A user equipment (UE) is configured to determine that half-duplex frequency division duplex (HD-FDD) is enabled by a network with which the UE is communicating, identify a collision between a cell-specific downlink reception and a cell-specific uplink transmission and implement a HD-FDD collision handling technique. A UE may also be configured to determine that half-duplex frequency division duplex (HD-FDD) is enabled by a network with which the UE is communicating, perform a first cell-specific uplink transmission at a first time and perform a first cell-specific downlink reception at a second time, wherein a guard period represents a time duration between the first time and the second time during which the UE is not to perform a second different cell-specific uplink transmission or a second different cell-specific downlink reception.

Embodiments of the present disclosure relate to random access in a communication system. A first device determines whether a contention-free random access resource is allocated from a second device for a first random access type. In accordance with a determination that the contention-free random access resource is allocated, the first device compares a target transport block size corresponding to the contention-free random access resource with a first transport block size configured for a first group of preambles available for the first random access type, and performs random access to the second device based on a result of the comparison.

Provided are a method and system for handling L1/L2 triggered mobility (LTM) to reduce mobile latency. The method may include: transmitting, by a serving distributed unit (DU) to a user equipment (UE), a request to perform an uplink sync with a target cell of a target distributed unit (DU), wherein the UE performs the uplink sync with the target DU including transmitting a preamble signal to the target DU upon receiving the request, wherein the target DU determines a best beam group (BG) for the UE upon receiving the preamble signal; receiving, by the serving DU, a Random Access Channel (RACH) preamble based on the best BG, wherein the RACH preamble originates from the target DU; and executing, by the serving DU, a serving cell change (SCC) for the UE to one of a prepared target cell based on the RACH preamble.

Embodiments of the present invention provide a method, a device, and a system for determining timing advance grouping. In one embodiment, a base station adds a component carrier (CC) for a user equipment (UE). The base station determines a timing advance (TA) group to which the added CC belongs. The TA group is a set of CCs that can share a TA. The base station sends identification information that identifies the TA group to the UE.

Disclosed is a method for conducting random access on a small cell under dual connectivity. The method includes that: a User Equipment (UE) sends a dedicated random access preamble corresponding to a designated small cell to a base station to which the designated small cell belongs on the designated small cell; and the UE receives a random access response message sent by a base station to which a master control cell in dual connectivity belongs or the base station to which the designated small cell belongs. The present disclosure also discloses a system for conducting random access on a small cell under dual connectivity, a base station, a UE and a computer storage medium.

The present invention relates to a wireless communication system. In detail, the present invention is a method for transmitting data to a base station (BS) at a user equipment. The method comprises: receiving information regarding a contention-based Physical Uplink Shared Channel (PUSCH) zone including a plurality of contention-based PUSCH blocks; allocating at least one contention-based PUSCH resource block for transmission of the data based on the contention-based PUSCH zone information; and transmitting the data to the base station (BS).

A target communications device receiving from a source communications device a notification that a user communications device is to be handed over from that source communications device, provides the source communications device with multiple component carrier information for use by the user communications device. The multiple component carrier information includes information indicating to the user communications device which of the multiple component carriers is to be used for initial access. The multiple component carrier information may be component carrier indexes. Communication devices may exchange component carrier indexes during a setup or updating procedure such as an X2 setup or updating procedure.

The present invention relates to a wireless communication system. More specifically, the present invention relates to a method and a device for performing RA procedure in EC mode in a wireless system, the method comprising: selecting a first random access preamble based on a first CE level, when the UE operates in EC mode with the first CE level, transmitting the first random access preamble for a configured number of times, which is determined based on the first CE level, to an eNB, receiving a BI from the eNB within a RAR window associated with the first random access preamble, calculating a BPV based on the received BI and the first CE level, and selecting and transmitting a second random access preamble based on a second CE level, wherein the second random access preamble selection and transmission are delayed by a random backoff time selected according to a uniform distribution between 0 and the calculated BPV.

A mobile station apparatus receives, on a PDCCH (physical downlink control channel), information used for initiating a random access procedure. The mobile station apparatus also transmits a random access preamble on a physical random access channel resource based on or in response to the information. Furthermore, the mobile station apparatus receives a random access response corresponding to the random access preamble on one specific downlink component carrier among a plurality of downlink component carriers where the one specific downlink component carrier linked to an uplink component carrier on which the random access preamble is transmitted on the physical random access channel resource.

The present invention relates to a method for determining whether a wireless device is reachable in a cell served by a radio network node. The method is performed in the radio network node. The wireless device is in connected mode in the cell and applies DRX. The method comprises allocating (510) a dedicated random access preamble to the wireless device. The dedicated random access preamble is to be transmitted by the wireless device to indicate that the wireless device is reachable in the cell. The method further comprises transmitting (520) an indicator of the dedicated random access preamble to the wireless device, and monitoring (530) for the dedicated random access preamble from the wireless device. The method also comprises determining (540) that the wireless device is reachable when receiving the dedicated random access preamble from the wireless device.