As Apple Inc. is rumored to be gearing up for the major event in mid-September, the next-generation iPhone 5 could be in the hands of consumers in first week of October.

A leaked internal memo from the U.S. carrier Sprint claimed that its employees can't take time-off during Sept. 30 to Oct. 15 due to a major phone release. The memo backs rumors that the highly anticipated iPhone 5 will be released in early October.

The memo doesn't state which major phone is to be released, but speculation is that it could be the iPhone 5, the Samsung Galaxy S 2 or the Motorola Droid Bionic.

Apple Inc. will issue press invitations on Sept. 14 to the iPhone 5 launch, which will take place in the San Francisco Bay Area on Sept. 21, according to CultofMac. The smartphone will be released in early October, with pre-orders starting Sept. 28.

This forecast falls in line with reports of Best Buy passing on the message to its employees that the iPhone 5 could be released in the first week of October.

Analysts are expecting the iPhone 5 to debut in October without 4G LTE. Peter Misek, an analyst at Jefferies, said that as the new iPhone in October will most likely be called the iPhone 5, the LTE iPhone will likely be named the iPhone 5S and will be launched in summer 2012 (though it could come earlier).

Misek expects the iPhone 5 to be available on all four major U.S. carriers -- Verizon, AT&T, T-Mobile and Sprint -- in October. In addition, China Telecom will get the iPhone in the calendar first quarter of 2012 and China Mobile is likely to get in 2013/2014, he said.

Meanwhile, the iPhone 5 is expected to boast of significant hardware and software upgrades, along with an 8-megapixel dual-LED flash camera and A5 dual-core processor found in the iPad 2, to give stiff competition to other dual-core smartphones found in the market today.

Apple may boost the speed of its A5 chip in the range of 1.2 or 1.5 GHz with 1GB RAM. The iPhone 5 is also rumored to feature iCloud, which will store photos, apps, calendars and documents, instead of the phone's memory storage.

Apple is rumored to be increasing the screen size of the iPhone 5 to compete with Android smartphones, probably going for a 4-inch screen, compared to the current iPhone 4 screen of 3.5 inches.

Apple is expected to release the iPhone 5 as a World Phone -- both GSM and CDMA compatible. Another rumor suggested that the iPhone 5 will feature a SIM card slot for other countries, allowing users to insert any SIM card when traveling abroad.

The smartphone will also feature Apple's iOS 5 and wireless syncing. Adding to the rumor mill, it seems that the UK carrier Vodafone could have accidentally leaked information about storage capacity and color for the next iPhone.

In a product listing for the Vodafone Sure Signal on its website, it implied that the iPhone 5 will be available in both black and white, with capacities of 16GB and 32GB. The listing can possibly be a typo. But it did mention four iPhone 5 models, in addition to the iPhone 4, iPhone 3GS and even the iPhone 3G, which was first released in 2008, Apple Insider reported.