# CERP: Cooperative and Efficient Routing Protocol for Wireless Sensor Networks
###### Abstract  
Wireless sensor networks (WSNs), constrained by limited resources, demand routing strategies that prioritize energy efficiency. The tactic of cooperative routing, which leverages the broadcast nature of wireless channels, has garnered attention for its capability to amplify routing efficacy. This manuscript introduces a power-conscious routing approach, tailored for resource-restricted WSNs. By exploiting cooperative communications, we introduce an innovative relay node selection technique within clustered networks, aiming to curtail energy usage while safeguarding data dependability. This inventive methodology has been amalgamated into the Routing Protocol for Low-Power and Lossy Networks (RPL), giving rise to the cooperative and efficient routing protocol (CERP). The devised CERP protocol pinpoints and selects the most efficacious relay node, ensuring that packet transmission is both energy-minimal and reliable. Performance evaluations were executed to substantiate the proposed strategy, and its practicality was examined using an Arduino-based sensor node and the Contiki operating system in real-world scenarios. The outcomes affirm the efficacy of the proposed strategy, outshining the standard RPL concerning reliability and energy conservation, enhancing RPL reliability by 10% and energy savings by 18%. This paper is posited to contribute to the evolution of power-conscious routing strategies for WSNs, crucial for prolonging sensor node battery longevity while sustaining dependable communication. Arduino-based sensor nodes; ContikiRPL; cooperative communications; RPL; routing; selective relaying 2323883433900/s232188343900/  
and Lossy Networks (RPL) [8], which operates over IPv6 [9]. It is a powerful routing system that can be readily tweaked to suit the user's needs by adjusting the weights of various objectives. While this is happening, RPL nodes may become unreliable as they choose routes that are less efficient than others [8]. Promoting RPL reliability by the selection of more stable and higher-quality routes remains an unresolved research challenge in RPL design. Several research efforts focus on improving the RPL protocol so that it can satisfy the stringent needs of WSNs in terms of energy savings, reliability, lifetime, latency, etc. RPL reliability can be improved by leveraging the wireless medium's broadcast capabilities to establish effective communication among its components. More precisely, channels from the source to the relay nodes, which have received a copy of the data packet, are utilized in every transmission strategy between any source-destination pair. This serves to instigate spatial diversity at the destination [10]. The recipient combines multiple signal duplicates, making use of the channel statistics established between itself and the different transmitters. In case of a transmission failure, a chosen relay is utilized to transmit the same data, providing a more energy-efficient alternative compared to a direct transmission from the source to the destination. Relay techniques become especially relevant when there is a significant distance, an extensive mid-range, or less-than-ideal channel conditions between the source and the destination. In this paper, we leverage this cooperative relay technique to enhance data transmission reliability and energy efficiency in an RPL protocol. Moreover, several studies performed on the subject of wireless communication were theoretical and have only been assessed via the use of simulation tools. In order to verify the efficacy of recently suggested methods in the wild, further test-bed trials are required. Our study departs from the aforementioned research by proposing \(CERP\), which is based on the preferred relay selection rule and is implemented in an Arduino-based node. More precisely, the main contributions of this paper are:  
1.