Interference Control Mechanism for 5G Indoor Micro Operators Utilizing Dynamic TDD

Abstract

Future 5G networks will increasingly target local small cell deployments complementing the coverage of the existing outdoor networks. To make the high-quality inbuilding deployments more cost-efficient, and to promote innovation and competition in the market, new local business and spectrum authorization models are needed. Recently proposed micro operator concept allows the establishment of building-specific 5G networks by different stakeholders through the availability of local spectrum micro licensing. However, in order to make the concept of local high-quality 5G networks feasible, impact of the interoperator interference on the performance of the victim micro operator needs to be understood. This paper presents system simulation results demonstrating how the required minimum separation distance between two uncoordinated micro operators utilizing dynamic TDD in the 3.6 GHz band can be decreased by controlling the base station transmission power of the interfering network based on the measurements performed by the victim network. Without any interference control mechanism the required minimum separation distance can become as large as 400 meters, but with the proposed mechanism the required separation distance can be more than halved, or even made equal to zero. It is also shown that the interference threshold resulting in the smallest minimum separation distance is highly scenario-dependent: it will depend both on the network layout and load of both the victim and the interfering micro operator.

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

“…It is assumed that uO1 has deployed only one base station and is serving only one user, while the uO2 network consists of four base stations, and the number of active users is set so that the average network load becomes equal to 90%. Furthermore, based on the results from the previous studies [11,12], uO1 is assumed to be the victim operator, while uO2 is the interfering operator.…”

“…Assuming that the cells within a micro operator's network are coordinated, while the cells belonging to different micro operators are uncoordinated, the following four interference scenarios are considered in the assumed system model [11,12]:…”

“…The impact of the interference between adjacent indoor micro operator deployments in the 3.6 GHz band has already been analyzed in [11] and [12]. The previous studies have among other things demonstrated that in order to secure a sufficient isolation between the uncoordinated micro operators, the required minimum separation distance (MSD) between the adjacent micro operator buildings can in some scenarios be as high as 400-500 meters.…”

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

“…More information on recent 3.5 GHz spectrum awards is presented in [18]. Harmful interference between two micro-operators can be avoided by using an appropriate separation distance between these local license holders [19], [20], and the separation distance can be further reduced by managing the inter-operator interference [21]. For protecting the possible incumbents in the band, the authors in [4] have proposed a method based on an extension of the licensed shared access (LSA) for granting local access rights.…”

“…Furthermore, no interference coordination mechanisms between the micro-operators either on time, frequency, spatial or power domain are assumed. 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.…”