问题
I'm developing an android app which is based on WiFi Direct technology(P2P), so I really need to know how many meters is the range of android WiFi direct performance.based on Android API Guides:
you can discover and connect to other devices when each device supports Wi-Fi P2P, then communicate over a speedy connection across distances much longer than a Bluetooth connection.
but knowing that is not enough for me. because of my aim I need numbers! I mean a range of distances in which Wi-Fi P2P works.
回答1:
Typical Wi-Fi devices extend their signal up to 100 meters. Source
However the biggest of horror of Wi-Fi is Line of Sight (LOS) which may drop your range dramatically.
That's because Wi-Fi signals at 2.4GHz or 5GHz frequencies. These are easily disrupted by interfering obstacles such as furniture, walls or even mirrors (whose metallic layer reflects the signal) or even water that absorbs the waves. If the app is to be used mostly outside, such obstacle count is supposedly greatly decreased.
Extra:
Wi-Fi signal strength is influenced by a factor called attenuation. Here's a Cool Table displaying the materials influence on the signal.
You might also want to keep in mind that Android Wi-Fi P2P (Wi-Fi direct) is available only since API 14 (4.0 ICS).
Though Samsung allowed using the Wi-Fi Direct ability to connect to devices since API 9 (2.3 Gingerbread).
Anyhow you might want to think if users are "there yet", to be using this standard.
I also liked this Video comparing Galaxy S3 and iPhone 5 connectivity to a GoPro Hero 3 Camera. The maximum range he reached was 100 yards (~90 meters) with perfect LOS.
EDIT:
Antenna-Theory a website dedicated completely to antenna's states that:
Wi-Fi Antenna Efficiencies for handheld mobile devices are typically on the order of -6 dB to -2 dB
While various online sources note that average laptop antenna efficiency is from -3dB to 3dB, which is not that much different from the cell phone.
You can't really figure out the actual numbers as it all really depends on the surroundings, the target's antenna and the users antenna.
Still phones tend to have lower range than that of the laptops and it's probably between 50-80 meters in clear sight.
Sorry but I can't provide more accurate information as i'm no physicist or a technician, and what you're asking for is pretty abstract :)
回答2:
This site says the range of WiFi-direct of phones is about 200 feet (~60 meters) while bluetooth has a range of 30 feet (~10 meters).
The official Wi-Fi direct site (see under the point "How far does a Wi-Fi Direct connection travel?") states that the maximum range of WiFi-direct is up to 200 meters (which is 656 feet), but I highly doubt that phones already achieve this range...
回答3:
"Wi-Fi Direct devices will operate at the same speeds or data rates and range as current Wi-Fi gear. This maximum of about 200 Mbps at 200 feet is much more than the 3 Mbps at 30 feet with Bluetooth. This means you can share and communicate much faster and farther with Wi-Fi Direct."
source: http://www.ciscopress.com/articles/article.asp?p=1620205&seqNum=2
回答4:
I've done my research on this in the past. Similarly with the other answers, I found that the maximum distance "The Wi-Fi Alliance" claims it to reach is 656 feet. I could be wrong, but I feel that it may be possible to connect both devices to an Apple AirPort device and extend it quite a bit.. Of course you can't expect all of your app purchasers to have one, but in the testing phases it may prove to be very useful.
来源：https://stackoverflow.com/questions/24586003/range-of-distances-in-which-wi-fi-direct-works