How to change Hybrid beamforming to digital in 'Massive MIMO Hybrid Beamforming' example

Hi, currently, I'm working on my thesis project for Multi-user communication. I'm using Massive MIMO Hybrid Beamforming example as a basis for my model. I would like to use digital beamforming instead of hybrid. Could you please tell me how can I acheive this?

Answer 1

[Vaibhav]

Hi Gopika

You can consider following the below key steps for transitioning to digital beamforming.

1. Review Hardware and Computational Needs: Account for increased complexity and cost due to one RF chain per antenna element.
2. Update System Model: Incorporate an RF chain for each antenna in the model and apply beamforming in the digital domain.
3. Implement Digital Beamforming Algorithms: Use algorithms like Zero Forcing or MMSE for weight calculation based on accurate CSI.
4. Adapt User Multiplexing Strategies: Leverage digital beamforming to support sophisticated user multiplexing.
5. Perform Simulation and Analysis: Focus on throughput, spectral efficiency, energy efficiency, and compare with hybrid beamforming.
6. Consider Practical Aspects: Analyze power consumption and hardware limitations.

You can refer to the below documentation shared on file exchange to get you started.

https://www.mathworks.com/matlabcentral/fileexchange/13864-digital-beamforming?s_tid=srchtitle_support_results_3_digital%2520beamforming

You can also refer to below official mathworks documentation to know more about Massive MIMO Hybrid Beamforming.

https://www.mathworks.com/help/phased/ug/massive-mimo-hybrid-beamforming.html

https://www.mathworks.com/help/phased/ug/introduction-to-hybrid-beamforming.html

Hope this helps you in getting started.

Answer 2

[Deepu]

To change the hybrid beamforming to digital beamforming in the Massive MIMO Hybrid Beamforming example in MATLAB, you would need to modify the beamforming algorithms and architecture. Here are the general steps you can follow:

1. Understand Hybrid Beamforming: Make sure you understand the difference between hybrid and digital beamforming. In hybrid beamforming, both analog and digital beamforming are used, while digital beamforming solely relies on digital processing.
2. Remove Analog Beamforming: In hybrid beamforming, analog beamforming is performed before digital beamforming. Remove the analog beamforming components from the system. This includes analog precoding/combining and analog beamforming matrix computation.
3. Modify Digital Beamforming: Enhance the digital beamforming part to compensate for the removed analog beamforming. This includes digital precoding/combining, digital beamforming matrix computation, and any other digital signal processing required.
4. Adjust Algorithms: Modify the beamforming algorithms to accommodate the changes made. Ensure that the system still meets your performance requirements.
5. Test and Validate: Test the modified system thoroughly to ensure that it behaves as expected. Validate its performance compared to the hybrid beamforming system and against your project requirements.
6. Documentation: Document the changes made to the system for future reference and reproducibility.

Without access to the specific code of the Massive MIMO Hybrid Beamforming example, I cannot provide specific code modifications. However, you would typically need to delve into the code related to beamforming, precoding, combining, and signal processing to make the necessary changes.