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The maximum likelihood (ML) detection is the optimal detection method for multiple-input multiple-output (MIMO) communication systems. The normal K-best sphere decoding algorithm (SDA) can guarantee a fixed throughput, but it induces a large bit error rate (BER) degradation. In order to achieve close-to-ML performance, the K value needs to be sufficiently large. Thus, it needs large computation with...
The exact performance analysis of MMSE (minimum-mean-square-error) combining for space diversity reception is studied in the presence of a single and multiple cochannel interference (CCI) sources, and compared to maximum-ratio combining (MRC). This paper considers digital cellular mobile radio systems with quadrature amplitude modulation (QAM) transmission and two diversity antennas in flat and quasi-static...
In this paper, we present a multistage group-decision-aid MUD (MG-MUD) for the uplink multirate code division multiple access (CDMA) systems. To provide good tradeoff between the performance and computational complexity, the new MUD is based on the widely MMSE criterion and constructed by a bank of group detectors in each stage. First, the users are classified into different groups according to their...
Phase noise causes common phase error (CPE) and intercarrier interference (ICI) in orthogonal frequency division multiplexing (OFDM) system. To mitigate the effects of phase noise, many schemes have been proposed, but they are either computationally complex or at the price of sacrificing spectral efficiency. In this paper, a continuous Hopfield neural network (HNN) is designed for OFDM signal receiver...
The multi-band orthogonal frequency division multiplexing (MB-OFDM) is an ultra wideband (UWB) technology that can transmit information at the maximum data rate of 480 Mb/s. When the simultaneous operating piconets (SOP) are located closely, the symbol collisions are expected to occur among the symbols transmitted over the same sub-band at the same time. This interference will decrease throughputs...
Adaptive modulation and power allocation schemes have been widely used in multiple-input multiple-output (MIMO) systems to enhance spectral efficiency while maintaining bit error ratio (BER) to a target level. We derive the spectral efficiency of orthogonal space-time block codes (OSTBC) that can be achieved by applying adaptive modulation and power allocation. Compared to non-adaptive power scheme,...
In this paper, the combined normalized and offset min-sum algorithm is proposed for efficient decoding of low-density parity-check (LDPC) codes in optical and magnetic storage systems. The proposed algorithm can be considered as a general case of the normalized and offset algorithms, and offers better BER performance compared to them. The performance improvement is presented for a partial response...
For high data rate ultra wideband communication system, performance comparison of Rake, MMSE and Rake-MMSE receivers is attempted in this paper. The effect of the number of Rake fingers and equalizer taps on the error performance by combating ISI are the major focus of our research. The bit error rate performances are investigated using semi analytical approach and Monte-Carlo simulation on IEEE 802...
Day by day popularity of wireless devices used to access the Internet is increasing. It indicates that in the near future TCP protocol will be frequently used over the wireless links. The wireless links characteristics are significantly different from characteristics of wired links. TCP (Transport Control Protocol) is basically designed for wired network. One of the main reasons for TCP's degraded...
Distinctiveness of users in biometric authentication can be limited when multiple samples of a user's biometric information differ due to intra-class variability in the acquisition, thus resulting in random correspondence between users. Most of the currently known methods based on error correcting codes, fuzzy vault have been proposed for protecting biometric data against the intra-class variability...
This study investigates how frequency offsets of multitone jamming affect the fast frequency-hopped binary frequency shift keying (FFH/BFSK) product-combining receiver (PCR) under additive white Gaussian noise (AWGN). We demonstrate the average bit-error-rate (BER) expressions of the FFH/BFSK PCR and the average BER expressions of an FFH/BFSK spread-spectrum (SS) communication system with frequency...
An optimum maximum-likelihood (ML) receiver is proposed and analyzed for fast frequency-hopped M-ary frequency-shift keying systems over frequency-selective Rayleigh-fading channels with multitone jamming and additive white Gaussian noise. The analytical bit-error rate expressions of the proposed optimum ML receiver are also derived based on the characteristic function approach, which is applicable...
This paper proposes a new combinational technology which is feasible to apply physical-layer network coding (PNC) to wireless fading channel. The key step of PNC is that sources broadcast signals simultaneously without orthogonal scheduling. Naturally, the signals overlap in the free space at the receivers. Since the signals from different sources are mutual independent, rooted on this rational assumption,...
A Bit-Error-Rate (BER) performance evaluation is presented for mu-Law companded QPSK modulated Mobile WiMax (IEEE802.16e) employing tail-biting convolutional coding (TBCC). The Down Link (DL) Partially Used Subcarrier (PUSC) deployment has been considered for this investigation. Equalized symbol power transmissions for uncompanded and mu-Law companded WiMax scenarios employing mu = 0.1, 1, 3, 10,...
UWB (Ultra Wide Band) technology is a reliable transmission scheme for wireless communication with high data rates. It is called as impulse radio, impulse radar or carrier free ultra high resolution scheme. UWB is defined as signals with fractional band width more than 20% of its central frequency or as signals with bandwidth more than 500 MHZ. UWB can be characterized with ultra-short duration pulses...
Turbo convolutional codes (TCC) are excellent error correcting codes as they show near Shannon capacity performance in communication systems. However, turbo decoders are computationally complex. Recently, a class of modified turbo codes called low complexity hybrid turbo codes (LCHTC) is proposed with bit error rate (BER) which is almost same as that of turbo codes. In this paper improved low complexity...
Performance of biometrics in human authentication can be limited when multiple samples of a user's biometric information differ due to intra-class variability in acquisition, storage or transmission of biometrics. Thus, random correspondence results between users. We formulate probability of random correspondence (PRC) by developing an information model of biometrics features as a noisy source. The...
In this paper, a novel audio steganography method is proposed. In this algorithm, first embedding threshold in the time domain is estimated. Then this threshold is used for data concealment in the time domain. The performance of the proposed scheme in terms of SNR (signal to noise ratio) and BER (bit error rate) is analyzed. An estimation formula that connects SNR with embedding threshold has been...
We evaluate the error performance of a selection diversity (SD) receiver over generalized-K fading channels. The bit-error rate (BER) expression is obtained directly from the cumulative distribution function (CDF), and thus eliminating the need for differentiating the CDF of the combiner output as in the analysis technique used hitherto. Using this approach, we are able to conveniently analyze the...
Error propagation from the relay to the destination is a major drawback of digital relaying protocols that substantially diminishes the cooperative diversity gain of the system. Appropriately designed selection relaying schemes can effectively mitigate this phenomenon and improve the diversity order, specifically when the source-relay channel state information (CSI) is not available at the destination...
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