  Low Earth Orbit (LEO) satellites are being extensively researched in the
development of secure Internet of Remote Things (IoRT). In scenarios with
miniaturized terminals, the limited transmission power and long transmission
distance often lead to low Signal-to-Noise Ratio (SNR) at the satellite
receiver, which degrades communication performance. A solution to address this
issue is the utilization of cooperative satellites, which can combine signals
received from multiple satellites, thereby significantly improve SNR. However,
in order to maximize the combination gain, the signal coherent combining is
necessary, which requires the carrier frequency and phase of each receiving
signal to be aligned.
  Under low SNR circumstances, carrier parameter estimation can be a
significant challenge, especially for short burst transmission with no training
sequence. In order to tackle it, we propose an iterative code-aided estimation
algorithm for joint Carrier Frequency Offset (CFO) and Carrier Phase Offset
(CPO). The Cram\'er-Rao Lower Bound (CRLB) is suggested as the limit on the
parameter estimation performance. Simulation results demonstrate that the
proposed algorithm can approach Bit Error Rate (BER) performance bound within
0.4 dB with regards to four-satellite collaboration.
