What is the disadvantage of changing MIMO 2x2 from NO_ADAPTIVE to CL_ADAPTIVE with Initial ADAPTIVE?

Hello Cesar,

From OL to CL, there is a trade-off. OL gets better throughput in fast moving environment and CL gets better throughput in stable radio conditions.

For NO_ADAPTIVE, i did not see any comparison in Huawei docs. but i would guess since there is not TM change, it is not recommended. i.e. wasting resources when radio conditions are not appropriate.

In our network, we use CL for LTE-TDD and OL for LTE-FDD.

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Hello @Cesar_Nunes, @sendyramen.

In this paper you have some trial results for Throughput, Latency for LTE MIMO.

The goal was to verify the functionality and performance of LTE equipment in realistic deployment scenarios, with a combination of stationary tests and drive tests, and it focuses on Single User Throughput, Sector Throughput, Latency, and MIMO performance verification.

The conclusion is to use MIMO CL_Adaptive, because it consumes less RBs and get higher DL throughput.


Paper Conclusion: From the measurement results, we can conclude that the non adaptive modes consumes a lot of radio resources which causes throughput and coverage degradation, to optimize resource consumption, the adaptive mode is much favored, specifically, Closed-loop adaptive mode (CLAdaptive) consumes the minimum of radio blocs (5.55) in order to improve performance, and a throughput of more than 31 Mbit/s.

My question is: is this recommendation still valid?

When is it recommended to use: OC_Adaptive?

As from the paper:

The different DL antenna configuration discussed previously can be adjusted according to the channel conditions, traffic conditions, and mobile capability, we distinguish 2 MIMO modes:

Adaptive Mode:

  • OL_ADAPTIVE: dynamic switching between TxDiv (TM1) and SM-MIMO (TM2) based on Channel Quality Indication (CQI) and Rank Indication (RI) reports.*
  • CL_ADAPTIVE: dynamic switching between one codeword and two codeword based on Channel Quality Indication (CQI), Rank Indication (RI) reports and Precoding Matrix Indicator (PMI).*
  • OC_ADAPTIVE: Users could switch automatically between Open-loop and closed loop Adaptive Modes.*

Fixed Mode:

  • NO_ADAPTIVE: Only type of MIMO transmission is used, TM2, TM3, TM4 and TM6 could be configured on the system.*

Anyone implemented this trial with Mimo Adaptive switch to No_Adaptive and Fixed Mimo Mode set to TM4?


Yes brother… It has a very good outcome… But improvement will come mainly in urban area, where mobility is low… In high mobility TM3 is preferred

why TM-4 consumes alot of RB: 46.23?

That’s very strange, i am thinking same.

If the testing is done in moving them during handover no adaptive TM4 performance can be impacted.