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An efficient full-rate linear dispersion (LD) code is designed over correlated Rayleigh fading channel. This code is suitable for mobile station in LTE-Advanced system where a code with two antennas and three time slots is required and the orthogonal Alamouti code can not be appUed. For this purpose, we first derive a closed-form formula for the ergodic achievable information rate of an LD coded multi-input...
Three modulation schemes are compared for underwater acoustic communications: M-ary frequency-shift keying (MFSK), direct-sequence spread spectrum (DSSS, single carrier), and frequency-repetition spread spectrum (FRSS, multi-carrier), which is a special case of frequency-division multiplexing. The MFSK receiver is based on energy detection, whereas DSSS and FRSS are coherent schemes equipped with...
In this paper, performance of a novel analytic model of direct sequence code division multiple accesses (DS-CDMA) using diversity with maximal ratio combining (MRC) scheme is observed under the influence of multipath Rayleigh fading and multi-access interference (MAI) varying different system parameters and properties of PN sequences. The analysis presents a mathematical expression for bit error rate...
In this paper we describe and simulate an accurate Bit Error Rate (BER) estimator for a chip level Wiener equalizer and combined equalizer/interference canceller for employment with the CDMA MIMO High Speed Downlink Packet Access (HSDPA) feature of the Third Generation Partnership Project (3GPP). In the 2 × 2 MIMO system two data streams may be transmitted in the downlink to each user equipment (UE)...
WiMAX is a wireless technology which offers high data rate transmission in broadband. In this paper, the architecture of the WiMAX physical layer simulator is presented. The main blocks are implemented with the aid of the Matlab programming language and the bit error rate (BER) curves are presented in Rayleigh fading channel.
In this study, we analyze the role of interleavers in OFDMA system for ensuring uniform BER performance amongst the active users and also investigate their respective PAPR properties. At first considering a generic system in a slowly changing multipath channel where high dispersion in the individual users performance exists, we apply different types of interleaving and show that they in general help...
This contribution presents low computational complexity versions of orthogonal frequency division multiplexing (OFDM) modulation scheme for the implementation of clustered-OFDM systems for data transmission in the passband frequency. Among the proposed schemes, which are named Hermitian symmetric OFDM (HS-OFDM) I and HS-OFDM II, the HS-OFDM II can offer computational complexity reduction in comparison...
We investigate the use of impulsive ultrawide band (I-UWB) modulation over medium voltage (MV) power line channels for low data rate communications. In particular, we consider a MV network where a channel measurement campaign has been carried out. In this paper, we firstly describe the MV test network. We study the statistics of the MV channels in terms of both root-mean-square delay spread (RMS-DS)...
Ultra-wideband communications system with pre-coders based on time-reverse channel impulse response have been shown to yield improved bit error rate performance for a given signal to noise ratio. However, as the channel impulse response is usually quite long, the implementation of the full time-reversed precoders involves high implementation complexity. We propose two implementation methods that will...
An uncoded IDMA system with chip accumulation for partial users is proposed. The rate-1 accumulators are employed for partial users. Simulation gives an optimal number Ks of partial users for K-user uncoded IDMA system with the lowest BER. Simulation results show that the performance of the proposed system is improved, compared with the conventional IDMA system, especially for few users and in high...
This paper presents a cyclic delay-division multiple-access (CDDMA) scheme, in which users are distinguished by different chip-level cyclic delay methods. Because a number is enough to represent a user's identity, there are only a few bits needed to store or communicate between the transmitter and receiver, which simplifies the communication system and reduce the system cost. A very low-cost iterative...
This paper presents the impact of phase noise on the performance of a communication link with QPSK digital modulation. For example, how phase noise affects bit error rate is demonstrated with detailed simulations. Also, this paper illustrates how phase noise affects the receiver signal constellation diagram and employs a model for simulating the phase noise. More importantly, this paper shows clearly...
In the current internet, Transmission Control Protocol (TCP) is used as the most popular transport layer protocol. However, the end-to-end throughput of TCP degrades significantly when operates in wireless networks. Frequent retransmission timeout is one of the well-known problems of TCP end-to-end throughput degradation over wireless networks. In wireless networks, a retransmission timeout is inevitable,...
In this paper, the exact symbol error probability expression for a decode-and-forward cooperative relaying scheme using quadrature amplitude modulation (QAM) in the presence of Rayleigh fading and Bernoulli-Gaussian impulsive noise is derived. Different from, we only consider the practical receiver structure at the destination without requiring any knowledge of impulsive noise. Also, the source retransmission...
Non-coherent UWB receivers are often implemented using energy detection architectures which are very sensitive to noise in the channel and interference. Therefore, the receiver bandwidth plays an important role since the total noise and interference energy is proportional to this bandwidth. This work provides analytical expressions to find the optimal receiver bandwidth and quantifying the effect...
This paper considers the problem of power allocation for cooperative communication with multicast in coded wireless sensor networks (WSNs). We formulate and solve the problem using a cross-layer optimization framework, in which a simplified cooperative communication scheme that does not require channel state information (CSI) is considered. When compared against conventional cooperative and non-cooperative...
Spectrally Efficient Frequency Division Multiplexing (SEFDM) systems aim to reduce the utilized spectrum by multiplexing non-orthogonal overlapped carriers. Since the per carrier transmission rate is maintained, SEFDM yields higher spectral efficiency relative to an equivalent Orthogonal Frequency Division Multiplexing (OFDM) system. Yet, due to the loss of the orthogonality, detection of the SEFDM...
Traditional transmitted reference (TR) systems for Ultra-Wideband (UWB) communications separate the reference and data-modulated signals in the time domain, thus requiring at the receiver a delay component which is difficult to implement. To circumvent this drawback, frequency-shifted reference (FSR-TR) systems employ an analog carrier to make the reference and data-modulated signals orthogonal with...
In this paper, we investigate the joint effects of high-power amplifier (HPA) nonlinearity, in-phase/quadrature-phase (I/Q) imbalance and crosstalk, on the performance of multiple-input multiple-output (MIMO) transmit beamforming (TB) systems, and propose a compensation method for the three impairments together. The performance of the MIMO TB system equipped with the proposed compensation scheme is...
Detection and error rate performance of weak M-ary chirp spread-spectrum (MCSS) signals in Middleton's class-A noise are addressed. The structure of the optimal weak-signal receiver is derived and consists of a zero-memory nonlinearity (ZMNL), a function of first-order noise density, followed by Gaussian MCSS correlator receiver. Bit error rate (BER) bounds on the performance of this receiver are...
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