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Sprint may be following the path of larger rivals AT&T and Verizon Wireless when it comes to its shared data plans.

The nation's third-largest wireless carrier by subscriber is holding a trial to test out the efficacy of a family data plan, according to a person familiar with the company's plan. It is also testing out discounted versions of its Framily and individual plans, CNET has learned.

The trials are part of a broader effort by Sprint to figure out a way of turning around its flagging fortunes. The company continues to be squeezed at the high end by AT&T and Verizon, while a resurgent T-Mobile is slowing catching up with its own aggressive slate of customer-friendly programs.

Sprint has been slow to recover because of the languishing pace of its network upgrades. While Verizon and AT&T can boast about the breadth of their LTE coverage, and T-Mobile talks up the speed of its network, Sprint has been busy upgrading both its LTE and older 3G networks market by market. It has recently taken to boasting of having the "newest network."

The fastest Sprint service, which runs off three different bands of wireless spectrum, is marketed under the Spark brand, but the enhanced network is available in only 24 cities.

Sprint has vowed to be more aggressive under the ownership of Japanese carrier SoftBank. The trials represent a willingness to undercut its competitors.

The family data plan trials will be held in San Diego; Portland, Ore; and Las Vegas. Here are the options and prices:

Screenshot by Roger Cheng/CNET

In addition to the data, customers would have to pay an additional access charge to add a device. For plans with 1GB to 10GB, it costs $25 to add a smartphone, while it costs $15 to add a smartphone for a 20GB plan or above. The access fees are standard parts of the plans offered by AT&T and Verizon.

Sprint is offering annual upgrades for customers who have at least a 20GB plan in San Diego and Portland. In Las Vegas, an annual upgrade requires a fee of $5 a month.

The plans are designed so customers save more as they opt for more data. The $20 plan for 1GB, for instance, is only $5 cheaper than the comparable AT&T plan. But the 30GB plan is $75 cheaper than AT&T's $225 version.

Sprint is also testing out a discounted version of its Framily plan in Buffalo, N.Y.; Philadelphia; and Providence, R.I. The altered plan starts at $45 a month, or $10 less than the official Framily plan. It drops to a bottom of $25 a month at five people, while the official plan doesn't hit $25 until seven people join up under the same friends and family program.

Customers in Buffalo and Philadelphia who pay the extra $20 for unlimited data will also be eligible for an annual upgrade, while the Providence customers need to pay a $5 monthly fee for the annual upgrade.

Lynn La/CNET

Lastly, Sprint is testing out a new individual plan in Chicago, Minneapolis and West Michigan. Customers who pay full price for their smartphone, bring their own device, or pay for their phone in monthly installments are eligible for a $50 unlimited plan or $40 plan for 3GB of data a month.

It's a significant savings from the individual unlimited data option for a Framily plan, which costs $75 a month, excluding the cost for a smartphone.

Unlimited data customers in Chicago and Minneapolis are eligible for annual upgrades, while West Michigan customers will have to pay a $5 fee each month for their annual upgrade.

Sprint wouldn't comment on the specific trials, but acknowledged that they do happen from time to time.

"Sprint is always looking for ways to improve the customer experience, and we often conduct targeted market trials before launching a product or service," said a company spokeswoman.

Sprint's trials underscore the notion that the carrier is moving away from being simply the "unlimited data" carrier and at least considering offering a variety of plans to meet its customers' needs.

If some of these trials do take hold, Sprint will have a few attractive options at its disposal.