A base station may determine a Doppler metric associated with a wireless channel and a user equipment (UE). The Doppler metric may be determined from received information related to Doppler effects measured by the UE or from directly measured Doppler effects associated with uplink data received from the UE. Based on the determined Doppler metric, the base station may select one or both of a reference signal (RS) density and a channel estimation technique for the wireless channel and associated UE. The base station may transmit an indication of the RS density to the UE. Downlink data bursts and uplink data bursts may include RSs and data according to the indicated RS density. Further, the base station may transmit to the UE, an indication to communicate using the selected wireless channel estimation technique.

Disclosed are a signal transmission method and a base station, the method: generating a PCRS used in order to remove phase noise from a downlink signal; mapping the PCRS at predetermined intervals on a region, in which a data channel is mapped, in a downlink resource region; and transmitting the PCRS to a terminal.

Provided are a vehicle-to-everything (V2X) signal transmission method performed by a terminal in a wireless communication system and an apparatus using the same. The method comprises: determining a symbol for transmitting a specific signal related to V2X communication; and transmitting the specific signal in the determined symbol, wherein the determined symbol is determined from among symbols other than symbols overlapping with a power transient period between a transmission power-on state and a transmission power-off state.

Embodiments described herein provide a system for transmitting high efficiency long term training field (HE-LTF) symbols for multiple wireless spatial streams over a wireless channel. An advanced P-matrix design is used to construct HE-LTF symbols that are processed by a receiver such that channel properties such as channel estimates or carrier phase error are determined prior to receiving all HE-LTF symbols. Tone multiplexing of wireless spatial stream is also used to transmit multiple spatial streams based on an assignment of sets of spatial streams to sets of tones available for transmission, increasing the throughput of the transmission system. The advanced P-matrix design and tone multiplexing are used in combination to achieve calculate channel properties before receiving all HE-LTF symbols while minimizing power fluctuation among the high efficiency short training field symbol and the HE-LTF symbols.

Disclosed are a signal transmission method and a base station, the method: generating a PCRS used in order to remove phase noise from a downlink signal; mapping the PCRS at predetermined intervals on a region, in which a data channel is mapped, in a downlink resource region; and transmitting the PCRS to a terminal.

A channel estimation method and circuit. The channel estimation method, adapted for a receiving device of a multi-input multi-output wireless LAN system, comprises the following steps. Firstly, performing a first channel estimation operation on a long training field to obtain a plurality of first composite channel estimation values related to the long training field. Then, performing a second channel estimation operation on a signal field to obtain a plurality of second composite channel estimation values related to the signal field, and performing a third channel estimation operation on a data segment to obtain a plurality of first channel estimation values related to the data segment. Next, obtaining a plurality of second channel estimation values according to the first composite channel estimation values and the second composite channel estimation values, and adjusting the first channel estimation values related to the data segment according to the second channel estimation values.

A channel measurement method in a wireless communication system and an apparatus therefor are disclosed. Specifically, a method for measuring a channel by a terminal in the wireless communication system may comprise the steps of: receiving, from a base station, a reference signal on part of antenna ports within a two-dimensional antenna port array; measuring channels for the part of antenna ports on the basis of the reference signal received from the base station; and reconstructing a channel for an antenna port which is not used for transmission of the reference signal within the two-dimensional antenna port array, using the channel measurement result, to reconstruct channels for all antenna ports within the two-dimensional antenna port array.

The present invention relates to an apparatus and method for transmitting through an adaptive channel using a channel state. According to one embodiment of the present invention, a method for a remote node to transmit through a channel includes the steps of: intermittently receiving a forward channel signal transmitted from a host node; estimating a reverse channel state on the basis of the received forward channel signal; and determining whether or not the estimated reverse channel state satisfies preset channel conditions, and adaptively transmitting a reverse channel signal according to the determined result.

What is disclosed is a method for wireless communication comprising receiving a wireless communication via a receiver of the mobile communication device, deriving a demodulation reference signal from a first plurality of symbols of the wireless communication; creating a channel estimation matrix using the demodulation reference signal; inverting the channel estimation matrix to obtain a channel pseudo-inverse matrix; deriving a tracking reference signal from a second plurality of symbols of the wireless communication; calculating a phase shift for one or more additional symbols based on the tracking reference signal; determining a corrected channel pseudo-inverse matrix for the one or more additional symbols by adjusting the channel pseudo-inverse matrix according to the calculated phase shift; and controlling the receiver to accomplish data detection using the corrected channel pseudo-inverse matrix on one or more orthogonal frequency division multiplexing subcarriers.

A method for a user equipment (UE) to receive physical downlink control channels (PDCCHs) is provided. The UE receives configuration information for a first control resource set that includes a number of symbols in a time domain and a number of resource blocks (RBs) in a frequency domain, configuration information indicating a first number of N.sub.bundle,1 frequency-contiguous RB s, and a PDCCH in the first control resource set in a number of frequency distributed blocks of N.sub.bundle,1 RBs. The UE assumes that a demodulation reference signal associated with the reception of the PDCCH has a same precoding over the N.sub.bundle,1 RBs. A method for constructing a search space to reduce a number of channel estimations that the UE performs for decoding PDCCHs, relative to conventional search spaces, is also provided.