LTE Cat 1 VS LTE Cat 4
The Right Choice in Modem Selection
In order to gain a better understanding of the difference between LTE Cat 1 and LTE Cat 4 we
will first discuss the need for cellular IoT and give a brief definition of the technologies before
undertaking a more detailed evaluation.
The evolution of cellular IoT transpired in direct response to the popularity and ubiquity of IoT
technologies and protocols that have become common place within todays connectivity
landscape. The need for low-power consumption and wide-area networks has grown unabated
with the traditional cellular offering previously not being ideal due to consuming too much power
and increased costs for most low data rate IoT deployments. However, the market needed the
level of guaranteed service and infrastructure that could only be deployed by the cellular
providers coupled with low power and wide-area coverage. The new generation of cellular
technologies, LTE Cat 1 and LTE Cat 4 resolve the power and cost problem while retaining the
guaranteed service and infrastructure benefits.
LTE Cat 1 represented the original response offering a robust and viable alternative using
existing LTE network based on the 3GPP Release 8 protocol. This offered a ready built and
global infrastructure for IoT deployments.
Since the initial release there have been many further iterations in fact 14, the most prominent
and widely adopted remain Cat 1 and Cat 4 which align to most of the today's IoT requirements
as shown in Table 1. The question of whether to use Cat 1 or Cat 4 really comes down to your
application and choice of technology stack.
In the creation of your technology stack, you will need a gateway or a device connection to the
internet driving automated conversion of your data and offering a method of displaying that data
in a portal. Siretta, the Industrial IoT Company, offers a range of market leading Cat 1 and Cat 4
Siretta Limited - Enabling Industrial IoT https://www.siretta.com | +44 1189 769000 | sales@siretta.com
modem solutions. They come in industrial enclosures with their own antenna and power
supplies and are pre-certified, secure and ready for immediate deployment reducing time to
market. The only decision to consider is do I need Cat 1 or Cat 4?
The main variances are found when examining data rates in both the downlink and uplink, along
with power requirements. However, additional selection criteria for consideration includes:
Geographic location: continent, country
Type of data: numeric data, text, video streaming
Interface type: RS232, USB, Wi-Fi, Ethernet
Software Options: Over the air upgrade (FOTA), TCP stack, IP services
OS Support: Windows, Linux, Mac
Data rate requirements and power consumption are in most cases pre-determined by end
application. LTE Cat 4 offers an uplink speed ten times faster and a downlink speed fifteen
times faster than LTE Cat 1 measured in Mbps. In examining speed and power requirements
Cat 4 devices are better aimed at higher data rates. For anything video based that is essential
in real time viewing.
It is however feasible that your product and data requirements may fall between Cat 1 and Cat
4, and that you could have a degree of flexibility on your data rate. This being the case you
have two further options to consider, power consumptions and the cost of airtime. There is
always a trade off in any design, unfortunately the higher the data rate the higher the power
consumption generating a higher cost airtime contract.
Currently there are a number of products available with LTE Cat 1 and LTE Cat 4 that offer ultra
low power modes such as Siretta’s ZETA-NLP-LTE1 which is an LTE Cat 1 ultra low power
industrial modem. This is achieved by reducing the actual connection to the network effectively
holding the device in standby until data is required. In this mode power can be reduced to
around 1 milliamp making this perfect for remote devices which Siretta supports.
As can be seen in Table 2 above even the lowest power version of the LTE Cat 4 device uses
significantly more power than the lowest power LTE Cat 1 Device.
In addition to your primary decision around speed and power consumptions there are other
concerns to consider. Both LTE Cat 1 and LTE Cat 4 can cover the majority of frequency bands
and it will be necessary to select the model required for the specific region of deployment as
globally there are 72 bands with no device capable of covering them all. Selection will be by
Siretta Limited - Enabling Industrial IoT https://www.siretta.com | +44 1189 769000 | sales@siretta.com
territory. See table 3:
Connection to OEM equipment needs some thought, most modems offer RS232 interfaces
which is supported by new and legacy equipment in the field, some have a parallel ports and
additionally some provide general purpose interface (GPIO). Most have built in readers for a
SIM card and socket connections for external antennas, usually by SMA. They have a status
LED and power connection either fixed or plug in. All modems have an interface for setting up
and generally this is through the RS232 port or can be remotely using a web browser and the
device communicating through an internet connection. Additionally, some devices communicate
directly using Linux or Windows CE and can be integrated into the user equipment software.
This can save time and cost.
As described LTE Cat 4 devices generally have more user interfaces such as GPIO, ADC
(Analog to Digital Convertor) and additional serial ports. Table 4 below is a comparison of 2
such devices.
Siretta Limited - Enabling Industrial IoT https://www.siretta.com | +44 1189 769000 | sales@siretta.com
Making the decision on which device to select is made easier using Siretta’s Modem Selector
Tool. Siretta has various models available for LTE Cat 1, both the low power ZETA-NSP-LTE1
and ultra low power ZETA-NLP-LTE1, in addition to LTE Cat 4 with the high performance ZETA-
N-LTE, ZETA-NEP-LTE4 with GPIO, secondary serial port & ADC and ZETA-GEP-LTE4 with
GPIO, secondary serial port, ADC & GNSS. The ZETA range of products also provide
backwards compatibility to the existing European 3G / UMTS and 2G / GSM cellular networks.
The selection between LTE Cat 1 and LTE Cat 4 is almost always predetermined by the
application and data rate requirements. As seen in many typical IoT solutions the data
packages are typically small with power consumption remaining a primary factor. Although there
are 14 iterations under the 3GPP, LTE Cat 1 and LTE Cat 4 remain the nearest equivalent to
LPWAN and will continue to be a critical component of the cellular solutions within the IoT
space. Additionally, by being part of a licensed band it is expected that QoS (quality of service)
and SLA’s (service level agreements) will ensure a more robust answer to your connectivity
requirements both now and moving forwards in an ever competing market.
The solution architect of course still retains a significant degree of influence on the standards
used and by choosing to use lower data rates they can reduce costs in elements such as
airtime. It is however worth a note that lower bandwidths can potentially reduce quality or
increase the time of transmission.
Once the decision on data has been made, the user can determine how feature rich the
interface will be. For some users it may still be necessary to choose LTE Cat 4 even with lower
data rate requirements to gain GPIO or additional inputs required for their technology stack.
Alternatively LTE Cat 4 can offer benefits on power usage for transmitting large files compared
with LTE Cat 1.
Siretta are a leading manufacturer and developer of IoT products, IoT software and IoT
solutions with a specialty in providing these for Industrial markets and business to business
applications. Siretta have extensive knowledge and experience within IoT with a focus on
cellular technologies in support of 2G (GPRS), 3G (UMTS), 4G (LTE), NB-IoT and LTE
Category M. Products include cellular modems & terminals, routers, cellular network analysers,
RF antennas, RF adapters and low loss RF cables.
Siretta Limited - Enabling Industrial IoT https://www.siretta.com | +44 1189 769000 | sales@siretta.com
Powered by TCPDF (www.tcpdf.org)
