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In this paper, the effect of the carrier frequency offset (CFO) on system performance was investigated by computer simulations in single carrier Frequency Division Multiple Access (SC-FDMA) system. By computer simulations, figures of signal-to-noise ratio (SNR) versus symbol error rate (SER) of the system with and without CFO are obtained. Besides, the figure of SNR versus SER is obtained for different...
A novel concept of orthogonal frequency division multiplexing (OFDM) multiple input multiple output (MIMO) radar for automotive applications is presented in this paper. Multiple transmit antennas are multiplexed via OFDM subcarrier interleaving. Such a multiplexing enables a simultaneous operation of transmit antennas, while the complete bandwidth is utilized by each of them. Whereas the known OFDM-MIMO...
The channel estimate and carrier frequency offset (CFO) acquisition are two essential bases for multiple-inputmultiple-output (MIMO) and orthogonal frequency division multiplexing (OFDM) techniques. In high-mobility scenario, the fast time varying channel and the serious Doppler frequency shift will make the channel tracking and CFO estimation much more challenging. In this paper, the achievable limits...
In this paper a method for joint estimation of the speed of a vehicle and its distance to a road side unit (RSU) is introduced. On the rooftop of the vehicle a uniform circular array (UCA) antenna is mounted, which receives orthogonal frequency division multiplexing (OFDM) modulated signals from the RSU over an additive white Gaussian noise (AGWN) channel. After estimating the two dimensional angle...
During these years, mobile telecommunication system based on LTE has been largely studied and has formed a mature technical system. For special application scenarios and business requirement, a comprehensive and new generation of railway mobile telecommunication system based on LTE is bound to take shape via innovative researches and technology improvements. Under fast- moving scenario of high-speed...
Power adaptation is crucial to maximize the system capacity for orthogonal frequency multiple access (OFDM) systems, where power delay profile (PDP) should provide instantaneous signal power distribution. This paper proposes a cooperative PDP estimation method to mitigate the impact of imperfect CSI in vehicle-to-infrastructure (V2I) communication systems. To obtain accurate PDP, the movement characteristics...
In urban environments, a multipath propagation and the Doppler effect are dominant phenomena that negatively affect the quality of service in wireless communications and realization of location methods. This paper presents the localization method of emission source in urban terrain for NLOS conditions based on the Doppler effect. To this aim, authors use the signal Doppler frequency (SDF) method....
In this paper, we propose a timing synchronization method for orthogonal frequency division multiplexing (OFDM) systems by exploiting the averaged differential correlations of preamble symbol. For the designed simple preamble whose second half-symbol is the complex conjugate of the first one in the time-domain, the proposed timing synchronization method has an impulse-shaped timing metric. Simulation...
Cooperative communication or distributed multi- input multi-output (DMIMO) system is an emerging paradigm for increasing spectral efficiency, coverage extension, small cell deployment. In such a system, the signal received at the destination is characterized by multiple carrier frequency offset (MCFO) and channel gains as relays are distributed over space. On the other hand, as orthogonal frequency...
Cooperative communication or distributed multi-input multi-output (DMIMO) system is a key enabler of coverage extension and enhancement of link reliability. The fundamental difficulty in deployment of DMIMO is synchronization, tracking independent oscillators and propagation delays. On the other hand, as orthogonal frequency division multiplexing (OFDM) is very sensitive to multiple timing offset...
A novel blind carrier frequency offset (CFO) estimation method for orthogonal frequency division multiplexing (OFDM) systems using constant modulus constellations is proposed in this study. CFO is estimated by minimizing a hybrid cost function which is formulated using properties of the covariance matrix and the magnitude of two nearby OFDM symbols. The performance of the proposed method is compared...
In the process of wireless communication, channel effects are always a factor of degradation in offered quality. Major channel effects such as noise effects, fading, multipathing, Doppler shift etc., results in degradation in the observed quality of service for the communication system. Various approaches are developed towards the appropriate estimation of these channel effects at the receiver side...
In this paper, we propose a joint soft iterative detection scheme utilizing expectation maximization (EM) and low density parity check (LDPC) codes for multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) systems. A soft iterative MIMO detector is introduced, by exploiting soft-input soft-output in the detection and decoding, the tractable extrinsic information efficiently...
In this paper, a timing synchronization technique for orthogonal frequency division multiplexing (OFDM) systems in visible light communications (VLC) environments is presented. The proposed synchronization scheme is based on the timing estimation method by Park et al. [1], but considering a new preamble weighted by Shapiro-Rudin sequences [2]. The performance of the new designed method is evaluated...
The issues of carrier frequency offset (CFO) and channel estimation are very important for multi-input multi-output orthogonal frequency division multiplexing (MIMO-OFDM) wireless communication systems. In this paper, the problems of CFO and channel estimation are considered. An adaptive estimation algorithm is proposed. It can estimate CFO and channel parameters at the same time. Since the estimation...
The major drawback of Orthogonal Frequency division Multiplexing (OFDM) is sensitivity to carrier frequency offset which it is due to difference between carrier frequencies in the transmitter and receiver (due to difference between oscillators in the transmitter in the receiver) and the movement of mobile station. This carrier frequency offset generates inter-carrier interference (ICI) and inter-symbol...
Long Term Evolution (LTE) is one of the standards in 4G cellular technologies which offer different data rates for voice, video conference and other services. The Orthogonal Frequency Division Multiple Access (OFDMA) is a well suited multiple access scheme of LTE for supporting variable bit rate services. OFDMA-based Cellular communication network face serious challenges in providing good Quality...
Doppler effect causes loss of orthogonality in Orthogonal Frequency Division Multiplexing (OFDM), which in turn may severely degrade receiver performance. In high data rate underwater acoustic communication (UAC), the effect of Doppler shift varies considerably over OFDM frequency band. In the past and current UAC OFDM literature [1]– [6], the frequency domain Doppler shift is presented in terms of...
The existing blind noise estimation called cyclic prefix based noise estimation without knowledge of a priori signal is simulated along with input of DVB-T and the multipath channel ITU-T pedestrian model A. The simulation is done by means to know NMSE and noise uncertainty over time observation with varied SNR. The NMSE shows a very good result and close to the result of the previous research. The...
The demand for the wireless communication is growing rapidly from last few years. Demand arises a lot of advancement in the communication. In this paper introduction of IDMA, complete analysis and comparison of IDMA with CDMA and OFDM is done for the single access channel. IDMA introduce the interleaving technique as means of user separation instead of digital signatures in CDMA and subcarriers in...
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