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Multiple Input Multiple Output (MIMO) systems use multiple transmit and receive antennas to achieve higher data rates by transmitting multiple independent data systems. Transmission errors can be reduced by using Hybrid Automatic Repeat request (HARQ) combining techniques with MIMO systems. We propose two novel MIMO HARQ combining methods which are based on using pre-combining only and a joint post...
Lattice reduction algorithms, such as the LLL algorithm, have been proposed as preprocessing tools in order to enhance the performance of suboptimal receivers in MIMO communications. In this paper we introduce a new kind of lattice reduction-aided decoding technique, called augmented lattice reduction, which recovers the transmitted vector directly from the change of basis matrix, and therefore doesn't...
Polarized MIMO systems are an efficient solution for reducing inter-antenna correlation while maintaining compact terminal size. In this paper, a time-variant statistical channel model is proposed for tri-polarized antenna systems. The model is based on a coherent and a scattered component, where each component includes inter-channel correlation and cross-polar discriminations. The temporal variations...
This paper investigates throughput-efficient relay ARQ protocols for single carrier MIMO systems with amplify-and-forward relaying. We focus on reducing the multiplexing loss due to the half-duplex operation at the relay. We introduce two new relaying protocols where both ARQ and relaying are jointly targeted. Compared to the conventional relaying techniques, the proposed mechanisms require only one...
In-Band On-Channe (IBOC) digital audio broadcasting (DAB) is a method of digital audio radio , which could transmit analog FM and digital audio simultaneously. However, due to the existence of fading and interference in FM bands, transmit capacity has reached its limitations for the bandwidth, thus, adding digital transmission in the crowded FM band is a challenging proposition. Diversity is one of...
The throughout of wireless communication systems can be improved by adding multiple antennas at the transmitter and receiver to create multiple-input multiple-output channels. To avoid the prohibitive complexity involved in the ML detectors, some special detectors were proposed to improve the performance-complexity trade-off, such as zero-forcing (ZF), minimum mean-square (MMSE), vertical Bell labs...
In wireless environment, the channels are really affected by a number of factors such as: fading, interference, noise. In most of wireless communications, we have applied the training sequences as known signal at the receiver for estimating the channel as well as the transmitted signal. Nowadays, many paid services in the entertainment industry have required the high security for their data and this...
Unlike that of terrestrial sensor networks, the physical layer design of Underwater Acoustic Sensor Networks (UW-ASNs) faces far more challenges because of the limited band-width, extended multipath, refractive properties of the medium, severe fading and large Doppler shifts. This paper takes a tutorial overview of the physical properties of acoustic propagation, modulation schemes and power efficiency...
A near-optimal signal detection algorithm with complexity of O(K log K) is proposed for K -input, K -output linear Gaussian vector channels. The proposed algorithm is based on the searching for a monotone sequence with maximum likelihood, under the ranking of sufficient statistics. It is proved that the algorithm can reach the optimal detection result in the case that all cross-correlation values...
As China's continuous improvement in the degree of information, the wireless communication network has covered all regions of the country, and information has also brought a great deal of information network security issues. In this paper, firstly, the information security emergency response procedures and disposal system are proposed according to the comprehensive analysis of weak links in information...
Although many researchers have written about OFDMA transmission system, it needs more attention and analysis in next generation wireless networks. This paper is aimed at studying the performance analysis of OFDMA in WiMAX IEEE 802.16m and 3GPP LTE Advanced systems Communication in hybrid environment systems. This study further focuses on Downlink and Uplink models. Finally, it summarizes simulation...
Based on the analysis of the technical principles and the system model of the MIMO and OFDM technologies, a simple DVB-T wireless communication system is constructed. The system is composed of transmitter, channel, receiver, and so on. Space-time coding is done in the transmitter, the signal is launched after OFDM modulation, and the process of the receiver is the inverse process of the transmitter...
We consider the K-link constant coefficient multiple-input-multiple-output interference channel (MIMO IFC) where inter-link interference is treated as Gaussian noise (Noisy MIMO IFC). Starting from Interference Alignment (IA) constraints, analytical conditions that need to be satisfied in order to admit an IA solution for such a MIMO IFC are derived. For a given degrees of freedom allocation, these...
This paper provides a performance comparison of soft MMSE and max-log demodulators for multiple-input multiple-output (MIMO) bit-interleaved coded modulation (BICM) systems with imperfect channel state information. We use the capacity of the equivalent modulation channel as a code-independent performance metric. Our results show that the conventional approach of mismatched demodulation is noticeably...
In this paper, we present and analyze a rate-adaptive multiuser orthogonal random beamforming (ORBF) system. The goal is to maximize the average spectral efficiency (ASE) while satisfying a target bit error ratio (BER) constraint. We first derive the cumulative distribution function of the post-scheduling signal-to-interference-plus-noise ratio (SINR) with a new approach. The average BER and the ASE...
Cooperative diversity is one of the promising solutions to overcome the channel impairments and provide high data rate coverage. It has been studied for different channel fading as Rayleigh, Rice and Nakagami-m. Nevertheless, for a decode and forward relaying over composite fading including simultaneously multipath and shadowing, outage results have ever appeared. Using the Nakagami probability density...
Opportunistic interference management (OIM) is an approach that can asymptotically achieve dirty paper coding (DPC) capacity in the downlink of wireless cellular networks with minimum feedback requirement. With K antennas at the base station and M mobile users in the cell, the proposed technique requires only K integer numbers related to channel state information (CSI). This multiplexing gain of K...
In this paper we analyze the sum rate of zero-forcing (ZF) precoding in MISO broadcast channels with limited feedback, transmit correlation and path loss. Our analysis assumes that the number of transmit antennas M and the number of users K are large, while their ratio remains bounded. By applying recent results from random matrix theory we derive a deterministic equivalent of the signal-to-interference...
In this work we study a two-user multiple antenna system under quasi-static fading employing a novel scheme that combines cooperation and iterative multiuser detection based on minimum mean square error estimation. We investigate three different receivers: a joint detector for the two users, a separate (per-user) detector, and a distributed matrix-Alamouti detector. We show that the separate detector...
The statistical properties of the capacity of narrowband double Hoyt fading channels are studied. Toward this end, analytical expressions for the probability density function (PDF) and cumulative distribution function (CDF) of the instantaneous channel capacity process are derived. Furthermore, for the characterization of the dynamical behavior of the time-varying channel capacity, expressions are...
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