Xperia Z5 slow wifi downlink on 2.4 Ghz

[tiholov]

Hi,

I have Xperia Z5 (E6653) with SW ver. 32.2.A.5.11. From few weeks I found very slow wifi downlink on 2.4  Ghz, uplink is ok, also uplink and downlink on 5Ghz are ok. No issues with some laptops, tablets and smart phones connected on the same network. I tried to change AP configuration, but wihout any success. Used four different APs and the result is always similar downlink 3-4 mbps and 30 mbps uplink which is maximum from my ISP. I done some factoty resets.The signal is -48 dBm and sometimes downlink is less than1mbps. When I'm very close to AP the phone reaches about 50 mbps. I have a colleague with the same device/ same SW and on the speed test at the office her results are always higher with 10-20 mbps on downlink than mine.

Test scenarios:

- different wifi chanels on 20 Mhz

- different channel combinations on 40 Mhz.

- different AP locations 

Do you know why the phone is not able to use both channels on 2.4 Ghz N300 and connection speed is always 144 instead 300 mbps?

Are there different HW ver. of Z5 due to different results with my colleague or my phone is just fauty and need to visit the service😀

Thank you in advance for any suggestions

[NeoBeum]

I think 2.4GHz  defaults to N and 5GHz defaults to AC for the Xperias because of the SISO and MIMO limitations

[tiholov]

Hi again,

The main board has been replaced, but nothing changes. Same bad experience slow downlink on Wi-Fi 2.4 GHz and no problem with uplink and 5 GHz. Obviously the problem was not on the mainboard or the new one has the same problem.

Do you have any suggestions or I have to bring the device back to the service