Inter-Slot Frequency Hopping with DMRS Bundling for NR Coverage Enhancement

Coverage performance promotion is crucial for operators when commercializing wireless networks, to this end, enhancement based on inter-slot frequency hopping with demodulation reference signal (DMRS) bundling was introduced and standardized in 3GPP, where frequency hopping in unit of slot-bundle is enabled. However, existed hopping pattern may result in an unbalanced slots distribution between different frequency positions that causes performance degradation. In this paper, we present and analyze a modified hopping pattern, which involves the system frame number in determining the hopping position. The proposed pattern has very small standardization impact but can effectively address the unbalanced issue. The performance gain of the modified hopping pattern is validated by link-level simulation, where about 0.7 dB gain can be observed in some typical case.