Multi-Pair Cable Measurements for 5G Indoor Service Provisioning

This paper considers the 5G new radio (NR) indoor service provisioning scenario where the CPRI link terminates at remote radio unit (RRU) in the building and multi-pair cable, i.e. CAT-5, is used to provide connectivity between distributed antenna unit (DAU) and RRU. The paper focuses on the de-tailed methodology for multi-pair copper channel measurement including measurement equipment specifications, their respective settings, measurement parameters i.e. characteristics impedance, insertion loss (IL), far-end-crosstalk (FEXT) and near-end-crosstalk (NEXT). The measurements include the cables for next-generation multi-pair system, where multi-pair cables, i.e. CAT-5 cables, are used from the RRU to the DAUs in a building. Conventionally, many multi-pair cables share the same duct in a building and interfere with each other, therefore two parallel multi-pair CAT-5 cables of 50m each are considered for the measurement scenario. This setup result in 4 twisted pairs terminate at each DAU and this configuration is termed as next-generation multi-pair MIMO (NGMM). The number of twisted pairs is increased by using the Phantom mode circuit connected to the opposite ends of each CAT-5 cable and the resulting configuration is called next-generation multi-pair super MIMO (NGMSM). The cable parameters have been measured for frequencies up to 1 GHz and 250 MHz for NGMM and NGMSM, respectively. DL data rate of each configuration is examined by applying conventional block diagonalization.