Carrier Frequency Offset (CFO) refers to the difference between the actual carrier frequency of a transmitted signal and the carrier frequency at the receiver. In communication systems, especially those using wireless or radio frequency signals, maintaining accurate carrier frequency synchronization is crucial for reliable data transmission. Accurate carrier frequency synchronization is particularly important in high-data-rate communication systems, where even small frequency offsets can lead to performance degradation. Ongoing research and advancements in signal processing techniques continue to improve the robustness of communication systems against frequency offset effects.

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Blind Cyclic Prefix-based CFO Estimation in MIMO-OFDM Systems

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Low-complexity estimation and correction of carrier frequency offset (CFO) are essential in orthogonal frequency division multiplexing (OFDM). In this paper, we propose a low overhead blind CFO estimation technique based on cyclic prefix (CP), in multi-input multi-output (MIMO)-OFDM systems. We propose to use antenna diversity for CFO estimation. Given that the RF chains for all antenna elements at a communication node share the same clock, the carrier frequency offset (CFO) between two points may be estimated by using the combination of the received signal at all antennas. We improve our method by combining the antenna diversity with time diversity by considering the CP for multiple OFDM symbols. We provide a closed-form expression for CFO estimation and present algorithms that can considerably improve the CFO estimation performance at the expense of a linear increase in computational complexity. We validate the effectiveness of our estimation scheme via extensive numerical analysis.

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