Cognitive radio (CR) is a revolutionary paradigm that releases spectrum and enables secondary users (SUs) to opportunistically access under-utilized spectrum. Due to the great economic value of spectrum, CR technology has also promoted many spectrum-trading designs in cognitive radio networks (CRNs). Unfortunately, most existing designs rely on the premise that the SUs hand-held devices have powerful CR capability, which may not be easily embedded into lightweight small-sized radios of SUs' devices. Besides, existing designs mainly focus on per-user based spectrum trading for single-hop communications, and lack deep understanding of multi-hop end-to-end service provision. Moreover, the prevalent idea of choosing the best band makes secondary services vulnerable to interruption due to the returns of primary users. Finally, to facilitate spectrum trading, more accurate information of spectrum availability should be provided. Motivated by these facts, this project aims to construct a framework to investigate the spectrum trading in multi-hop CRNs, which includes the study of (1) designing a novel CRN architecture to facilitate the accessing of SUs without CR capability, (2) extending spectrum trading for multi-hop CR communications, (3) harvesting spectrum under spectrum uncertainty, and (4) constructing a fine-grained mobile spectrum map. The results of this project can advance the state of the art in spectrum trading designs and enrich the scientific knowledge of network designs and network economics. The project is thus crucial to the success of CRNs, which can provide great opportunities for job creation, greater productivity, and economic growth. This project also involves research publications/talks, curriculum development, minority student recruitment, training and mentoring, and outreach to K-12 students.