Advantages of Beamforming | Disadvantages of Beamforming
This page covers advantages and disadvantages of beamforming techniques. It mentions beamforming advantages or benefits and beamforming disadvantages or drawbacks. It provides links on different types of beamforming techniques.
What is Beamforming?
The formation of beam in the desired direction with appropriate power is known as beamforming. Beamforming employs facility to vary power of the beams and their directions with the help of amplitude/phase variations. Antenna arrays are used instead of single antenna in beamforming system in modern wireless systems. Earlier days, mechanical rotation based mechanism was employed for steering the antenna or antenna array and separate mechanism for power amplication of beams (i.e. antenna patterns) was used.
Following are the types of beamforming techniques.
• Analog Beamforming: In this type, precoding is applied to analog signal after DAC and before transmission over the air.
• Digital Beamforming: In this type, precoding is applied to digital signal or baseband signal before DAC. After the DAC the beamformed signal is transmitted over the air after RF conversion.
• Hybrid Beamforming: It utilizes benefits of both analog and digital beamforming types. Here precoding is applied in both analog domain and digital domain at radio frequencies (RF) and baseband frequencies respectively.
Beamforming equations used in analog type:
Wk= ak *ejsin(θk)
Wk= ak*cos(θk) + j* ak sin(θk)
Wk represents complex weight for kth antenna in the array.
ak is relative amplitude of weight.
θk is phase shift of weight.
➨Weights are being applied to analog signals in analog beamforming.
Refer Analog beamforming vs Digital beamforming>> and Hybrid Beamforming basics and types>>.
Benefits or advantages of Beamforming
Following are the benefits or advantages of Beamforming:
➨It boosts the power of beams in the desired direction and hence farthest subscribers can also be reached by telecom cell towers or base stations. This increases supporting capacity of a cellular tower in terms of number of subscribers.
➨It can also reduce the power of the beam for nearby subscribers and hence interference issues near to the cell towers can be avoided.
➨As mentioned it increases C/N ratio of the signal and hence the signal can withstand against noisy and attenuating channel environment. This increases coverage capacity of the cell tower or base station.
➨It is widely used with MIMO in latest wireless technologies viz. Mobile WiMAX (IEEE 802.16e), LTE, LTE-Advanced, 5G etc. due to its immunity against fading and interference.
Drawbacks or disadvantages of Beamforming
Following are the disadvantages of Beamforming:
➨Hardware complexity is higher due to use of multiple antennas and other hardware systems.
➨The beamforming system requires use of advanced high processing DSP chip due to use of mathemical algorithms in the design.
➨Due to increased hardware resources and use of advanced DSP chip, cost of beamforming system is higher compare to non-beamforming system.
➨Power requirement in beamforming system is higher due to use of more resources. Hence battery in beamforming system drains faster.