In various variations of this embodiment the position of the starting OFDM symbol may be determined by determining that the position of the starting OFDM symbol is at an initial OFDM symbol position in the second subframe when the result of the LBT indicates that the carrier frequency became unoccupied during a terminal part of the first portion of the first subframe. Determining the position of the starting OFDM symbol may also include determining that the position of the starting OFDM symbol is that and eighth OFDM symbol position in the second subframe when the result of the LBT that the carrier frequency became unoccupied during the second portion of the second subframe. Here the second portion of the second subframe may comprise the initial through the seventh OFDM symbol positions of the second subframe and wherein the second subframe comprises fourteen OFDM symbol positions. In some embodiments the base station also transmits the control channel starting from the determined position of a starting OFDM symbol.

Additionally, in various embodiments the base station performs physical downlink shared channel (PDSCH) transmissions to the UE in the first subframe using the first UE-specific reference signal pattern when the duration of the first portion is not greater than the duration of the last three OFDM symbols of the first subframe. The base station may also perform PDSCH transmission to the UE in the first subframe using a second UE-specific reference signal pattern when the duration of the first portion is greater than the duration of the last three OFDM symbols of the first subframe.