LTE-NR Spectrum Sharing via MBSFN Subframe Alignment

The patent converts the potentially harmful overlap between NR reference signals and LTE MBSFN subframes into a beneficial arrangement by configuring NR CSI-RS and TRS to specifically overlap with MBSFN subframes. This converts what would normally be interfering signals into useful NR reference signals that can be transmitted without degrading LTE PDSCH performance, since MBSFN subframes have different signal structures. The harmful overlap is transformed into a benefit by selecting the specific time resources (MBSFN subframes) where overlap occurs.

The patent applies local quality by making the time resource allocation specific to certain LTE subframe types. NR CSI-RS and TRS are configured to overlap only with MBSFN subframes (a specific local time resource), while avoiding overlap with non-MBSFN subframes. This localized approach allows MBSFN subframe reuse without causing collisions in other subframes, optimizing spectrum utilization in specific time regions while maintaining overall system performance.

The patent segments the time domain into different types of subframes with different orthogonality requirements. MBSFN subframes are identified and specifically configured to carry NR reference signals, while non-MBSFN subframes maintain traditional LTE orthogonality. This segmentation allows NR to use flexible numerologies in MBSFN subframes without compromising waveform orthogonality in other subframes, enabling both adaptability and reliability.