User equipment, a network node and methods therein for enabling device-to-device (d2d) communication in a radio communications network

A first User Equipment, UE, capable of enabling Device-to-Device, D2D, communication with a second UE in a radio communications network, the first UE being configured to perform the D2D communication on downlink cellular resources in the radio communications network,

• the first UE being configured to measure received signal strengths of Reference Signals, RS, of downlink cellular resources from one or more network nodes in the radio communications network, determine a first subset of downlink cellular resources for which the measured received signal strength of RS is above or equal to a threshold value, and transmit information indicating the determined first subset of downlink cellular resources to a network node serving the first UE in the radio communications network in order to enable the D2D communication.

A method performed by a network node for enabling Device-to-Device, D2D, communication between a first and a second User Equipment, UE in a radio communications network, the network node being configured to assist the D2D communication by assigning downlink cellular resources in the radio communications network to the D2D communication, the method comprising:

• receiving, from the first UE, information indicating a first subset of downlink cellular resources;
• determining a second subset of downlink cellular resources of the downlink cellular resources that is orthogonal to the received first subset of downlink cellular resources, which said second subset of downlink cellular resources is to be used by the first UE in the D2D communication with the second UE;
• transmitting information indicating the determined second subset of downlink cellular resources to at least the first UE.

A network node capable of enabling Device-to-Device, D2D, communication between a first and a second User Equipment, UE in a radio communications network, the network node being configured to assist the D2D communication by assigning downlink cellular resources in the radio communications network to the D2D communication,

• the network node being configured to receive, from the first UE, information indicating of a first subset of downlink cellular resources, determine a second subset of downlink cellular resources of the downlink cellular resources that is orthogonal to the received first subset of downlink cellular resources, which said second subset of downlink cellular resources is to be used by the first UE in the D2D communication with the second UE, and transmit information indicating the determined second subset of downlink cellular resources to at least the first UE.