## 2 Related Work
This protocol excels in energy consumption network balancing and the reduction of contention in the MAC between nodes by its ability of decomposing traffic over different channels or time-slots. However, a detailed implementation method of the MAC component is lacking, which leaves the assumptions open for verification. Although ROR also uses the CSMA technology, CSMA is carefully regulated by introducing a VCG-based initiative determination forwarding scheme that limits contention at the MAC layer and, thus, greatly reduce collision, which is, also, a major concern in wireless sensor-based networks. Reactive routing for mobile cognitive radio _ad hoc_ networks (CAODV) [17] is also a modification of AODV. Although the CAODV is also designed for reactive routing to ensure link quality, the proposed scenario is only suitable for nodes having multiple transceivers. Although the authors claim that the assumptions of the algorithm also hold for single radio scenarios if specific underlying channel coordination mechanisms, like [30], are applied. However, the applicability of this claim is open for proper verification. This is because the layout presented in [30] requires all nodes to negotiate and decide on data channels via a common control channel. Thus, if this is applied to CAODV, the issue of deciding on channels without ascertaining their quality will persist. Hence, CAODV will have to fall back to multiple transceivers to achieve instantaneous quality information at the point of route, which is not a favored design requirement for CRSNs. Other related works include the probabilistic routing protocol based on prior information (PRP) [31], which expands upon the Dijkstra routing algorithm by introducing a routing metric that enables the nodes to select channels and routes based on the documented performance of the channels during previous transmissions. The metric is formulated based on naive Bayes inference and uses an m-estimate probability to make the route decisions more realistic. The source node first broadcasts a route discovery packet. This packet is disseminated across all the nodes to the sink. This packet enables individual nodes to calculate the cost function of choosing any of its neighbors based on the formulated routing metric. At this stage, channels are tagged to neighbor nodes. During the process of routing, when the PU arrives, the affected node can easily change the path without jeopardizing the entire routing process. Notwithstanding the ability of the network to reconfigure the route, the energy required to implement the Dijkstra routing algorithm can prove to be non-trivial, especially in the case of CRSN. Distributed best-route selection for multipath routing (DBMR) [32] investigates multipath routing selection in performance optimization under energy-constrained CRAHNs via distributed and heuristic routes selected by secondary users (SUs) with the aim to improve end-to-end delay, while taking energy into consideration. Multipath routing is modeled as a restless bandit stochastic process optimization problem that allows secondary users to select routes considering the dynamic occupancy of a licensed spectrum and energy based on a finite-state Markov chain (FSMC) model. This solution also offers protection to the PU transmission by varying the SU's transmission power in each hop with respect to the PU's occupancy in each channel.