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In underwater acoustic networks (UWANs) with bidirectional communication links, channel state information (CSI) plays an important role since having a good channel knowledge allows system performance enhancements. Two communicating nodes can use the information obtained by their respective channel estimation in order to adjust the transmission parameters to the channel characteristics. However forward...
In this paper, we present the baseband receiver design for IEEE 802.11ah. We study several key receiver algorithms, including coarse frequency offset estimation and coarse timing synchronization, fine frequency offset estimation, fine timing synchronization, channel estimation and MIMO equalization. For channel estimation, we propose to use decoded SIG field to improve its estimation. To further improve...
In this work, we present an acoustic modem system that transmits data using multicarrier modulation through the air interface. The choice for this type of modulation over single carrier modulation arises from the need for an efficient use of the limited bandwidth, the minimization of multipath effects as frequency fading. The system transmits data using sound waves resting on the output and input...
This paper considers a wireless power transfer system with multiple antennas by using the multicarrier signal waveforms. A prior art optimizes the waveform with the channel state information at the transmitter (CSIT) to improve the energy harvesting efficiency of the receiver with the non-linear model. The impact of the imperfect CSIT on the energy harvesting capability is studied as a function of...
Recently underwater wireless communication has been receiving a lot of attention as it is essential to facilitate new industries and applications such as deep sea mining, ocean monitoring, submarine communication, and so on. Latest studies have showed Space-Frequency Block Code (SFBC) OFDM which was studied thoroughly in radio wireless communication is a promising candidate for underwater acoustic...
This paper studies the channel estimation and equalisation of orthogonal frequency-division multiplexing (OFDM) systems over doubly selective channels. We consider practical channel estimation schemes based on basis expansion model (BEM) and clustered pilots. We investigate the influence of the parameters of the channel estimation scheme, including the dimensionality of the BEM basis and bandwidth...
Conventional correlation-based frame synchronization techniques can suffer significant performance degradation over multi-path frequency-selective channels. As a remedy, in this paper we consider joint frame synchronization and channel estimation. This, however, increases the length of the resulting combined channel and its estimation becomes more challenging. On the other hand, since the combined...
In a binary input additive white Gaussian noise (BIAWGN) channel, belief propagation (BP) decoding for luby transform (LT) codes requires the knowledge of the signal-to-noise ratio (SNR) at the receiver to achieve its optimal performance. An erroneous estimation of the SNR at the decoder is referred to as “SNR mismatch”. SNR mismatch can significantly degrade the BP decoding performance of LT codes...
Generalized frequency division multiplexing (GFDM) with the flexible structure is one of the promising candidates for the fifth generation wireless communication system. This paper focuses on training sequence design that is used in the estimation of in-phase(I) and quadrature(Q) imbalance parameters on GFDM receivers as well as frequency selective channel. Combining with the structure of low complexity...
Multichannel receivers are usually employed in high-rate underwater acoustic communication to achieve spatial diversity. Passive time reversal combined with a single-channel adaptive decision feedback equalization (PTR-DFE) is a low-complexity solution to achieve both spatial and temporal focusing. Block-based PTR-DFE (BB-PTR-DFE) extends PTR-DFE to time-varying channels. Multichannel DFE (M-DFE)...
Due to the broadcast nature of the wireless medium, private communications are easily eavesdropped. This has spurred extensive research into secret key establishment using physical layer characteristics of wireless channels. In all these schemes, the shared secret keys directly originate from the physical features of the real wireless channel, which is highly dependent on the communication environment...
A new adaptive algorithm is proposed for implementation of channel estimation for Orthogonal Frequency Division Multiplexing-Interleave Division Multiple Access (OFDM-IDMA)-based wireless communication systems. This is named the variable forgetting factor modified recursive least mean square (VFF-MRLS) algorithm. The modification imposed is based on the enforcement of a constraint on the a posteriori...
In this paper, we propose distance and path loss based weighted centroid localization (WCL) algorithms for video capsule endoscope (VCE) using the received signal strength indicator (RSSI). We evaluate the performance of both algorithms considering real channel characteristics of human body. One of the major challenge in RSSI based VCE localization is the shadow fading and multi-path propagation effects...
Spectral efficiency and capacity of Land Mobile Satellite (LMS) systems can be enhanced by using MIMO (Multiple Input Multiple Output). Polarization diversity is an efficient technique to realize MIMO in LMS communications. Polarization diversity employs different polarization to realize multiple independent propagation paths. Dual polarized antennas offer a space and cost effective alternative compared...
Multiuser Detection (MUD) and Channel Estimation techniques in Space-Division Multiple Access aided Orthogonal Frequency Division Multiplexing (SDMA-OFDM) systems recently received intensive interest in receiver design technologies. The maximum likelihood (ML) MUD that provides optimal performance has the cost of a dramatically increased computational complexity. The minimum mean-squared error (MMSE)...
The problem of secure communication with the multi-antenna transmission in fading channel is an essential task. The fading channel is one of media for the eavesdropper to intercept when transmitting data. We investigate method for security in wireless communication. In particular, we focus on confidential transmission of pseudo-random location of subcarrier to increase security. This security method...
The paper proposes a fast multi-target detection technique based on simultaneous sensor data fusion for a binary wireless sensor network in a pre-deployed configuration. The synchronous binary sensors are circularly arranged in an area with the sink node on the central axis such that the line-of-sight communication dominates. All the binary sensors employed for detecting rapidly changing targets are...
In this work, the optimization of the analog transmit waveform for joint delay-Doppler estimation under sub-Nyquist conditions is considered. Based on the Bayesian Cramer-Rao lower bound (BCRLB), we derive an estimation theoretic design rule for the Fourier coefficients of the analog transmit signal when violating the sampling theorem at the receiver through a wide analog pre-filtering bandwidth....
Filter bank-based multicarrier (FBMC) systems have been considered as a prevalent candidate for replacing the long established cyclic prefix (CP)-based orthogonal frequency division multiplexing (CP-OFDM) in the physical layer of next generation communications systems. In particular, offset quadrature amplitude modulation (OQAM)-based FBMC has received increasing attention due to, among other features,...
It is indispensable to take a low complexity and high accuracy channel estimation algorithm into account under rapidly growth in wireless communication. In this paper, we propose an algorithm for channel estimation using complementary sequence (CS). By utilizing the fantastic autocorrelation property of CS, time domain channel estimation can be easily achieved. We analyzed the complementary sequence,...
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