Following a previous good post of Ahmad Dawara on number of layers vs. SINR in mobilenetworks, this document, being part of the major MCNS training portfolio (https://mcns5g.com/), is the second part of MCNS posts in LTE MIMO technology, providing more insight on the 3GPP standards related to LTE MIMO Transmission Mode 7 and Transmission schemes of beamforming and TM3.
In 5g nsa lte deployment is quite mature mostly on low frequencies (f< 2 GHz) to expand the coverage.
Mobile operators are lately implementing the LTE antenna technology using 8T8R antenna modules for enhanced capacity (throughput) expansion due to multi-layer multiplexing as well as coverage enhancements due to beamforming capabilities.
In low SINR conditions LTE TM7 is generally more robust than TM2 since it can adapt to lower SINR conditions by utilizing advanced MIMO techniques, spatial diversity, and beamforming to improve signal quality and maintain communication reliability.
Moreover TM3 and TM4 are designed for use in MIMO (Multiple Input Multiple Output) systems and can be considered an enhanced version of TM2 since they supports open and closed-loop spatial multiplexing respectively, which involves the use of feedback from the receiver to adaptively adjust transmission parameters for better performance in good SINR.
On the other hand TM3, being more focused on open-loop spatial multiplexing, may struggle in low SINR conditions as it heavily relies on the quality of the received signal.
This is why vendors (i.e. Ericsson) implements LTE TM7 feature with variable functionality based on SINR. For more useful and insightful details on MIMO technology and antenna beams please refer also to Emil Björnson excellent presentations at KTH Royal Institute of Technology.
For more technical details you are mostly invited to the MCNS MIMO training courses (i.e. https://lnkd.in/dnNWYcHx)
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