Joint detection and channel estimation for broadcast OFDM systems using hybrid Zadoff Chu pilots

In this paper we propose a hybrid Zadoff-Chu (ZC) based pilot sequence suitable for OFDM broadcast systems. While maintaining the same scattered pilot structure and the same power level as in DVB-T2, we replace the phase values by a ZC combined sequence. This combined sequence can either carry information bits through a repetition of small ZC patterns, or serve just as a very robust fine time domain synchronization mechanism. We present the design methodology for different OFDM systems, the possible ZC patterns sequences valid for signaling and provide a recommended structure for DVB-T2 like systems. Simulation results show that, without degrading the pilot channel estimation, an additional time domain synchronization more robust than P1 of DVB-T2 is achieved in each OFDM symbol. The proposed structure can be used as a design basis for future broadcast systems to build on, where a separate preamble will no longer be needed, thus, reducing the frame overhead.