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In this work a space-frequency block coding (SFBC) system is considered, which is compliant to the Long-Term-Evolution (LTE) specification. The Cramer-Rao bound (CRB) for the mimimum mean-square error (MMSE) of the channel estimator for an SFBC receiver is calculated comparing optimum versus robust Wiener interpolation. Further a lower bound on the bit error ratio (BER) of a binary phase-shift keying...
A new method for frequency synchronization based upon Zero-Intermediate Frequency (zero-IF) receiver and characteristics of the received signal's power spectrum for MC-DS-CDMA-Uplink system is proposed in this paper. The variance for Carrier Frequency Offset (CFO) estimators of MC-DS-CDMA-Uplink is compared with that of an OFDM system to estimate the CFO. Our study and results show that the MC-DS-CDMA...
The Wiener Interpolation Filter is commonly used to reconstruct a stochastic process from noisy samples. We focus on the case of a multi-dimensional stochastic process and the practical example of application of the filter for estimation of mobile radio propagation channels at a wireless receiver. We show that computational complexity of the implementation can be considerably reduced by exploiting...
Impulse-radio ultra-wideband (IR-UWB) radios are slated to be the next generation of transceivers that can support power-constrained applications such as wireless sensor and body area networks. However, despite inherent advantages of UWB transmission due its large signal bandwidth, adoption of IR-UWB radios is hampered by relatively complex receiver structures. In this overview paper, we will first...
This paper presents a reconfigurable inner receiver for the LTE, DVB-H, and IEEE802.11n (WLAN) radio systems, all of which are based on orthogonal frequency division multiplexing (OFDM). The receiver is implemented in the CAL language. An FPGA-based hardware implementation is synthesized from RTL generated from the CAL description. The purpose of our work is to investigate the feasibility of dataflow...
Cognitive radio systems are perspective solution for effective utilization of frequency spectrum. Essential feature of cognitive radio devices is scanning of certain frequency band and consequent decision making whether this band is used by primary user or not. In this paper several methods for detecting signals of analog and digital TV broadcasts are described and simulation results are presented...
The demand for very high-quality connectivity for in-home distribution of data and multi-stream entertainment is increasingly motivating the development of high-speed power-line communication technologies offering more than hundreds of Mbit/s. In this paper, to achieve such data rates, power-line multiple-input multiple-output solutions are further investigated. The beamforming scheme, for an ideal...
This paper deals with channel estimation for Orthogonal Frequency Division Multiplexing (OFDM) systems over time-varying fading channels. In conventional methods, the least-squares (LS) estimate is obtained over the pilot subcarriers, and next interpolated over the entire frequency grid. Those methods only exploit the frequency-domain correlation of the channel. In this paper, we propose to exploit...
This work considers the problem of channel estimation in the context of non-binary-LDPC-coded OFDM transmission over doubly-selective multipath channels. The potential of channel encoding is exploited to derive an iterative Wiener-filter-based estimation method using both time and frequency autocorrelation of the channel. The proposed algorithm can use either the soft information or the hard decisions...
Timing and frequency synchronization are the important task in receiver. In this paper, an efficient timing and carrier frequency offset (CFO) estimation method for orthogonal frequency division multiple access/ time division duplexing (OFDMA/TDD) mode in IEEE 802.16-2004 standard (WiMAX) is represented. This method has high performance and jointly estimates timing error and CFO. The performance is...
Multiple access interference (MAI) is the major limiting factor for the channel capacity especially when it is desired to have large number of users (overloaded) in DS-CDMA system. We propose a scheme which removes MAI with very little computations. The scheme is based on two requirements, firstly, presence of a user called `Pseudo-user' whose data is already known to the receiver and secondly, cross-correlation...
In traditional analysis to the performance of MBSFN uncorrelated shadow fading is used. In some cases this assumption does not capture the behaviors of the shadow fading. In this paper, a novel analytical model of system, user equipment receiver and correlated shadow are proposed firstly, then the performance measures were introduced, the changes in coverage due to correlation among the received signal...
Correlated scattering occurs naturally in frequency-selective fading channels and its impact on the performance needs to be understood. In particular, we answer the question whether the uncorrelated scattering model leads to an optimistic or pessimistic estimation of the actual average capacity. In the paper, we use majorization for functions to show that the average rate with perfectly informed receiver...
In this paper we introduce an improved version of the turbo layered orthogonal lattice detector (T-LORD), recently presented. This implementation, namely K-Best T-LORD, misses the performance of the turbo MAP detector by only few tenths of dB in various configurations, like the fully enhanced T-LORD. However, its complexity is quadratic in the number of transmitting antennas instead of exponential...
A method is developed for acoustic time synchronization/pulse acquisition suitable for use in reverberant multipath environments. This scheme uses two identical broadband synchronization pulses for the acquisition, and it is motivated by passive phase conjugation. The first pulse is used as a preamble pulse and replaces the replica signal later to correlate with the second pulse. Within the coherent...
We present a compressive wide-band spectrum sensing scheme for cognitive radios. The received analog signal at the cognitive radio sensing receiver is transformed in to a digital signal using an analog-to-information converter. The autocorrelation of this compressed signal is then used to reconstruct an estimate of the signal spectrum. We evaluate the performance of this scheme in terms of the mean...
This paper presents an analytical model for symbol error rate (SER) calculation of a polarization receive diversity system with equal gain combining (EGC) of the received signals. Ricean fading statistic characterizing wireless communication channel is assumed. Pade rational approximation to the moment generating function (MGF) of the output SNR (signal-to-noise ratio) is used in the case of EGC....
This paper demonstrates noncoherent detection of multicarrier UWB signals, using a multichannel autocorrelation receiver (AcR) frontend. The receiver detects the energy of the subcarrier signals. In principle, the receiver estimates the energy spectrum of the received multicarrier signal. It computes a Fourier transform of the AcR output signals, which are samples of an autocorrelation function of...
The Multiband OFDM Alliance (MBOA), established to formulate an industry-based standard for UWB communications, suggested dividing the 3-10 GHz spectrum to 14 sub-bands. Motivated by the sub-band approach, this paper presents measurement results of the mean (excess) delay and RMS delay spread. We also analyze channel gain vs. terminal separation and frequency. We characterize the dependence of the...
This paper shows an efficient implementation of symbol synchronization and frequency equalization algorithms for OFDM (orthogonal frequency division multiplexing) based systems. The aim is to have a low complexity realization that can be implemented on a FPGA (Field Programmable Gate Array), to obtain an area-efficient receiver. The algorithms are described theoretically, and hardware considerations...
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