Some communications between communication devices are device-to-device transmissions, in which one communication device receives a transmission directly from another communication device, i.e. other than via one or more intermediate nodes such as fixed transceivers of a network.
Device-to-device transmissions may be broadcast, group-cast or multi-cast and unicast transmissions.
Device-to-device transmissions may be used, for example, for the effective distribution of public safety information.
Device-to-device transmissions may comprise (a) network-controlled transmissions in which a network decides which radio resources of a pool of resources are to be used for a device-to-device transmission; or (b) more autonomous transmissions in which the transmitting communication device itself decides which radio resources of a pool of resources to use for a device-to-device transmission.