Low Speed Digital RoF Transmitter Linearizer Using Sub-band Signal Processing Technique

In this paper, we propose a digital sub-band (SB) filtering layout for Radio-over-Fiber (RoF) downlink transmitter. A proof-of-principle demonstration of 4 and 8 SB processing for a 256 QAM 100 MHz-bandwidth long-term evolution advanced (LTE-A) signal is presented. To alleviate the high processing speed required for next generation 5G signals, perfect reconstruction quadrature mirror filters (QMFs) are used to split and downsample a contiguous-carrier signal into smaller SBs: each containing part of the frequency content. Through measurements and simulation results, this paper demonstrated that the overall signal quality is maintained while achieving a reduction in the processing speed as well as an improvement in the adjacent carrier power ratio (ACPR). Our results demonstrate the advantages of the proposed technique in RoF transmitters networks.