What Is Gigabit-Class LTE? How 4G Fills the Gap before 5G
By Marco Argenton
April 29, 2020
By Marco Argenton
April 29, 2020
While 5G receives much attention these days, Gigabit LTE represents its lesser-known precursor — an evolution of 4G LTE that can provide dependable mobile broadband access at speeds that even surpass those of wired broadband connections. With carriers rolling out 5G at break-neck speed, coverage is improving fast, but Gigabit LTE is widely available now and with nationwide coverage worldwide.
With the fourth-generation mobile communication standard (4G) came a greater focus on data transmission. Previous generations of cellular standards centered mainly on voice and text capabilities, catering to pre-smartphone consumers. For the growing needs of smartphones and mobile broadband communication, the LTE-Advanced (LTE-A) standard was approved in 2011 (3GPP Release 10), delivering peak download data rates of 1 Gbps.
Gigabit LTE capabilities were enhanced with the rollout of LTE-Advanced Pro (LTE-A Pro), a standard approved circa 2015 with 3GPP’s Release 13, to take 4G a step further, providing peak download speeds into the 3 Gbps range depending on networks’ availability of high carrier aggregation (up to 32 20-MHz carriers allowed in LTE-A-Pro). Key technologies and strategies come together to enable LTE-A Pro to clear a path for these ultrahigh-speed connections, which are sometimes faster than traditional wired broadband access.
These technologies include:
Mobile network operators (MNOs) can provide increased data speeds by combining the data-carrying capabilities from multiple sections of the radio spectrum known as “carriers” to send and receive data. Carrier aggregation combines an MNOs’ often non-contiguous carriers within one or more spectrum bands, expanding the width and carrying capacity of the data pathways to allow for higher capacity and speeds. Gigabit LTE typically requires five or more carriers aggregated to push theoretical data rates to peak at levels higher than 3 Gbps.
To increase data-carrying radio spectrum capacity, LAA uses the unlicensed 5 GHz band in conjunction with the licensed spectrum by the MNO. Licensed spectrum is known as “cleared spectrum.” Nobody other than the licensee is using that spectrum within the regional boundaries of the license. Unlicensed spectrum is available to a variety of uses like Wi-Fi, which also functions within the 5 GHz band. LAA must work around these other users applying techniques like Listen-Before-Talk (LBT) function to identify and utilize unused channels.
Quadrature Amplitude Modulation (QAM) is an efficient two-domain encoding strategy that leverages both amplitude and frequency modulations to encode information in the radio waveforms. The higher the QAM number, the more information the waveforms can carry. Before 256-QAM, there was 64-QAM modulation. When 64-QAM is used, there can be 6 bits of information in each encoded symbol such that 2^6 equals 64. In 256-QAM, there are 8 bits of information that can be packed in the same symbol such that 2^8 equals 256. This makes 256-QAM bit rates to be 30% faster than 64-QAM bit rates. This increased data rate comes with a caveat that 256-QAM requires a better signal to noise ratio (SNR) than 64-QAM, so when a radio is in good reception and gets a strong signal, it can perform 30 percent better than the older system that is based on 64-QAM.
Just as carrier aggregation achieves higher bandwidths with multiple carriers, so does MIMO with multiple antenna paths per band. Gigabit LTE networks have standardized on four antennas on the base station and four on the device. These antennas improve spectral efficiency, and therefore data speeds, allowing the equipment to connect more efficiently with the steadiest available signals.
While Gigabit LTE and 5G are similar, a few key details set them apart. 5G adds more available frequencies, primarily in the ultrahigh millimeter wave (mmWave) spectrum. Since mmWave towers provide limited coverage, mass adoption of 5G will require significant new infrastructure to be constructed, which will take time.
Another differentiator is that 5G networks can work in two modes: standalone (SA) or non-standalone (NSA). SA indicates that the system is operating with all 5G radio and core networks, while NSA means it is using both LTE and 5G resources combined in different modes.
The availability of Gigabit LTE offers the clear advantage of easier adoption at this point. Unlike 5G, it doesn’t require constructing new towers or redesigning device antennas to cope with the demands of mmWave technology. For businesses around the world, Gigabit LTE offers many of the benefits of 5G without design challenges. Here are a few ideal use cases for Gigabit LTE:
Businesses and agencies frequently need to spontaneously add network connectivity to sites and venues out of reach of the existing infrastructure. Wired connections using copper or fiber can be extremely expensive and require long lead times to install. Deploying a cellular router to deliver Gigabit LTE broadband access to these sites is more cost-effective and, in cases like natural disasters and pop up events, the only available option.
There are several industrial applications in which Gigabit LTE is crucial (e.g., security applications requiring high bandwidth). If a company needs to monitor remote locations with video cameras streaming 24/7, Gigabit LTE is the most reliable method to achieve that.
Gigabit LTE provides an inexpensive, efficient solution for companies that need to set up internet connections at branch offices or temporary stores. It requires minimal setup — the operator switches on an LTE router and provides connectivity in a matter of minutes.
Even if an office maintains a wired connection to the internet and head office, Gigabit LTE can be a backup system. Downtime can be expensive, costing a small- to medium-sized business between $8,580 and $215,637 per hour. A Gigabit LTE backup system costs very little by comparison and provides insurance against such losses.
As we await denser coverage of 5G with its new infrastructure, Gigabit LTE offers an accessible, affordable and efficient solution that’s available today.