Base station-side and user equipment-side apparatuses and methods, and wireless communication system

An apparatus for a user device side of wireless communications, comprising:

• processing circuitry configured to:
• in response to an uplink schedule grant of uplink transmitting resources on an unlicensed frequency band with respect to the user device, perform energy detecting on the unlicensed frequency band using an energy detection threshold, wherein the uplink schedule grant includes information of a priority level for the user device to make use of the uplink transmitting resources, and
• determine, according to the information of the priority level and a result of the energy detecting, whether the uplink schedule grant is valid, wherein the processing circuitry is configured to determine whether the uplink schedule grant is valid according to information of priority level of at least one second user device in the case that the user device does not have the highest priority level and the energy detecting indicates the unlicensed frequency band being idle, and wherein the at least one second user device performs energy detecting in response to other uplink schedule grants for the same uplink transmitting resources and detects that the unlicensed frequency band is idle;
• and
• a transceiver configured to receive information of the uplink schedule grant from a base station side, wherein the transceiver is configured to receive from a primary user device at predetermined time-frequency resources a notification of the uplink schedule grant being valid, wherein the primary user device receives other uplink schedule grants for the same uplink transmitting resources and has the highest priority level, and when the transceiver fails to receive the notification at the predetermined time-frequency resources, the transceiver interchanges with the second user device respective information of priority level, and
• wherein the predetermined time-frequency resources are located at the last symbol of a previous sub-frame of a PUSCH sub-frame corresponding to the uplink schedule grant, and
• wherein in a case that the notification is transmitted on the unlicensed frequency band and the previous sub-frame of the PUSCH sub-frame is a downlink sub-frame, the downlink sub-frame is configured to be a truncated physical downlink shared channel sub-frame.