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Ming-min Zhao

Publications and source records attributed to Ming-min Zhao.

2 recordsLinked to original sources

Distributed State Estimation over Wireless MIMO Fading Channels with Imperfect CSI

We consider distributed state estimation of a linear plant under stabilizing feedback over wireless multiple-input multiple-output (MIMO) fading channels, where channel-estimation noise corrupts the channel state information (CSI) used for information fusion. We propose a distributed estimator that combines local prediction, communication over wireless MIMO channels, and a posterior update based on local information and communicated data. Each sensor uses noisy pilots to estimate its aggregated wireless MIMO fading channel, and a pilot-noise bias correction recovers the required neighboring-data differences in conditional mean. We first analyze the mean estimation error and show that a Chebyshev design of the communication weights achieves a prescribed decay factor $d\in(0,1)$ satisfying the sensing conditions, with finitely many communication updates per plant sample at every finite signal-to-noise ratio (SNR) gain. We then characterize mean-square stability and the effects of SNR gain and receive-array size on the state estimation mean-square error (MSE), including its transient and steady-state value. In the ideal-communication limit, we show that the square root of the absolute MSE deviation from its steady-state value decays as $o(d^k)$. Numerical simulations verify the theoretical results and show substantial performance gain compared to various state-of-the-art baselines.

eess.SY↗

Separate Source Channel Coding Is Still What You Need: An LLM-based Rethinking

Along with the proliferating research interest in Semantic Communication (SemCom), Joint Source Channel Coding (JSCC) has dominated the attention due to the widely assumed existence in efficiently delivering information semantics. Nevertheless, this paper challenges the conventional JSCC paradigm, and advocates for adoption of Separate Source Channel Coding (SSCC) to enjoy the underlying more degree of freedom for optimization. We demonstrate that SSCC, after leveraging the strengths of Large Language Model (LLM) for source coding and Error Correction Code Transformer (ECCT) complemented for channel decoding, offers superior performance over JSCC. Our proposed framework also effectively highlights the compatibility challenges between SemCom approaches and digital communication systems, particularly concerning the resource costs associated with the transmission of high precision floating point numbers. Through comprehensive evaluations, we establish that empowered by LLM-based compression and ECCT-enhanced error correction, SSCC remains a viable and effective solution for modern communication systems. In other words, separate source and channel coding is still what we need!

cs.IT↗