In various embodiments, the eNB 104 may use some or the entire truncated portion 404 of the subframe with truncation 406, for example (n+2), to perform LBT. The eNB 104 may also use some part of the truncated portion 404 of the subframe with truncation 406 as an idle period (e.g., the duration of the idle period may be similar to the DIFS period described in IEEE 802.11 specifications). After the eNB 104 performs LBT and determines that the carrier is free, the eNB 104 may also use some part of the truncated portion 404 of the subframe with truncation 406 to transmit a ‘carrier holding signal’ or ‘carrier busy signal’ until the next LTE pilot/data/control transmission can begin to ensure that other devices sensing the carrier detect that the carrier is occupied by the eNB and defer their transmissions (not specifically shown). The ‘carrier holding signal’ may be transmitted with the same power level or PSD level as the subsequent LTE pilot/data/control transmission. The ‘carrier holding signal’ may be a narrowband signal or a wideband signal and may/may not be centered within the operating channel on the unlicensed carrier frequency.

From a UE 106 perspective, it is beneficial for the UE 106 to be able to determine or to be provided information defining which of the received subframes in the subframe structure 400 are subframes with truncated transmissions 406 and the number (m) of OFDM symbols truncated in the truncated portion 404 of the subframes with truncation 406. If this information is not made available to the UE, the UE may attempt to receive the signals/channels transmitted by the eNB in a manner that assumes that the subframes therein do not have any truncation, which will lead to estimation/decoding errors that will cause retransmissions and inefficient carrier usage.