Interference Between 5G Indoor Micro Operators Utilizing Beamforming and Dynamic TDD in 26 GHz Band

Abstract

Future 5G networks will increasingly target local small cell deployments complementing the coverage of the existing outdoor networks. Moreover, the establishment of buildingspecific high-quality 5G networks by different stakeholders through local spectrum availability has gained increasing attention and new concepts, such as the micro operator, have emerged. To make these kinds of local 5G networks a reality, feasible spectrum sharing models are needed, which calls for a thorough understanding of the impact of the inter-operator interference on the performance of the victim micro operator. This paper presents system simulation results evaluating the feasibility of the local 5G micro operator concept for a scenario where two uncoordinated micro operators, sharing the same channel in the 26 GHz band, have deployed their networks on the same floor. The obtained results indicate that such highly local deployment is feasible in the given band if the penetration loss of the wall separating the micro operators is at least equal to 57 dB, corresponding approximately to a 17 cm thick concrete wall. The required isolation between the operators depends highly on the deployment scenario and therefore, feasible operation is possible in some deployments even with lower wall penetration losses. This highlights the fact that the worst case inter-operator interference levels alone do not properly model the specifics of the co-existence scenario, and can lead to overly protective requirements regarding the channel assignments.

Performance Comparison of Alternative Indoor 5G Micro-Operator Deployments in 3.6-GHz and 26-GHz Bands

“…As discussed for example in [19]- [21], the obvious price of such uncoordinated TDD operation is the inter-network interference between the downlink and the uplink resulting in high isolation requirements between networks. By synchronizing the networks, the impact of the inter-network interference, and hence also the required level of isolation, can be reduced in particular for the clearly uplink-limited scenarios [40], but at the cost of a considerably reduced flexibility for the micro-operators to satisfy their service needs. Therefore, the approach chosen in this paper is to evaluate the performance of a few different deployment options, affecting both the level and the impact of the inter-network interference, to make the co-existence scenario between uncoordinated micro-operator TDD networks more feasible.…”