In a third group of examples, cross-carrier scheduling grants for DL or UL transmission on another carrier may be sent by the first communication device 101 along with the DRS on the scheduling SCell, such as the second cell 132. In a multi-carrier scenario, the first communication device 101, e.g., an eNB, may transmit DRS with control signals and no PDSCH on one or more unlicensed carriers while sending PDSCH with full random backoff on other unlicensed carriers.

In another exemplary implementation, the scheduling grant that may be sent by the first communication device 101 with DRS on the scheduling cell may be a joint grant which is valid across multiple carriers in the same TTI, or burst of TTIs.

The first, second and third group of examples may be combined. For the multi-subframe UL scheduling and the DL scheduling for future frames, the DCI may need a new field which specifies the number of subframes for which the resource allocation indicated by the DCI may be valid.

DRS with Common Search Space Control Signaling

In a fourth group of examples, control signals associated with the (E)PDCCH common search space of UEs, that is, the region of the DL subframe wherein all UEs may check for control signals, such as system information or transmit power control commands for example, may be sent by the first communication device 101 in DRS subframe/s without PDSCH in the DRS occasion with the DRS being transmitted either with no CCA or with a short CCA.