Originally, when the International Telecommunications Union (ITU) determined what was considered 4G, LTE, WiMAX, and HSPA+ did not make the cut. However, operators began using ‘4G’ term for LTE WiMAX and HSPA+ as they started commercial roll outs, making ITU to reconsider its position. In December 2010, ITU accorded “LTE-Advanced” and “WirelessMAN-Advanced” the official designation of IMT-Advanced which ITU considers ‘4G’.  ITU also acknowledged that ‘4G’ may also be applied to the forerunners of these technologies, LTE and WiMax, and to other evolved 3G technologies providing a substantial level of improvement in performance and capabilities with respect to the initial third generation systems now deployed.

Now, carriers are fighting to stay at the forefront of innovation by developing the next-generation true 4G network, LTE-Advanced, despite the fact that most of the world is still lagging in terms of commercial LTE rollout.

A brief summary of status of mobile carriers’ LTE-A penetration is provided below.

SK Telecom

• SK Telecom has successfully tested their core LTE-Advanced technologies as of July 5th, 2012
• CoMP* (Coordinated Multi-Point) technology commercialized in January 2012
• eICIC** (Enhanced Inter-Cell Interference Coordination) technology successfully tested in collaboration with Qualcomm and Nokia Siemens Network
• Plans to commercialize Carrier Aggregation*** towards the end of 2013

Yota

• Yota has launched the first commercial network using LTE Advanced, though its vendor, Huawei, also describes it as a test LTE-A network
• LTE Advanced technology has been installed on 11 base stations in the city, and initial transmissions have achieved the target 300 megabits speed
• No user terminals are yet available
• Expects delivery of the first devices in the first half of 2013

Sprint

• Sprint plans to deploy its LTE-Advanced network
• 800 MHz spectrum by first half of 2013

AT&T

• AT&T confirms LTE-Advanced deployment in 2013

T-Mobile

• T-Mobile has signed multi-year agreements with Ericsson and Nokia Siemens Networks
• 3GPP Release 10 equipment will be provided by the two companies
• LTE-Advanced trials set to begin this summer
• Broad LTE deployment on track for 2013

Clearwire

• Clearwire plans to deploy an LTE Advanced-ready network by June 2013
• Will allow for peak rates of 168Mbps through carrier aggregation
• Will not be in commercial products until 2014

Telstra

• Telstra could possibly operate advanced LTE services on the 900 MHz and 1800 MHz bands
• Plans to upgrade approximately 7,500 cell sites and base stations over the next 12 months

NTT DoCoMo

• NTT DoCoMo has begun building test network near Tokyo
• Achieved downlink speeds of around 1Gbps and uplinks of around 200Mbps in LTE Advanced lab tests

Additionally, T-Mobile and Verizon have acquired additional Advanced Wireless spectrum licenses in 218 markets across the U.S

Diffusion of LTE in Europe is relatively weak due to several constraints and restrictions. EE is currently the sole provider of LTE in UK, launched on October 30, 2012

According to Strategy Analytics U.K. Senior Analyst Scott Bicheno,  South Korea and the U.S. are a year or more ahead of other regions such as Europe in rolling out such services, and that "South Korean operators like SK [Telecom] will be right at the forefront of that emerging growth wave."

* CoMP allows for smooth data flow by controlling frequencies between macro base stations.
** eICIC is a solution that adjusts mixed interference that occurs between macro and compact base stations.
*** Carrier Aggregation efficiently integrates multiple frequency spectrums.