Non-orthogonal multiplexing (NOM) is a novel superposition coding scheme that has been recently proposed to improve the throughput of wireless systems. However, restricting the number of multiplexed packets to two limits the throughput improvement of NOM to 100% in best case scenarios. Therefore, this work presents a generalized NOM (GNOM) design with unlimited number of multiplexed packets. In the multiplexing process, new and retransmitted packets due to automatic repeat request are combined while considering the impact of channel conditions on the power assigned per packet. The proposed GNOM employs an efficient heuristic algorithm to perform the power assignment and multiplexing decisions. Moreover, the complexity can be controlled by enforcing a limit on the maximum number of multiplexed packets per transmission, making it suitable for Internet of Things nodes with diverse computational capabilities and quality of service requirements. The obtained results demonstrate the effectiveness of proposed scheme, which offers up to 200% throughput improvement at moderate signal to noise ratios (SNRs), and up to 700% at high SNRs. Furthermore, the new scheme can reduce the transmission power consumption by up to 6 dB in the high SNR region.Index Terms-Internet of Things (IoT), Internet of Vehicles (IoV), Internet of Drones (IoD), automatic repeat request (ARQ), vehicle to infrastructure (V2I), vehicle-to-vehicle (V2V), nonorthogonal multiple access (NOMA), non-orthogonal multiplexing (NOM), throughput.
I. INTRODUCTIONT He integration of Internet of Things (IoT) in various applications has been growing vastly in the last decade, which triggered the introduction of more specific applications such as Internet of Drones (IoD) [1]-[4] and Internet of Vehicles (IoV) [5]-[9], or even more advanced configurations that include both IoD and IoV. Human and machine-centric IoT applications include transportation, smart cities, healthcare, agriculture, environment, retail, and smart homes. These Hamad Yahya and Emad Alsusa are with the