BEAMFORMING: EXPLAINED
What is beamforming, and how does it work?
While beamforming is not a necessarily new concept, the idea, which originated as early as 1905, has seen an uptake since the inception of Wi-Fi and 5G technologies.
Beamforming is a radio frequency technique that helps optimize signal strength and minimize interference by targeting wireless signals towards a specific endpoint or receiving device using an array of sensors and antennas.
As opposed to a broadcast antenna that broadcasts a wireless signal in all directions, beamforming concentrates the wireless signal towards a single target, like a phone or laptop. This helps in achieving quicker data rates and less interference and signal dispersion as opposed to a direct connection that does not employ beamforming technology.
Additionally, more than one antenna can be used to direct the signal to the receiving device. In a regular scenario, a single antenna can broadcast signals omni-directionally. When multiple antennas close to one another are used, beamforming is employed.
Beam steering develops the concept of beam formation, where signals from radiating elements are phased differently, and this phase shifting enables the signal to be directed at a particular receiver.
In the case of a cellular network like 5G, the network can direct different frequency beams in different directions to cater to multiple users. The base station can track the mobile user by dynamically calculating the direction of a signal as the device moves. The endpoint may even change to another beam if the initial beam is unable to follow and track the device.
Beamforming superimposes two beams and directs them in a specific direction, offering a higher signal quality to the receiving antenna. This is also done without increasing transmitting power, which helps in achieving quicker transfer rates and fewer errors.
Adjacent users may also realize less interference when attempting to pick up and use other signals because beamforming stops or cuts down transmission from unintended directions.
A powerful and tightly directed signal can be realized when beamforming is correctly done. But when it’s not, heavy interference and loss of signals can be the end result.
When a beamforming tower, router, or access point sends out RF signals, throughput, fewer interferences, and improved signals can be realized if the receiving device points in the direction of the transmitting router.
If the end devices support beamforming, the need to be in the path of the beam from the transmitter is no longer necessary.
Before delivering data, a beamforming transmitter, including routers and access points, gathers information regarding transmission paths. This information can include the receiving terminal’s location, distance, speed, noise level, and other QoS parameters. They use these parameters to modify and concentrate the signals in specific directions to achieve greater distance and faster data transfer rates. This also helps in lessening the chances of collisions.
Beamforming techniques
- Analog beamforming
Analog beamforming uses phase shifting to send the same signal from multiple antennas, where the transmitted signal is set to different phases, creating an antenna pattern that points in a specific direction.
- Digital beamforming
In this technique, there are diffident signals for each antenna in a digital baseband, and different phases are applied to different frequency bands, enabling digital beamforming to be more flexible. Numerous independent beams can then be steered in any direction by a digital beamforming processor, a method that is particularly useful for spatial multiplexing.
- Hybrid beamforming
Hybrid beamforming, as the name implies, combines both analog and digital beamforming techniques. 5G base stations typically employ hybrid beamforming. In this case, analog beamforming is used alongside digital precoding, which is used to support multi-stream transmission, to form the patterns transmitted from an antenna array.
- Massive MIMO
Massive MIMO (multiple input, multiple output) is a wireless networking antenna technology where multiple antennas are used at both the transmitting and receiving ends. Massive MIMO uses a common frequency that is steered in multiple directions and requires digital signal processors.
The different times of arrival for the signals create multiple time division multiplexing channels, which provide path redundancy.
Massive MIMO is especially common in Wi-Fi and 5G.
- Beam steering
Beam steering changes the phase of input signals on each radiating antenna element. In this method, an endpoint is tracked and a signal is steered towards it, while different signals can also be sent to other devices.
Benefits of beamforming
- Since signals are only beamed in intended directions, signal interference between devices is minimized or avoided altogether.
- Analog beamforming has low power requirements and is thus relatively simple to implement.
- faster data transfer rates and fewer errors on received data
- In cellular communication, higher signal quality reaches the receiving device, increasing the coverage capacity of the cell tower due to signal concentration.
Limitations of Beamforming
- Beamforming technology costs more than traditional systems
- Apart from the cost of more antennas and hardware required for beamforming systems such as MIMO, the setup can become complex and resource-intensive.
- Beamforming calculations may require more computing resources and power
Beamforming in 5G
- 5G technology is plagued by obstacles such as interference and range limitations, and beamforming can be used to overcome or mitigate such weaknesses. When a signal is focused towards a receiving mobile device or endpoint, interference between individual beams is minimized.
Massive MIMO uses multiple antenna arrays and spatial multiplexing to transmit multiple independent signals.
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Implementing beamforming, particularly on a large scale, can be prohibitively expensive due to the complex hardware and components required, such as antennas, transceivers for each antenna, and computing power necessary to process the complex algorithms.
If the components are not carefully considered and put together, the performance will be adversely affected.
Even consumer-grade products such as routers and access points are currently prohibitively expensive enough to warrant adoption on a small scale.
