Description
A Hidden Markov Model is a discrete-state sequence model with a Markov transition kernel and per-state emission distributions. In CSI sensing it appears as a lightweight temporal model on top of frame-level features: activities-as-states, occupancy-bucket transitions, gait-cycle phases. Discrete-state Markov chains are also used inside cellular-automata transition probabilities for crowd modelling.
When it's used
- Sequence-level smoothing of frame-level CSI predictions
- Activity-of-daily-living pipelines
- Cellular-automata transition modelling
Limitations
- Discrete-state assumption is restrictive
- Transition matrices need either supervision or EM training
- Outperformed by RNNs / Transformers given enough data