If the latest reports turn out to be true, Sony is all set to launch a series of mid-range smartphones including the Xperia Z4, Xperia Z4 Compact, and Z4 Ultra, at the upcoming Mobile World Conference in early 2015 with a view to challenge its competitors in the mobile device market.

According to Christian Today, rumors regarding the specs and features of these smartphones have already appeared on the Internet and tech enthusiasts as well experts are both eagerly waiting for their launch.

The Xperia Z4 will be succeeding the Japanese mobile manufacturer's current flagship phone - the Xperia Z3. Speculation says that the handset will sport a 5.4-inch quad HD Triluminos display and pack a Snapdragon 805 or 810 processor coupled with 4 GB RAM. The Sony Xperia Z3 will boast the company's latest 21-MP Exmor IMX230 camera sensor and have a 3300 mAh battery. It will run on Google's latest mobile operating system Android 5.0 Lollipop.

On the other hand, the Sony Xperia Z4 Ultra will mark the company's entry into the phablet market and compete with the recently released iPhone 6 Plus from the Apple stable and Samsung's Galaxy Note 4. According to rumors, this smartphone-tablet hybrid handset will be very slender and sport a 5.9-inch HD Triluminos display, powered by Snapdragon 805 processors, have a 4 GB RAM, a 16-MP rear and a 3.2-MP front-facing camera with a 3300 mAh battery.

The soon-to-be-released Xperia Z4 Compact will be somewhat smaller and moderate compared to the Xperia Z4. It will come with a 4.7-inch screen display paired with 1080p full HD resolution, a 64-bit Snapdragon 810 processor, 3 GB RAM, and 32 GB internal storage accompanied by a microSD slot. Its rear camera will be a grand 20.7-MP, while the front-facing camera will be 5-MP.

It is rumored that apart from these smartphones Sony will also launch another mid-range handset named Xperia E4, which will succeed the current Xperia E3, which was released at the IFA 2014 in September this year. A report by GSMArena says that this device will have a 5-inch screen display, powered by Media Tek's quad-core MT6582 SoC paired with Cortex-A7 cores clocked at 1.3 GHz in addition to 1 GB RAM.

While Sony has yet to confirm the launch of these smartphones, it is being speculated that the company may announce them at the Consumer Electronics Show (CES) scheduled for January 2015 or at the Mobile World Congress (MWC) in March 2015.