Time and frequency self-synchronization in dense cooperative network

Dense cooperative network involves communication and coding among multiple uncoordinated nodes. The distributed nature of cooperative networks results in both carrier frequency offset (CFO) and timing offset (TO) that degrade the performance of collaborative communication. Hence, network synchronization is mandatory to guarantee network operations. This paper proposes a novel method to perform joint time and frequency synchronization in presence of large TOs and CFOs by extending the principle of consensus method to synchronization. The estimation is based on assigning to all nodes the same training sequence based on Zadoff-Chu (ZC), that is arranged to decouple CFO from TO in symbol and frame synchronization. The synchronization is based on weighted consensus algorithm to reach synchronization in a connected network by using the superposition of the waveforms from all transmitting nodes as an ensemble of reference timing for synchronization. Time and frequency synchronization is guaranteed in multi-node interference scenario without the need to assign to every node an independent ZC sequence, and thus without any coordination.