System and methods for controlling out-of-network D2D communications
First Claim
1. A method by a user equipment (UE) for selecting a synchronization master for device-to-device (D2D) communication, the method comprising:
- receiving, by a first UE, a discovery signal from a second UE, the discovery signal comprising a timing reference and a synchronization signal that indicates a synchronization state of the second UE, the synchronization signal being an in-coverage signal when the second UE is inside a coverage area of a cellular network and an out-of-coverage signal when the second UE is outside of the coverage area of the cellular network, the discovery signal having been received on a predefined uplink carrier;
determining whether the first UE is to act as a timing slave entity or a timing master entity during a D2D communications session between the first UE and the second UE based on whether the synchronization signal received from the second UE is the in-coverage signal or the out-of-coverage signal;
participating, by the first UE, in the D2D communication session with the second UE over the predefined uplink carrier as the timing slave entity or the timing master entity, wherein the first UE synchronizes the D2D communication session according to the timing reference received from the second UE when the first UE is the timing slave entity, and wherein the first UE synchronizes the D2D communication session according to its own timing reference when the first UE is the timing master entity;
receiving, by the first UE, authorization from the cellular network, the authorization indicating the first UE is permitted to act as the timing master entity; and
switching, by the first UE, to a timing master mode in response to receiving the authorization from the cellular network.
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Abstract
Embodiments are provided herein for determining a synchronizing master for device-to-device (D2D) communication in a cellular network environment. In an embodiment, a user equipment (UE) receives a discovery signal comprising a timing reference, and determines a transmitter of the discovery signal. In accordance with the determination of the transmitter of the discovery signal, the UE performs one of synchronizing to the timing reference in the discovery signal and transmitting a second discovery signal. The UE performs the synchronizing to the timing reference if the transmitter of the discovery is a cellular network. Alternatively, the UE transmits the second discovery signal upon determining that the transmitter of the discovery signal is a second UE that is out of coverage of a cellular network.
21 Citations
18 Claims
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1. A method by a user equipment (UE) for selecting a synchronization master for device-to-device (D2D) communication, the method comprising:
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receiving, by a first UE, a discovery signal from a second UE, the discovery signal comprising a timing reference and a synchronization signal that indicates a synchronization state of the second UE, the synchronization signal being an in-coverage signal when the second UE is inside a coverage area of a cellular network and an out-of-coverage signal when the second UE is outside of the coverage area of the cellular network, the discovery signal having been received on a predefined uplink carrier; determining whether the first UE is to act as a timing slave entity or a timing master entity during a D2D communications session between the first UE and the second UE based on whether the synchronization signal received from the second UE is the in-coverage signal or the out-of-coverage signal; participating, by the first UE, in the D2D communication session with the second UE over the predefined uplink carrier as the timing slave entity or the timing master entity, wherein the first UE synchronizes the D2D communication session according to the timing reference received from the second UE when the first UE is the timing slave entity, and wherein the first UE synchronizes the D2D communication session according to its own timing reference when the first UE is the timing master entity; receiving, by the first UE, authorization from the cellular network, the authorization indicating the first UE is permitted to act as the timing master entity; and switching, by the first UE, to a timing master mode in response to receiving the authorization from the cellular network. - View Dependent Claims (2, 3, 4, 5)
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6. A method by a user equipment (UE) for selecting a synchronization master for device-to-device (D2D) communication, the method comprising:
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receiving, by a first UE, a discovery signal on a predefined uplink carrier from a second UE, the discovery signal including a timing reference and a synchronization signal indicating a synchronization state of the second UE; determining whether the first UE or the second UE is to act as a timing master entity during a D2D communications session between the first UE and the second UE based on the synchronization signal received from the second UE; participating, by the first UE, in the D2D communication session with the second UE over the predefined uplink carrier, wherein the first UE synchronizes the D2D communication session according to the timing reference received from the second UE when the second UE is the timing master entity, and wherein the first UE synchronizes the D2D communication session according to its own timing reference when the first UE is the timing master entity; receiving, by the first UE, authorization from a cellular network, the authorization indicating that the first UE is permitted to act as the timing master entity; and switching, by the first UE, to a timing master mode in response to receiving the authorization from the cellular network. - View Dependent Claims (7, 8, 9)
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10. A first user equipment (UE) for selecting a synchronization master for device-to-device (D2D) communication, the first UE comprising:
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at least one processor; and a non-transitory computer readable storage medium storing programming for execution by the at least one processor, the programming including instructions to; receive a discovery signal from a second UE, the discovery signal comprising a timing reference and a synchronization signal that indicates a synchronization state of the second UE, the synchronization signal being an in-coverage signal when the second UE is inside a coverage area of a cellular network and an out-of-coverage signal when the second UE is outside of the coverage area of the cellular network, the discovery signal having been received on a predefined uplink carrier; determine whether the first UE is to act as a timing slave entity or a timing master entity during a D2D communications session between the first UE and the second UE based on whether the synchronization signal received from the second UE is the in-coverage signal or the out-of-coverage signal; and participate in the D2D communication session with the second UE over the predefined uplink carrier as the timing slave entity or the timing master entity, wherein the first UE synchronizes the D2D communication session according to the timing reference received from the second UE when the first UE is the timing slave entity, and wherein the first UE synchronizes the D2D communication session according to its own timing reference when the first UE is the timing master entity; receive authorization from the cellular network, the authorization indicating the first UE is permitted to act as the timing master entity; and switch to a timing master mode in response to receiving the authorization from the cellular network. - View Dependent Claims (11, 12, 13, 14)
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15. A first user equipment (UE) for selecting a synchronization master for device-to-device (D2D) communication, the first UE comprising:
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at least one processor; and a non-transitory computer readable storage medium storing programming for execution by the at least one processor, the programming including instructions to; receive a discovery signal on a predefined uplink carrier from a second UE, the discovery signal including a timing reference and a synchronization signal indicating a synchronization state of the second UE; determine whether the first UE or the second UE is to act as a timing master entity during a D2D communications session between the first UE and the second UE based on the synchronization signal received from the second UE; participate in the D2D communication session with the second UE over the predefined uplink carrier, wherein the first UE synchronizes the D2D communication session according to the timing reference received from the second UE when the second UE is the timing master entity, and wherein the first UE synchronizes the D2D communication session according to its own timing reference when the first UE is the timing master entity; receive authorization from a cellular network, the authorization indicating the first UE is permitted to act as the timing master entity; and switch to a timing master mode in response to receiving the authorization from the cellular network. - View Dependent Claims (16, 17, 18)
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Specification