A user equipment (UE) of re-organizing a timing advance group (TAG) is provided. The UE includes: a receiving unit for receiving, from a serving base station, secondary serving cell (SCell) configuration information which includes a first field and a second field, the first field including an ScellIndex of an SCell to indicate a removal of the SCell, the second field including at least one of the ScellIndex to indicate an addition of the SCell and a TAG ID indicating a TAG of the SCell, and a radio resource control (RRC) processing unit for performing the addition of the SCell after performing the removal of the SCell from one or more SCells configured in the UE, and for reorganizing the TAG by including the SCell in the TAG.

A signal interface unit for a distributed antenna system includes a channelized radio carrier interface configured to communicate an uplink channelized radio carrier for a radio frequency carrier to a channelized radio carrier base station interface; an antenna side interface configured to receive an uplink digitized radio frequency signal from the distributed antenna system communicatively coupled to the antenna side interface, wherein the uplink digitized radio frequency signal includes baseband data having bits; and a signal conversion module communicatively coupled between the channelized radio carrier interface and the antenna side interface and configured to convert between the uplink digitized radio frequency signal and the uplink channelized radio carrier at least in part by performing an adjustment of the bits included in the baseband data for the uplink digitized radio frequency signal received from the distributed antenna system to comply with requirements of the channelized radio carrier base station interface.

The present disclosure provides several methods, user equipment (UEs) and base stations for transmitting uplink signals. After receiving uplink synchronization command information, the UE may transmit an uplink signal on at least one idle unlicensed cell. Besides, the UE may try to transmit the uplink signal on multiple uplink signal resources within an uplink signal transmission window. By using the present disclosure, transmission probability of uplink signals may be improved, and time delay of uplink synchronization may be shortened.

Systems, apparatuses, and methods are described for wireless communications. A base station may configure for a wireless device access configurations on different uplink carriers, such as a supplemental uplink carrier and a non-supplemental uplink carrier. Control information may indicate that the wireless device may use a second uplink carrier, for example, if an access procedure fails on the first uplink carrier.

It is provided an apparatus, including synchronizing means adapted to synchronize with a cell of a cellular communication system based on a synchronization signal and to obtain a cell identification of the cell; receiving means adapted to receive a symbol only on one or more subcarriers and subframes which carry at least one symbol of a physical broadcast channel; first obtaining means adapted to obtain a common demodulation reference symbol based on the cell identification and the received symbol; demodulating means adapted to demodulate a signal received on the physical broadcast channel based on the common demodulation reference symbol; user equipment means adapted to provide a user equipment functionality of the communication system.

The present invention defines multiple synchronizing signal resource candidates from/in which a synchronizing signal can be transmitted or detected. The base station according to the present invention transmits a synchronizing signal from a synchronizing signal resource, which corresponds to at least the cell identifier of a cell which is associated with the synchronizing signal, the time synchronization of the cell, the length of a cyclic prefix which is applied to the cell, or the type of the base station, among the multiple synchronizing signal resource candidates. The user equipment according to the present invention can obtain information on at least the cell identifier, the time synchronization with the cell, the length of the cyclic prefix, or the type of the base station, on the basis of the synchronizing signal resource in which the synchronizing signal has been detected.

Methods, systems, and devices for mobility state estimation in a heterogeneous network are disclosed herein. User equipment (UE) includes circuitry to perform a mobility state estimation (MSE) operation to determine an MSE state for the UE, and a receiver to receive, from a cell in a heterogeneous third generation partnership project (3GPP) network, mobility state information corresponding to movement of the UE within the heterogeneous 3GPP network. The circuitry is configured to update the MSE state based on the mobility state information received from the cell. The UE may also include a transmitter to communicate the updated MSE state to the cell.

In a wireless communication method, a terminal device obtains a first uplink (UL) alignment timer, where the first UL alignment timer corresponds to a first timing advance group (TAG), the first TAG corresponds to a first serving cell group, the first serving cell group comprises at least one serving cell, and the first UL alignment timer is used for UL synchronization maintenance for the at least one serving cell in the first serving cell group.

Aspects are presented herein of apparatuses, systems, and methods for secondary cell group (SCG) addition. A wireless device may establish communication with a first base station that is comprised in a master cell group (MCG) and a second base station that is comprised in the SCG. The wireless device may maintain timing advance (TA) parameters for performing uplink communication with the second base station. The wireless device may perform a plurality of signal quality measurements after receiving an indication to deactivate the SCG. The wireless device may determine whether to reuse the TA parameters for communicating with the second base station after receiving an indication. The determination may be based on comparing one or more signal quality measurements of the second base station to one or more signal quality thresholds.

Methods and apparatuses for measurement reference signals and synchronization signals. A user equipment (UE) includes a transceiver and a processor operably connected to the transceiver. The transceiver is configured to receive a primary synchronization signal (PSS), a secondary synchronization signal (SSS), and a primary broadcast channel (PBCH). The processor is configured to decode cell identification information from at least the PSS and the SSS and to decode a master information block (MIB) from the PBCH. The PSS, the SSS, and the PBCH are time-division multiplexed. A same set of sequences are used for the PSS and the SSS for different carrier frequencies and different sub-carrier spacing values.