  In this letter, we propose a joint time synchronization and channel
estimation (JTSCE) algorithm with embedded pilot for orthogonal time frequency
space (OTFS) systems. It completes both synchronization and channel estimation
using the same pilot signal. Unlike existing synchronization and channel
estimation algorithms based on embedded pilots, JTSCE employs a maximum length
sequence (MLS) rather than an isolated signal as the pilot. Specifically, JTSCE
first explores the autocorrelation properties of MLS to estimate timing offset
(TO) and channel delay taps. After obtaining these types of delay taps, the
closed-form estimation expressions of the Doppler and channel gain of each
propagation path are derived. Extensive simulation results indicate that
compared to its counterparts, JTSCE achieves better bit error rate (BER)
performance, close to that with perfect time synchronization and channel state
information.
