How to Pick the Right 4G LTE Technology for Your Business Needs and Applications

Harald Remmert, CTO, Cellular Solutions , Digi International
July 31, 2018

With the shutdown of 2G and 3G networks looming on the horizon, many organizations are faced with the difficult question of “So, what’s next?” The key question to really ask is, “Well, what is the application?” Meaning, what is the current or projected use case and how will it be impacted by the new LTE technology. In addition, ask yourself where are you today and where do you want to be in five years; and most importantly, what business problems are you trying to solve with the new network capabilities?

You’ll soon find there are many items associated with those key business and technology questions that need to be further analyzed:

• Bandwidth: determine whether you need data transferred in bursts or as a steady feed over time; and decide if you need to transfer only a few bytes or several GB each day.
• Data Plan: evaluate if data will be needed in real time, or if a several second, minute or hour delay is tolerable, and choose the most economical plan.
• Connectivity: decide if your organization’s communication requirement is to be localized across a building, plant, or a city – or even across a country or worldwide. Consider whether you must always remain online, and if downtime could put you at the risk of lost revenue, regulatory penalties or safety violations.
• Environmental: assess whether your equipment will be in a climate-controlled environment or outdoors in harsh, even hazardous settings. Determine if AC power will be available, or if battery or solar power is the only option.
• What about 5G? Finally, weigh the pros and cons of waiting for 5G. Do you want to take on a bleeding-edge technology in its initial stages, or would you rather rely on a proven leading-edge technology like 4G? Will a bleeding edge technology make your application or its output better? Keep in mind that 4G is also evolving into 5G over time.

Today, we are at a fork in the road. One path can leverage Gigabit LTE for high-speed applications in retail, enterprise or transportation industries that need to connect sites or people with mains-powered, high bandwidth – and higher cost – solutions. The other path can leverage 4G LTE optimized for IoT applications in industrial locations to connect machines and other critical assets that require low bandwidth, low cost, and low- or battery-power as indicated by the chart below.

4G LTE Evolution for IoT

Each 4G LTE technology has its pros and cons, while carriers considering a roll out of LTE-M or NB-IoT as a secondary network only adding to the complexity. Here’s a deeper dive into the technology options for IoT devices:

• CAT 1: represents a good fit for many single-device IoT applications with mains-power, such as digital signage and kiosks, industrial controllers and security cameras. It is globally available where LTE is accessible.
• CAT 3/4: with the potential of speeds up to 100-150 Mbps, this technology is designed for IoT routers connecting multiple devices. However, it may be excessive for most single-device IoT applications.
• CAT-M/LTE-M: fits traditional 2G-type applications, devices that require mobility, such as asset trackers, as well as battery-powered IoT sensors. Defined in 2016, it is not yet fully globally available, but is predominant in North and Latin American and Asian markets with early LTE adoption.
• NB-IoT: best fit for battery-powered devices that do not require mobility, such as fixed-asset sensors. Also defined in 2016, it is not globally available as this time, but suits markets with late LTE adoption, like Europe.

4G LTE Evolution for Gigabit LTE

Now let’s go down the other path with a look at Gigabit LTE and the 4G evolution to 5G.
The 3rd Generation Partnership Project (3GPP) is a collaborative group of telecommunications associations that defines the standards to build the foundation of cellular networks, such as LTE.

Since its initial release in 2008, LTE (Long Term Evolution) has evolved, and continues to evolve towards 5G over time. Typically, 3GPP releases a major update of the standard every three years, followed by a minor release. To differentiate between major LTE releases, 3GPP introduced marketing names such as LTE-Advanced and LTE Advanced Pro. Release 13/14 were a key milestone for Gigabit LTE because the speed doubled to 1.2Gbps. Release 15, to be released later in 2018, will be the first standard defining 5G.

Source: Telit

Four Requirements to Achieve Gigabit LTE Speeds

1. More RF channels and carrier aggregation: think multiple highways to transport more vehicles. Gives you better us of the available spectrum, as many carriers don’t have 20 MHz of licensed spectrum per band available.

• Higher peak data rates
• More capacity for bursts of usage

Source: Qualcomm

2. Higher-order modulation (HOM) (see Figure #2): think of a bus versus a car to transport more people (i.e., data) per vehicle, where the cellular network and device are constantly adjusting the modulation based on signal conditions. The downside of HOM is that a noisy or weak signal is harder to demodulate, which can result in retransmissions and lower speeds.

• 16-QAM: 4 bits/symbol
• 64-QAM: 6 bits/symbol, 25% improvement over QAM-16
• 256-QAM: 8 bits/symbol, 33% improvement over QAM-64
• 1024-QAM: 10 bits/symbol, 25% improvement over QAM-256.
  

3. More MIMO (Multiple Input, Multiple Output) antennas: think multi-lane highway with traffic moving on two directions (using multiple antennas to both transmit and receive data in parallel). Most devices today have two antennas per cellular modem, while Gigabit LTE devices will require four antennas to achieve higher speeds. For many devices, this means moving from direct-attach to cabled antennas.

4. More spectrum: the use of licensed, shared or unlicensed spectrum (3.5GHz/5GHz) for additional bandwidth now includes License Assisted Access (LAA) and Citizens Broadband Radio system (CBRS).

• Citizens Broadband Radio System (CBRS)
  1. As of April 2015, the FCC authorized shared commercial access of the 3.5GHz band with incumbent military radars and fixed satellite stations
  2. The CBRS spectrum is assigned individually by Spectrum Allocation Server (SAS), 3 priority access levels
• MulteFire
  1. MulteFire Alliance is a new industry alliance promoting private networks based on LTE technology
  2. MulteFire scales from LTE for IoT to Gigabit LTE
  3. It is not part of any 3GPP standard yet, but is considered for Rel. 16
  4. MulteFire could someday replace Wi-Fi networks
     

Private LTE networks provide new opportunities for either enterprises to deploy secure communication for increased flexibility and added security, or for the Industrial IoT (IIoT) to build a private network, for example in remote farming or mining sites to run industrial IoT devices and applications.

4G LTE Advanced Pro is here today and paving the way to 5G as outlined above. Though, you will not see Gigabit LTE speeds right away. You can expect speeds above 100 Mbps under good conditions on licensed LTE networks. Even higher speeds will become possible where unlicensed spectrum and infrastructure become available.