iPhone 4 Brings Better Wi-Fi, Or Does It?
June 18, 2010
The iPhone 4 supposedly has an updated WiFi radio, which is advertised to add 802.11N support. However, some wireless aficionados quickly cried foul once they found out the details.
While known to many simply as "Wi-Fi," there is actually many different versions of this wireless connection standard. Wireless first began reaching wide adoption with what is called 802.11b, which operates at the same frequency as many home cordless phones, 2.4GHz. The data transfer speed on 802.11b was limited to 11Mb, so as more and more people started using it, interest got high for a newer and faster standard. Two competing standards shortly followed, 802.11a and 802.11g. Both offered similar speed and signal improvements, but while 802.11g continued to use the 2.4Ghz frequency, 802.11a operated at 5Ghz. This meant that for cards and access points to be backwards compatible, 802.11a devices would need two radios, while 802.11g would only need one. While the 5GHz range offered some benefits over 2.4GHz, 802.11a was never as widely adopted as 802.11g.
Recently, the 802.11n standard was adopted. It combines the "best of both worlds" in that it uses both the 2.4GHz and 5GHz frequencies. 802.11n also adds what they call "MIMO" which means you actually make multiple connections, instead of just one. These changes give 802.11 serious boosts in both speed and signal.
By now you're wondering, "what does this have to do with the iPhone 4?"
During the WWDC keynote, Steve Jobs announced 802.11n support on the new iPhone 4. He also showed the new antenna system, which uses part of the frame to boost signal strength. After the keynote, Apple's website was updated to include all the new iPhone 4 details. Of particular note was one detail about its wireless capabilities: "802.11b/g/n Wi-Fi (802.11n 2.4GHz only)." What this means technically, is that while the iPhone supports 802.11n, it only does so on one of the two available frequencies. While this does mean you will not see the same performance you get out of a desktop or laptop that supports both, you will still see improvements over 802.11b and g. Why doesn't it support 5GHz? Well, as mentioned previously, it would mean adding a second radio and sacrificing some degree of space and battery life. This has to be weighed against the possible performance gains on the particular device.
The iPhone is still relatively slow compared to modern desktop and laptops. Also, iPhone users are generally not transferring large files. Because of these factors, it is easy to see why Apple's engineers opted to drop the 5GHz radio.
So while the iPhone 4 may not be getting the full potential of 802.11n, the iPhone user will likely never notice the difference in a real world environment.
