With the country's largest mobile carriers in an all-out war to capture the business of American consumers, each of them would love to think they'll come out on top.

To be sure, anyone paying attention is probably aware those efforts lately have increasingly involved offering more attractive early-upgrade plans.

Let's take a look, then, at what's being offered so far.

Anything they can do...
T-Mobile (TMUS -0.06%) got the party started a little over two months ago when it unveiled its mildly confusing "JUMP" program, and has since battered consumers through an advertising campaign featuring the slogan, "Upgrade when you want, not when you're told."

The thing is, in addition to paying an upfront cost for their phones, T-Mobile subscribers must also fork out a flat $10 per month fee for the service. Even then, they're only allowed to upgrade their existing device twice every 12 months, but only beginning six months after the initial enrollment.

Of course, JUMP also includes a comprehensive handset protection program for which other carriers charge between $7 and $8 per month. As fellow Fool Evan Niu pointed out, however, many consumers would probably be just as well off simply paying full retail price for their phones, then selling them to another user six months down the road on eBay or Craigslist after accounting for depreciation.

Unsurprisingly, AT&T (T 1.02%) and Verizon (VZ 1.17%) each followed suit only a few days later with their comparatively straightforward "AT&T Next" and "Verizon Edge" upgrade programs.

While neither program requires an upfront payment for the phone, and both enable subscribers to upgrade early -- after one year for AT&T Next, and six months for Verizon's Edge -- subscribers must still opt to make monthly payments on their devices ranging from $15 to $50 per month. What's more, to get the "free" upgrades, AT&T and Verizon require you to have paid at least 60% and 50% of the original phone's total cost, respectively.

Anyone who actually studies the economics of these two programs, then, will quickly realize they're likely not worth the cost considering the fact neither company is actually lowering their monthly service fees to offset the lack of a subsidy offered to the consumer.

...Sprint can do better?
Meanwhile, notably absent in all this so far is Sprint Nextel (S). However, according to a recent CNET report, that could all be about to change.

Apparently, based on leaked documents shown in the report, the folks at Sprint could be gearing up to launch an early upgrade program of their own this Friday, aptly dubbed "One Up."

Call me crazy, but I'm thinking it's no coincidence Friday also happens be the same day Apple is launching its colorful new family of iPhones.

Better yet, Sprint may be looking to combine the best features of the aforementioned plans into One Up.

Like Verizon and AT&T, Sprint's program would allow customers to grab a phone with no money down and instead pay for the device in 24 monthly installments. At same time, Sprint would provide a $15 discount to its unlimited talk, text, and data plan that costs as little as $65 per month. T-Mobile, by comparison, charges $70 a month for a similar unlimited plan.

Then, after one year, Sprint customers will be able to upgrade to a new phone by trading in their existing device. Naturally, though, if a they exit the service before their phone is paid off completely, they'll be required to pay the remaining balance the following month.

Foolish takeaway
Even so, if the rumors turn out to be true, Sprint's One Up plan will not only make it look good in customers' eyes, but also put more pressure on T-Mobile, Verizon, and AT&T to make additional concessions to their own less-impressive early upgrade programs.

That said, it's also worth noting Sprint effectively capped its latest 4G LTE expansion on Monday by adding LTE service to 34 new markets, bringing its total to 185 markets nationwide, with the aim of covering 200 million people by the end of 2013.

You can bet rest of the industry wants to do everything it can to prevent Sprint from reaching that goal, but I think it's safe to say One Up certainly won't hurt its chances.