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A multi-channel approach for MAC protocols is one of the most significant issues in recent research trend of WSNs. Numerous studies on multi-channel MAC protocols have focused on how to select and allocate channels efficiently to links or nodes. However, existing studies do not consider interferences from different communication technologies in the same band such as IEEE 802.11 in ISM band. In addition,...
Industrial Wireless Sensor Networks (IWSNs) consist of a central manager, gateways and field devices with sensing, signal processing and wireless communication capabilities. Convergecast is a many-to-one industrial communication paradigm which is used for process measurement and control applications. Convergecast scheduling in IWSNs is to determine the smallest length conflict-free assignment of timeslots...
This paper examines the efficiency of a simple distributed algorithm, called Round-2, for further decreasing the size of connected dominating set (CDS) in ad hoc networks and evaluates its performance based on neighbors-covered and neighbor-pair-connected algorithms under two categories of local static priority information: node-identifier-based and node-degree-based. The Round-2 algorithm decreases...
In this paper, we propose a new improved TH precoding algorithm, which intends to solve the problem of high bit error rate (BER) from traditional THP algorithm when the channel is in bad condition, and compare the performance with different classic ZF-THP and MMSE-THP. Also the conclusion is verified by emulation. Based on the Precoding module algebra, we proposed the Reduce Grid Algorithm which has...
According to the cost and power consumption of wireless communication receiver under high-precision quantization, this paper discusses the effect on the performance of channel estimation for OFDM systems with low-precision quantization. Theoretical analysis and simulation results show that the low-precision quantization degrades the system performance. However, the optimized channel estimation algorithm...
This paper is concerned with the iteration identification algorithm for Hammerstein model with complex-valued input for the fact that the existing algorithms are not valid for complex input. Based on the stochastic gradient algorithm, the extended stochastic gradient algorithm is proposed by defining new cost function for complex input. The extended hierarchical multi-innovation stochastic gradient...
Power line communication is a promising candidate of smart grid applications. Organizations such as IEEE and ITU-T have published standards to cover applications of power line communication in smart grid. However, recent research reveals that indoor power line channel is a time-varying channel which may cause severe intercarrier interference to the OFDM systems in those standards. It is known that...
Multicast congestion control is essential to avoid congestion collapse and ensure fair competition in bandwidth with unicast. This paper presents a classification on existing multicast congestion control schemes. A main contribution in this paper is that we characterize multicast congestion control by a parameters tuple {traffic regulation, group management, data layering and coding, router function}...
In the circumstances of GEO (geostationary earth orbit) satellites cooperation, a practical and efficient traffic load balancing method is presented in this paper. The mathematical analysis and simulation show that the proposed method improves the overall balance of satellite communication systems and expands the single GEO satellite transmission ability by lowering the transmission delay and increasing...
For the problem of increasingly scarce spectrum resources, improving bandwidth efficiency is to be solved. Drawing on traditional techniques based on CDMA (Code Division Multiple Access, CDMA) communication, this paper puts forward a transmission system in the same bandwidth of LFM and voice SSB signal. Theoretical analysis and simulation results showed that LFM and voice SSB signal can be transmitted...
Low power wide area (LPWA) networks are power-constrained and work on industrial, scientific, medical (ISM) bands. The scheme of clear channel assessment (CCA) has a great influence on network performance, and the most important characteristics of CCA methods for LPWA networks are high detection probability and power saving. For different wireless networks, carrier sensing (CS), one of the CCA methods,...
The number of mobile subscribers has increased by 399 million in 2013, of which WCDMA/HSPA subscribers account for 68%. Meanwhile, various short-size packet services, such as web browsing, instant messaging and social network applications, are growing rapidly, leading to a sharp increase in signaling load and limit the network capacity to allocate resources efficiently in High Speed Uplink Packet...
As compared to uncoded unitary space-time modulation (USTM), channel coded USTM has received increased attention for its large coding gain. However, low-density parity-check (LDPC) coded USTM has only received limited attention. This paper proposes a scheme of combining LDPC code with USTM for noncoherent MIMO communication system over Rayleigh flat fading and additive white Gaussian noise (AWGN)...
This paper presents a dual-band bandpass filter with tunable centre frequencies. The proposed filter is mainly implemented by two λ / 2 resonator and three varactor diodes. By adjusting all varactors can adjust the centre frequency of the two passband, if Cv1 is fixed, only tuned Cv2 can achieve first pass band fixed while the second passband could be adjusted. When adjusted the frequency of both...
In this paper, we propose an efficient routing algorithm based on AODV for the Mobile Hybrid Wireless Networks (MHWNs), which consists of the mobile ad hoc networks (MANETs) and an infrastructure wireless networks (such as cellular networks). In MANETs, the performance of the networks has been greatly challenged by the mobility from nodes and link state changes, while the link in cellular networks...
Focused on the spectrum sensing in low signal-to-noise ratio, we propose a novel spectrum sensing method based on locally linear embedding (LLE) and random forest (RF). From the received radio signal, a set of cyclic spectrum features are first calculated, and the LLE computes low dimensional, neighbourhood preserving embeddings of high dimensional data for classification. Then the detecting signal...
In cognitive radio (CR), energy detection is a simple and feasible method to get reliable detection results on the presence of primary user (PU) in perfect channel. In imperfect channel, single-threshold cooperative spectrum detection has been proposed to improve energy detection performance, however it is sensitive to noise interference. In order to solve this problem, double-threshold cooperative...
In this paper, we investigate the impact of the asynchronism on the performance of a Cognitive Radio (CR) network, using the underlay paradigm. We are also compareing this effect depending on which modulation technique we are using. We provide a new the theoretical aspect of interference analysis in the context of orthogonal frequency division multiplexing (OFDM) and the Filter Bank Multicarrier (FBMC)...
Spectrum occupancy measurement and analysis is a very important aspect in frequency resource planning by the reason of frequency shortage for the increasing wireless systems. It is also useful in spectrum sensing in the context of cognitive radio, especially in unlicensed band. Given that, a dynamic decision threshold computing method based on SOM Neural Network in spectrum occupancy analysis is proposed...
In [1] and [2], we have proposed a novel metric for evaluating the capacity to the total energy consumption ratio of Multiple Input Multiple Output (MIMO) systems. We have considered the context of Wireless Sensor Networks (WSNs) and we have evaluated the proposed metric over the distance between the transmitting and the receiving sides. We have identified the optimal MIMO system configuration for...
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