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This paper considers the two-user interference relay channel where each source wishes to communicate to its destination a message that is confidential from the other destination. Furthermore, the relay, that is the enabler of communication, due to the absence of direct links, is untrusted. Thus, the messages from both sources need to be kept secret from the relay as well. We provide an achievable...
This paper presents a new coding scheme that considerably increases the efficiency of the channel in multicast setting. Specifically, we study the scenario where three terminals exchange their messages via a satellite gateway. The main difference between the proposed scheme and conventional three-way relay channel is the use of joint channel and network coding. This allows three terminals to transmit...
In this paper, we investigate the detection of single-carrier transmission over frequency selective fading channels with symmetric alpha-stable (SαS) noise. To mitigate the effects of the inter-symbol interference (ISI) cased by multi-path propagation and the destructive impulsive noise, a non-linear myriad filter is firstly adopted and an asymptotic statistic method is then introduced for to analyze...
A technology of improving the security of telecommunications systems is offered. The main features of the technology is the adaptation of turbo codes in conditions of jamming, which give rise to uncertainties in the process of decoding turbo codes, and the use of encryption algorithms and protection against network attacks. This technology can significantly improve the stability of the system to the...
Spread spectrum (SS) modulation is one of the most commonly used methods for data hiding. However, the capacity of SS-based methods is rather limited. To improve the hiding efficiency, this paper presents a method that employs the parallel combinatory spread spectrum (PCSS), in which the hidden data can be transmitted in parallel with a combination of a few pseudo noise sequences. An informed embedding...
Pilot signal reuse in neighboring cells causes the pilot contamination, and performance will degrade significantly in a multi-cell, massive MIMO uplink system. In this paper, based on Principle Component Analysis (PCA), Independent Component Analysis (ICA) and a few pilot signals, a new decoding method is proposed. In this method, we implement the PCA to reduce the dimension of the received signals...
Non-orthogonal multiple access (NOMA) has been attracting a lot of attention as a promising downlink multiple access scheme for LTE enhancements and 5G. This paper introduces an overview of the concept, performance evaluation gains and our experimental trials related to NOMA. The goal is to clarify the benefits of NOMA over orthogonal multiple access (OMA) such as OFDMA adopted by Long-Term Evolution...
This paper presents a low-complexity detection scheme, which consists of a lattice sphere decoder (LSD), for Orthogonal Frequency Division Multiplexing (OFDM) systems. The inter-carrier interference (ICI) resulting from selective fading channel destroys the orthogonality of the OFDM signal and poses a significant limitation on wireless OFDM systems. The aim of this paper is to propose an efficient...
Power consumption minimization in Wireless Sensor Networks (WSNs) has been discussed extensively in literature. Usually, a central node (a receiver) in WSNs consumes large amount of power due to the necessity to decode every received packet regardless of the fact that the transmission may suffer from packets collision. Current collision detection mechanisms in WSNs have largely been revolving around...
Filter bank multicarrier is one of the candidates for next generation mobile radio systems. Using filtered sub-channels reduces side-lopes as well as interference among sub-channels. Symbols overlap in time and are not separated by a cyclic prefix resulting in inter-symbol inference as well as interference from adjacent sub-channels under multi-path propagation. Equalization methods known from OFDM...
This paper gives an brief survey on full-duplex relaying. First, we discuss the importance of full-duplex communications and its major drawback, known as self-interference. We provide a overview of the state-of-the-art on self-interference cancellation techniques from antenna design to digital cancellation. Then, we assess current developments in full-duplex relaying, some promising protocols and...
This paper analyzes the bit error rate (BER) performance of grouped frequency division multiple access (GFDMA) using a tool known as finite length analytical tool (FLAT). We derive the equations of the FLAT method including the variance of the equalizer output signal for different iterations. We use this value to calculate the BER of the equalizer output when a specific set of sub-carriers are assigned...
In frequency-hopping systems, the multiple-access interference (MAI) occurs when more than one user appear on the same frequency at the same time. In this paper, we address the multi-user detection (MUD) problem for slow frequencyhopping (SFH) system with binary phase shift keying (BPSK). We first built a MAI model taking the hopping patterns and the phase offset into account, whereby the MAI is considered...
Among the linear precoding techniques block diagonalization (BD) based schemes are well-known transmit strategies employed in the downlink of multiuser MIMO (MUMIMO) systems. Employing BD type precoding algorithms at the transmit side suppresses multi-user interference (MUI) by converting a MU-MIMO broadcast channel into multiple single-user MIMO (SU-MIMO) channels and then decomposing the SU-MIMO...
Wireless Sensor Networks (WSNs) have been considered one of the very promising technologies for the implementation of smart grid. WSN-based smart grid communication protocols have been focused on extending the node's lifetime which is heavily depends on the energy consumption of the node. Since wireless sensors are typically deployed in an ad hoc fashion and operate off of a limited energy source,...
This paper considers the cross-tier interference mitigation for macro-femto networks under the reverse time division duplexing (RTDD) mode. A joint interference alignment (IA) and avoidance scheme is proposed. To mitigate the interference caused by femtocells at the macrocell base station (MBS), the signals of femtocells are aligned into the the null-space of the MBS's signal. The problem of the optimal...
In Compressed Sensing, a real-valued sparse vector has to be reconstructed from an underdetermined system of linear equations. However, in many applications of digital communications the elements of the unknown sparse vector are drawn from a finite set. The standard reconstruction algorithms of Compressed Sensing do not take this knowledge into account, hence, enhanced algorithms are required to achieve...
Femtocell access points (FAPs) has emerged as to improve the coverage and capacity of next generation network. However, dense femtocell deployments can cause severe interference. In this paper, a FAPs' cooperation approach is proposed to solve the interference problem. In particular, for uplink transmissions, the cooperative FAPs are allowed to form a group (i.e., coalition) to optimize their sum-rate...
The Cognitive Multiple Access Z-Interference Channel consists of a MAC channel that receives interference from an external transmitter. In a previous work we studied this model where both MAC users are cognitive and showed that an encoding scheme based on Dirty Paper coding attains the capacity region for the Gaussian case. In this work we assume that only one MAC user is cognitive and show that the...
This paper considers the selection of users and corresponding uplink decoding in multi-user multiple-input multiple-output (MU-MIMO) multi-cell systems, applicable to future wireless networks with centralized processing at the wireless controller (WC). Two-layer decoding is proposed. First, for all active mobile stations (MSs) the spatial streams are decoupled at the pre-assigned base stations (BSs)...
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