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Indoor localization has been actively researched in recent years due to the increasing demand for location-awareness services. However, to balance localization accuracy and system cost is always a challenge for indoor localization systems. Radio frequency identification (RFID) is a promising technology to achieve both goals, because of its reasonable cost and reliability. In this paper, we propose...
This paper deals with the robustness of soft iterative decoders in impulsive interference modeled by Middleton class A distribution, epsilon-contaminated Gaussian noise or a sum of a Gaussian thermal noise and an impulsive alpha-stable noise. The inputs of belief propagation decoder should be the log-likelihood ratios of the received symbols. But in case of impulsive interference, their computation...
Ultra-wideband (UWB) radios are expected to be the next generation of the transmission systems that can support high data rate and power-constrained applications. Since the UWB signals have wide bandwidth, two problems arise, namely the high speed analog-to-digital-converter (ADC) required at the receiver side and the coexistence with other narrowband interference (NBI) systems that share the same...
In an Attitude and Heading Reference System (AHRS), the heading estimation is generally achieved by measuring the Earth's magnetic field. However the Earth's magnetic field is easily distorted by magnetic interference from ferrous or magnetic objects. The traditional AHRS algorithm fuses the magnetic measurement into the estimation process of three attitude angles, acceleration and angular velocity...
Exploiting Radio Signal Strength Indicator (RSSI) estimation method to conduct indoor localization in wireless sensor networks offers a new approach to serve object tracking and improve the tracking precision. When the object is closer the line-of-sight link between the transmitter and the receiver, it is more likely to arouse the attenuation or amplification of the RSSI signal. In this paper, the...
This paper aims at providing a solution for blind interference threshold estimation in an underlay cognitive network. Unlike the traditional methods that mainly depend on pre-cooperation between primary and secondary users to settle on a predefined threshold. For threshold estimation, blind detection of modulation and signal-to-noise ratio (SNR) are used. For the sake of beamforming, several localization...
Interference is one of the key deterrents to cloud adoption, and is known to cause severe degradation in application performance, costing service providers in lost revenues. In this paper, we present UIE, a user-centric approach to detecting and, importantly, estimating the degree of interference experienced by user applications in the cloud. UIE employs queueing theory to model the impact of resource...
Link estimation is a fundamental component of forwarding protocols in wireless sensor networks. In low power forwarding, however, the asynchronous nature of widely adopted duty-cycled radio control brings new challenges to achieve accurate and real- time estimation. First, the repeatedly transmitted frames (called wake-up frame) increase the complexity of accurate statistic, especially with bursty...
Ultra wide band impulse radio(UWB-IR) transmission and its energy detection are effective to realize simple sensor network, wireless body area networks(BAN), etc. Under such network environments, simultaneous communication between many nodes is required and code division multiple access(CDMA) is one of the candidates of multiple access schemes. However, under multiple access situations, the degradation...
Cache-related preemption delay (CRPD) analysis is crucial when designing embedded control systems that employ preemptive scheduling. CRPD analysis for single-level caches has been studied extensively based on useful cache blocks (UCBs). As high-performance embedded processors are increasingly used, which are often equipped with multi-level caches, CRPD analysis for cache hierarchies also needs to...
In vehicular networks, high mobility and limited transmission range of Road-Side Units (RSU) cause dynamic topological changes and result with interference occurred by transmission of vehicles. Moreover, due to the limited bandwidth of IEEE 802.11p based vehicular communication, providing a fair share of network resources among vehicles is essential for an efficient network management. Therefore,...
Extracting a narrowband signal from a mixture of signals is the goal in this paper. The directions of arrival of all signals are assumed to be unknown and possibly rapidly time-varying. We show that the combination of the matrix pencil method together with a variation of the minimum variance distortionless response beamformer is able to satisfactorily extract the signal-of-interest.
This paper proposes a channel estimation algorithm for the High Speed Uplink Packet Access (HSUPA) system supporting the 64-QAM modulation and operating in a high Signal-to-Interference and Noise Ratio (SINR) regime. The algorithm is aimed to overcome limitations of the conventional approach which is based on simple correlation of the received signal with the pilot sequence and has insufficient performance...
This paper presents a novel digital beamforming to improve channel quality. By estimating the received channel impulse response (CIR) to calculate the arrival of angle (AOA) of received signal, and we scan the AOA to adjust the weighting vector of received signal and improve the channel quality. The performance of system with digital beamforming can improve 16 dB signal to noise ratio (SNR) in non-line...
This paper studies the performance of hierarchical modulation-based image transmission over cognitive radio systems operating with imperfect channel sensing results and also imperfect channel state information (CSI) regarding the interference link between the secondary transmitter and primary receiver. First, closed-form bit error rate (BER) expressions for high priority (HP) data and low priority...
The channel quality indicator (CQI) is an important LTE parameter that is used to cope with the channel variations. The accuracy of the CQI calculation depends on the channel and the noise variance estimations. In this paper, we study the effect of the noise variance estimation on the CQI calculation. We assess the performance of a widely-used CQI algorithm, the mutual information effective SINR mapping...
In-band full-duplex transmission allows a relay station to theoretically double its spectral efficiency by simultaneously receiving and transmitting in the same frequency band, when compared to the traditional half-duplex or out-of-band full-duplex counterpart. Consequently, the induced self-interference suffered by the relay may reach considerable power levels, which decreases the signal-to-interference-plus-noise...
In the static and exclusive spectrum allocation paradigm, the spectrum-access parameters for a service are chosen to mitigate potential harmful-interference and ensure minimum performance under worst-case conditions. The new dynamic spectrum-sharing paradigm necessitates dynamically defining and enforcing the spectrum-access rights while accommodating the dynamics of the RF environment and the spectrum-access...
This paper deals with the pilot contamination problem for multi-cell massive multiple-input and multiple-output (MIMO) mobile communication systems. The pilot contamination effect constitutes a major bottleneck for overall performance. Most of researches on pilot decontamination ignore the fact that different users can be distinguished by the direction of arrivals (DoA), even the users in different...
In this paper, we investigate the detection of single-carrier transmission over frequency selective fading channels with symmetric alpha-stable (SαS) noise. To mitigate the effects of the inter-symbol interference (ISI) cased by multi-path propagation and the destructive impulsive noise, a non-linear myriad filter is firstly adopted and an asymptotic statistic method is then introduced for to analyze...
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