Tuesday, July 06, 2010

iPhone 4 mixed signals

You can't have escaped the hooha about the iPhone 4 and the antenna design / now apparent oversight of apple on every iPhone ever regarding the algorithm used to calculate RSSI (received signal strength indication). I worked in mobile phone comms until 3 years ago when I moved into doing work with tetra radios.

The way the story has been covered has been your typical bad science reporting, with this morning's BBC slot by some fellow from "click" explaining the problem.

Much as I love apple's products, the last 10 years of consumer electronics have persuaded me of one thing; resist the urge and don't be an early adopter. The iPhone 3GS I've got was around for quite a while before I got hold of it, and even then I only went for it because it finally offered the features I'd been enjoying in phones for many years. Kudos to apple for not rushing features out btw, which is one reason why this 3GS is a joy to use.

I've done a lot of apple defending in the past, but the iPhone 4 appears to have been something of a cockup. The antenna design is, I think, a good basic idea - internal antennas are a compromise and will never get as good a signal as a proper or stub antenna. Apple locating the surface of the signal receiver around the edge is a good idea, but the co-locating of the wifi antenna and the close proximity (allowing the 3G/2G antenna to ground through it) were poor design choices.

I had thought, in my admitted admiration for the polished feel of apple products, that this must have been some small software issue but now I think I know how this poor design got through. Secrecy. Pete Stewardson from work takes credit here, it didn't occur to me at all.

See, apple have to field trial phones like the rest of us. They love the slavering anticipation their product cycle produces, and hence they keep a tight lid on things; iPhone 4 was no different. So, to keep the physical design a secret, they had testers using the devices inside a case which gave the phones a 3GS "look".

This, of course, insulated the antenna from the testers' hands. And totally masked the antenna grounding issue. Woops.

What is happening now with apple suggesting that the rssi meter algorithm has "always been wrong" and that they were "astonished" to discover this, this I think is a total damage limitation exercise. If the meter had been wrong all along I simply cannot believe that 3 iterations of the iPhone would not have seen it fixed. Simple field trials would have shown it up.

Sean Cody, where are you matey and can you give me the lowdown!

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