High-efficient Multi-carrier Combination and Division Algorithm for Multi-service DRoF System

Aiming at the problems of low bandwidth utilization, severe inter-carrier interference, and the difficulty in service upgrades in the current digital radio over fibre (DRoF) system, this paper proposes a multi-carrier combination and division algorithm based on digital baseband modulation. The algorithm modulates the sub-carrier in the digital baseband domain and realizes multi-carrier combination and division in the limited frequency band. Besides, it adjusts the parameters in real time according to the bandwidth and insertion loss of each channel. In this way, the algorithm improves the frequency band utilization, optimizes the inter-carrier interference and the signal-to-noise ratio, reduces the transmission link rate. In this paper, a complete simulation system of multi-carrier combination at the transmitting end and multi-carrier division at the receiving end is built. And the three-carrier combination and division performance test are completed in the multi-service digital distributed antenna system (DDAS). Simulation and experimental results show that the algorithm greatly improves the signal transmission performance of adjacent frequency multi-channel systems, implying that the algorithm can be applied to various multi-service communication systems.