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1. Mitigation of the spectrum sensing data falsifying attack in cognitive radio networks

   https://doi.org/10.1080/23335777.2020.1811387  

   Biswas, Rajorshi; Wu, Jie; Du, Xiaojiang; Yang, Yaling (September 2020, Cyber-Physical Systems)

   Cognitive radio networks (CRNs), which offer novel network architecture for utilising spectrums, have attracted significant attention in recent years. CRN users use spectrums opportunistically, which means they sense a channel, and if it is free, they start transmitting in that channel. In cooperative spectrum sensing, a secondary user (SU) decides about the presence of the primary user (PU) based on information from other SUs. Malicious SUs (MSUs) send false sensing information to other SUs so that they make wrong decisions about the spectrum status. As a result, an SU may transmit during the presence of the PU or may keep starving for the spectrum. In this paper, we propose a reputation-based mechanism which can minimise the effects of MSUs on decision making in cooperative spectrum sensing. Some of the SUs are selected as distributed fusion centres (DFCs), that are responsible for making decisions about the presence of PU and informing the reporting SUs. A DFC uses weighted majority voting among the reporting SUs, where weights are normalised reputation. The DFC updates reputations of SUs based on confidence of an election. If the majority wins by a significant margin, the confidence of the election is high. In this case, SUs that belong to the majority gain high reputations. We conduct extensive simulations to validate our proposed model. 

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2. Cognitive Overlay for Inter-system Cellular Dynamic Spectrum Sharing in the Downlink

   Everett, Jared S.; Mark, Brian L. (June 2021, IEEE International Conference on Communications workshops)

   null (Ed.)

   This paper assesses the feasibility of a novel dynamic spectrum sharing approach for a cellular downlink based on cognitive overlay to allow non-orthogonal cellular transmissions from a primary and a secondary radio access technology concurrently on the same radio resources. The 2-user Gaussian cognitive interference channel is used to model a downlink scenario in which the primary and secondary base stations are co-located. A system architecture is defined that addresses practical challenges associated with cognitive overlay, in particular the noncausal knowledge of the primary user message at the cognitive transmitter. A cognitive overlay scheme is applied that combines superposition coding with dirty paper coding, and a primary user protection criterion is derived that is specific to a scenario in which the primary system is 4G while the secondary system is 5G. Simulation is used to evaluate the achievable signal-to-interference-plus-noise ratio (SINR) at the 4G and 5G receivers, as well as the cognitive power allocation parameter as a function of distance. Results suggest that the cognitive overlay scheme is feasible when the distance to the 5G receiver is relatively small, even when a large majority of the secondary user transmit power is allocated to protecting the primary user transmission. Achievable link distances for the 5G receiver are on the order of hundreds of meters for an urban macrocell or a few kilometers for a rural macrocell. 

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3. MIA: A Transport-Layer Plugin for Immersive Applications in Millimeter Wave Access Networks

   https://doi.org/10.1109/INFOCOM53939.2023.10228878  

   Wu, Zongshen; Huang, Chin-Ya; Ramanathan, Parameswaran (May 2023, IEEE)

   The highly directional nature of the millimeter wave (mmWave) beams pose several challenges in using that spectrum for meeting the communication needs of immersive applications. In particular, the mmWave beams are susceptible to misalignments and blockages caused by user movements. As a result, mmWave channels are vulnerable to large fluctuations in quality, which in turn, cause disproportionate degradation in end-to-end performance of Transmission Control Protocol (TCP) based applications. In this paper, we propose a reinforcement learning (RL) integrated transport-layer plugin, Millimeter wave based Immersive Agent (MIA), for immersive content delivery over the mmWave link. MIA uses the RL model to predict mmWave link bandwidth based on the real-time measurement. Then, MIA cooperates with TCP’s congestion control scheme to adapt the sending rate in accordance with the predictions of the mmWave bandwidth. To evaluate the effectiveness of the proposed MIA, we conduct experiments using a mmWave augmented immersive testbed and network simulations. The evaluation results show that MIA improves end-to-end immersive performance significantly on both throughput and latency. 

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4. Massive MIMO Cognitive Cooperative Relaying

   https://doi.org/10.1007/978-3-030-23597-0_8  

   Dinh, S.; Liu, H.; Ouyang, F. (June 2019, Springer LNCS Wireless Algorithms, Systems, and Applications)

   This paper proposes a novel cognitive cooperative transmission scheme by exploiting massive multiple-input multiple-output (MMIMO) and non-orthogonal multiple access (NOMA) radio technologies, which enables a macrocell network and multiple cognitive small cells to cooperate in dynamic spectrum sharing. The macrocell network is assumed to own the spectrum band and be the primary network (PN), and the small cells act as the secondary networks (SNs). The secondary access points (SAPs) of the small cells can cooperatively relay the traffic for the primary users (PUs) in the macrocell network, while concurrently accessing the PUs’ spectrum to transmit their own data opportunistically through MMIMO and NOMA. Such cooperation creates a “win-win” situation: the throughput of PUs will be significantly increased with the help of SAP relays, and the SAPs are able to use the PU’s spectrum to serve their secondary users (SUs). The interplay of these advanced radio techniques is analyzed in a systematic manner, and a framework is proposed for the joint optimization of cooperative relay selection, NOMA and MMIMO transmit power allocation, and transmission scheduling. Further, to model network-wide cooperation and competition, a two-sided matching algorithm is designed to find the stable partnership between multiple SAPs and PUs. The evaluation results demonstrate that the proposed scheme achieves significant performance gains for both primary and secondary users, compared to the baselines. 

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5. Interference Spreading through Random Subcarrier Allocation Technique and Its Error Rate Performance in Cognitive Radio Networks

   https://doi.org/10.3390/s20195700  

   Kachroo, Amit; Popuri, Adithya; Ibrahim, Mostafa; Imran, Ali; Ekin, Sabit (October 2020, Sensors)

   null (Ed.)

   In this letter, we investigate the idea of interference spreading and its effect on bit error rate (BER) performance in a cognitive radio network (CRN). The interference spreading phenomenon is caused because of the random allocation of subcarriers in an orthogonal frequency division multiplexing (OFDM)-based CRN without any spectrum-sensing mechanism. The CRN assumed in this work is of underlay configuration, where the frequency bands are accessed concurrently by both primary users (PUs) and secondary users (SUs). With random allocation, subcarrier collisions occur among the carriers of primary users (PUs) and secondary users (SUs), leading to interference among subcarriers. This interference caused by subcarrier collisions spreads out across multiple subcarriers of PUs rather than on an individual PU, therefore avoiding high BER for an individual PU. Theoretical and simulated signal to interference and noise ratio (SINR) for collision and no-collision cases are validated for M-quadrature amplitude modulation (M-QAM) techniques. Similarly, theoretical BER performance expressions are found and compared for M-QAM modulation orders under Rayleigh fading channel conditions. The BER for different modulation orders of M-QAM are compared and the relationship of average BER with interference temperature is also explored further. 

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