Rate Distortion Approach to Joint Communication and Sensing With Markov States: Open Loop Case
Colton P. Lindstrom, Matthieu R. Bloch
TL;DR
This work extends the rate-distortion framework for joint communication and sensing to settings where the state evolves as a Markov process and past estimates inform current sensing. It shows that Bayesian filtering remains optimal for state estimation and derives an open-loop capacity–distortion region $C^{(open)}(D)=\lim_{n\to\infty} \max_{P_{X^n}\in\overrightarrow{\mathcal{P}}_D^{(n)}} \frac{1}{n}\sum_{i=1}^n I(X_i;Y_i|S_i)$, with a detailed construction of the cost-constrained input set. The beam pointing specialization illustrates how beam-switching and multi-beam strategies impact the tradeoff, using Kalman filtering for sensing with Gauss–Markov dynamics and two open-loop strategies, including a formal bounding framework and numerical comparisons. The results offer practical insights for designing JCAS systems that jointly optimize communication rate and state tracking in dynamic environments, informing beamforming and resource allocation choices in future networks.
Abstract
We investigate a joint communication and sensing (JCAS) framework in which a transmitter concurrently transmits information to a receiver and estimates a state of interest based on noisy observations. The state is assumed to evolve according to a known dynamical model. Past state estimates may then be used to inform current state estimates. We show that Bayesian filtering constitutes the optimal sensing strategy. We analyze JCAS performance under an open loop encoding strategy with results presented in terms of the tradeoff between asymptotic communication rate and expected per-block distortion of the state. We illustrate the general result by specializing the analysis to a beam-pointing model with mobile state tracking. Our results shed light on the relative performance of two beam control strategies, beam-switching and multi-beam.
