| 摘要 |
Power control for transmission of a discovery signal in a communication network (Figure 1), in particular for a D2D (Device-to-Device) discovery signal. A network control element, such as an enodeB (10, Figure 1), configures transmission power parameters usable for determining a transmission power to be set by a communication device, such as a UE (20, Figure 1), for transmitting a discovery signal for a specific communication mode. The configured transmission power parameters are sent from the enodeB to the UE by means of an information element, such as a dedicated system information block (SIB) S30. In the UE, the transmission power parameters are used to set the transmission power for transmitting the discovery signal in the specific communication mode S50. In a further embodiment the discovery signal may itself comprise a power information element indicating whether or not, and possibly how, the transmission power used for transmitting the discovery signal differs from a common transmission power reference value (Figure 2). The discovery signal including the power information element may further be used to determine path loss and/or link quality over the D2D link (Figure 6). In a particular further embodiment a UE capable of communicating simultaneously a cellular mode uplink signal and a discovery signal for a specific communication mode may scale its transmission power in accordance with a maximum transmission power threshold for the device. The discovery signal may be scaled first and if this is insufficient to meet the threshold the cellular uplink signal may also be scaled (Figure 10).
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