Optimal Training Sequences for Joint Timing Synchronization and Channel Estimation in Distributed Communication Networks
For distributed multi-user and multi-relay cooperative networks, the received signal may be affected by Multiple Timing Offsets (MTOs) and multiple channels that need to be jointly estimated for successful decoding at the receiver. This paper addresses the design of optimal training sequences for efficient estimation of MTOs and multiple channel parameters. A new Hybrid Cramer-Rao Lower Bound (HCRB) for joint estimation of MTOs and channels is derived. Subsequently, by minimizing the derived HCRB as a function of training sequences, three training sequence design guidelines are derived and according to these guidelines, two training sequences are proposed.