Cooperative Delay Diversity scheme with low complexity channel estimation in integrated satellite/terrestrial systems

This paper aims at investigating some simple cooperative relaying strategies which rely on the exploitation of the Delay Diversity (DD) technique in a DVB-SH compliant hybrid satellite/terrestrial network. In particular the combination of the proposed cooperative system with the Cyclic Left Sample-Shift of the received signal is adopted in order to simplify the channel estimation process. The opposite effects of the Cooperative Delay Diversity technique and the Cyclic Left Sample-Shift on the equivalent channel transfer function are analysed: particularly, the two algorithms can coexist without any mutual impingement. Simulation results confirm the effectiveness of the proposed schemes in the mitigation of the Non-Line-Of-Sight (NLOS) propagation drawbacks and in the simplification of the channel estimation: the first positive effect is caused by the increase of the frequency selectivity of the equivalent channel perceived by the receiver (Cooperative DD technique) whereas the second result is due to the reduction of the frequency selectivity of the channel transfer function, which is used in the equalization process (Cyclic Left Sample-Shift).