Channel selection and switching methods in dynamic spectrum networks: A survey

Abstract

The Cognitive Radio (CR) networks architecture is critical for addressing the challenges associated with dynamic spectrum utilization. CR users have the capability to access both licensed and unlicensed bands, enabling efficient spectrum utilization. However, the heterogeneous nature of CR networks presents significant challenges due to coexistence with primary networks and diverse Quality of Service (QoS) requirements. This survey explores spectrum management and adaptive protocols in CR networks, focusing on spectrum handoff. Spectrum handoff involves the transfer of ongoing transmissions from occupied frequency bands to available ones. It discusses target channel selection techniques for spectrum handoff, which are effective for per-slot throughput maximization, latency in spectrum handoff and minimizing cumulative delay in multiple handoffs. The survey also highlights the use of Markov chain models and queueing networks to analyse spectrum handoff schemes and suggests the use of proactive or reactive sensing based on sensing time. A comparison of the effects of spectrum handoff on the data delivery time, channel utilization and latency performance in CR networks was made, offering insights for future research and development in this field.