Converging networks pave the way to 5G deployment

As Dr Pleros and Dr. Miliou, of the Aristotle University of Thessaloniki, Greece, explain, events with a particularly high concentration of spectators are a good illustration of how this can be problematic: “Imagine 10,000 fans uploading a photo or video of a player scoring a goal on their favourite social network, almost simultaneously.

This creates a huge amount of traffic which is very difficult to satisfy, and it only gets worse as objects like cars become connected and self-driving: for the car to make the right decision on how to move, an enormous amount of data from a high number of sensors is required.”

This is where Next-Generation Networks (NGNs) come in, or at least have to. Unlike the linear evolution seen from 3G to 4G networks, the Internet of Things requires a full-blown paradigm shift where each device is served according to its needs.

This requires heterogeneous networks, wireless data rates than can go up to 10Gb/s, latency lower than 5msec, and the capacity to withstand a much higher end-user density – all this without additional energy cost.

As there is no such thing as a single technological path to get there, finding the right one requires dedicated, well-trained researchers putting potential solutions to the test, together. This is precisely what Dr Pleros and Dr. Miliou aimed to do under the COMANDER project, with a focus on the seamless convergence of fibre and wireless networks.

“Fibre-wireless networks are currently considered as a must for future 5G fronthaul networks, but back when COMANDER started, we still didn’t know whether this solution should be favoured,” Dr. Pleros explains.

“By training young researchers and bringing synergies between people from the fields of photonics and wireless technologies, we could set the first cornerstones towards converging fibre and wireless networks, and help, to some extent, defining fibre-wireless networks as the path to be followed.”

The COMANDER approach essentially consists in reducing cost and energy consumption by stripping antennas back to the basics. “We know that NGNs will feature a much higher number of antennas, basically small-cell antennas that will be plugged on lamp-posts or other convenient locations.

But if each of these antennas is intelligent enough to serve its mobile users, as is currently the case, then the cost and energy consumption for the whole system will become prohibitive,” Dr Miliou says. “If we want to reduce cost and energy consumption, we need these antennas to be almost dummy repeaters.”

COMANDER therefore places network intelligence at the BaseStation – a central location using optical interfaces as well as Medium-Transparent Medium Access Control (MT-MAC) mechanisms to ensure NGN intelligence whilst meeting performance targets.

As Dr Miliou points out, NGN intelligence is extremely important for low-cost deployment as “it means that the end-user can exchange traffic with the BaseStation regardless of whether the intermediate link includes only wireless, optical or both as transmission media.”

All in all, the project team has designed and demonstrated a converged fibre-wireless network architecture for providing up to 1Gb/s wireless data rates using mm-Wave wireless connectivity. The team even exploited the converged infrastructure to use advanced concepts like Network Coding as ways to further reduce latency and energy consumption.

“We are witnessing increasing interest from major industrial telecom operators and vendors to get involved in activities that promote network convergence and migration from the CPRI standard to Ethernet packet-based communication, while at the same time continuously adopting more optical technologies and photonic chips. All these areas have been pioneered by COMANDER, and we are really proud about this,” Dr Pleros concludes.