Article explains where the individual IoT technologies have their limits and what benefits have well-known Ethernet and other networks and protocols based on it.
Ethernet remains the favourite network for both IT and industry
HW group produces IoT products for environmental monitoring, energy consumption monitoring and industrial applications. Poseidon2, Damocles2, and STE2, the industry-leading environmental monitoring products, use the wire-based Ethernet and Wi-Fi standards that are most suitable for the industrial environment. For mobile applications or technologies, where standard Ethernet is not available, we designed the ARES product line with GSM / GPRS connectivity, and also the LTE, which offers the same features with higher bit rate.
The HW group solutions has a number of common features:
- Immediate availability of measured data in applications
- Warning and alarm functions
- Deployment of devices in IT infrastructure and industry
- High level of data security
- Support for a wide range of software applications and platforms
- Remote control and management of devices
These features require a reliable, stable connection with a high level of security of transport and communications services, which today provide especially standards derived from Ethernet.
What can Ethernet, WiFi and others do?
Ethernet is known mainly as a standard computer network. For IoT is overlooked, because for many people, IoT is a matter of wireless. But a wireless solution brings issues of signal strength, interference, noise, radio standard compatibility and security. Ethernet, however, does not have any limits on speed, encryption, the volume of data transferred, and is therefore the first choice for Industrial IoT (IIoT) applications. Ethernet, in addition to data transfer, also provides power to the device feature (PoE – Power over Ethernet), which can facilitate power in a number of applications.
It should be added that conventional Ethernet by wire also has a number of wireless alternatives because other Networks use the same transport and communication protocols to fully replace Ethernet.
WiFi or wireless Ethernet in most todays corporate buildings and public spaces represents standard. It allows high bandwidth and encryption security. For stationary applications where high power consumption is not essential, a reliable alternative to wired Ethernet. The default setting is more complex, but it can be solved in a number of ways.
GPRS / LTE
GSM, resp. GPRS is bit neglected interface in the world of IoT. IoT is considered to be a modern and progressive technology, while GSM for history, for those who want to use GPRS data on 3G or 4G Networks. But GPRS is a reliable interface, and if you do not require the transmission of dozens of MB data, it is completely satisfactory. Coverage is perfect in most countries, and although a number of operators have already been notified of this network being shut down and replaced by LTE Networks, GSM will still be there for some time. Under low costs can often have data in the order of dozens of MB per month for free. You can take advantage of the classic Ethernet, IP communication, such as http (s), so you do not have to open any special communication ports, SSL security, and so on. GSM represents a classic client / server communication, and if you use TCP / IP communication, it’s also confirmed and you’re sure the data arrived at the destination.
LTE is more interesting from IoT layman’s point of view, but it is important to note variation among LTE standards, in combination with the IoT term abbreviation. At this point, when we write about LTE, we mean the TDD and FDD standards, which are referred to 4G Networks. That’s the classic mobile phone network. It has the same benefits as GPRS, plus high bandwidth. These networks probably swap the classic GSM / GPRS in future.
Both GSM and LTE Networks are ideal for mobile applications because they are able to automatically re-register themselves to the strongest point without loss of connection automatically when in motion. This is a big advantage against Lora, Sigfox or LTE cat M1 / NB-IoT. In addition, they allow you to send data to any IP address, that is, anywhere, and you are not bound to the cloud and therefore the operator’s application.
While GSM / GPRS Networks are unified across the globe (or there are 4 standards that can be met by one device), the situation in LTE Networks is more complex, and it is often necessary to use different devices with regional bandwidth and protocol variation.
LTE cat M1/NB-IoT
NB-IoT (Narrowband) is a subset of LTE cat M1. Both networks benefit from IP protocol, making it easier to use than Lora or SigFox.
While NB-IoT is designed exclusively for IoT devices and has a very limited bit rate (<250 kbps for download and <20 kbps for upload), as well as the volume of data being transferred. The bandwidth is 200 kHz. There is also limited switching between the connection points, because as long as NB-IoT has at least some connection, the data message is sent. But as the communication is mostly conducted after a UDP / IP unverified protocol, data is lost easily in mobile network. Therefore, NB-IoT is primarily suitable for stationary applications with extremely high energy efficiency requirements.
LTE cat M1, as opposed to NB-IoT, supports voice Voice Over LTE (VoLTE) and has a transfer rate of up to 1MB /s. In addition, Cat M1 allows you to switch from one wireless cell to other, so it’s suitable for mobile and mobile applications such as telematics and fleet management. Here, however, the data volume must be kept within the bandwidth and VoLTE is used more for voice messages than for calls.
If we considered LTE standard worldwide different, the NB-IOT, and LTE cat. M1 are more complex. There are a few more standards. Fortunately, this is only a matter of physical layer editing, so the production of different models means just fitting other component and does not affect the application.
HW Group prepares IoT products based on NB-IoT, respectively. LTE cat.M1 for 2019, their application deployment is assumed in the industry. The big advantage of this technology is both a connection to the standard mobile network, where can be expected stable operation, as well as duplex communication without need of cloud storage provider. Customer can choose cloud application or storage to use. Their earlier deployment is hindered, in particular, by small network expansion and opaque pricing policy for operators.
What are the other technologies and their limitations?
|Frequency||Bandwidth||Bit rate||Range||Target server||Capacity||Note|
|BT||2,4GHz/ 5GHz||1MHz||max 1Mbit||10-100m||User||No limits|
|WiFi||2,4GHz/ 5GHz||40MHz||max 150Mbit||10-100m||User||No limits|
|GSM/ GPRS||800/ 900/ 1800/ 1900MHz||200kHz||172kbit||10-15km||User||No limits|
|3G (UMTS/ HSPA+)||800-2100MHz||5MHz||384kbit||5-10km||User||No limits|
|LTE cat M1||450-3500MHz||1,08MHz||1Mbit||5-15km||User||No limits|
|NB-IoT||800MHz||200kHz||200kbit||5-15km||User||Transmitting time 1% per hour||High latency 1.6 –10s|
|LoRa||433/ 868/ 913/ 915MHz||125/250kHz||50kbit||5-15km||Operator||Transmitting time 1% per hour|
|LoRaWAN||433/ 868/ 913/ 915MHz||125/250kHz||50kbit||5-15km||Operator/ User||Transmitting time 1% per hour|
|SigFox||< 1GHz||200kHz||100/ 600bit||10-50km||Operator||Transmitting time 1% per hour, max 140 messages/ day||max. 216byte/ hr effective|
LoRa / SigFox
These are two communication interfaces developed for simple IoT applications:
SigFox operates in the 868 MHz non-licensed ISM band (906MHz in the US), which covers unlicensed short-range technology, such as part of home weather stations, garage door control, but also wMbus, wireless sensor technology. This is related to the need to minimize costs. SigFox was designed intentionally as a lightweight protocol for small message transfer. Fewer data means less power consumption and therefore longer battery life. The baud rate is 100 or 600 bits / sec. 12 bytes of useful data (plus some overhead) are transmitted over 2 seconds.
LoRa is a reliable wireless technology that also uses the 868 MHz bandwidth, but the data rate is in the range of 0.25kbps – 50Kbps. The basic element of this technology is spread spectrum modulation, which makes LoRa resistant to interference. Other advantage of this technology is the two-way communication and the ability to switch between connecting points. A great disadvantage is the complexity of the setting parameters.
In both cases, data transmission is secure. Coding is performed on the application layer using AES128 and multi-bit authentication. Also, in both cases, transmission time is limited (ie 1% transmission time per hour – only 36s!) not only with low consumption but also with limited bandwidth. In both cases, one message may contain only a few tens of bits (not bytes!). It allows to send very short message types (light, off, fault, temperature transmission, but ne more complex reports or datalogs).
At the same time, for both types of networks, the criteria for transmission reliability are set to a different level than for standard Ethernet. While Ethernet is now operating with 99.9999 percent reliability criteria, LoRa and Sigfox have a default error rate around 5 percent. This is due to the limitation of broadcasting times and the possibility that the cell can be overwhelmed at the moment. The transmission error is not solved by the device, the data are broadcast at the next time slot. For applications for which both networks are designated, this level of reliability is sufficient.
These IoT Networks (along with NB-IoT or LTE cat M1) are also called Low Power WAN (Low Power WAN) LPWAN to emphasize low power consumption and therefore the ability to power from batteries and accumulators. The device achieves long-term battery life (5-10 years) based on the limitation of data transmission (eg. once per day).
In addition, thin communication protocol of LPWAN networks does not allow remote management diagnostics and setting of devices or sensors. Each sensor must be managed on site, almost battery powered low-cost sensors have not any space to modify operating parameters. These features move classic Ethernet based networks up not only for industrial and IT segments but also for all remote control applications.
Original article was published on HW group’s web site: HW group