An open source SDR-based NOMA system for 5G networks

With the rapid advent of various new applications and services, the anticipated use of bandwidth and frequency resources is beyond expectation in future mobile networks. To maximize spectral efficiency, novel radio access techniques need to multiplex users in the most suitable combinations of frequency and radio resources. Non-orthogonal multiple access (NOMA) is one of the candidate radio access techniques for improving spectral efficiency in the 5G mobile network through multiplexing users in the power domain, which has never been explored in past and current communications systems. While the concept of NOMA was proposed several years ago, the performance of NOMA has only been verified in theory but not in practice. In this article, we first introduce the state of the art in open source SDR. Due to the high flexibility and reconfigurability of open source SDR, we choose general-purpose-processor-based SDR to implement our NOMA system, which is based on an open source LTE program. Over-the-air experiments are carried out on the designed NOMA system for the purpose of performance evaluation, and to demonstrate its potential in future 5G mobile networks.