"In five years, since the first launch of LTE by TeliaSonera in 2009, there has been explosive growth in LTE network deployments as the entire ecosystem -- operators, vendors and stakeholders combined -- progress the technology," commented Chris Pearson, President of 4G Americas. "As LTE becomes the foundation of the wireless landscape, LTE-Advanced is the evolutionary step for increased speed and network capacity. We are beginning to see activity around LTE-Advanced including initial launches and devices."

In March of this year, AT&T launched LTE-Advanced in Chicago making them the first major U.S. carrier to offer the service. It is expected that all four national U.S. carriers -- AT&T, Sprint, T-Mobile and Verizon -- will launch LTE-Advanced in 2014 and 2015. The world's first LTE-Advanced network using Carrier Aggregation was commercially launched in South Korea by SK Telecom (which included a compatible handset) in June 2013. Carrier Aggregation is important for carriers around the world as it allows them to create larger spectrum swaths by combining disparate spectrum assets. The larger the spectrum swaths, the better the efficiency of LTE. However, Carrier Aggregation is just one component of LTE-Advanced. It also includes other elements such as Coordinated Multi-Point (CoMP), Self-Optimizing Networks (SON), small cell enhancements, Enhanced Inter-Cell Interference Coordination (eICIC) and advanced Multi-Input Multi-Output (MIMO) antenna technology to improve network performance and capacity.

The leading technology for mobile network operators relies on carrier aggregation, called LTE-A Category 6. “LTE-A Category 6 is the number one priority for operators as they look to deploy the next speed enhancement to their networks,” said Robert Rango, Executive Vice President and General Manager, Mobile and Wireless Group, Broadcom.

LTE-A Category 9 is next on the path, and you’d better believe that vendors and operators are already trialing this. Ericsson, for example, hit 450 Mbps download speeds during a Cat-9 test in November.

LTE-Advanced is also making its way into public safety solutions and small cells. In November, Nokia Networks demonstrated the world’s first LTE-A small cell that leveraged carrier aggregation to deliver better than 200 Mbps. In Australia, Telstra and Motorola Solutions have signed a memorandum of understanding to further develop public safety broadband solutions based on the LTE Advanced Network for Emergency Services (LANES) capability, products and services developed by Telstra. This capability will be enhanced by Motorola Solutions’ dynamic prioritization, smart public safety applications, interoperability solutions and public safety optimized devices.

The push to 5G

The future of LTE is the application of LTE-Advanced technologies in fifth-generation mobile networks, or 5G. Although most analysts don’t expect to see 5G in commercial deployment until 2020, Huawei and MegaFon promise to deliver a 5G network in time for the 2018 FIFA World Cup. To ensure testing of a full-scale 100% 5G experience, Huawei says it will be introducing the latest mobile technologies such as SCMA, full duplex, and cloud base station to the 5G network.

Not surprisingly, Huawei is investing heavily in 5G research and development. It has created a 5G innovation program with SingTel, is exploring 5G for driverless cars, and has partnered with SK Telecom, KT, and LG UPlus in Korea to build 5G networks.

The company has also rolled out the concept of “4.5G.” According to Huawei, “4.5G technology would further extend the capability of LTE-A to enable more diverse applications, better user experiences and easier and cost-effective deployment, which would all contribute to a better connected world in the near future.”

Regional competitor ZTE calls this “Pre-5G", and is already working with China Mobile to test the technology. “With next-generation 5G technologies being deployed in 2020, there were industry concerns over what technologies will be used in the next six years,” said Dr Xiang Jiying, ZTE's CTO of wireless products, at an LTE World Summit in Amsterdam in July. “To address this, ZTE proposes to apply some of the 5G technology on top of 4G to meet users' requirements.”

Even before 5G arrives, massive MIMO reference codes, such as the CSI-RS (channel state information reference signal) should be modified to support hundreds of antenna ports, and the terminals should also be modified for the feedback of hundreds of PMIs (Pre-coding Matrix Indicator).