  Integrated sensing and communication (ISAC) will greatly enhance the
efficiency of physical resource utilization. The design of ISAC signal based on
the orthogonal frequency division multiplex (OFDM) signal is the mainstream.
However, when detecting the long-range target, the delay of echo signal exceeds
CP duration, which will result in inter-symbol interference (ISI) and
inter-carrier interference (ICI), limiting the sensing range. Facing the above
problem, we propose to increase useful signal power through coherent
compensation and improve the signal to interference plus noise power ratio
(SINR) of each OFDM block. Compared with the traditional 2D-FFT algorithm, the
improvement of SINR of range-doppler map (RDM) is verified by simulation, which
will expand the sensing range.
