arXiv:2610.33181v1 Announce Type: new Abstract: This paper studies the impact of synchronization offsets and CSI feedback delay on coherent joint transmission (CJT) in distributed MIMO-OFDM systems. Unlike conventional co-located MIMO, distributed CJT is highly sensitive to transmitter-dependent synchronization impairments because coherent combining requires phase, frequency, and timing alignment across geographically separated transmitters. Received signal models are derived for residual timing offsets, carrier frequency offsets (CFOs), sampling clock offsets (SCOs), phase noise, and channel variations accumulated during channel state information (CSI) feedback delay. The corresponding spectral efficiency (SE) expressions quantify the degradation in capacity due to loss in coherent-combining gain caused by residual phase rotations, inter-carrier interference (ICI), and precoder misalignment. The SE expressions are numerically evaluated to determine synchronization requirements for maintaining negligible SE degradation, yielding the following findings: a Gaussian-distributed start-time jitter with a standard deviation below 10\% of the sampling period results in negligible SE degradation, with the SE loss decreasing from 0.68\% at an SNR of 0 dB to 0.17\% at 40 dB. A normalized CFO standard deviation of 0.001 also results in negligible ICI-induced degradation, with the SE loss increasing from 0.05\% at an SNR of 0 dB to 2\% at 40 dB. At an SNR of 26 dB, limiting the SE loss to 5\% yields feasible operating points with clock-error standard deviations up to 50 ppb, Doppler-delay products up to 0.1, and phase-tracking error standard deviations up to $40^{\circ}$ at carrier frequency of 3.5 GHz with 30 kHz sub-carrier spacing with 15.36 MHz sampling rate.