Method and apparatus for transmitting device-to-device (D2D) synchronization signals

Patent metadata

Field	Value
Publication number	US-10075930-B2
Application number	US-201615143812-A
Country	US
Kind code	B2
Filing date	May 2, 2016
Priority date	May 4, 2015
Publication date	Sep 11, 2018
Grant date	Sep 11, 2018

Abstract

A method and apparatus in a first User Equipment (UE) that reduces the number of required transmissions when transmitting device-to-device (D2D) synchronization signals or broadcast channels in a wireless network. The first UE determines its level of interest in being received by a second UE that is within network coverage, and adapts a time pattern for transmission of synchronization signals or broadcast channels, depending on the determined level of interest of the first UE. The first UE's interest may be determined by analyzing a type of service that the first UE is interested in performing, and concluding the first UE is interested in being received by the second UE only when the first UE is interested in performing a certain type of service.

First claim

What is claimed is:

1. A method in a first User Equipment (UE) for transmitting device-to-device (D2D) synchronization signals or broadcast channels, said method comprising:
determining, at the first UE, the first UE's level of interest in being received by a second UE that uses a same or a different synchronization reference signal, wherein determining the first UE's level of interest includes:
analyzing the first UE's interest in performing a certain type of service;
determining whether the second UE is compatible with the certain type of service; and
concluding the first UE is interested in being received by the second UE only when the first UE is interested in performing the certain type of service, and when the second UE is compatible with the certain type of service; and

adapting, at the first UE, a time pattern for transmission of synchronization signals or broadcast channels, depending on the determined level of interest of the first UE.

2. A method in a first User Equipment (UE) for transmitting device-to-device (D2D) synchronization signals or broadcast channels, said method comprising:
determining, at the first UE, the first UE's level of interest in being received by a second UE that uses a same or a different synchronization reference signal; and
adapting, at the first UE, a time pattern for transmission of synchronization signals or broadcast channels, depending on the determined level of interest of the first UE,
wherein determining the first UE's level of interest includes:
analyzing a type of service that the first UE is interested in performing; and
concluding the first UE is interested in being received by the second UE only when the first UE is interested in performing a certain type of service;

wherein the first UE is outside network coverage, and the step of determining the first UE's level of interest further includes determining whether the first UE is interested in performing commercial discovery or Public Safety discovery, wherein the time pattern for transmission of synchronization signals or broadcast channels is different for commercial discovery and Public Safety discovery; and
wherein the step of adapting the time pattern for transmission includes selecting an appropriate time pattern based on the determination of whether the first UE is interested in performing commercial discovery or Public Safety discovery.

3. A method in a first User Equipment (UE) for transmitting device-to-device (D2D) synchronization signals or broadcast channels, said method comprising:
determining, at the first UE, the first UE's level of interest in being received by a second UE that uses a same or a different synchronization reference signal; and
adapting, at the first UE, a time pattern for transmission of synchronization signals or broadcast channels, depending on the determined level of interest of the first UE; and
wherein determining the first UE's level of interest includes:
determining whether the second UE is inside a coverage area of an eNodeB;
when the second UE is inside the coverage area of the eNodeB, determining whether the second UE is capable of relaying a synchronization reference signal that originated from the eNodeB; and
when the second UE is capable of relaying the synchronization reference signal that originated from the eNodeB, determining the first UE is interested when the first UE desires to synchronize with the eNodeB.

4. A method in a first User Equipment (UE) for transmitting device-to-device (D2D) synchronization signals or broadcast channels, said method comprising:
determining, at the first UE, the first UE's level of interest in being received by a second UE that uses a same or a different synchronization reference signal; and
adapting, at the first UE, a time pattern for transmission of synchronization signals or broadcast channels, depending on the determined level of interest of the first UE; and
wherein when the second UE uses the same synchronization reference signal, adapting the time pattern includes performing one of:
transmitting synchronization signals only at a time coinciding with a discovery resource pool; or
refraining from transmitting any synchronization signals.

5. A method in a first User Equipment (UE) for transmitting device-to-device (D2D) synchronization signals or broadcast channels, said method comprising:
determining, at the first UE, the first UE's level of interest in being received by a second UE that uses a same or a different synchronization reference signal; and
adapting, at the first UE, a time pattern for transmission of synchronization signals or broadcast channels, depending on the determined level of interest of the first UE;
wherein when the second UE uses a different synchronization reference and is outside a coverage area of an eNodeB, adapting the time pattern includes periodically transmitting synchronization signals or broadcast channels only during a device-to-device (D2D) interval or until the first UE changes its relay preference.

6. A method in a first User Equipment (UE) for transmitting device-to-device (D2D) synchronization signals or broadcast channels, said method comprising:
determining, at the first UE, the first UE's level of interest in being received by a second UE that uses a same or a different synchronization reference signal; and
adapting, at the first UE, a time pattern for transmission of synchronization signals or broadcast channels, depending on the determined level of interest of the first UE;
wherein when the second UE uses a different synchronization reference and is inside a coverage area of an eNodeB, adapting the time pattern includes:
receiving a synchronization reference signal from the second UE;
determining whether the synchronization reference signal originated from the eNodeB;
when the synchronization reference signal originated from the eNodeB, performing one of:
transmitting synchronization signals or broadcast channels only at a time coinciding with a discovery resource pool; or
refraining from transmitting any synchronization signals or broadcast channels; and

when the synchronization reference signal did not originate from the eNodeB, periodically transmitting synchronization signals or broadcast channels.

7. An apparatus in a first User Equipment (UE) for transmitting device-to-device (D2D) synchronization signals or broadcast channels in a wireless network, said apparatus comprising:
a transceiver; and
a processor coupled to a non-transitory memory that stores computer program instructions, wherein when the processor executes the instructions, the processor controls:
an interest determining circuit configured to determine the first UE's level of interest in being received by a second UE that uses a same or a different synchronization reference signal; and
a transmission time pattern adapting circuit configured to adapt a time pattern for transmission of synchronization signals or broadcast channels, depending on the determined level of interest of the first UE;
wherein the interest determining circuit is configured to determine the first UE's level of interest by:
analyzing the first UE's interest in performing a certain type of service;
determining whether the second UE is compatible with the certain type of service; and
concluding the first UE is interested in being received by the second UE only when the first UE is interested in performing the certain type of service, and when the second UE is compatible with the certain type of service.

8. An apparatus in a first User Equipment (UE) for transmitting device-to-device (D2D) synchronization signals or broadcast channels in a wireless network, said apparatus comprising:
a transceiver; and
a processor coupled to a non-transito

Assignees

• Ericsson Telefon Ab L M

Inventors

• Sorrentino Stefano

Classifications

• H04W8/005

  Discovery of network devices, e.g. terminals · CPC title

• H04W56/001 Primary

  Synchronization between nodes · CPC title

• H04W76/14

  Direct-mode setup · CPC title

• H04W56/0025

  synchronizing potentially movable access points · CPC title