LTE can already support low latency services for many use cases for smart energy such as smart metering, controlling the charging of electric vehicles, monitoring and controlling wind farms and operation of microgrids, but what can be done to ensure the availability of services even in radio network overload conditions? Now new services are being introduced to support so called “machine type communications” with low cost devices opening up many new business cases for energy providers. What do these new services provide and do these new LTE services have characteristics suitable for smart energy use cases? Even lower latency services are planned for the next releases of LTE – what new services could they offer to energy providers?
These questions are answered by Dr Fiona Williams, Research Director for Ericsson, who will be presenting the upcoming webinar, LTE for smart energy - the latest results on LTE performance for renewable energy communications.
The webinar will expand on how the energy industry can use LTE as a communications network for a range of smart energy use cases that were investigated by Ericsson in an experimental set up, using a live LTE network, in a laboratory at the University of Aachen.
The energy use cases modelled and investigated
Ericsson investigated four use cases in order to have a representative set of use cases for LTE communications in smart energy contexts. As energy providers increasingly need to optimize their networks to include renewable energy sources and distributed control of energy production and use, the use cases reflect the new contexts of energy network operations. Real data was used as a basis for the models. The use cases focused on the use of LTE for communications for:
- Wind farm control and monitoring - cellular communications are often used for communications with wind farms so this is a use case for many energy providers today.
- Electric vehicle charging control - in this scenario, the energy provider can reduce or stop charging of e-vehicles to reduce the network load for short periods of time.
- Microgrid operation - LTE was used as the communications network to monitor and control a microgrid. To stress the LTE communications, we assumed that the grid was controlled and monitored in close to real time conditions in which messages were sent with a high frequency.
- Smart meter communications - again, the LTE network was stressed with very frequent smart meter reading measurements and control signals.
All four use cases represent central control applications in which LTE could be used as a communications network to support applications with a delay requirement of <120ms. The use of Manufacturing Message Specification (MMS) protocol was assumed for all the communications so that the results of the use cases could be compared with each other.
During the experiment, the use case scenarios were modeled on a power network simulator, generating streams of messages as they would be sent by real use cases, using the MMS protocol. The messages were relayed from the simulator to a laptop with an LTE dongle attached to it, which transmitted the messages over the air to the nearby live LTE base station supported by the Ericsson LTE core network.
The delay with which each message was received was measured under normal conditions and in radio network overload conditions. It is rare that a radio network overload occurs, explains Dr Williams.
The LTE features that were investigated include:
- QoS (quality of service) provisioning (standardized in LTE Release 8). This allows for data prioritization which is especially helpful in overload situations. This is available in today’s LTE networks.
- Low complexity devices (standardized in LTE Release 12). These devices are expected to be released into the market from next year. Expected to cut costs of LTE modems by 50%, utilities can use this to deploy LTE modems and LTE communications for many of their use cases. Rel-12 introduces a new low complexity devices category (Cat-0). These will also reduce 50% of devices’ complexity and use power saving mode to increase battery lifetime to 10+ years. They use single receive antennas and the peak data rate is reduced to 1Mbps. Also the use of half duplex FDD instead of full duplex is enabled.
- Semi persistent scheduling. A technique used to reduce latency for discussion in standardization as part of Release 14 and based on 1ms transmission interval and conditional transmission based on the data availability. This technique offers advantages by improving the latency and performance of low complexity devices.
“Low complexity devices are coming and they should be on the market next year. They offer very good prospects and opportunities for energy providers to use LTE in new ways and it changes their business case from an energy provider perspective,” explains Dr Williams.
There are many sectors which are planning to use cellular networks and to connect devices in many ways across many sectors. These include M2M type communication, which is growing in all sectors including utilities, critical infrastructures, agriculture, and smart manufacturing to list just a few. “These sectors plan to use cellular networks in new ways in the future to automate processes in real time enabling them to reap the benefits of lower costs and greater productivity,” explains Dr Williams.
Massive machine type communication (MTC) is a growing area and LTE can provide low cost devices that have low energy usage and are designed for small data volumes compared to downloading videos for instance but there are massive numbers of devices to manage and sometimes long ranges to cover with communications having long physical ranges.
During the webinar, the highlights of the LTE latency results will be expanded on. One highlight in particular points to the fact that when it comes to messaging, there was no significant increase in delays even in the condition of a radio network overload.
What the results mean for energy providers
Power network operators can use public and private LTE networks to meet their requirements for centralized control applications, requiring delays of <120ms, with cost effective communications services and low complexity devices.
New and less complex devices will provide very good performance results, particularly when latency reduction techniques are applied to the new category zero devices. The results of the studies mean that category zero devices will be very useful to utilities enabling them to use LTE for use cases which might not have been economic with full complexity, more costly devices, explains Dr Williams.
She points out that Ericsson offers support to energy providers by offering innovative consultancy and systems integration services, LTE products supporting QoS provisioning for energy use cases, and LTE products supporting MTC devices for energy use cases.
After the presentation, there will be time for questions so that you can understand what is available and how you can deploy the services using public or private LTE networks or a combination of both. Register here for the webinar.