Networks have always been hierarchical in nature. Devices have connected to and communicated with one or more base stations ever since the birth of cellular communications. However, new technology enablers in 5G New Radio (NR) will allow devices to connect directly to one another using a technique called sidelink communications. Sidelink is the new communication paradigm in which cellular devices are able to communicate without relaying their data via the network. That means cars, robots and even consumer gadgets could create their own ad hoc networks without using the radio access network as an intermediary.
In the past decade new types of cellular services that go beyond traditional mobile broadband have had a strong impact on the scoping and development of the 5G NR standard. These new cellular services were motivated by the business and economic needs of making the 3GPP ecosystem capable of supporting industrial requirements ranging from direct automotive communication between vehicles to industrial automation with Ultra-Reliable Low-Latency Communication (URLLC) for mission-and business-critical applications. But these same technologies can also be used for consumers to enhance their communication experience. For instance, sidelink proximity services would allow devices to discover and communicate with one another at extremely high data rates and low latency, making them ideal for peer-to-peer gaming and streaming services as well as enhanced AR, VR and other wearable device communications.
All these new services require end-to-end solutions, meaning both the network and device characteristics and capabilities need to tightly integrated. The first step occurs in the pre-standard/concept development work.
In contrast with uplink and downlink, where resource allocation and link adaptation are controlled by the network, in sidelink the device performs both functions autonomously. In other words, the device gains more control of how to use network resources. At the same time, it is expected that Release 17 will introduce support for sidelink-based relaying and that in future releases multi-link relay will also be considered. Sidelink is also a candidate for future releases as an Industrial IoT enabler. By restricting the communication link to one hop, latency is greatly reduced, which is key to mission-critical industrial applications. Furthermore, sidelink is a potential solution for public safety ensuring direct communication or relayed communication between devices.
Another potential use case is multi-hop relaying where multiple sidelink connections are used to leap from to device to achieve better power consumption, overcome link budget constraints, and enhance latency and reliability. Gaming and entertainment services with AR/VR can also take advantage of sidelink, as will body networks, using direct 5G connections to replace the Bluetooth and eventually Wi-Fi links that currently connect these devices. The result could be a revolutionary change in the communication architecture for many consumer devices. Instead of providing a different radio interface for every use case, device vendors could rely solely on 5G as the link for wide-area, local-area and personal-area communications.
Nokia has a long-standing tradition of working both the device and network sides of the 3GPP ecosystem. To reinforce this end-to-end view of the 3GPP ecosystem, Nokia Bell Labs’ Device Research Group has been tasked with the mission of driving high-quality device innovation standardization support. This device research will ensure continuous focus on true end-to-end performance for the next generations of both devices and networks, for instance the 5G NR ecosystem. Sidelink is the perfect example of this focus on end-to-end innovation as it will enable a whole new field of devices and services not yet imagined.