Abstract Thermal failures of busbar gas chambers in gas-insulated metal-enclosed switches (GIS) are common, and the failure points usually internal spring contacts. To study this phenomenon depth, paper constructs a 3D electrical-thermal-mechanical coupling simulation model contacts, calculates contact resistance thermal fingers by Cooper-Mikic-Yovanovich (CMY) theory, investigates distribution temperature rise considering gravity conducting rods, performs thermal-fluid real circuit breaker...

Spectrum sensing is an essential technique for cognitive radios. This paper addresses the spectrum under uncertain noise power and proposes adaptive algorithm. The decision threshold of energy detection derived, which based on weighted probability false alarm. By means estimating signal power, able to adapt fluctuation. Simulation results show that proposed algorithm has robustness uncertainty. It can be used detecting various kinds without any knowledge or power.

The demand for wideband communication in the coastal area (i.e., ≤ 100 km from coastline) has been rapidly increasing recent years. Compared to terrestrial scenario, environment long-distance and highly dynamic channels, devices are more strictly constrained by energy supplies. While RLNC fountain erasure-correction property is suitable transmissions over it suffers high coding coefficient delivery cost decoding complexity. In this article, we look into application of sparse network systems....

Relay transmissions play an important role in many types of communication systems. In this paper, we consider packet-level coded over lossy relay links with the finite-buffer and coding coefficients delivery cost constraints. We propose a low-complexity scheme where packets are encoded from sequentially formed random subsets source called batches. The recodes only buffered belonging to same batch maintain code sparsity, lowering packet header overhead decoding complexity compared linear...

This letter proposes a sparse network code based on band matrices for lossy networks. The proposed is precoded, has no wrap-around, and allows only limited number of bands. Compared with existing works, the simplifies decoding, enables more flexible recoding, able to significantly reduce reception overhead that might be caused by recoding.

Routing in wireless mesh networks based on cognitive radio environment is a challenge due to dynamic channel selection. When nodes look for routing and schedule channels, allocation seems unbalanced sometimes. To increase the utility of unlicensed bands throughput with learning mechanism, route tree-based assignment algorithm, which statics metric priorities while common control not needed, proposed this paper. Each node accesses AP fewer hops process tree initialization. This scheme may...

Data dissemination to multiple users within a predetermined deadline is commonly required function in many emerging wireless scenarios. In this paper, we propose data scheme enhanced by device-to-device (D2D) communications and random linear network coding (RLNC), where the broadcast D2D links are used simultaneously with on-the-fly RLNC accelerate dissemination. The probability distribution of completion time using either pure or systematic analyzed assuming finite field size, under general...

This paper compares the end-to-end (E2E) fountain codes and random linear network coding (RLNC) for lossy multi-hop short-packet communications, under constraint that coefficient overhead imposed by RLNC recoding is non-negligible. The decoding failure probability (DFP) of analyzed computed as a function most relevant parameters. A DFP minimization problem formulated numerically solved from cross-layer perspective. By comparing using optimized parameters, shown to be higher than E2E codes,...

Multiple channels can increase network capacity by transmitting traffic on different in an interference area. Firstly, efficient distributed joint routing and channel allocation strategy for cognitive wireless mesh networks is proposed this paper. The main purpose of to maintain the diversity neighborhood channels. Simulation results show that compared link-based algorithm multichannel network, average throughput approximately increases 50%, delay reduces 50% with new algorithm. Then, a...

Cognitive radio (CR) is an effective way to improve the utilization of spectrum resource. This paper focuses on resource allocation in cooperative relay cognitive networks and proposes optimized algorithm. In algorithm, when channel between primary source destination good, user (PU) selects a best sub-channel transmit its data directly, while secondary users (SUs) use remaining idle sub-channels their own data. When poor, SUs work as relays PU cooperate transmitting We study joint...

Abstract This paper considers the spectrum sensing technique for cognitive radio‐based on energy detection. It proposes an improved algorithm by linearly combining criteria of probability detection and false alarm. Then, optimal decision threshold is derived in proposed linear combination (LC) algorithm. The performance primal user significantly using LC algorithm, especially under low signal‐to‐noise ratios. Simulation results verify effectiveness with different kinds primary signals....

Radio frequency fingerprint (RFF) based authentication of wireless devices can be used in the fields access security at physical-layer networks and radio spectrum management. However, stability RFF is easily damaged by multipath fading channel mobile communications. An fingerprinting method with nonlinearity in-phase quadrature (IQ) imbalance transmitter proposed for chunk-based orthogonal division multiplexing (OFDM) on a Hammerstein system parameter separation technique, which cancels...

With the development of society and progress technology, more ocean activities are carried out. It results in booming deep-sea diving. The use helium-oxygen mixture (as a kind breathing gas) solves physiological problems divers saturated diving, but it brings about Heliumspeech voice communication problem, drop speech intelligibility. There is no doubt that effective must be provided for supporting life work deep-sea. This paper describes mechanism forming heliumspeech, discusses effects...

Cognitive emergency communication networks can meet the requirements of large capacity, high density and low delay in communications. This paper analyzes properties users cognitive networks, designs a multi-objective optimization proposes novel bacterial foraging algorithm based on effective area (MOBFO-EA) to maximize transmission rate while maximizing lifecycle network. In algorithm, is proposed prevent from falling into local optimum, diversity uniformity Pareto-optimal solutions...

Radio Frequency (RF) fingerprinting is one physical-layer authentication method for wireless communication, which uses the unique hardware characteristic of transmitter to identify its true identity. To improve performance RF Fingerprint (RFF) based on preamble with fixed duration, a nonlinear payload symbols proposed OFDM communication bit mapping scheme QPSK. The system modeled as Hammerstein containing and multipath fading channel. A parameter separation technique orthogonal polynomial...

A general rate-distortion (RD) model for block-based video coding is proposed in this study. Based on model, an innovative characteristic called texture-complexity (TC), which defined as a function of discrete cosine transform (DCT) coefficient distribution and distortion-quantisation (DQ) relationship well variance residual block, presented rate control. Moreover, adaptive linear TC forward-prediction established to estimate the incoming image head bits prediction optimal allocation method...

This paper studies a power minimization problem of an orthogonal frequency-division multiplexing modulated two-way amplify-and-forward relay wireless sensor network (WSN). The objective is to develop effective strategies for controlling the transmit levels WSN nodes and assigning bit rates among different subcarriers minimize overall network, while ensuring end-to-end target two sources. By using channel knowledge at transmitters, two-step method proposed solve problem, resulting in joint...

In order to realize the function of accurate measurement, multipoint collection and wireless transmission on various environmental monitoring factors in workshop, a workshop environment system is proposed based technology internet things. A number nodes are set up each collect variety information, then transmit data server by network, which provides theoretical basis for managers staff master situation take timely prevention disposal. The test results demonstrate that has good reliability,...