The age of Gigabit LTE is here. Australian operator Telstra will begin commercial service in late February, starting with a single mobile-hotspot device. Smartphones capable of 1Gbps cellular downlinks should be available shortly thereafter. These devices will not only accelerate existing services but deliver new capabilities as well.
Less than two decades ago, the first 1Mbps smartphones appeared, delivering broadband data rates into the palm of your hand. The new devices are 1,000 times faster, achieving speeds that only a fiber-optic broadband connection can match.
While today’s phones are fine for streaming video files in HD and even emerging 4K formats, Gigabit LTE delivers enough bandwidth for streaming 360-degree video. Virtual-reality applications use these files, often at frame rates of up to 60fps, to create immersive viewing experiences. Gigabit LTE enables mobile users to access these experiences using their phone as a VR viewer.
The faster data rate also enables nearly instantaneous access to even large files stored in the cloud. In this way, the cloud becomes an extension of the phone, providing essentially infinite storage that is always available from any device. Similarly, Gigabit LTE provides fast access to songs, shows, and movies from the cloud.
The new technology also boosts the uplink rate to 150Mbps. This improves the quality of video calls due to the greater resolution and frame rate of the images. Sharing high-resolution photos and videos becomes easier with a faster connection.
Keep in mind that, as with all cellular connections, the peak data rate is rarely achieved. Unless radio reception is nearly perfect, the connection will fall back to a lower speed. In real world conditions, Gigabit LTE could achieve 90Mbps to as much as 300Mbps, two to four times the speed of typical (Cat6) LTE connections.
Achieving these higher data rates is not easy. The operator must support 256-QAM, one step above the highest modulation in most LTE equipment. The new modulation boosts the throughput of a single 20MHz-width channel to 200Mbps in the usual 2×2 MIMO mode. Moving to 4×4 MIMO, which requires four antennas, doubles that data rate to 400Mbps. Combining two 4×4 channels with one 2×2 channels yields 1.0Gbps, as the figure shows.
Many operators, however, don’t have licenses for three 20MHz channels. These operators can still reach 1.0Gbps using a combination of licensed and unlicensed spectrum. Operators can access unlicensed spectrum using the LAA protocol that is part of the new 3GPP Release 13 version of LTE.
Gigabit LTE isn’t just about the speed. Using higher modulations and 4×4 MIMO improves spectral efficiency, that is, the number of bits per channel. Thus, the new technology allows operators to transmit more data to customers without adding expensive new spectrum. Even customers that don’t have the latest phones will benefit, since the customers with fast connections will complete their downloads sooner and free spectrum for other users in the same sector.
Telstra’s launch features a NETGEAR hotspot based on Qualcomm’s Snapdragon X16 LTE modem, the industry’s first chip to implement Gigabit LTE. The company also provides the WTR5975, which combines all the RF transceivers required for up to four channels in a single chip. The first Gigabit LTE smartphones will use Qualcomm’s Snapdragon 835 processor with X16 LTE, which combines the new modem and a high-end application processor. Smartphones based on the Snapdragon 835 will begin shipping within the next few months. Other modem-chip vendors are also developing Gigabit LTE products but will reach the market later than Qualcomm.
Although Telstra is the first operator to deploy Gigabit LTE, you don’t have to go Down Under to achieve this blazing speed. AT&T, Deutsche Telekom, EE, NTT DoCoMo, Sprint, T-Mobile, and Vodafone all plan to deploy the new technology by the end of 2017, bringing it to Europe, Japan, and the U.S.
These leading operators can differentiate from their competitors by offering the fastest possible data rates. Gigabit LTE enhances the customer experience and enables new services such as streaming 360-degree video and on-demand virtual reality. To show off their ultrafast networks, operators favor high-end smartphones that support the latest cellular features. Only the combination of the fastest phones and the fastest networks will deliver the full capabilities of Gigabit LTE to end users.
Linley Gwennap is Principal Analyst, Mobile at The Linley Group and editor-in-chief of Microprocessor Report. Development of this article is funded by Qualcomm, but all opinions are the author’s.
