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.

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, systems, and devices for wireless communication are described. A user equipment (UE) may receive a downlink (DL) signal from a base station on one or more DL beam(s). The UE may identify a selected DL beam of the one or more DL beam(s) for communications from the base station to the UE. The UE may transmit a scheduling request message to the base station using at least one of a resource or a waveform selected based at least in part on the selected DL beam.

Methods and systems for coordinating simultaneous transmission by two or more access points over a single channel of a wireless medium are disclosed. In one aspect, a method includes determining, by a first access point, a time when the first access point and a second access point will transmit simultaneously over the channel, and transmitting, by the first access point, over the channel at the time.

Methods for time synchronization among communication nodes in a vehicle network are disclosed. An operation method of a first communication node includes: transmitting a first frame requesting verification of time synchronization to a second communication node; receiving a second frame including information indicating a link delay time of the second communication node from the second communication node; receiving a third frame including information indicating a transmission time of the second frame from the second communication node; and verifying time synchronization between the first and second communication nodes based on the information included in the received second and third frames.

Methods, systems, and devices for wireless communication are described. A user equipment (UE) may receive a downlink (DL) signal from a base station on one or more DL beam(s). The UE may identify a selected DL beam of the one or more DL beam(s) for communications from the base station to the UE. The UE may transmit a beam recovery or beam tracking message to the base station using at least one of a resource or a waveform selected based at least in part on the selected DL beam.

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.

The embodiments disclose a method of determining guard period for downlink-to-uplink switching in an access point of a time division duplex radio communication network. For each of a plurality of terminal devices served by the access point, the method comprising obtaining measurement information on uplink transmission delay of the terminal device due to the downlink-to-uplink switching and propagation delay; determining a time length of a guard period with respect to the terminal device based on the measurement information; assigning a time period scheduled for transmitting a uplink subframe with the time length as the guard period with respect to the terminal device; and informing the terminal device of the assignment.

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.

A wireless network with at least one base station and a plurality of associated terminals for the exchange of payload data and control data and at least one common transmission channel which is available for access to several terminals is described. The base station is configured to control access to the common transmission channel and the terminals are configured to send at least an access signal to the base station for the purpose of obtaining access to the common transmission channel. Different start moments and different preambles can be assigned to the terminals for transmitting their respective access signals.