Today’s mobile radio technology too slow to cope with many future applications

Real-time mobile data transmission is the basis for a variety of new applications. Examples of these applications are car-to-car communication, inter-machine communication and the ”tactile Internet“. All require the interaction of a large number of participants or, better, of sensors, which must have very short signalling times with delay (known technologically as latency) of only milliseconds, and data and signal connections that are so absolutely reliable that there are no outages. None of today’s wireless technologies is up to these requirements. For example, the LTE (Long Term Evolution) standard was developed mainly for high data throughput.

”Fast wireless“ worked on minimising latency in basic 5G technology

The ”fast wireless“ project, therefore, explored, developed and evaluated basic technology for fifth generation (5G) mobile communications with minimal latency so that mobile devices and control units can network in real time. A major focus was on developing transmission concepts that allow the principles of low latency and high reliability.

IMMS’ contributions to the future means of 5G communications

IMMS defined the requirements for real-time operating systems that will communicate by 5G, supported the other partners in the project on the specifications of suitable interfaces between the communications layers and developed components which will permit latency-critical elements to be partitioned into their hardware and software elements. The technology developed in the project has been used by IMMS in a demonstration model, applying the algorithms of the project partners.
As future machines or robots will be operating in closed-loop regulation systems to achieve process optimisation on the basis of data transferred by 5G, IMMS has cooperated with Dresden University of Technology to create an inverted pendulum demonstrating the principle. The pendulum shows that a 5G wireless signal route with minimal latency is, indeed, essential for such new applications but also that all the hardware and software in the system must be configured to work in real time.

Control of an inverted pendulum with low latency data transfer demonstrates the new principles for 5G

The aim of the system is to maintain the vertical orientation of the pendulum in its state of unstable equilibrium. The pendulum is 9 cm long and stands upright on a 0.2 mm narrow edge on a moving linear axis, see Figure 1. To ensure it stays in its orientation and position, the pendulum is observed by a camera. To keep it actively in balance, its angle is constantly communicated by wireless in real time to the control system of the axis, using the new 5G mobile radio standard. The data would arrive too late if technology currently in use, such as LTE, were used: the pendulum would fall over. The latency of the data transmission in the IMMS demonstrator is with just 100 µs per data packet well below the target of 1 millisecond required for the 5G standard.

IMMS has thus done more than implement a complete prototype system with its new algorithms and communications components; more than show a practical application of low-latency communications in cellular radio. It has also provided a clear demonstration of the significance of low latency for the benefit of an audience unfamiliar with the subject.