| name | covert-bosonic-sequential-detection |
| description | Covert communication over bosonic channels using blockwise sequential detection — receiver-centric framework exploiting linear vs quadratic information growth asymmetry between Bob and Willie for optimal signaling design. Use for covert quantum communication, bosonic channel analysis, sequential detection systems. |
| metadata | {"arxiv_id":"2606.18666","published":"2026-06-17","authors":"Qipeng Qian, Yuntao Qian"} |
Covert Blockwise Coding with Sequential Detection
Core Methodology
Key Information-Theoretic Asymmetry
- Bob's post-change information growth: Linear in small-signal regime
- Willie's detectability: Quadratic quantum relative entropy law
- This asymmetry enables covertness: Bob detects signals Willie cannot distinguish from noise
Design Principles
- Each block = binary super-symbol (active/inactive)
- Minimum detection-segment length: Enables Bob detection before block end while staying covert to Willie
- Asymptotically optimal signaling: Uniform across detection segment under per-block covertness budget
- Single-pass CUSUM detector crosses threshold within block with exponentially high probability
Framework Components
- Block structure: Detection segment + payload segment per block
- Receiver design: General-dyne measurement (physically realizable)
- Sequential detection: CUSUM-based change-point detection within each block
- Covertness budget: Per-block constraint on Willie's detection probability
Activation Keywords
- Covert quantum communication, bosonic channels
- Sequential detection, CUSUM detection
- Quantum covertness, quantum relative entropy
- 隐蔽量子通信，顺序检测
Usage Patterns
Pattern 1: Covert Quantum Link Design
Design covert communication links over thermal-loss bosonic channels by exploiting the linear/quadratic information growth asymmetry between legitimate receiver and eavesdropper.
Pattern 2: Sequential Detection in Quantum Systems
Apply CUSUM-based sequential detection within finite transmission horizons where detection must complete before block ends.
Pattern 3: Covertness Budget Allocation
Under per-block covertness constraints, use uniform signaling strategy across detection segment — proven asymptotically optimal.
Pitfalls
- Framework assumes fixed physically realizable general-dyne receiver — optimal receiver design not addressed
- Analysis asymptotic — finite-block-length corrections needed for practical systems
- Quadratic Willie detectability law applies only to small-signal regime
- Single-pass CUSUM optimality assumes known pre/post-change distributions
