A wireless device transmitting a D2D discovery signal at a power determined by a base station to minimise interference with uplink retransmissions

摘要

A wireless device 22 transmits a device-to-device (D2D) discovery signal using the same transmission resource that is used for transmitting uplink retransmissions to a base station 30 by a second wireless device. The D2D discovery signal is transmitted at a power that is determined in accordance with a control signal received by the wireless device 22 from the base station 30. This helps prevent or minimise interference or collision between D2D discovery signals being transmitted by the one device and uplink retransmissions being transmitted by the second device and which make use of the same transmission resource. Aspects of the invention include: the transmission resource being an LTE Physical Uplink Control Channel PUCCH or a PUSCH; the D2D discovery signal transmitted at a frequency that alternates over time between two frequencies; the Power determined in accordance with a signal received from the BS based on channel conditions; the Power of D2D discovery signal at the BS is less than uplink retransmission received at the BS from other wireless devices.