Table 1 Review of the existing metatheoretic optimization algorithms-based clustering schemes contributed to enhancing energy stability and network lifetime in CRSNs.

Stephan and Suresh Joseph¹⁶

Particle swarm optimization-based energy efficient clustering scheme.

It determined an optimal number of clusters and CH identity by incorporating features of the PSO algorithm.

It suffers from the problem of premature convergence and poor solution diversity.

Wang et al.¹⁷

Ion motion inspired optimization-based centralized cluttering approach (IMIOCCA)

It was proposed with the capability of determining the optimal number of CHs and CMs in the network, and It was proposed with dynamic characteristics that get adopted with the attributes of the network such that information about the sink position is identified for better packet delivery

It still possesses the problem of channel assignment problem which may be idle in some specific situations when the amount of data traffic is comparatively high.

Noor et al.¹⁸

Efficient clustering scheme for CRSN called network stability-aware clustering (nsac) protocol

They have mentioned that the metrics dealing with channel availability are not secured and have focussed on tuning parameters

The factors considered for CH selection and optimal route determination are not completely exhaustive.

Devi and Umamaheswari¹⁹

Cluster based cooperative spectrum sensing optimization techniques-based cluttering

It aids in overcoming the overhead in CH selection as well as cluster formation, thus conserving energy and adapting to dynamic changes in topology

It is only topology dependent and cannot dynamically adapt to the changes in the requirements of the data traffic.

Ramkumar and Vadivel²⁰

Whale optimization routing protocol (WOAP)

This WOAP was proposed as one of the significant methods which helped in determining the best routes between the constructed clusters to enhance the network efficiency and at the same time minimizing the packet delay in the network.

It suffers from the process of spectrum sensing scarcity which may result in poor performance of the network in energy stability

Deng et al.²¹

Intelligent resource allocation scheme depending on the clustering of nodes during the process of energy harvesting in CRSNs.

The intelligent resource allocation scheme aids in determining optimal number of clusters which form the fundamental clustering structure, and serves time-triggered traffic periodically and uses priority-based schedule with respective

It is only ideal for network environment which completely depends on the time-triggered traffic, and hence it cannot be suitable for low data traffic situations.

Wang and Ge²²

Multihop clustering routing protocol using radio frequency energy harvesting (MCRPRFEH

It was proposed with a non-linear energy harvesting model which helped in handling the issues concerned with channel assignment and energy efficiency with optimised allocation of resources.

The channel allocation and resource assignment need to be improved depending on the requirements of the data traffic and energy utilization

Binyamin and Ragab²³

Modified dwarf mongoose optimization algorithm (MDMOACA)

This MDMOACA scheme mainly targeted on self-organizing the deployed number of sensor nodes into groups termed clusters.

The number of clusters constructed are moderate in number and needs improvement in sustaining maximized degree of energy efficiency.

Sharada et al.²⁴

An adaptive ant colony distributed intelligent based clustering scheme (AACDICS)

This AACDICS approach estimated optimal number of CHs using the phenomenon of distributed cluster-based sensing and connectedness, and it is implemented over a system model which comprises of uncertain number of PUs and SUs in CRSNs

It mainly focuses on the factors of SNR, and its impact over the spectrum sensing phenomenon, and hence other factors of impact are only marginally considered during implementation process

Wang et al.²⁵

An imperfect spectrum sensing-based multi-hop clustering routing protocol (ISSMHCRP)

This ISSMHCRP was proposed for handling the degree of imbalance in terms of residual energy possessed by the selected CHs in the network, and it specifically included the merits of simultaneous wireless information and power

The number of clusters constructed during the clustering process is comparatively high, and energy stability still possesses a room of improvement.