Analysis of Preamplifier Lineups for 5G OpenRAN Radio Unit

This paper presents an experimental evaluation of preamplifier lineups to be applied in Fifth Generation (5G) Open Radio Access Network (O-RAN) Radio Units (O-RU), focusing on their performance, efficiency, and reliability. Three preamplifier lineups are proposed to compose the O-RU Radio Frequency (RF) module operating in the n78 frequency band (3.3 to 3.8 GHz) with an average output power of 5 dBm for Power Amplifier Module (PAM) excitation. They are evaluated in terms of gain, linearity, and out-of-band emissions using 64 QAM and 256 QAM 5G signals with a maximum bandwidth of 100 MHz. The results highlight preamplifier solutions with higher linearity achieving Adjacent Channel Leakage Ratio (ACLR) levels of approximately 55 dBc and Error Vector Magnitude (EVM) below 1%.