What is the fastest way to transfer huge files beween two android powered devices?

Question

What is the fastest way to transfer huge files (e.g. 500MB) between two android powered devices? Bluetooth? WiFi direct? Beam? or maybe USB on-the-go?

Answer 1

There are many variables that affect the performance of each method you've mentioned.

Additionally there's also the necessary configuration and requirements that each device must have in order to have solutions like this working.

As requested, lets summarize and compare possible performances between USB; Wi-Fi and Bluetooth:

USB:

USB performance can be extremely low or very high, depending on the available USB version, which in turn, combined with the SDcard reading/writing speed on each device allows us to accurately measure and ascertain the transfer speed.

There's also the physical limitation of the USB cable length that for some scenarios becomes a limitation.

USB 1.0: 1.5 Mbit/s (Low-Bandwidth) and 12 Mbit/s (Full-Bandwidth)

USB 2.0: 480 Mbit/s (effective throughput up to 35 MB/s)

USB 3.0: 5 Gbit/s (625 MB/s) which is more than 10 times as fast as USB 2

Wi-Fi

Wi-Fi looses limitations like cable length, but then again we need to account for the 802.11 protocol being used, the signal strength and range to accurately measure results:

┌────────────┬─────────────────────────────────┬──────────────────────────┐
│  Protocol  │  Data rate per stream (Mbit/s)  │  Approximate range (m)   │
│            |                                 ├────────────┬─────────────┤
│            |  Bandwidth of 20 MHz            |   indoor   |   outdoor   │
├────────────┼─────────────────────────────────┼────────────┼─────────────┤
│  802.11a   │  6, 9, 12, 18, 24, 36, 48, 54   │     35     │     120     │
├────────────┼─────────────────────────────────┼────────────┼─────────────┤
│  802.11b   │  1, 2, 5.5, 11                  │     35     │     140     │
├────────────┼─────────────────────────────────┼────────────┼─────────────┤
│  802.11g   │  6, 9, 12, 18, 24, 36, 48, 54   │     38     │     140     │
├────────────┼─────────────────────────────────┼────────────┼─────────────┤
│  802.11n   │  7.2, 14.4, 21.7, 28.9, 43.3,   │     70     │     250     │
│            │  57.8, 65, 72.2,                │            │             │
│            │                                 │            │             │
│            │  With Bandwidth of 40 MHz:      │            │             │
│            │  15, 30, 45, 60, 90, 120,       │            │             │
│            │  135, 150                       │            │             │
└────────────┴─────────────────────────────────┴────────────┴─────────────┘

More about Wi-Fi protocols from Wikipedia.

Bluetooth

While we need to ascertain several influencing factors to determine if Wi-Fi is faster than USB, Bluetooth is with no doubt in last place wen we speak about transfer speed. Designed as a proprietary open wireless technology standard for exchanging data over short distances, the maximum speeds are bellow the two concurrent options:

┌─────────────┬─────────────┬─────────────────────────────────────────┐
│   Version   │  Data rate  │  Maximum application throughput         │
├─────────────┼─────────────┼─────────────────────────────────────────┤
│  1.2        │  1 Mbit/s   │      0.7 Mbit/s                         │
├─────────────┼─────────────┼─────────────────────────────────────────┤
│  2.0 + EDR  │  3 Mbit/s   │      2.1 Mbit/s                         │
├─────────────┼─────────────┴─────────────────────────────────────────┤
│  3.0 + HS   │                                                       │
├─────────────┤  theoretical data transfer speeds of up to 24 Mbit/s  │
│  4.0        │                                                       │
└─────────────┴───────────────────────────────────────────────────────┘

More about Bluetooth from Wikipedia.

---

Summary

Based on the specifications for each method and their respective version, my classification ordered by fastest-to-lowest would be:

1. USB ^{assuming version 2.0, since 1.0 is way slow and outdated}
2. Wi-Fi
3. Bluetooth

Answer 2

If your android devices have removable SD card slot, the fastest way to transfer big files is to physically move the SD card from one device to another.