Timing synchronization: Compared to the categorized papers for carrier synchronization in Table 5, the categorized papers for timing synchronization in Table 6 have greater similarity.
The categorized papers differ in terms of channel model, channel estimation requirements, or pilot/training requirements.
As detailed in Table 20, the categorized papers differ with respect to proposing an estimation or compensation design.
As detailed in Table 15, the categorized papers differ in channel model, providing joint channel estimation, requiring CSI or training, proposing estimation or compensation, or providing lower bound.
Almost all categorized papers study carrier synchronization only, [263 290], except the authors in [291] consider ranging scheme to propose timing estimation in OFDMA uplink communication system.
As detailed in Table 19, the categorized papers differ in respects of providing joint channel estimation, requiring CSI or training, proposing estimation or compensation, or providing lower bounds.
All categorized papers consider DS spread spectrum technology and study the carrier synchronization alone [294 301], where as identified in the second column of Table 14, [294, 295] consider single-carrier communication and [296 301] consider multi-carrier communication.
In addition, as detailed in Table 14, the categorized papers differ with respect to channel model, providing joint channel estimation, requiring pilot/training, proposing estimation or compensation of multiple CFO, or providing lower bound.
The categorized papers differ in the sense that training sequence design is proposed in [248], joint CFO estimation and compensation with channel estimation is studied in [249], and CFO estimation alone is proposed in [250].
Finally, as detailed in Table 18, the categorized papers may also differ with respect to providing joint channel estimation, requiring CSI or training, proposing estimation or compensation, or providing lower bounds on estimation of synchronization parameters.
