Optimization of throughput and autonomous sensing in random access cognitive radio networks

The main advantages of random access networks are the ability to work with little or no infrastructure and independent transmission of users. Thus, users themselves in a random access network decide when to access the channel. Design of cognitive radio (CR) users in random access networks necessitates integrating unique functions such as spectrum sensing, policy and configuration databases, and self-configuration, etc. Spectrum sensing is especially crucial in terms of determining the channel availability and characterization. The traditional approach to cognitive radio network assumes a centralized spectrum sensing through cooperation of the CR users. However, such centralized approach adds additional level complexity which may not be desired in random access networks. In this paper, we investigate autonomous sensing and random access protocols for cognitive radios such that independent transmission of CR users is still allowed. The proposed methodology eliminates the control channel required in traditional collaborative sensing while preserving gains from cooperation and maintaining tolerable interference levels to the primary users of the spectrum. Our proposed design methodology is demonstrated using the slotted ALOHA protocol as the MAC layer due to its simplicity.