A time synchronization mechanism based on Software Defined Radio of general-purpose processor
Hongliang Duan, Dengshan Huang, Yi Huang, Yiqing Zhou, Jinglin Shi · 2012
In recent years, Software Defined Radio (SDR) has become one of the major research concerns in mobile communications for the advantages of flexibility and versatility. Most of the air-interface processes such as signal processing and data multiplexing are done on a programmable software environment. The latest SDR platforms utilize the power of general-purpose processor (GPP) to perform all of the real-time computations and several wideband communication systems are prototyped. Nevertheless, the lack of universal real-time timing control and synchronization process make implemented GPP-based SDR platforms difficult to simulate time crucial multi-user cellular communication scenarios. Focus on the problem of time synchronization on SDR platforms, this paper presents a software-based time synchronization mechanism, which is called software time synchronization (STS). On that basis, a real-time and high precision clock source is designed on GPP-based SDR platforms and the multi-user communication system is synchronized utilizing round-trip delay (RTD) algorithm. Long-term experiments showed that a SDR prototype using STS is able to simulate TDMA-based cellular communications. The results also indicate that the STS synchronization errors are within several microseconds.