The present disclosure relates to a 5G or pre-5G communication system for supporting a higher data transmission rate than a 4G communication system such as LTE. An embodiment of the present specification relates to an apparatus and a method for MIMO transmission and reception in a closed-loop beamforming system. A communication method of a base station, according to one embodiment of the present invention, may comprise the steps of: transmitting information for channel measurement to a terminal; receiving channel-related information from the terminal; transmitting a first symbol via at least two antennas; and transmitting a second symbol via the at least two antennas by applying different channel mapping rules to the second symbol in the at least two antennas. One embodiment of the present invention can improve overall performance without downward leveling by a symbol transmitted via an antenna having low average channel power.

A wireless communication system based on millimeter wave (mmWave) radio frequency (RF) repeaters includes a first communication device. The first communication device includes a digital signal processor configured to provide access to a first type of communication network to a plurality of communication systems that are communicatively coupled to the first communication device via a plurality of different type of wireless networks. A plurality of radio frequency (RF) signals corresponding to different communication protocols is obtained via the plurality of different type of wireless networks. The obtained plurality of RF signals corresponding to different communication protocols are merged into a mmWave RF signal of a specified frequency. The mmWave RF signal of the specified frequency is transmitted to a second communication device.

This invention presents methods comprising a BS with a plural of antennas capable of beamforming two or more spatial multiplexed streams with two or more antennas on UEs; using one or more of relays to project the capacity of the BS to cover one or more UEs; the BS estimating the uplink channel state information (CSI) between each antenna on the BS and each antenna on the one or more UEs using pilots transmitted from the UE antennas in the presence of the relays which amplifies and forwards the one or more pilots; and, the BS making use of the perseverance of the reciprocity of the over the air channel by the symmetry of the DL and UL paths of the relays to obtain the downlink CSI using the estimated uplink CSI that includes the effect of the relays.

The present inventive concept relates to a method for designing an optimal analog precoder for improving frequency spectrum efficiency in a millimeter wave-based multi-user massive MIMO-based hybrid beamforming system and a hybrid beamforming system applying the same, and more specifically, to a method for designing an optimal analog precoder using an approximation technique and an iterative optimization algorithm, and a hybrid beamforming system to which the same is applied.

The present disclosure discloses a signal sending method and device. The method includes: receiving, by a base station, an uplink pilot signal sent by authorized user equipment, and determining a direction vector parameter and a first channel fading parameter of a channel calculating, according to the direction vector parameter and the first channel fading parameter, a first signal beamformer parameter, determining a transmission area of an artificial noise signal according to the direction vector parameter, and calculating a second signal beamformer parameter; and processing a to-be-transmitted signal by using the first signal beamformer parameter and the second signal beamformer parameter, and transmitting the processed signal. In this way, in a non-target direction, energy leakage of the secrecy signal to the authorized user equipment is relatively small, and transmitted artificial noise signals are concentrated in an area with a relatively high secrecy signal leakage risk.

Systems and associated methods for reciprocity calibration of multiple-input multiple-output (MIMO) wireless communication are disclosed herein. In one embodiment, a method for reciprocity calibration of the MIMO system includes transmitting a pilot symbol by a transmitter (TX) of the reference antenna and receiving the pilot symbol by receivers (RXes) of antennas of a base station as r.sub.i,0 pilot symbols. (Index “i” denotes individual antenna “i” of the base station, and “0” denotes the reference antenna.) The method further includes transmitting the received pilot symbols by TXes of the antennas of the base station, receiving the pilot symbols transmitted by the antennas of the base station by the reference antenna as r.sub.0,i pilot symbols, and calculating non-reciprocity compensation factors as

[00001]$\frac{r_{i,0}}{r_{0,i}}.$

A transmitter supports beamforming function using a plurality of antenna elements. The transmitter includes a dither signal generator which, in operation, generates pseudo random sequence signals as dither signals for lower bits of digital signals, the pseudo random sequence signals being different from each other, the digital signals each corresponding to respective one of the plurality of antenna elements, and a plurality of digital-to-analog converters which, in operation, adds the dither signals generated by the dither signal generator to the lower bits of the digital signals, and converts only upper bits of addition results of the digital signals and the dither signals into analog signals.

A method and apparatus are disclosed for handling beamforming in a wireless communication system. In one embodiment, the method includes receiving a second signal indicating a number of beam sweeping from a cell, wherein there are multiple network nodes in the cell and at least two network nodes of the cell have different beamforming capabilities. The method also includes receiving a first signal from any network node of the cell at multiple time intervals based on the number of beam sweeping.

Briefly, in accordance with one or more embodiments, an apparatus of a user equipment (UE) comprises baseband circuitry including one or more processors to decode a secondary synchronization signal (SSS) or a beam reference signal (BRS) received from an evolved Node B (eNB) to select a Tier-1 sector for receiving downlink transmissions from the eNB, decode a downlink control channel message received from the eNB at one or more fixed time offsets after the UE decodes the SSS to obtain index information for the Tier-1 sector to identify the Tier-1 sector, and if the Tier-1 sector has changed initiate a random access procedure to select an updated Tier-1 sector, and generate an updated Tier-1 sector index message to report to the eNB.

It is provided a method performed by a beamformer device for channel sounding in a network including a beamformer device and at least one beamformee device. In each round of channel sounding, the beamformer device may send an announcement message including identification information of beamformee devices included in a list when the list is not empty and clearing the list, wherein the beamformee devices included in the list have moved a distance exceeding a threshold value.