1. A transmitter for a wireless communication system comprising:a processor and memory storing executable instructions that, when executed by the processor, configure the processor to provide at least the following operations:
stop a transmission of a first downlink burst such that the transmission ends prior to a predetermined gap interval that is before a downlink subframe in a discovery signal measurement timing configuration (DMTC) window of the wireless communication system; and
transmit a second downlink burst in the DMTC window using listen-before-talk (LBT) based on load based equipment (LBE);
wherein transmission of the second downlink burst within the DMTC window is started time-aligned or subframe-aligned with a discovery signal transmission interval, the LBE based LBT is used in the DMTC window with a first defer period, the LBE based LBT is used outside of the DMTC window with a second defer period and the first and second defer periods are derived differently.