A communication device for handling channel access in an unlicensed band comprises a storage device for storing instructions and a processing circuit coupled to the storage device. The processing circuit is configured to execute the instructions stored in the storage device. The instructions comprise receiving an uplink (UL) grant from a network, wherein the UL grant indicates the communication device to perform an UL transmission in a transmission time interval (TTI); performing a listen-before-talk (LBT) procedure on a first carrier in response to the UL grant; and aborting the LBT procedure, when the communication device senses the first carrier to be busy before the TTI according to the LBT procedure.

A mobile station in a wireless communication network. The mobile station includes a radio communication that transmits an access request message to a base station via a first communication resource, and receives a timing adjustment in response to the access request message from the base station. The mobile station also includes an adjustment value storage unit that stores the timing adjustment, and a control unit that adjusts access timing corresponding to a second communication resource based on the timing adjustment value stored in the adjustment value storage unit. The radio communication unit then communicates with the base station via the first communication resource and the second communication resource.

In order to provide a transmission device and transmission method with which a response signal for random access preamble transmitted from a preamble transmission device is efficiently transmitted, setting unit in base station sets a first resource candidate group, which enables terminal capable of receiving a latch response transmitted by demodulation reference signal (DMRS) transmission to be selected, and a second resource candidate group, which enables terminal incapable of receiving a latch response transmitted by DMRS transmission but capable of receiving a latch response transmitted by cell-specific reference signal (CRS) transmission to be selected. Control unit selects DMRS transmission as the latch response transmission method when a resource in which latch preamble has been received is included in the first candidate group, but selects CRS transmission as the latch response transmission method when the resource is included in the second resource candidate group.

Methods and apparatuses are described for wireless communications. Cells may be grouped into a plurality of cell groups. A wireless device may transmit a plurality of preambles. The wireless device may also transmit a packet using a transmission power that is based on a power ramp-up of the preambles.

Methods and apparatuses are described for wireless communications. Cells may be grouped into a plurality of cell groups. A wireless device may transmit a plurality of preambles. The wireless device may also transmit a packet using a transmission power that is based on a power ramp-up of the preambles.

Methods and apparatuses are described for wireless communications. Cells may be grouped into a plurality of cell groups. A time adjustment may be determined and applied to uplink transmission timing of a cell group. A transmission timing difference between a first cell group and a second cell group may be determined. If the transmission timing difference exceeding a threshold, one or more devices may stop transmitting uplink signals via one or more secondary cells and/or may stop applying the timing adjustment for a cell group.

Embodiments of the present invention provide a preamble sequence transmission method, apparatus, and system. The method includes: acquiring system information or a physical broadcast channel (PBCH) that is broadcast by a base station, wherein the system information or the PBCH comprises a preset physical random access channel (PRACH) that comprises m preset radio frames and a number of repetition times of a preamble sequence n, which is used for random access, m being a positive integer and wherein 1≦n≦10 m; and sending the preamble sequence to the base station, the preamble sequence being sent at n preset resource locations of the preset PRACH, where the preamble sequence is the format of 1 ms, or the format of 2 ms, or the format of 3 ms.

Improvements to signaling procedures for use in physical random access channel (PRACH)-based proximity detection are disclosed. Signaling and signaling processes from a serving base station may trigger a more efficient and reliable transmission of PRACH from related user equipment (UE). At the dynamic power nodes (DPNs) monitoring for such PRACH-based proximity, features are disclosed which establish neighbor lists for more efficient management of detection and proximity activation.

A method of managing an access attempt for accessing a cellular network (82) is described. The method is performed by a communication device (40) and comprises sending (84), to a radio network node (60) of the cellular network (82), an access request message for requesting access to the cellular network (82), and receiving (88), from the radio network node (60), an access response message for the access request message. The access response message comprises a wait indication indicating to wait for a resumption indication before resuming the access attempt. The resumption indication indicates to resume the access attempt, and the method also comprises, in response to the received wait indication, waiting (90) to resume the access attempt. The communication device (40) is in an idle mode and the access response message is received after a random access response message. Alternatively, the communication device (40) is in a connected mode and the resumption indication is received via a physical downlink control channel. Therefore load control of load associated with the access attempt of the communication device (40) may be accomplished in a fast, easy and flexible way.

Management of receiver sensitivity in a packet based wireless communication system is achieved by controlling a clear channel sensing process which determines if the channel is clear for use, governed by a sensitivity to use of the channel. The sensitivity of the clear channel sensing process is effected by monitoring transmission performance over a plurality of emissions, and making adjustments to the sensitivity based on comparison of that performance with a performance criterion.