I admit I know very little about how cell phone networks work, but why would the phone need to transmit anything to determine network congestion? Surely it could figure this out just by listening, right? Maybe with the help of the towers periodically broadcasting their utilization?
Phones already do that. It's the bar graph we already have.
There are multiple reasons why it's not terribly useful:
1.) Signal quality depends on many different variables, and fluctuates wildly from second to second. You can have a great signal at one moment, but if the guy next to you starts a call, the radio in their phone will ramp up to the full 500mW, and drowns out the tower. You can have a signal graph that realistically reflects "signal strength", and it'll jitter constantly, and the grandmas will complain.
As you may have noticed from every cell phone advertisement in the last decade, marketing is heavily invested in the notion of bars. It's in brands, logos, ad copy, everything. More bars are better.
If engineers ran the company, they'd just stick the SNR in dBm at the top of the screen and it'd be wonderfully pure and objective; and everybody else would hate it, and the company would go bankrupt. So we have "bars", and the bars lie.
