Analog Beamforming: Advantages and Disadvantages

This page covers the basics of analog beamforming, along with its advantages and disadvantages.

Introduction

The purpose of beamforming is to improve coverage by using an antenna array to control the amplitude and phase of signals. There are three main types of beamforming based on different architectures:

• Analog beamforming
• Digital beamforming
• Hybrid beamforming

What is Analog Beamforming?

In analog beamforming, the amplitude and phase variation is applied to the analog signal at the transmitter end. At the receiver, signals from different antennas are combined before Analog-to-Digital Conversion (ADC). It’s well-suited for frequency-flat beamforming applications.

Figure 1: Analog Beamforming Block Diagram

W_k = a_k _ e^jsin(θk) W_k = a_k _ cos(θk) + j * a_k sin(θk)

Where:

• W_k represents the complex weight for the k^th antenna in the array.
• a_k is the relative amplitude of the weight.
• θk is the phase shift of the weight.

Weights are applied to analog signals in analog beamforming.

Benefits or Advantages of Analog Beamforming

The following are the benefits or advantages of analog beamforming:

• Simple hardware implementation.
• Hardware can fit within the lattice at high frequencies (all silicon array only).
• Benefits from the full array gain.
• Offers the lowest system DC power.
• Best for coverage due to low power consumption and cost characteristics.

Drawbacks or Disadvantages of Analog Beamforming

The following are the drawbacks or disadvantages of analog beamforming:

• Only one data stream feeds the antenna elements. This limits the data rate and flexibility of the architecture.
• Not ideal for capacity and flexibility requirements, unlike digital beamforming.
• Cannot be used in frequency-selective beamforming applications, unlike digital beamforming.
• The number of beams are fixed in hardware.