This disclosure provides systems, methods, apparatus, and computer programs encoded on computer storage media, for relative timing drift correction for distributed multi-user transmissions. In one aspect, a first access point (AP) may receive a first signal from a second AP. The first signal may be associated with a channel sounding procedure to be performed substantially simultaneously by the second AP and the first AP. The first AP may then receive a second signal from the second AP, and prior to a substantially simultaneous transmission by the second AP and the first AP. The second signal may include timing information relative to the first signal. The first AP may determine a start time of the substantially simultaneous transmission at the first AP based on the timing information, and may initiate the substantially simultaneous transmission according to the determined start time.

Provided are a network synchronization system and a synchronization method for a network system that achieve network synchronization for a network between geographically apart points. The network synchronization system includes a first communication device positioned at a first point, a second communication device positioned at a second point being different from the first point, and a third communication device configured to communicate with the first communication device and the second communication device, and receive synchronization information relating to the first communication device from the first communication device, and then transmit the synchronization information relating to the first communication device to the second communication device.

A crystal-free wireless device includes a frequency calibration module and a local radio frequency (RF) oscillator having a first frequency and configured to communicate with the frequency calibration module. The crystal-free wireless device also includes a relaxation ring oscillator configured to communicate with the frequency calibration module. The relaxation ring oscillator is further configured to receive a calibration signal or periodic radio frequency packets from a wireless network and provide a reference signal to the frequency calibration module. The relaxation ring oscillator is a crystal-free oscillator. The frequency calibration module is configured to generate a calibration signal that is fed back through a Frequency Locked Loop (FLL) to the local RF oscillator to calibrate the local RF oscillator. The calibrated local RF oscillator is configured to generate a clock signal.

Exemplary of embodiments of the disclosure include a method which includes determining, by a first device, whether the first device has a current time and transmitting a request for the current time to a second device if the first device does not have the current time. The second device is in a local network. The method further includes receiving, by the first device, the current time from the second device, authenticating a certificate based on the current time received from the second device, and establishing a network connection to the local network based on the authenticated certificate.

Aspects of the present disclosure include methods, apparatuses, and computer readable media for establishing a first communication link with a base station (BS), establishing a second communication link with a second UE, generating a timing advance group (TAG) capability report comprising a plurality of link-specific TAG numbers supported by the UE, wherein a first TAG number of the plurality of link-specific TAG numbers is associated with the first communication link and a second TAG number of the plurality of link-specific TAG numbers is associated with the second communication link to the BS, and transmitting the TAG capability report to the BS.

Target based control of synchronization signals in D2D communication A radio device detects (11) at least one first synchronization signal from one or more further radio devices (12, 13). Depending on the at least one detected first synchronization signal, the radio device (11) selects at least one of the one or more further radio devices (12, 13). Further, the radio device (11) transmits a second synchronization signal, excluding the selected at least one further radio device (12) as a transmission target of the second synchronization signal.

The embodiment of the present disclosure provides a time code synchronization method, which includes following steps of: determining a target master node and one or more target slave nodes of a network system among the plurality of nodes; periodically sending a data packet to the one or more target slave nodes by the target master node, wherein the data packet includes a first time code and serial number information of the target master node; compensating the first time code according to the serial number information to obtain a second time code, and synchronizing the second time code by the one or more target slave nodes.

Systems, methods, and instrumentalities are disclosed to manage interference caused by D2D communications. A wireless transmit receive unit (WTRU) may include a processor. The processor may be configured to perform one or more of the following. The processor may determine to send information using a device-to-device transmission via a resource pool from a plurality of resource pools. Each resource pool may be associated with a range of reference signal receive power (RSRP) values. The processor may determine a RSRP measurement of a cell associated with the WTRU. The processor may select a resource pool from the plurality of resource pools based on the RSRP measurement of the cell. The RSRP measurement of the cell may be within the range of RSRP values associated with the selected resource pool. The processor may send the information using the selected resource pool.

A method of UE includes receiving a radio resource control (RRC) message for configuring bandwidth parts (BWPs) of a serving cell, receiving a physical downlink control channel (PDCCH) indicating activation of a first BWP, performing a BWP switching to the first BWP indicated by the PDCCH, and starting a first downlink BWP timer associated with the first BWP. A UE includes a transceiver, and at least one controller coupled with the transceiver, the at least one controller configured to receive an RRC message for configuring BWPs of a serving cell, receive a PDCCH indicating activation of a first BWP, perform a BWP switching to the first BWP indicated by the PDCCH, and start a first downlink BWP timer associated with the first BWP.

Dynamic User Equipment (UE) beam switching for millimeter wave (mmWave) measurements in asynchronous networks is discussed in which a UE configured with a plurality of UE beams receives timing information of detected cells in an asynchronous network, and calculates, based on the timing information, a maximum offset for the detected cells indicating a timing difference between a pair of cells of the detected cells that is larger than a timing difference between any other pair of the detected cells. A UE beam switch from a UE beam to another UE beam of the plurality of beams is scheduled based on the maximum offset, which includes using the maximum offset to determine how often the UE beam switch can be performed. Other aspects and features are also claimed and described.