Methods to enable scheduling and control of direct link communication in cellular communication systems

A first wireless transmit/receive unit (WTRU) comprising:

• a transmitter configured to transmit a request for device-to-device (D2D) communication resources to an enhanced Node B (eNB), wherein the request includes a D2D buffer status report indicating a buffer size of at least one D2D logical channel;
• a receiver configured to receive a D2D grant for multiple transmission time intervals (TTIs), wherein the D2D grant provides:
• a set of resources to be used for D2D transmissions, a resource hopping assignment and transmit power control (TPC) information;
• a processor configured to determine scheduling assignment (SA) resources to transmit an SA, based on the received D2D grant;
• the processor further configured to determine D2D transmission parameters, wherein at least one of the determined D2D transmission parameters is determined based on at least the received D2D grant and another one of the determined D2D transmission parameters is a modulation and coding scheme (MCS) determined via a radio resource configuration (RRC) signal received from the eNB;
• the processor further configured to determine D2D data resources to transmit D2D data, based on the received D2D grant;
• the transmitter further configured to transmit the SA on the determined SA resources prior to transmitting the D2D data, wherein the SA includes the determined D2D transmission parameters;
• and
• the transmitter further configured to transmit, to a second WTRU, the D2D data on the determined D2D data resources indicated in the SA in accordance with the received resource hopping assignment, received TPC information and determined D2D transmission parameters.

A method for use in a first wireless transmit/receive unit (WTRU), the method comprising:

• receiving an allowed device-to-device (D2D) resource pool from one or more system information blocks (SIBs);
• selecting a subset of resources from the received D2D resource pool to utilize for D2D transmission;
• transmitting a scheduling assignment prior to transmitting D2D data on at least a portion of resources indicated in the scheduling assignment, wherein the scheduling assignment is based on the selected subset of resources;
• and
• transmitting D2D data, to a second WTRU, on the resources indicated in the scheduling assignment;
• wherein a D2D transmission buffer is determined to be non-empty prior to transmitting the D2D data.