RRU comparison: 2T2R with MIMO2x2 vs 4T4R with MIMO2x2 feature

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21

As long as both RRUs have same power per port, channel bandwidths and bands, same carrier power configurations it won’t impact the DL coverage or PDSCH throughput in 2x2 MIMO (2 port RRU) vs 2x2 MIMO (4 port RRU) scenario.

So you first need to check max and configured power per port of other 4T4R RRU.

Now comes the UL coverage and that depends how other RRU is deployed like 4WRD is deployed with it (2T4R scenario)?

If 4WRD is deployed, there is gain of at least 3 dB in UL coverage and therefore PUSCH throughput will also increase compared to 2T2R.

UL SU-MIMO is not considered yet.

Normally 4T4R RRUs are deployed with 4x4 MIMO packages and scheduler determines dynamically the rank in UL and DL separately based on link adaptation.

So with RANK 4 you get the max throughput by using each antenna paths as separate data stream with normal coverage (cell center).

With Rank 1 you get the low or ‘best effort’ throughput with max coverage (cell edge) by using the antenna paths as diversity.

22

Some vendor makes a secret 2T2R differently. :grin:

23

It is subjective.

  1. How are you utilizing your antennas? Are you forming narrow beam towards the UEs or multiple sectoral wide beams?
  2. Do you prioritize to cover large cell radius or have more uniform coverage and fill the coverage holes?
  3. Coverage is mostly limited by UL also. For UL irrespective of DL TX Power, MIMO will give better gain.
24

Hi,
I suppose the answer is simple.
It depends on port configuration,
For example, 4t4r with 2t2r feature:
If instead of port A and B, configuring the port A and D will provide less cross talk issue .then it will improve throghput.

Although this is an idea and i didn’t test it.:grinning:

27

a simple understanding:

xTxR like a lane of road, xMIMO like the whole road

2T2R with 2MIMO, means the total 4 lanes are assembled into 2 roads
4T4R with 2MIMO, means the total 8 lanes are assembled into 2 roads

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