Network entity, user device, and method for setting up device to device communications

Abstract

A communications system is provided. A network device controls the setting up of a device to device communication link, as sent between a device in the core network and the base station(s) servicing the relevant mobile devices, including disclosure of the common security information for two mobile devices to communicate securely over the direct device to device communications link.

1 . A network entity comprising:
 a processor; and   a transceiver circuit;   wherein the processor is configured to set up security for direct communications between user equipments (UEs),   wherein the transceiver circuit is configured to send, to a first UE in a first message and to a second UE in a second message, security information from which the first UE and the second UE can calculate a security key for protecting user plane traffic sent using direct communications between the UEs,   wherein each of the first message and the second message are respectively protected using a further security key previously provided to the UE to which the message is sent.   
     
     
         2 . A user equipment (UE) comprising:
 a transceiver circuit; and   a processor;   wherein the transceiver circuit is configured to receive, from a network entity, security information from which the UE and another UE can derive a security key for protecting user plane traffic sent using direct communications between the UEs,   wherein the security information is received by the UE in a first message and by the another UE in a second message,   wherein each of the first message and the second message are respectively protected using a further security key previously provided to the UE at which the message is received,   wherein the processor is configured to derive, using the received security information, the security key for protecting user plane traffic, and to establish direct communications with the another UE, and   wherein the processor is further configured to protect user plane traffic sent using direct communications between the UEs.   
     
     
         3 . A communication control method comprising:
 controlling setting up of security for direct communications between user equipments (UEs); and   sending, to a first UE in a first message and to a second UE in a second message, security information from which the first UE and the second UE can calculate a security key for protecting user plane traffic sent using direct communications between the UEs;   wherein each of the first message and the second message are respectively protected using a further security key previously provided to the UE to which the message is sent.   
     
     
         4 . A communication control method for a user equipment (UE), the communication control method comprising:
 receiving, from a network entity, security information from which the UE and another UE can derive a security key for protecting user plane traffic sent using direct communications between the UEs;
 wherein the security information is received by the UE in a first message and by the another UE in a second message, and 
 wherein each of the first message and the second message are respectively protected using a further security key previously provided to the UE at which the message is received; 
   deriving, using the received security information, the security key for protecting user plane traffic;   establishing direct communications with the another UE; and   protecting user plane traffic sent using direct communications between the UEs.