Techniques are described for facilitating an inter-Radio Access Technology (RAT) selection or measurement process for a dual-mode or a multi-mode device. For example, a wireless communication method includes a network node transmitting to a communication node a system information block (SIB) that includes information about Radio Access Technologies (RATs). The information includes any one or more of a first carrier priority value and a first threshold value of a serving frequency associated with a RAT, a second carrier priority value and a second threshold value of a serving cell associated with the RAT, an indicator to indicate existence of one or more additional RATs, carrier information for the one or more additional RATs, and access information to access the one or more additional RATs.

Apparatuses, methods, and systems are disclosed for determining a beam for preamble transmission. One apparatus includes a processor that determines a beam from multiple beams for preamble transmission. In response to the multiple beams including one or more beams configured with a contention-free resource, the one or more beams configured with a contention-free resource have a higher priority than other beams of the multiple beams.

The present invention provides a method and device for transmitting/receiving an uplink signal. When a user equipment of the present invention is configured by multiple cell groups and multiple pieces of uplink control information (UCI) to be transmitted by the user equipment in a subframe are generated, the user equipment separately transmits, to the multiple cell groups, the UCI one by one from the piece of UCI having the highest priority, and drops the pieces of UCI having lower priorities among the multiple pieces of UCI.

A mobile communication system includes a control device and a base station device. Data communication between the control device and the base station device is conducted using a fixed-length data size and a variable-length data size. The control device transmits information indicating whether a data size of the data communication has a fixed length or a variable length. The base station device receives the information from the control device.

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.

A method and apparatus for supporting a device-to-device (D2D) communication between user equipments (UEs) are provided. The method of a device-to-device (D2D) communication between user equipments (UEs), the method includes: receiving, at a transmission (Tx) UE, resource assignment information transmitted from an evolved NodeB (eNB), the resource assignment information being associated with a D2D discovery signal to be transmitted in a discovery period; determining, at the Tx UE, that a D2D discovery signal associated with a first discovery type and a D2D discovery signal associated with a second discovery type are to be transmitted in a first subframe included in the discovery period; and in the first subframe, transmitting the D2D discovery signal associated with the second discovery type and dropping the D2D discovery signal associated with the first discovery type.

Disclosed is a wireless communication base station apparatus whereby it is possible to prevent degradation of throughput of LTE terminals, even when LTE terminals and LTE+ terminals are present together. In this apparatus, a setting section (105) sets in each subframe a resource block in which is arranged a reference signal that is employed solely by LTE+ terminals, based on the pattern of arrangement of reference signals employed solely by LTE+ terminals. In the case of symbols that are mapped to antennas (110-1) to (110-4), an arrangement section (106) arranges the characteristic cell reference signals employed by both LTE terminals and LTE+ terminals in all of the resource blocks in a single frame. In contrast, in the case of the symbols that are mapped to the antennas (110-5) to (110-8), the arrangement section (106) arranges in some of the resource blocks, that are set in accordance with the setting results input from a setting section (105), the characteristic cell reference signals that are employed solely by the LTE+ terminals.

Disclosed is a wireless communication base station apparatus whereby it is possible to prevent degradation of throughput of LTE terminals, even when LTE terminals and LTE+ terminals are present together. In this apparatus, a setting section (105) sets in each subframe a resource block in which is arranged a reference signal that is employed solely by LTE+ terminals, based on the pattern of arrangement of reference signals employed solely by LTE+ terminals. In the case of symbols that are mapped to antennas (110-1) to (110-4), an arrangement section (106) arranges the characteristic cell reference signals employed by both LTE terminals and LTE+ terminals in all of the resource blocks in a single frame. In contrast, in the case of the symbols that are mapped to the antennas (110-5) to (110-8), the arrangement section (106) arranges in some of the resource blocks, that are set in accordance with the setting results input from a setting section (105), the characteristic cell reference signals that are employed solely by the LTE+ terminals.

Wireless communications are described. A wireless device may be configured to transmit a first signal via a first cell group that may overlap in time with a second signal via a second cell group. The wireless device may adjust a signal transmission power of at least one of the first signal or the second signal. Additionally or alternatively, the wireless device may drop at least one of the first signal or the second signal. Adjusting and/or dropping at least one of the first signal or the second signal may be based on the overlap in time of these signals satisfying a duration threshold and a total power to transmit the first signal and the second signal exceeding a power threshold.

Wireless communications are described. A wireless device may be configured to transmit a first signal via a first cell group that may overlap in time with a second signal via a second cell group. The wireless device may adjust a signal transmission power of at least one of the first signal or the second signal. Additionally or alternatively, the wireless device may drop at least one of the first signal or the second signal. Adjusting and/or dropping at least one of the first signal or the second signal may be based on the overlap in time of these signals satisfying a duration threshold and a total power to transmit the first signal and the second signal exceeding a power threshold.