Coverage planning and optimization is one of the most crucial tasks for a radio network operator. Efficient coverage optimization requires accurate coverage estimation. This estimation relies on geo-located field measurements that are gathered today during highly expensive drive tests (DT) and will be reported in the near future by users' mobile devices thanks to the Third-Generation Partnership Project (3GPP) minimization of drive tests (MDT) feature. This feature consists of an automatic reporting of the radio measurements associated with the geographic location of the user's mobile device. Such a solution is still costly in terms of battery consumption and signaling overhead. Therefore, predicting the coverage on a location where no measurements are available remains a key and challenging task. This paper describes a powerful tool that gives an accurate coverage prediction on the whole area of interest: It builds a coverage map by spatially interpolating geo-located measurements using the Kriging technique. This paper focuses on the reduction of the computational complexity of the Kriging algorithm by applying fixed rank Kriging (FRK). The performance evaluation of the FRK algorithm both on simulated measurements and real field measurements shows a good tradeoff between prediction efficiency and computational complexity. In order to go a step further toward the operational application of the proposed algorithm, a multicellular use case is studied. Simulation results show good performance in terms of coverage prediction and detection of the best serving cell. Index Terms-Coverage map, expectation-maximization (EM) algorithm, fixed rank Kriging (FRK), radio environment map (REM), spatial statistics, wireless network. 0018-9545 . Her current research interests include radio propagation, measurements and field trials, channel modeling, radio network planning and optimization in wireless networks, and geo-location techniques in both cellular and internet-of-things networks.
Braham et al. REF built the coverage maps by applying the fixed rank Kriging interpolation to further reduce the computational complexity compared with the traditional 80768 VOLUME 7, 2019 Kriging interpolation.
Fixed Rank Kriging for Cellular Coverage Analysis
IEEE Transactions on Vehicular Technology
IEEE Transactions on Vehicular Technology
Computer Science