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The response of a DPbS3200 infrared detector irradiated by a nanosecond pulsed laser and CW laser has been investigated to study laser-induced interference. A laser interference experiment system was constructed to measure the time-varying response signal. A nanosecond pulsed laser and a CW laser of 10 Hz were used, with a 1064 nm wavelength and a millimeter-scale irradiation spot diameter. Firstly, the characteristics of transient interference signals induced by pulsed lasers were analyzed. Then, the characteristics of response signal interference by both CW laser and pulsed laser irradiation were further investigated. The results showed that the pulsed laser only produced transient interference. However, the CW laser led to a significant amplitude reduction of the response signal, which could continuously interfere in the operating time. For transient interferences, the amplitude of the interference signal increased linearly with the laser fluence. The relation between the pulse repetition rate of the incident laser and the operating frequency of the detector determined the numbers of transient interference signals in one response period; for the interference induced by both the CW laser and pulsed laser, CW laser interference played a leading role when CW laser power density increased to 4.1 W/cm2 or more. As the CW laser fluence reached 6.1 W/cm2, the PbS infrared detector was no longer able to detect any signal, which caused temporary blindness. In the end, a probit model was used to determine the interference threshold.

The 5G frequency band is extremely close to the operating frequency band of radio altimeters (RAs), so an in-depth study of the possible interference of 5G’s key parameters on RAs is especially necessary to ensure aviation safety. In this paper, the interference magnitude of 5G waveforms on an altimeter was measured by simulating the Adjacent Channel Leakage Power Ratio (ACLR) values for different sub-carrier spacing (SCS) and channel bandwidth configurations. Furthermore, interference injection experiments on simulated 5G signals and the interference thresholds of a frequency-modulated continuous wave (FMCW) altimeter were compared to experiments on the effects of the different configurations of 5G SCSs, channel bandwidths, and center frequency points. The interference thresholds of this FMCW altimeter were found to be in the range of 1 dBm to 6 dBm and −4 dBm to 0 dBm under the interference of 5G signals at the center frequency points of 3.7 GHz and 3.9 GHz. These results provided a certain reference for the engineering judgement margin of the interference thresholds.

Cognitive radio networks, efficient spectrum utilization remains challenging due to the conflicting requirements of maximizing secondary user access while protecting primary user transmissions. To resolve this problem, an integrated framework namely COgnitive Spectrum Management through Optimized Sharing (COSMOS) that synergistically combines NOMA-based spectrum sharing and traffic-aware interference threshold management based on dynamic network topology to maximize spectrum utilization while ensuring quality of service for all network participants. COSMOS allows multiple SUs to access the same spectrum simultaneously through power domain multiplexing with proper channel thresholds to ensure PUs are not adversely affected. Adapting the SU network topology based on traffic, delay, and energy requirements allows for more efficient resource utilization and can significantly improve overall network performance. Dynamically adjusting interference thresholds based on different traffic types (critical, non-critical, random) can enhance QoS while maximizing spectrum utilization. Extensive simulations demonstrate that COSMOS significantly outperforms existing approaches, achieving up to 37% higher throughput, 32% improved spectral efficiency, and 44% better energy efficiency while maintaining 95% primary user protection ratio. The framework shows particularly strong performance in handling heterogeneous traffic, improving critical flow success rates by 42% under high network loads. COSMOS represents a significant advancement in cognitive radio network management, offering a comprehensive solution to spectrum scarcity while satisfying diverse quality of service requirements in next-generation wireless networks.

Small herbivores are important biological factors affecting plant productivity and species richness in the grassland ecosystem of the Tibetan Plateau. However, the response of different grassland types to the disturbance of the \"endemic species\" plateau pika ( ) remains unclear. In this study, two representative grassland types, alpine meadow and alpine steppe, were taken as research objects to compare the effects of pika disturbance on vegetation structure and function indicators, and to explore the disturbance response threshold of these ecosystems. The results showed that the alpine steppe was more sensitive to pika disturbance, with significant decreases in biomass, vegetation height, and coverage even at low disturbance levels. In contrast, alpine meadows exhibited greater resilience, maintaining higher productivity and species diversity under moderate disturbance conditions. Notably, the functional index of alpine meadow peaked under moderate disturbance, while alpine steppe rapidly transitioned to a degraded state. These differences highlight the varying disturbance thresholds between the two grassland types. This study highlights the vulnerability of alpine grassland ecosystems to pika disturbance and provides a strong scientific basis for designing effective grassland management and ecological restoration strategies.

The coordinated multi point (CoMP) transmission technique is considered a key feature in future wireless network to improve both cell edge users throughput by exploiting interference. However, to provide CoMP transmission several BSs need to be active, which eventually increases network energy consumption. The simultaneous active multiple BSs with different transmission characteristics in heterogeneous environment cause interferences on each other. In this paper, we study the energy efficient radio resource management (EE-RRM) scheme for heterogeneous wireless networks to reduce interference. In particular, our aim is to allocate subcarrier power by optimizing EE metric and minimize interference with knowledge of channel state information between BSs and user equipment. The EE-RRM problem is a fractional programming problem. In order to solve, we use Charnes–Cooper transformation technique and transform it into an equivalent concave optimization problem. The numerical results of our work present the effect of different interference, rate and power thresholds on the EE metric.

In this study, the problem of determining the power allocation that maximises the energy efficiency of cognitive radio network is investigated as a constrained fractional programming problem. The energy-efficient fractional objective is defined in terms of bits per Joule per Hertz. The proposed constrained fractional programming problem is a non-linear non-convex optimisation problem. The authors first transform the energy-efficient maximisation problem into a parametric optimisation problem and then propose an iterative power allocation algorithm that guarantees ε-optimal solution. A proof of convergence is also given for the ε-optimal algorithm. The proposed ε-optimal algorithm provide a practical solution for power allocation in energy-efficient cognitive radio networks. In simulation results, the effect of different system parameters (interference threshold level, number of primary users and number of secondary users) on the performance of the proposed algorithms are investigated.

Cognitive radio networks (CRNs) are applied to solve spectrum scarcity. In this study, the authors propose an efficient power control game to improve its performance based on outage probability of primary user in a spectrum-underlay CRN. The interference threshold deduced from outage probability and normalised signal to interference plus noise ratio are used to develop a novel non-linear pricing function, which is a key element of obtaining Pareto improvement in non-cooperative power control game. In addition, an efficient swarm intelligent algorithm originated from eco-group activities is designed in detail to accelerate the convergence speed and improve the energy-efficiency. Theoretical analysis and simulation results are presented to prove the effectiveness and superiority of the proposed power control game.

This work investigates power allocation algorithms for capacity maximization of a non-contiguous orthogonal frequency division multiplexing (NC-OFDM) based cognitive radio (CR) user coexisting with multiple active primary users (PU), under total power budget, sub-channel power and overall interference constraints. Based on the spectral distance between specific subcarriers and PU bands, the scheme allocates power among a minimum number of PU adjacent subcarriers with a water level that is different from the ‘far-away’ subcarriers. The proposed ‘ n - adjacent ’ approach is subjected to both aggregate and individual PU band interference constraint. Unlike some of the existing methods, the proposed method is capable of meeting the constraints including the contribution of ‘good quality’ subcarriers even when they are close to PU bands. Comparison of results for a wide range of power budget shows that the improved method, using the same complexity, can achieve higher cognitive user capacity with greater power allocation efficiency.

In this paper, a utility-based game-theoretic model is proposed to study the joint power and rate control problem in spectrum underlay fashion in cognitive networks. The authors adopt a novel utility function based on cognitive network which focuses on social optimal resource allocation through pricing. Further, they show an interference threshold elasticity perspective, which is the key for primary network to maximize its utility by increasing its transmitted power to adjust the tolerable interference constraint. The cognitive network can also increase its total throughput capacity. In Stackelberg game, the primary user and the cognitive radio users interact with each other by adjusting their own actions. The cooperative cognitive networks model follows the \"best-effort\" principle as well as the win-win perspective of primary-cognitive user. Numerical simulations are conducted to demonstrate the performance of the model. The results show that the PU network can get more profit and also the CRU network can increase its total throughput capacity by the adjustment of the interference threshold.

In this study, the optimal power allocation (OPA) problem is studied for the two-way relay channel employing the analogue network coding protocol with the asymmetric traffic requirements in a cognitive radio network. The OPA scheme is proposed by maximising the sum-rate of the success delivery bit from the secondary user (SU) perspective subject to the sum-power constraint and the interference power threshold (IPT) constraints to the primary user (PU). In particular, for the purpose of accomplishing the power allocation more realistically, the interference to each other between the PU and the SU and the relay is taken into consideration and by solving the optimisation problem composed for each case, the closed form expressions of each node power are obtained. All the simulation results have demonstrated that the system with the proposed scheme outperforms the equal power allocation (EPA) scheme irrespective of the IPT. When the IPT constraint is introduced, the sum-rate of the success delivery bit of the SU communication converges to a certain level with the increasing total power. Meanwhile, the proposed strategy is superior to the conventional EPA scheme for any relay location, which is more remarkable when the relay is located on either end node regardless of the traffic symmetry or the asymmetry.