Interference Handling Challenges toward Full Duplex Evolution in 5G and Beyond Cellular Networks

Full duplex is a scheme that changes the duplexing paradigm in wireless communication networks. Enabled by self-interference cancellation methodology, it unlocks the potential to improve frequency utilization efficiency and reduce resource allocation latency. However, embracing the full duplex scheme in a mobile network can lead to complications in terms of cross-link interference among network entities. As a matter of fact, a successful network integration for the scheme must consider handling these emerging types of interference. On the other hand, diversification in evolving 5G networks - struggling to address unprecedented broad demands - allows the opportunity to consider full duplex operation at a newly emerging network entity type, which is the integrated access and backhaul (IAB) node. Indeed, this might be the beginning of a network adoption series for the scheme. For instance, the non-terrestrial network, another newly emerging use case, can be the next to benefit from full duplex resource utilization. On the matter of standardized solutions, 3GPP has specified several cross-link interference handling mechanisms, which eases the integration process of the scheme at the network infrastructure level, and paves the way for later phases of user equipment adoption. This incremental network adoption ensures the required technological maturity of self-interference cancellation. In practical terms, self-interference cancellation requirements depend on device type and its deployment environment. As the environment defines the properties of the self-interference channel, it must be known to the self-interference canceller. To assess the full duplex adoption feasibility in the IAB use case, we present experimental study outcomes of self-interference channel measurement addressing the outdoor deployment scenario of an IAB node.