Beamforming (Simple Overview)

[Ali_Khalaf]

Massive MIMO,combines two main ideas: MU-MIMO and beamforming. This setup helps send stronger, more focused signals directly to each user instead of broadcasting signals in all directions, like previous networks did. This targeted signal delivery reduces interference and increases network capacity, so more people can get high-quality connections without slowing each other down.

Creating a Focused Beam

To achieve narrow, powerful beams, engineers rely on two main techniques:

• Antenna: Deploying many small antennas in an array allows them to work together, creating a more focused, direct signal path.
• Phase Shifting: Adjusting the timing (phase) of the signals from each antenna allows the beam direction to be precisely determined and prevents any interference with other users.

Steering the Beam for Moving Users!

When users move, we need to keep the beam aimed at them. This is done by changing the signal timing (called phase shifts) and adjusting strength for each antenna. This keeps the beam narrow and accurately pointed, even if the user moves around.

Three Types of Beamforming:

Beamforming uses various methods, each suited to specific use cases, and the primary choice for 5G is hybrid beamforming.

1. Analog Beamforming:
   Analog beamforming uses one RF chain to create a single, strong beam of signals. This RF chain includes the transmitter/receiver (TRX), DAC,PA, which are all essential for transmitting signals effectively. This method is great for short distances but can only focus on one user or area at a time.

2. Digital Beamforming:
   on the other hand, gives each antenna its own RF chain. This allows the system to create multiple beams at the same time, serving many users simultaneously. This flexibility makes it excellent for dense environments, but it comes with higher power consumption and costs due to the need for more hardware

3. Hybrid Beamforming:
   combines the strengths of both analog and digital beamforming. It uses a mix of analog techniques for directing signals but also incorporates digital processing, allowing for multiple beams to be formed with fewer RF chains than a fully digital system. This makes it efficient and well-suited for high-density areas, like urban environments, where many users need coverage

Why Beamforming and Massive MIMO Matter?

By focusing signals directly at each user, massive MIMO with beamforming allows 5G networks to connect more people with faster speeds. When combined with spatial multiplexing (reusing the same frequencies for different users), 5G achieves much higher data capacity. With high-frequency waves (like mmWave), 5G can handle even more data in busy areas, bringing faster speeds and smoother connections

Beamforming

Beamforming

Beamforming Gain

3D Beamforming (FD MIMO)

Beamforming & MIMO Trade-Offs

Beamforming - How to Steer Beams?

Beamforming Type - Analog

Beamforming Type - Digital

Beamforming Type - Hybrid

Beamforming - Benefits and Limitations

That’s it

LinkedIn:

Alali Khalaf on LinkedIn: #massivemimo #beamforming

[Londynan]

re 5) 4x4 MIMO. The way you describe it is done on analog beamforming. In digital beamforming (i.e. most FR1 MaMIMO panels) you are not dividing antenna elements into sub groups like that, instead you transmit all signals on all antennas (so you don’t lose antenna gain) and signals are multiplexed via precoding.

[Ali_Khalaf]

Hello
Wondering What the meaning of Sub-array ?
I mentioned that 8 antenna elements in one group
And if you go to the post in LinkedIn you will see a good discussion …

[Londynan]

Sub-array is group of antenna elements, they are combined together to transmit a single radio signal. They can be combined in a fixed manner (like 2-3 antenna elements wired together) or via configuration (typical for different CSI-RS [GoB] patterns). Effectively, number of your subarrays in a plane determines angular scanning range of an antenna array in that plane.
I don’t see where you have mentioned 8 antenna elements in one group.

[Ali_Khalaf]

I meant antenna elements the Dipoles, not the antenna in general…
Beamforming Only (Single Beam) as the first one
When using just one beam (pure beamforming) with a 64T64R antenna, the energy is focused strongly in one direction. This provides high coverage and signal quality for that single user, but there’s no MIMO happening.
4x4 MIMO with 64T64R the third one
If you switch to 4x4 MIMO, you can support up to 16 users. Each user gets 4 antenna elements dipoles assigned to them.However, the directivity of each beam is less sharp because each beam only has 4 elements instead of 64. This reduces the range and coverage per user, but allows you to serve more users simultaneously with MIMO… check the next post on LinkedIn you will see the Sub array overview…

[Londynan]

“If you switch to 4x4 MIMO, you can support up to 16 users. Each user gets 4 antenna elements dipoles assigned to them.However, the directivity of each beam is less sharp because each beam only has 4 elements instead of 64” - that’s not how multi-layer digital beamforming is done (but I have already said that in my first comment). We are in disagreement, but that’s ok

[python_OHSR]

Thank you so much!