Age-aware channel selection and packet-size optimization for jamming-resilient cognitive radio networks under heavy-tailed spectrum availability

Abstract

Cognitive radio allows secondary users to exploit idle licensed spectrum while protecting primary users (PUs), but transmissions fail if a PU returns or jamming occurs. Thus, packet size and channel assignment must be jointly optimized to balance throughput and interruption risk. Unlike prior work that assumes memoryless exponential PU activity and jammer-free intervals, in practice spectrum-occupancy measurements often deviate from the exponential distribution and may exhibit heavy-tailed behavior, making channel age informative. This paper develops a jamming-aware, age-aware contention-based optimization framework with success-probability and signal-to-noise ratio (SNR) constraints. It also derives exact success expressions and a closed-form packet-duration approximation. The main novelty is the coupled channel/packet decision under non-memoryless PU/jammer interruption, exact age-conditioned probability-of-success (PoS), and closed-form packet sizing with exact discrete projection. This provides a lightweight continuous packet-duration candidate, maps it to the practical discrete packet alphabet, and admits it only after exact PoS/SNR rechecking. Simulations show improved throughput over fixed-packet and memoryless methods under realistic PU and jamming distributions.