Centralized radio access networks (C-RAN) are widely recognized as an enabling technology for the evolution of cellular systems, including 5G and beyond. However, the concept is not limited to 3GPP cellular systems and licensed frequency bands. In recent years, unlicensed low-power wide-area networks (LPWANs) have become popular for a variety of Internet of Things (IoT) applications. Those LPWANs can also leverage the concepts that popularized the C-RAN for cellular systems, such as coordinated multi points (CoMP), cell-free MIMO, and resources virtualization. In this paper, we first identify the requirements of popular unlicensed LPWAN technologies and detail the components of a C-RAN architecture that meets those requirements. We then present a proof-of-concept prototype implementation of the proposed architecture that supports the LoRa modulation, one of the most popular LPWAN technologies, and evaluate the latency and processing load of the system.