Interference Avoidance using Spatial Modulation based Location Aware Beamforming in Cognitive Radio IOT Systems

摘要

The Internet of Things (IOT) is a revolutionary communication technology which enables numerous heterogeneous objects to be inter-connected. In such a wireless system, interference management between the operating devices is an important challenge. Cognitive Radio (CR) seems to be a promising enabler transmission technology for the 5G-IOT system. The “sense-and-adapt” smart transmission strategy in CR systems can help to overcome the problem of multiple access interference (MAI) in IOT systems. In this paper, a 5G-IOT smart infrastructure system is arranged in the form of CR based virtual antenna array (VAA) system. In VAA based wireless system, knowledge of users’ locations can help the transmitter to achieve interference avoidance by steering the main beam towards the intended recipient. This idea has been applied to the VAA-IOT system, where smart antenna array based location aware beamforming are applied at both transmitter and receiver cluster of smart sensors with the help of spatial modulation principle. The waveform of choice for the CR-IOT clusters is Generalized Frequency Division Multiplexing (GFDM) while corresponding waveform for the primary user (PU) cluster is conventional Orthogonal Frequency Division Multiplexing (OFDM). Computer simulation shows that under multipath fading conditions, the implemented system can reduce the interference to the primary user (PU) system, leading to better coexistence.