Apple's upcoming smartphone plans have the rumor mill churning at full speed, and a new report claims the Cupertino giant will start production this quarter.

If this proves to be true and Apple does indeed ramp up production of the so-called "iPhone 5S" in the second quarter, the company could unleash the next iPhone as soon as this summer. This, in turn, would be a change from the iPhone 5 launch schedule Apple pursued last year.

The new purported details about Apple's smartphone plans come from the Wall Street Journal (WSJ). Additional rumors also point to a less expensive iPhone model with a different casing material. The cheaper iPhone will reportedly retain the 4-inch display of the iPhone 5.

While the WSJ's report on Tuesday, April 2, does not bring any surprising details, it does fall in line with earlier reports speculating on Apple's 2013 plans for its smartphone lineup. Last month, for instance, parts allegedly from the "iPhone 5S" surfaced online, further suggesting that Apple's next iPhone could be nearing production.

On the other hand, back in January KGI Securities analyst Ming-Chi Kuo claimed that the next iPhone might include a fingerprint sensor beneath the home button for secure transactions. The WSJ makes no mention of this feature. Kuo, however, has a strong track record when it comes to predicting Apple's future plans, so there's a good chance his predictions will prove accurate once again.

In terms of a cheaper iPhone, speculation spread like wildfire that Apple is targeting the low-end smartphone market, particularly in developing countries where consumers tend to purchase unsubsidized, contract-free phones. A lower-cost iPhone will allegedly target China and Brazil in particular. The handset will reportedly sport a plastic or polycarbonate body that would allow the Cupertino giant to slap a lower price tag. The current iPhone 5 boasts an elegant metal back, while the iPhone 4S and iPhone 4 sport glass cases.

Apple is yet to announce anything officially, but when multiple sources point to the same thing there usually is a grain of truth somewhere in there. On the other hand, Apple is bound to be working on a new iPhone, but the rumored launch timeline is a bit different. The company released its last devices in the fall instead of the summer, but who knows? Maybe the Galaxy S4 debut hurried things up.