Contents
What is null steering beamforming?
We propose a null steering beamforming algorithm allowing us to suppress the interference based on the genetic algorithm (GA). The method used to calculate the position perturbations of selected elements is based on minimization of the power at the null locations and the power fluctuation in the main beam.
Does beamforming prevent interference?
Recently, beamforming techniques have been introduced to reduce the interference by redirecting the transmission towards the desired users only. While such beamforming enables better interference mitigation and improved network performance, the concerns on its effectiveness in dense deployment environments are arising.
What is null steering?
Zero-forcing (or null-steering) precoding is a method of spatial signal processing by which a multiple antenna transmitter can null the multiuser interference in a multi-user MIMO wireless communication system.
What is beamforming in wireless communication?
Beamforming is a technique that focuses a wireless signal towards a specific receiving device, rather than having the signal spread in all directions from a broadcast antenna, as it normally would. The resulting more direct connection is faster and more reliable than it would be without beamforming.
What is the main idea of beamforming?
In applications of beamforming in communications systems, the basic idea is to optimally process signals received over different antennas, or the signals which are to be transmitted over different paths, by adjusting the signal amplitudes and phases, to form a strong beam toward the direction of interest, and at the …
What is zero forced receiver?
Zero Forcing Equalizer refers to a form of linear equalization algorithm used in communication systems which applies the inverse of the frequency response of the channel. The Zero-Forcing Equalizer applies the inverse of the channel frequency response to the received signal, to restore the signal after the channel.
Why is precoding used?
Precoding is a technique that exploits transmit diversity by weighting the information stream, i.e. the transmitter sends the coded information to the receiver to achieve pre-knowledge of the channel. The receiver is a simple detector, such as a matched filter, and does not have to know the channel state information.
What is the benefit of beamforming?
Beamforming improves the spectral efficiency by providing a better signal-to-noise ratio (SNR). Working with other antenna technologies such as smart antennas and MIMO, beamforming boosts cell range and capacity. That means mobile device users get stronger, clearer signals.
How does a nuller work in adaptive beamforming?
An adaptive nuller places spatial nulls in the direction of greatest power but does not constrain the weights to create spatial gain in any particular direction. Because our SOI is below the noise floor, the nuller can’t sense it and won’t intentionally attenuate the SOI signal.
How to suppress interference in adaptive beamforming Part 1?
Part 1 of this adaptive beamforming tutorial explains how to suppress the interference and lays the foundation to steer gain to specific locations. Let’s talk about good old sine waves for a moment. Sine waves are represented by the equation where is the amplitude, is the frequency in radians, is time, and is the phase.
Why does a nuller try to suppress the signal?
If the signal is above the noise floor and is detectable by the nuller, the nuller will treat the SOI as interference and try to suppress the signal. Because nullers do not constrain gain in any particular direction, it is possible that the nuller will place a sympathetic null in the direction of the SOI.
Is the covariance matrix in adaptive beamforming the same?
Some adaptive beamforming tutorials will call a covariance matrix. Do not be fooled, this is a spatial correlation matrix. Those tutorials and papers that claim to be a covariance matrix typically assume the received signal is zero mean, in which case the correlation matrix and the covariance matrix are the same.