Long Term Evolution (LTE) routers or 4G routers are a type of network router that can provide mobile broadband internet connectivity to devices via a WiFi, Ethernet, or USB connection. They are characterized by their use of fourth-generation long-term evolution (4G LTE) and LTE-Advanced wireless modems, modules, or PCI Mini Cards to drive high-speed data transfer over cellular networks.

What is LTE?

The specifications and standards for LTE were developed and released in 2004 by the Third Generation Partnership Project (3GPP). It builds on the existing cellular standards and infrastructure of the Universal Mobile Telecommunication System (UMTS).

Key characteristics of Long Term Evolution:

• LTE delivers full-duplex communications links using frequency-division duplexing (FDD) or time-division duplexing (TDD) depending on the frequency band used.
• The mobility of LTE can support devices moving at speeds of up to 350 kilometers per hour, with coverage of 5 to 100 km.
• Individual channel bandwidths are between 1.4 and 20 MHz
• LTE uses Quadrature Phase-Shift Keying (QPSK) for modulation of both its uplink and downlink carrier signal.
• The multiple access schemes used by LTE are Single Carrier Frequency Division Multiple Access (SC-FDMA) for a 50 Mbps uplink and Orthogonal Frequency Division Multiple Access (OFDM) for downlink speeds of 100 Mbps or more.
• LTE uses antenna diversity and spatial multiplexing with MIMO to enhance its performance and speed. The use of MIMO in LTE increases the downlink speeds that can be achieved up to 300 Mbps.
• LTE is low latency (10 mS).

Advantages of LTE Routers:

LTE cellular technology can be used to create wireless networks of any size, from Personal Area Networks (PANs) to Wireless Wide Area Networks (WANs) with routers capable of supporting industrial and enterprise-level networking. The routers can be used as both the primary means of connectivity or a backup.

LTE and LTE-Advanced (LTE-A) have a demonstrable uplift in speed compared to the third generation predecessor cellular technologies. The use of the cellular network imparts mobility to these routers meaning that they can be deployed anywhere with suitable cellular coverage.

This significant advantage provides agility and flexibility in network deployment. This has meant that LTE routers have been used for a wide variety of applications including in-vehicle connectivity, M2m/IoT, and of course consumer home networking.

How does an LTE router work?

The LTE router functions by forwarding and receiving data packets between its cellular modem and devices that are connected to it. The router itself is not connected to the internet. It is reliant on the cellular modem which connects to the service provider’s network for its internet connection. The service is distributed to client devices via WiFi (802.11), Ethernet (802.3), or USB, depending on the configuration of the router.

Do LTE routers have a WiFi radio?

Not all LTE routers use WiFi to transfer internet connectivity to a client device. To deliver WiFi, the router PCB must have an 802.11 transceiver embedded which are usually 2.4 GHz and 5GHz as well as the WiFi antennas necessary for the performance of the wireless network. A router that carries both WiFi and LTE radios will require a careful design with impedance matching, voltage management, and isolation of these critical components as well as their antennas.

LTE cellular modems may be integrated (on-board) in the router or connected via a USB or Ethernet cable to the modem. Other cellular router designs have a modifiable PCB router board with a PCI slot for connection of a cellular module in the form of a mini PCI Express card. This means that a PCI card of choice can be installed, for example, the Sierra Wireless MC7455 which is a Cat 6 LTE modem that is compatible with the leading cellular carriers. M.2 cards are an alternate and more compact type of internally mounted cellular card that is noted for their energy performance. Some routers will carry both M.2 and PCIe connectors or a PCI to M.2 adapter can be used. Once mounted the modems are secured in place on the router board with small screws.

To function LTE routers also require an active SIM card which can be inserted into a slot on the device. The SIM card is necessary to connect to the carrier network. If a micro SIM card is used, a SIM card adapter is typically required for insertion. Firmware may also be needed to configure the router to communicate optimally with its modem, especially if the router is self-built.

Many plug-and-play LTE routers have limitations on the networks and frequencies that can be used and prevent SIM swapping.

LTE routers are reliant on good cellular signal coverage and quality antennas for optimal performance.

All cellular routers require adequate signal strength, which is usually greater than is necessary for mobile internet on a phone or hotspot. The cellular carrier used for an LTE router should be selected for good performance in the location where the router is used. One of the advantages of using a multi-band module like the MC755 is that the module uses inter-Radio Access Technology (RAT) and inter-frequency cell reselection to select and handover between cells or frequencies to provide the best connectivity and performance.

Where signal strength is poor external LTE antennas and cellular boosters can be used to improve the signal that drives the router in areas that are remote or have poor coverage. Both internal and external LTE antennas are directly connected to the LTE modem within the router via either U.FL or MHF4 pigtail connectors which are usually attached to a bulkhead SMA connector. Special insertion tools are typically used to attach the U.FL or MHF4 connector to the card.

Antenna selection is critical to the performance of an LTE router.

Cellular carriers use a broad range of frequencies to deliver LTE connectivity to end-user devices like routers and so the antennas used by cellular routers should be matched to the frequency bands used by the LTE carrier selected.

LTE router specifications

LTE routers vary in their specifications depending on the application required and the carrier networks they use. In North America and EMEA, cellular carriers for LTE routers include:

• VERIZON
• AT&T
• SPRINT
• BELL
• VODAFONE
• EE

They are typically rated by the LTE UE Category, explained below. Category 6 or higher is preferable for supporting dual-band WiFi output. Typical enterprise-level LTE-A routers have the following specifications:

• Depending on the modem, LTE routers will support multiband LTE as well as multiband WCDMA / HSPA / HSPA+ / DC HSPA+
• The type of LTE supported can vary by category with Categories from Cat.4 (uplink speed 50 Mbps and downlink speed 150 Mbps) to Cat.12 (uplink speed 150 Mbps and downlink speed 600 Mbps). Routers used for IoT or M2M applications used Cat-M1 LTE which is specifically developed for Low-Power Wide-Area Networking (LP-WAN).
• The WiFi carried is typically 802.11ac which is dual-band (2.4 GHz / 5 GHz).
• LTE routers also have 1x1 MIMO WiFi antennas (433 Mbps).
• The router carried one 802.11 Service Set identifier (SSID) per radio.
• Most end-user routers are capable of serving up to 10 client devices.
• As mentioned above the typical interfaces of LTE routers include Ethernet (10/100/1000), Recommended Standard 232, and USB.

LTE router antennas

LTE router antennas need to be specifically matched to the LTE router setup and its application. If the router provides WiFi connectivity, both WiFi antennas and LTE antennas will be required.

The LTE antennas used for consumer home networking solutions will differ from those used in rugged environments or those used in remote outdoor settings. Antennas may be internalized, PCB-mounted units, or external antennas which are often selected because they provide enhanced coverage and performance.

LTE MIMO antennas for LTE routers

Both LTE and WiFi use multiple-input and multiple-output (MIMO) to multiply the capacity of their radio link, enhancing speed and performance. MIMO is an essential component of LTE technology and involves the use of multiple transmitting and receiving antennas to send multiple data signals over a single channel simultaneously, exploiting multipath propagation for higher data rates and more robust wireless links, especially where bandwidth is limited.

LTE will only function optimally with more than one antenna and cellular modems carry connectors for MAIN and auxiliary (AUX) antennas. Many routers use a 4x4 MIMO antenna solution, this can be achieved with an all-in-one 4x4 or paired 2x2 antennas.

We offer a broad range of RoHS-compliant LTE antennas that are compatible with the leading LTE routers. Our LTE router antennas are suitable for:

• Home networking
• Backup and ADSL replacement
• M2Mb and IoT
• Cellular modem/ PCI card development kits

Antennas used will depend on the coverage available and whether they are installed outdoors or indoors. If cell towers are distant directional panel LTE antennas pointed towards the tower or paired Yagi LTE antennas are popular choices.

Key applications of LTE Routers:

The ability of LTE to handle high-speed, high throughput data transfer with excellent latency and precision, makes it a competitive alternative to wire-line networking. Cat6 LTE is also a solution for providing internet access in areas where broadband service coverage is limited or prohibitive in cost.

LTE routers can be used to provide primary connectivity, usually with a fallback to 3G connectivity if there is any deterioration in LTE service. Rapid deployment of a wireless wide area network with LTE completely bypasses the costs of running cables and can be undertaken anywhere with cellular coverage.

When used as a WAN backup, LTE routers add resilience to an existing network. If the primary network suffers outage or failure the LTE router provides a non-terrestrial data path that is proven to be resilient in mission-critical situations. Integrated LTE router solutions and be configured to automatically provide connectivity if the primary network link fails or provide increased bandwidth to prevent overload of the primary network.

[A] LTE routers for vehicle networking

LTE networking is designed for speed and mobility making it advantageous for advanced wireless connectivity and networking in vehicles. With fast uplink and downlink speeds, data can be rapidly exchanged with the vehicle and retained for cloud storage or real-time processing.

LTE routers are preferentially deployed in vehicle fleets that are used for commercial and public safety work due to their ability to support the necessary video, voice, and data applications reliably, in hazardous environments and evolving situations. Integrated networking can be accessed by personnel wherever the cellular network extends. Vehicle routers typically combine LTE, WiFi, and GPS with network management software that allows the router to be directed to deliver specific functionality. Performance 4G vehicle routers provide multi-network connectivity and can utilize private cellular networks for access to secure back-office systems and databases such as those that hold criminal records.

Emergency departments such as the police routinely have LTE wireless routers installed in incident response vehicles and cruisers. These routers provide them with the connectivity they rely on in the field. Also other public vehicles including:

• Fire engines
• School buses
• Utility vehicles

LTE routers can provide connectivity for a range of widely used devices, within the vehicle and body-worn on personnel including:

• Vehicle telemetry means that the vehicle status including its performance, handling, and engine diagnostics can be constantly monitored.
• LTE routers can also be used to support Wifi-based Land Mobile Radio, Ethernet DVR modules, and cameras that are installed in the vehicle. This means that not only are mission-critical communications facilitated but audio and video data can be uploaded for real-time cloud storage.
• Also, the router can provide connectivity for body-worn devices used by Law Enforcement or EMPs including cameras, radios, and e-ticketing devices.

Commercial vehicles, like haulage fleets that are fitted with LTE Vehicle Routers, can benefit from implementing cellular-based and WiFi technologies that improve the safety and efficiency of Heavy Goods Vehicles.

• LTE routers can support C-V2X technologies including anti-collision warning systems. As they take advantage of the cellular network for connectivity to interact with C-V2X enabled traffic signage and transportation infrastructure.
• Driver Fatigue Monitoring is now seen as critical to the prevention of accidents. Several proprietary systems provide real-time data on driver condition including pupil dilatation and eye fatigue for early-warning. These and other parameters can be monitored remotely via an LTE-supported wireless connection.
• Fleet Management Systems that use LTE to drive their connectivity enable fleet managers to have greater oversight, responsiveness, and communication with their drivers. An added benefit is that LTE’s speed and high data rates are often delivered at a lower cost than legacy 3G devices.

[B] 4/G LTE routers for industrial M2M and IoT applications

Cellular routers can provide the connectivity needed for a broad range of cellular and commercial IoT applications. The coverage, reliability, and afforded by cellular networks means that networked devices, industrial components, and appliances can send and receive data in volume for precision monitoring and control.

LTE networking with routers is also very flexible meaning that low-power wide-area network (LP-WAN) LTE-M applications can be supported simultaneously with the output of audiovisual devices that may use more bandwidth and data.

Specific applications are diverse ranging from surveillance cameras to Point-Of-Sale (POS) technology. Other IoT and M2M applications include:

• LTE routers for asset tracking

LTE routers are also used for precision asset tracking in real-time, almost anywhere in the world. This type of high speed and bandwidth connectivity means that not only the location but also the condition and security status of goods in transit or storage can be continually monitored. This type of accuracy and reliability enables companies to remain agile and responsive if problems arise and the ability to tackle issues decisively and with confidence.

One of the key challenges faced by IoT is the varied and sometimes remote environments networked objects are located in. This can lead to problems with maintaining uptime of the services and technologies that rely on a router for their connectivity.

High specification LTE routers can combine GPS satellite connectivity with LTE and WiFi where necessary to facilitate continuity in locating and monitoring assets.

In remote areas where cellular connectivity is limited, GPS coverage can be used, in dense urban settings where GPS performs poorly, LTE is harnessed and in the indoor setting WiFi can provide continuity of performance.

• LTE routers for remote monitoring

4G/LTE routers are integrated into wireless monitoring solutions for a range of industrial machines including:

• Generators: The status and performance of a generator or power system can be continuously monitored with real-time automated alerts for commonly reported events.
• Lighting: Critical lighting systems on airport runways or cell towers are legally required to be always on. An LTE-supported system can immediately alert managers to failed lighting so that compliance can be maintained.
• Industrial refrigeration: requires careful thermostatic control which can be monitored and adjusted remotely via LTE.
• Irrigation systems: and other agricultural solutions use LTE routers to make farming at scale more precise and resource-efficient.
• Sewerage systems: require continual monitoring and LTE connectivity can be used to update the status of a sewer system on a network-wide basis, with alerts for emergencies like overflows or pump failures.

Being able to monitor systems and machinery remotely reduces man-power requirements for these tasks. M2M-enabled equipment and components can notify personnel via phone, email, or SMS if they have failed. This facilitates prompt and targeted responses to system problems keeping downtime to a minimum. The location where the routers will be installed will determine the degree of ruggedization required for both the router and the antenna with many units being capable of long-term deployment out in the field.

• Cellular routers for security

Domestic and commercial security systems can use LTE modules to deliver the connectivity required for robust alarm-based monitoring of properties. Not only can LTE be used in the monitoring of the status of a property with sensor-based feedback from doors and windows, but it can also be used to instantly relay information on alarm or forced-entry events to law enforcement and relevant partners. LTE routers provide a more integrated solution than other home security technologies that rely on LP-WANs like  ZigBee or LoRa.

[C] LTE routers for infrastructure and utilities

The cellular network is uniquely positioned to support utility networks and grids due to its extensive coverage. This means that LTE routers can support utility or grid intelligence and operations at scale and a large number of utility companies have transitioned to using LTE for their  IoT applications.

LTE routers provide the connectivity required to support utility industry IoT applications including the creation of smart-grids that can draw on a combination of renewable and non-renewable energy sources for flexible and environmentally responsible power. LTE is also used for the connectivity required for end-user smart-metering meaning that customers can track their energy consumption conveniently.

Frequently Asked Questions

What are LTE categories?

LTE UE categories are distinct from those that pertain to Ethernet. These are User Equipment (UE) categories and pertain to any device used by end-users for LTE connectivity including routers, cellphones, and laptops.

The router used should have a category that is compatible with the devices it serves. The lower categories are often used by cellular modules for LTE-M or LP-WAN networking.

These Categories are used to inform cellular base stations (eNB) of the capability of the device being used so that it can provide data at the optimal speed for the device.

9 categories vary in their specification and performance. When evaluating an LTE router the category may also determine if it is capable of MIMO networking and the number of antennas that will be necessary for operation.

Here are the data rates for the most commonly encountered LTE UE categories:

What is 2x2 MIMO?

This is the arrangement of 2 sets of paired antennas that are used to create two data streams for a receiving device. This arrangement is advantageous as it is capable of doubling downlink throughput.

The payload is divided between the two data streams and uses a single frequency band/channel. The spatial multiplexing involved is achieved by isolating the antennas, usually by using orthogonal polarization (horizontally polarized pair / vertically polarized pair).

A 100% enhancement in performance of 2X2 wireless links is typically achieved only under controlled laboratory conditions. Real-world installations will be affected by physical structures and environmental conditions, though a marked uplift in speed and performance is noted. MIMO arrangements work best where the transmission paths remain distinct and do not interfere with one another.

What is 4X4 MIMO?

This more powerful form of MIMO aims to establish four data streams, generated by 4 transmitting antennas and 4 receiving antennas. This arrangement can achieve up to a 400% increase in throughput by distributing the data payload among the four antennas. It has started to supersede 2x2 MIMO due to its significant improvement in network performance. It has far greater design complexity than 2x2 relying on strategies other than antenna polarization to ensure that the individual data streams remain distinct.

What is the difference between an LTE router and tethering?

Tethering is a function available on mobile devices to allow their mobile internet connection to be shared with a limited number of devices (usually up to 8) over WiFi, USB, Ethernet, or Bluetooth.

The device that supplies the tethering service becomes a mobile “hotspot”. Hotspots are similar in function to a router but are limited in their functionality and are unable to perform the full-time role of a router. Tethering devices are usually battery-operated which limits the duration of service in comparison to a powered router. Rapid consumption of the contracted mobile data allowance and supplementary fees for tethering from the carrier also a problem.

Though an LTE router works similarly, the arrangement for sharing a mobile (cellular) internet connection is more formal as the device is specifically manufactured for this purpose. 4G routers require a SIM to operate and carry data plans that provide better value for money and reflect their more intensive use and coverage.

Are MiFi and LTE routers the same?

“MiFi” is a trademarked name used to describe a type of compact cellular router that functions as a mobile WiFi hotspot. Cellular carriers often retail branded mobile internet devices that deliver WiFi connectivity for up to 10 devices. 4G/LTE MiFi devices are Category 6 devices, which is the first Category of LTE advanced. The most advanced hotspots achieve downlink speeds of up to 300 Mbps by harnessing MIMO and Carrier Aggregation.

Do I need a cellular tower survey report for my LTE antenna?

Cellular tower surveys are useful for the proper planning of an LTE-driven wireless network. They can be used to determine the cellular carriers and coverage available at the site where a network is going to be deployed.

PDF reports and maps can be purchased, or the information obtained from individual cellular carriers. The detail provided usually includes.

• Locations of the closest cell towers to the proposed network.
• The cellular carriers available.
• Geographic data like distance and elevation.

These reports are used to determine the closest towers, assessment of line of sight, and the selection, direction, and mounting of antennas for the router.

In conclusion

LTE routers have emerged as a performance wireless networking solution that offers surprising flexibility and plasticity. These highly adaptable routers are able to support a continually expanding range of personal, commercial, and industrial applications and novel integrations for this technology are constantly being found. Antenna selection is critical not only to the performance of an LTE router but the integrity of the network it supports.