Vodacom 4X4 MIMO and 4G+

[DeTector]

@cavedog Got me an S8 a couple of days ago and compared it to the A5 2017 I had and noticed something of interrest. On the A5 there was a spot close to where I work in Stellenbosch where I got 4G+ and that was with band 3 (10mhz) and band 38 (20mhz). With the S8 at the same spot I noticed that it connects to band 38 (20mhz) only but utilizes MIMO. It does not show 4G+ and that got me interrested. In Service Mode one of the lines shows MIMO mode and next to that it was indicating 2. So assuming it used 2x2 MIMO as I do not know how to check the exact MIMO mode used on the Service Menu that is effectively the same as 2CA on band 38 (20mhz) x2 is it not? Although technically it is then using 40mhz spectrum it does not show as 4G+. Your input and thoughts on this?

 

[cavedog]

I never got a notification of this thread. Anyways sorry for late reply. I too can't seem to figure out the mimo mode values in service mode. It does not make sense. Since the S8 has 4 antennas to support 4x4 mimo there are some physical limitations. 2ca or 3ca will drop the mimo mode because the antennas are used to connect to the other LTE frequencies. Once you get 4x4 mimo all 4 antennas is used to connect to the same tower and same frequencies multiple times as you know.

There is no guides of the values showed in the service mode and it's hard to figure it out so if you ever do figure it out then would be nice if you shared it with me.

Also when you see 4G+ on Vodacom and service mode shows B1+B38 it's Vodacom roaming on Rain. Vodacom does not own spectrum in 2600MHz.

 

[sajunky]

Since the S8 has 4 antennas to support 4x4 mimo there are some physical limitations. 2ca or 3ca will drop the mimo mode because the antennas are used to connect to the other LTE frequencies. Once you get 4x4 mimo all 4 antennas is used to connect to the same tower and same frequencies multiple times as you know.

Very likely it will drop MIMO, physical limitations are real, but I can't say as a rule. Four antennas are required for 4x4 MIMO, but single antenna can serve multiple frequency bands at the same time. It is a number of HF amps and demodulators per antenna that matters.