Beamforming

beam formingbeamformerAntenna beamformingbeam-formingbeams or nullsDigital beamformingspatial beamforming
Beamforming or spatial filtering is a signal processing technique used in sensor arrays for directional signal transmission or reception.wikipedia
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Sensor array

broad-band sensorsuniform linear array
Beamforming or spatial filtering is a signal processing technique used in sensor arrays for directional signal transmission or reception.
The process of time-shifting signals using a well selected set of delays for each channel of the sensor array so that the signal is added constructively is called beamforming.

Butler matrix

Conventional beamformers, such as the Butler matrix, use a fixed set of weightings and time-delays (or phasings) to combine the signals from the sensors in the array, primarily using only information about the location of the sensors in space and the wave directions of interest.
A Butler matrix is a beamforming network used to feed a phased array of antenna elements.

Window function

Hamming windowwindow functionswindowing
Different weighting patterns (e.g., Dolph-Chebyshev) can be used to achieve the desired sensitivity patterns.
Window functions are used in spectral analysis/modification/resynthesis, the design of finite impulse response filters, as well as beamforming and antenna design.

Sonar

ASDICvariable depth sonaractive sonar
It has found numerous applications in radar, sonar, seismology, wireless communications, radio astronomy, acoustics and biomedicine.
To measure the bearing, several hydrophones are used, and the set measures the relative arrival time to each, or with an array of hydrophones, by measuring the relative amplitude in beams formed through a process called beamforming.

Hydrophone

hydrophoneshydrophobicunderwater microphone
In passive sonar, and in reception in active sonar, the beamforming technique involves combining delayed signals from each hydrophone at slightly different times (the hydrophone closest to the target will be combined after the longest delay), so that every signal reaches the output at exactly the same time, making one loud signal, as if the signal came from a single, very sensitive hydrophone.
The array may be steered using a beamformer.

Precoding

limited feedback precodinglinear precoding
Precoding is a generalization of beamforming to support multi-stream (or multi-layer) transmission in multi-antenna wireless communications.

IEEE 802.11ac

802.11acacWi-Fi 5
An increasing number of consumer 802.11ac Wi-Fi devices with MIMO capability can support beamforming to boost data communication rates.

Adaptive beamformer

Adaptive antenna systemadaptive beamforming
As the name indicates, an adaptive beamformer is able to automatically adapt its response to different situations.
See Constructive interference, and Beamforming.

MIMO

multiple-input multiple-outputMultiple-input multiple-output communicationsmultiple-input and multiple-output
MIMO is fundamentally different from smart antenna techniques developed to enhance the performance of a single data signal, such as beamforming and diversity.

Synthetic-aperture radar

synthetic aperture radarSARsynthetic aperture
The pulses are transmitted and the echoes received using a single beam-forming antenna, with wavelengths of a meter down to several millimeters.

Phased array

phased array radarphased-arrayphased-array radar
With narrow-band systems the time delay is equivalent to a "phase shift", so in this case the array of antennas, each one shifted a slightly different amount, is called a phased array.

Three-dimensional beamforming

Three-dimensional beamforming (3DBF), full dimension MIMO or tilt angle adaptation is an interference coordination method in cellular networks which brings significant improvements in comparison with conventional 2D beamforming techniques.

Multibeam echosounder

multibeam sonarmulti-beam sonarSeaBeam
Unlike other sonars, multibeam systems use beamforming to extract directional information from the returning soundwaves, producing a swath of depth readings from a single ping.

UMTS

WCDMAW-CDMATD-SCDMA
Using the same carrier frequency for uplink and downlink also means that the channel condition is the same on both directions, and the base station can deduce the downlink channel information from uplink channel estimates, which is helpful to the application of beamforming techniques.

Multi-user MIMO

MU-MIMOAdvanced MIMO communicationsmulti-user
CO-MIMO improves the performance of a wireless network by introducing multiple antenna advantages, such as diversity, multiplexing and beamforming.

Beam steering

steerablesteerable radio beams
Many sonar systems, such as on torpedoes, are made up of arrays of up to 100 elements that must accomplish beam steering over a 100 degree field of view and work in both active and passive modes.

WSDMA

Wideband Space Division Multiple Access
WSDMA is a beamforming technique suitable for overlay on the latest air-interface protocols including WCDMA and OFDM.

Smart antenna

smart antennasIntelligent antennaantenna
Smart antennas (also known as adaptive array antennas, digital antenna arrays, multiple antennas and, recently, MIMO) are antenna arrays with smart signal processing algorithms used to identify spatial signal signatures such as the direction of arrival (DOA) of the signal, and use them to calculate beamforming vectors which are used to track and locate the antenna beam on the mobile/target.

Pencil (optics)

pencil beamnarrow beampencil
See Beamforming for further details.

Zero-forcing precoding

zero-forcingNull-steering beamformer
In particular, null-steering is a method of beamforming for narrowband signals where we want to have a simple way of compensating delays of receiving signals from a specific source at different elements of the antenna array.

Synthetic-aperture magnetometry

SAM is a nonlinear beamforming approach which can be thought of as a spatial filter.

Aperture synthesis

synthetic apertureaperture synthesis imaginginterferometric imaging