see graph below in Fig. 4-26) For UMi LOS, 500mtr: 118 dB For UMi NLOS, 500mtr: 148 dB 170 Open Radio Access Network (O-RAN) Systems Architecture and Design Required SNR for successful decoding of signal at receiver: QPSK: 15 dB 16QAM: 20 dB 64QAM: 25 dB 256QAM: 30 dB gNB side gNB EIRP = 20*log10(# antenna elements) + 5 (antenna gain/element) - 11 + P01db 128 Antenna Elements and P01db = 15 dBm gives EIRP of 51 dBm UE Rx gain-NF = 20*logl0(# antenna elements) + 5 (antenna gain/element)-5 (NF) 32 antenna elements give Rx gain of 30 dB Received power is 51 dBm - 118 dB pathloss (500 m LOS) + 30 dB (Rx gain) = -37 dBm Thermal Noise = 10*log10(RF Bandwidth) - 173.83 RF bandwidth of 400 MHz gives Thermal Noise of -88dB SNR achieved = - 37 - (-88) = 51 dB or more than sufficient to decode the signal. Note that the additional pathloss associated with NLOS operation ( ~ 30 dB per graph above) would push the signal quality to support 16QAM only. Path loss for UMi LOS and NLOS = =f(distance) UMi LOS UMi NLOS FIGURE 4-26 28 GHz pathloss per 3GPP. Chapter 4 Hardware architecture choices Beam switch process steps In case the system is being built from individual subsystems that are not provided by a single vendor, the topic of mmWave RFIC control and beam switching is important to cover. Beam switching involves multiple stages: Assigning the beam weight(s), beam selection, beam weight application: Beam weight assignment involves writing a set of beam weights to RFIC internal memory. This operation is typically done through a set of SPI and/or I2C operations that to a sequence of write operations to the internal memory/register set. The internal memory will hold these beam weights to minimize the overhead associated with writing new beam weight for each beam selection iteration. Typically, this step involves writing a sequence of values (phase, amplitude, ) to the RFIC. Beam selection is the step in which a specific (set of) beam weight(s) out of the RFIC internal memory is passed to the RFICs/PAs/LNAs in the system. This stag