation.

9. The wireless terminal of claim 8, wherein, as a result of the selection/reselection operation, the processor is configured to select a candidate frequency for use in the device-to-device (D2D) communications.

10. The wireless terminal of claim 8, wherein, as the result of the selection/reselection operation, the processor is configured to select the high priority candidate frequency for use in the device-to-device (D2D) communications.

11. The wireless terminal of claim 8, wherein the processor is configured to require, during the cell selection/reselection operation, the wireless terminal to consider selection/reselection candidate frequencies at which the wireless terminal cannot receive or transmit device-to-device (D2D) signals to be of low priority candidate frequencies when the wireless terminal is capable of device-to-device (D2D) communications and is receiving or transmitting, or anticipating receiving or transmitting, device-to-device (D2D) signals on device-to-device (D2D) supported frequencies.

12. The wireless terminal of claim 8, wherein the processor is configured to require, during a cell selection/reselection operation, the wireless terminal to consider only cell selection/reselection candidate frequencies which are device-to-device (D2D)-supported frequencies when the wireless terminal is capable of device-to-device (D2D) communications and is receiving or transmitting, or anticipating receiving or transmitting, device-to-device (D2D) signals on device-to-device (D2D) supported frequencies.

13. The wireless terminal of claim 8, wherein the wireless terminal further comprises a transceiver configured to transmit device-to-device (D2D) signals using device-to-device (D2D) radio resources selected in accordance with the cell selection/reselection operation.

14. A method in a wireless terminal which is in wireless communications with a radio access node over a radio interface, the method comprising:

using a predefined RRC Idle Mode state transition to determine when a wireless terminal encounters an out-of-coverage situation for device-to-device (D2D) communications purposes; and

when the out-of-coverage situation is determined, the wireless terminal using pre-configured device-to-device (D2D) radio resources for the device-to-device (D2D) communications.

15. The method of claim 14, further comprising the wireless terminal transmitting device-to-device (D2D) signals to another wireless terminal using the pre-configured device-to-device (D2D) radio resources.

16. The method of claim 14, wherein the predefined RRC Idle Mode state transition comprises any one of the following:

(1) the wireless terminal moving to Any Cell Selection State;

(2) the wireless terminal moving to Camped Normally State on non-device-to-device (D2D) frequencies;

(3) the wireless terminal moving to Camped on Any Cell State on non-device-to-device (D2D) frequencies.

17. The method of claim 14, further comprising:

when the wireless terminal undergoes any one of a set of predefined RRC Idle Mode state transitions, starting an out-of-coverage counter provided that the out-of-coverage counter is not already running and is not already expired;

upon expiration of the out-of-coverage counter, the wireless terminal transmitting the device-to-device (D2D) signals using the pre-configured device-to-device (D2D) radio resources.

18. The method of claim 17, wherein the out-of-coverage counter is a clock which counts elapsing time units.

19. The method of claim 17, wherein the out-of-coverage counter is configured to count occurrences of detection of a network event or marker.

20. The method of claim 17, further comprising when the counter expires, the wireless terminal declaring itself out-of-coverage and transmitting the device-to-device (D2D) signals using the pre-configured radio resources.

21. The method of claim 17, further comprising when the counter expires, allowing the wireless terminal to transmit the device-to-device (D2D) signals using the pre-configured device-to-device (D2D) radio resources

22. The method of claim 17, further comprising at least temporarily stopping the counter if any one of the following occurs:

the wireless terminal finds a suitable/acceptable cell to camp on in device-to-device (D2D) supported frequencies;

the wireless terminal is no longer participating in device-to-device (D2D) services/communications;

the wireless terminal determines that the wireless terminal is out-of-coverage;

the wireless terminal leaves the Idle Mode.

23. The method of claim 14, further comprising, during a cell selection/reselection operation, permitting the wireless terminal to consider only cell selection/reselection candidate frequencies which are device-to-device (D2D)-supported frequencies when the wireless terminal is capable of device-to-device (D2D) communications and is receiving or transmitting, or anticipating receiving or transmitting, device-to-device (D2D) signals on device-to-device (D2D) supported frequencies.

24. The method of claim 14, further comprising, during a cell selection/reselection operation, requiring the wireless terminal to consider selection/reselection candidate frequencies at which the wireless terminal cannot receive or transmit device-to-device (D2D) signals to be of low priority candidate frequencies when the wireless terminal is capable of device-to-device (D2D) communications and is receiving or transmitting, or anticipating receiving or transmitting, device-to-device (D2D) signals on device-to-device (D2D) supported frequencies.

25. A wireless terminal which is in wireless communications with a radio access node over a radio interface, the wireless terminal comprising:

a processor configured;

to use a predefined RRC Idle Mode state transition to determine when a wireless terminal encounters an out-of-coverage situation for device-to-device (D2D) communications purposes; and

when the out-of-coverage situation is determined, to use pre-configured device-to-device (D2D) radio resources for the device-to-device (D2D) communications.

26. The wireless terminal of claim 25, further comprising a transmitter configured to send device-to-device (D2D) signals to another wireless terminal using the pre-configured device-to-device (D2D) radio resources.

27. The wireless terminal of claim 25, wherein the predefined RRC Idle Mode state transition comprises any one of the following:

(1) the wireless terminal moving to Any Cell Selection State;

(2) the wireless terminal moving to Camped Normally State on non-device-to-device (D2D) frequencies;

(3) the wireless terminal moving to Camped on Any Cell State on non-device-to-device (D2D) frequencies.

28. The wireless terminal of claim 25, wherein the processor is further configured:

when the wireless terminal undergoes any one of a set of predefined RRC Idle Mode state transitions, to start an out-of-coverage counter provided that the out-of-coverage counter is not already running and is not already expired;

upon expiration of the out-of-coverage counter, to transmit the device-to-device (D2D) signals using the pre-configured device-to-device (D2D) radio resources.

29. The wireless terminal of claim 28, wherein the out-of-coverage counter is a clock which counts elapsing time units.

30. The wireless terminal of claim 28, wherein the out-of-coverage counter is configured to count occurrences of detection of a network event or marker.

31. The wireless terminal of claim 28, wherein the processor is further configured, when the counter expires, to declare the wireless terminal out-of-coverage and to transmit the device-to-device (D2D) signals using the pre-configured radio resources.

32. The wireless terminal of claim 28, wherein the processor is further configured, when the counter expires, to allow the wireless terminal to transmit the device-to-device (D2D) signals using the pre-configured device-to-device (D2D) radio resources

33. The wireless terminal of claim 28, wherein the processor is further configured to at least temporarily stop the counter if any one of the following occurs:

the wireless terminal finds a suitable/acceptable cell to camp on in device-to-device (D2D) supported frequencies;

the wireless terminal is no longer participating in device-to-device (D2D) services/communications;

the wireless terminal determines that the wireless terminal is out-of-coverage;

the wireless terminal leaves the Idle Mode.

34. The wireless terminal of claim 25, wherein the processor is further configured, during a cell selection/reselection operation, to permit the wireless terminal to consider only cell selection/reselection candidate frequencies which are device-to-device (D2D)-supported frequencies when the wireless terminal is capable of device-to-device (D2D) communications and is receiving or transmitting, or anticipating receiving or transmitting, device-to-device (D2D) signals on device-to-device (D2D) supported frequencies.

35. The wireless terminal of claim 25, wherein the processor is further configured, during a cell selection/reselection operation, to require the wireless terminal to consider selection/reselection candidate frequencies at which the wireless terminal cannot receive or transmit device-to-device (D2D) signals to be of low priority candidate frequencies when the wireless terminal is capable of device-to-device (D2D) communications and is receiving or transmitting, or anticipating receiving or transmitting, device-to-device (D2D) signals on device-to-device (D2D) supported frequencies.