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I need to connect multiple ESP32 wifi clients to a single android phone, the android phone will be a wifi server,

I need to transfer 3Mbps of data from each ESP32 to the android phone simultaneously via wifi

I could not find a maximum number of ESP32 clients that can be connected to the server (android phone)

In general, I know the maximum no is anyway defined by the bandwidth usage as well.

How many ESP32 devices can connect and transfer data to an android phone same time?

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How many ESP32 WiFi devices can transfer data to an android phone same time?

... that's only limited by the number of devices that can be in the same IPv4 network that you put these devices in, and the number of WLAN devices your access point can deal with. So, something between 2⁷-2 to 2²⁴-2 devices.

I need to transfer 3Mbps of data from each ESP32

Aahh, different question!

So, the fastest standard supported by the ESP32 is IEEE802.11n, which, under ideal circumstances (point-to-point, 2 devices only) can do 150 Mbps raw data.

Including headers, non-ideal geometry, and the fact that multiple devices trying to access concurrently will greatly reduce that potential number of average transfer rate, you'd be happy if you still got 50 Mbps across, on average.

That'd be 18 devices streaming 3 Mbps. It's a bit optimistic, and assumes that you can always stream large chunks of data, so make sure there's enough buffering on each ESP32 device to allow for that!

Again, "being connected to the server" and "actively streaming 3Mbps, simultaneously" are two very different things.

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  • \$\begingroup\$ I did not understand - make sure there's enough buffering on each ESP32 device to allow for that!, also I am hoping to use socket to send data to the server, is it correct what I am trying to do? \$\endgroup\$
    – oppo
    Apr 3, 2020 at 11:30
  • \$\begingroup\$ To achieve a high average throughput, it is important that the data packets sent over WiFi are large. For large packets, you need to first have large amounts of data to send. That's what buffers are for. \$\endgroup\$ Apr 3, 2020 at 11:30
  • \$\begingroup\$ can you explain how did you do that rough calculation for 50Mbps, based on what theoretical data? \$\endgroup\$
    – oppo
    Apr 6, 2020 at 5:10
  • \$\begingroup\$ Mostly experience, but it's a reasonable number to get less than half of max rate throughput in a CS/CA system like Wifi when you're approaching saturation. \$\endgroup\$ Apr 6, 2020 at 6:48

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