Quantifying the Benefits of 64T64R Massive MIMO

Came across this study, which seems interesting: Data from the Sprint LTE TDD network, comparing performance side-by-side of 64T64R and 8T8R antenna systems.

From the results:

“We observed up to a 3.4x increase in downlink sector throughput and up to an 8.9x increase in the uplink sector throughput versus 8T8R (obviously the gain is substantially higher relative to 2T2R). Results varied based on the test conditions that we identified. Link budget tests revealed close to a triple-digit improvement in uplink data speeds.  Preliminary results for the downlink also showed strong gains. Future improvements in 64T64R are forthcoming based on likely vendor product roadmaps.”

7 thoughts on “Quantifying the Benefits of 64T64R Massive MIMO”

  1. Hi Emil, can you kindly elaborate upon the 8.9x UL throughput improvement compared to 8T8R. That sounds huge.

    1. If you can serve 8x more users with the same throughput as before, you will get an 8x improvement. In addition to that, the beamforming gain can ideally increase the SNR by 8x, but that will have a smaller impact on the throughput since it grows logarithmically with the SNR. But it is definitely a combination of serving multiple users and getting a better beamforming.

      1. Thanks for your reply. Though, I am trying to understand the difference in gains between Uplink & Downlink for the same setup. How can the UL throughput gains be 3 times the DL Tput gains, given that – beamforming gains & increase in served users applies to both?

        1. I don’t know the details of the measurement campaign, but I guess the 8T8R base station was using spatial multiplexing in the downlink but not in the uplink. In other words, they compare against a previous system with a better downlink implementation than uplink implementation.

  2. Sir, I am still confused between antenna elements, antenna port and antenna. And antenna port is same as channel rank? Please sir, would you clarify one more time?

    1. An antenna element is a physical unit that transmits and receive wireless signals over the air. An antenna port is a transceiver chain that generates signals that will be transmitted by antenna elements and processes the received signals obtained from antenna elements.

      The reason that one might want to separate between these things is that one antenna port often is connected to multiple antenna elements in practical implementations. Antenna elements are small and cheap, antenna ports are larger and more expensive. See Figure 4 in the following white paper for a case where 64 antenna elements are connected to different number of antenna ports: https://www.ericsson.com/en/reports-and-papers/white-papers/advanced-antenna-systems-for-5g-networks

      The word “antenna” might refer to any of these things. In academia, the words antenna is often synonymous with antenna port and antenna element since it is implicitly assumed that each antenna element is connected to one transceiver chain.

      1. Thank you very much sir.
        I am a M.TECH student from india, our professor recommended your book.
        Thank you for early reply and great video series on Multiple Antenna Communication.

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