Multi-objective cooperative medium access control protocols in wireless Ad-Hoc networks Mohsen Rafiee 1 • Rasool Sadeghi 2 • Sayed Mahdi Faghih Imani 1 Accepted: 8 December 2020 Ó The Author(s), under exclusive licence to Springer Science+Business Media, LLC part of Springer Nature 2021 Abstract Relay-based cooperative communications have been emerging as a novel paradigm in many wireless protocols. The IEEE 802.11 medium access control (MAC) protocols have attracted many cooperative techniques. The relay selection algo- rithms have a remarkable influence on the design and the performance of the cooperative MAC (CMAC) protocols. Most of the existing algorithms have been designed based on a single objective such as spectrum efficiency and energy efficiency. In this paper, two multi-objective CMAC protocols are proposed: FCGMAC and EECMAC. The FCGMAC employs a multiple relay selection algorithm providing the spectrum efficiency and fairness. The EECMAC exploits a single relay selection improving the energy efficiency and the spectrum efficiency. The proposed protocols have been simulated in the ns-3 network simulator and the simulation results indicate the improvement of network performance according to the design objectives. Keywords IEEE 802.11 Á Cooperation Á Relay selection Á Multi-objective Á Performance 1 Introduction The dynamic nature of wireless networks in recent years has attracted special attention from the research commu- nity. The considerable growth and deployment of mobile devices over the past decades lead to design new paradigms in wireless network architecture such as cooperative com- munications [1, 2]. The cooperative communications per- form the deployment of a relay node between the source and destination nodes. The relay node can overhear the channel and the signalling exchanged between its neigh- bour nodes. Then, a one-hop packet exchange will be replaced by a two-hop packet exchange using the relay if the cooperation is beneficial [3]. Although the cooperative communications appear in different OSI layers and various wireless technologies, many cooperative medium access control (CMAC) proto- cols of the IEEE 802.11 standard has been posed in recent years [3–8]. The special capabilities such as adaptive data rates and exchanging control packets before data trans- mission help the nodes in IEEE 802.11 networks to extract some metrics to select the relay node(s) according to the cooperation objective(s) [7]. Most of the existing CMAC focus on specific target objective improving a certain aspect of network perfor- mance. Different targets can be achieved using the asso- ciated metric(s) and distributed mechanism(s). Some CMAC protocols have the single objective of throughput improvement. The relay selection algorithms of this cate- gory choose the relay(s) providing the lowest delay in the path of source, relay, and destination. The earliest CMAC protocols with this mechanism are Cooperative Medium Access Control (CoopMAC) [9] and relayed Distributed Coordination Function (rDCF) [10]. The operation of the relay node selection in CoopMAC and rDCF is performed by the source node and the relay node respectively. & Rasool Sadeghi r.sadeghi@iauda.ac.ir Mohsen Rafiee mohsen.rafee@gmail.com Sayed Mahdi Faghih Imani smahdi.imani@googlemail.com 1 Department of Computer Engineering, Dolatabad Branch, Islamic Azad University, Isfahan, Iran 2 Department of Electrical Engineering, Dolatabad Branch, Islamic Azad University, Isfahan, Iran 123 Wireless Networks https://doi.org/10.1007/s11276-020-02521-x