Low-complexity user selection for rate maximization in MIMO broadcast channels with downlink beamforming

Area of Science:

• Wireless communication
• Signal processing
• Information theory

Background:

• Multiuser MIMO broadcast channels present challenges in optimizing sum rate due to complex user selection and resource allocation.
• Existing algorithms often struggle with computational complexity and efficiency in forming user groups.

Purpose of the Study:

• To develop a low-complexity algorithm for sum rate maximization in multiuser MIMO broadcast channels.
• To decouple user selection from resource allocation by creating quasiorthogonal user groups.
• To efficiently approximate null space projection power using physical channel metrics.

Main Methods:

• The algorithm decouples user selection from resource allocation.
• It exploits easily computable physical channel metrics to approximate null space projection power.
• User selection dynamics are modeled as an integer linear program.

Main Results:

• The proposed algorithm efficiently forms groups of quasiorthogonal users.
• It demonstrates high efficiency compared to existing literature algorithms.
• Achieves approximately 90% of the optimum user selection sum rate for a moderate number of users.

Conclusions:

• The developed algorithm offers a computationally efficient solution for sum rate maximization in multiuser MIMO broadcast channels.
• It provides a practical approach to user selection, significantly improving system performance.
• The method is effective in achieving a substantial portion of the theoretical maximum sum rate.