Advantages of Digital Beamforming | disadvantages of Digital Beamforming
This page covers advantages and disadvantages of Digital Beamforming and its basics. It mentions benefits or advantages of Digital Beamforming and drawbacks or disadvantages of Digital Beamforming.
Introduction: The purpose of beamforming is to achieve better coverage due to provision of
amplitude/phase variation with the help of antenna array. Following are the three main types of beamforming
based on different architectures.
• Analog beamforming
• Digital beamforming
• Hybrid beamforming
What is Digital Beamforming?
In digital beamforming, amplitude/phase variation (i.e. wk) is applied to digital signal after ADC/DDC conversion at the transmit end. In the receiver, received signals are first passed from ADC converters and digital down converters before summation operation. In this architecture, all the operations such as precoding, multiplexing, signal weighting, phase shifting etc. occurs in the digital domain which has many benefits. It is used in frequency selective beamforming applications.
The figure-1 depicts digital beamforming block diagram.
s(t) = x(t) +j*y(t)
Where, s(t) -> complex baseband signal
x(t) -> i(t) i.e. real part (I)
y(t) ->-q(t) i.e. imaginary part (Q)
j = SQRT(-1)
➨Complex weights are being applied to baseband signals (s(t)) in digital beamforming.
Unlike analog beamforming, digital beamforming supports multiple RF chains proportional to antenna elements in use. Refer analog beamforming vs digital beamforming for more information.
Benefits or advantages of Digital Beamforming
Following are the benefits or advantages of Digital Beamforming:
➨It offers simplified architecture in which each antenna has a dedicated RF chain and depending on the desired system requirements, silicon processes can fabricate entire RF chain.
➨The architecture is most flexible in which number of beams from antenna is variable as mumber of elements making up a beam. The beams are all steerable and algorithms can synthesize a drive signal to get maximum of any beam characteristics.
➨It can provide high number of beams.
➨The number of beams can be changed dynamically with no change in the hardware.
➨Each beam benefits from the full array gain.
➨Due to performance and capability, it is widely used in sub-6 GHz bands.
Drawbacks or disadvantages of Digital Beamforming
Following are the drawbacks or disadvantages of Digital Beamforming:
➨This architecture increases digital chip content. This increases cost and power consumption. It consumes highest DC power.
➨It offers I/Q signal routing complexity.
➨It offers LO signal routing complexity.
➨It offers highest hardware complexity i.e. full RF chain per element or column in the array.
➨Hardware can not fit within the lattice at high frequencies (no 2D scan capability for planar arrays).