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Filter bank multi-carrier with offset QAM(FBMC/OQAM) is a multi-carrier modulation technique that can be an alternative to conventional orthogonal frequency division multiplexing(OFDM) with cyclic prefix (CP) in wireless network. FBMC has a higher spectrum efficiency and effective emission power without CP. Because the orthogonality only exists in real domain, the channel estimation in FBMC/OQAM system...
Future broadband communication systems should provide low-complexity data processing, higher data rate, and stronger performance. Performance analysis itself is a critical stage in the field of wireless communications due to the nature of multipath fading that are encountered due to scatters. The ultimate performance measures are the bit error rate and average spectral efficiency of the system being...
Underwater acoustic (UWA) transmission schemes are an interesting area of communication research, in which achieving high data rate, low latency and high throughput is challenging task. In this paper, we trying to provide a survey on various efficient techniques which that includes channel estimation, channel equalization and efficient modulation schemes to achieve high data rate in the receiver using...
In this paper, we propose an efficient data exchange mechanism with a dedicated detection approach for Device-to-Device (D2D) communications. By involving in a third device as Relay Node (RN), both devices of interest can communicate with each other. Within an inband relay mode, Interleave Division Multiple Access (IDMA) is exploited to enable the third device to detect and decode the data of both...
Robust adaptive modulation (AM) is a promising technique to improve the spectrum efficiency (SE) of high speed railway (HSR) communication system. Although robust AM transmission schemes with assumption of block fading channel have been extensively investigated, which are no longer valid in the fast time-varying channel due to the channel variation in frame duration. This paper investigates the optimum...
The main focus of this paper is to study performance of two linear channel estimators, the Least Square Error(LS) and Linear Minimum Mean Square Error(LMMSE) for 2×2 and 4×4 VBLAST MIMO OFDM system with different modulation, BPSK, QPSK, 8QAM and 16QAM as well as with MMSE equalizer at receiver. Channel state information is useful at receiver to remove effect of channel in received signal for efficient...
Publishing the contents through internet we need a medium i.e Web browser. Hyper Text Markup Language is very helpful for writing the web contents and by the help of web browsers we publish our page on net. It is invented as an application so that people can take advantage to view immobile web pages in succession. Technologies improves and the web sites gain more advance features and have dynamic...
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...
Limited wireless spectrum coupled with the need to support co-existence mechanisms call for robust receivers and improved interference management. With a spectrum sharing operating mode, it is hard to model dynamic interference conditions in wireless networks. In the first part of this work, we have introduced an additive non-Gaussian channel (ANGC) model that captures a variety of interference sources,...
In this paper, we consider a multi-user communication system with dynamically varying interference on block fading channels. We focus on a multi-antenna receiver, single-antenna transmitters, and the case in which the receiver has no knowledge of the channel state information, interference dynamics, and the variance of the additive noise. Pilot-assisted transmission techniques are employed to enable...
Orthogonal frequency division multiplexing is one of the most successful multicarrier modulation techniques. This modulation technique is now used in many areas because of its intelligent bandwidth utilization and fast transmission. Channel estimation in OFDM is crucial for elimination of the distortions introduced by the channel. There are many parameters like fading, reflection, refraction and diffraction...
It is required to accurately estimate signal-to-noise ratio (SNR) without the a priori knowledge of modulation types and transmitted symbols in certain areas of communications. In this paper, we propose second-order and fourth-order statistics based estimators by oversampling the received signal. The expressions of the estimators under different scenarios are derived. From computer simulation, both...
In this paper, a channel identification technique using Second Order Statistics (SOS) is proposed for memoryless multiuser Volterra communication channels. The Parallel Factor (PARAFAC) decomposition of a third order tensor formed from spatio-temporal covariance matrices of the received signals is considered by using the Alternating Least Squares (ALS) algorithm. Modulation codes (constrained codes)...
The cooperative operation of multiple sensors, due to redundant radio signal reception, allows considerable gain in AMC performance. We here present an overview of the cooperative AMC solutions with centralized fusion, and also some results of their comprehensive analysis conducted under realistic application conditions for dispersive fading channels. Although the latest studies indicated that potential...
This paper analyzes the performance of space modulation techniques over generalized fading channels with imperfect channel estimation. In particular, a unified approach for calculating the pairwise error probability (PEP) of spatial modulation (SM) and space shift keying (SSK) modulation techniques for multiple-input multiple- output (MIMO) wireless communication systems is presented. A new, simple,...
To adapt to variation of polarization dependent loss (PDL) in depolarization channel, an adaptive polarization modulation scheme which can improve the spectral efficiency of polarization modulation system is proposed. In the proposed scheme, the transmitter adapts the optimal constellation size to the variation of the channel due to PDL while fulfilling a fixed target BER constraint, which is based...
The need for underwater reliable connections requested to provide different services as sea monitoring, devices control and camera images/videos may lead to require also large rate values. Due to the very limited bandwidth achieving few Khz, space diversity techniques can aid in this twofold mission. In this paper we investigate the use of an underwater acoustic MIMO technique, and jointly adopt the...
Radio resource allocation (RRA) algorithms are developed to enhance the spectral efficiency of downlink adaptive modulation and coding (AMC)-based orthogonal frequency-division multiple access (OFDMA) cognitive radios (CRs) under average transmit and peak interference power constraints. We consider the practical case of noisy channel-state-information (CSI) between cognitive transmitter (CTx) and...
This paper investigates the throughput performance using adaptive modulation and coding (AMC) focusing on the causes of impairment to Orthogonal Frequency Division Multiplexing (OFDM) - Multiple-Input Multiple-Output (MIMO) multiplexing. We first investigate the influence of a limited number of modulation and coding schemes (MCSs) and channel estimation error for MCS selection based on mutual information...
Spatial Modulation (SM) based on the use of antenna indices to transmit information in addition to the conventional signal constellations has been recently proposed to solve practical problems encountered in MIMO systems. In the literature, estimation of CSI for SM systems is simply investigated by RLS for slow fading channels. However, iterative receivers that offer significant performance gains...
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