Achieving 5G NR mmWave Indoor Coverage Under Integrated Access Backhaul

In this article, we introduce a novel millimeter wave (mmWave) access architecture, called mmWave over cable (mmWoC), for achieving effective indoor coverage under integrated access backhaul. The proposed mmWave access architecture is characterized by using an analog link over local area network cables to relay the frequency-converted signals between the mmWave small cell station at the outdoor and the mmWave antenna array in the indoor, so as to ensure line-of-sight transmissions for the indoor user equipment. We first develop a precoding process for the proposed mmWoC architecture where a cascaded radio–radio (R–R) mmWave channel (R–R channel) is seen at the mmWave base station. Then, rate analysis is provided for both the cascaded R–R channel and the cascaded radio–cable–radio channel (R–C–R channel). Furthermore, we investigate an efficient yet simple resource mapping scheme between the antenna signals and the cable subcarriers, namely nonconfigurable air-to-cable (NC-A2C), which ensures each cable subcarrier with sufficient capacity to meet the fifth-generation new radio (5G NR) requirement by manipulating the cable input powers. Simulation results indicate that the proposed NC-A2C scheduler can efficiently trade the capacity off for better control simplicity and cost effectiveness; and the proposed precoder can work well on the R–C–R indoor environment under the mmWoC architecture.