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In this paper, we study the design of network codes for multi-source, multi-relay networks over frequency non-selective slow fading channels. Specifically, we consider a system with M sources each having independent information to be transmitted to a common destination with the help of N relays (called an M - N - 1 system). A finite field (nonbinary) based method is suggested to design binary network...
This paper proposes a new coded cooperation scheme based on hierarchical modulation (HM), which can achieve full diversity gain for slow and fast fading. In the proposed scheme, a user multiplexes its own data and its partner's data as high and low priority streams in the HM. We show by an analysis of the pairwise error probability that the proposed scheme achieves a higher diversity order than other...
We present an improved decoding algorithm for joint turbo decoding and physical-layer network coding. Instead of decoding the individual (binary) messages separately at the relay, the proposed algorithm, from the superimposed faded signals, yields an XOR estimate of the sent messages. Moreover, we introduce a softening of the XOR values to improve the overall performance. Simulation results show that...
Space Shift Keying (SSK) is a novel low-complexity digital modulation technique for multiple antenna wireless systems. In SSK, blocks of data are encoded in the index of a specific transmit antenna of the antenna array, which is switched on for data transmission while all the other antennas radiate no power. Recent results have shown that SSK can outperform, with low computational complexity, conventional...
This paper describes a novel mechanism for joint decoding of the network coded symbols in a multi-way relay node. The mechanism, based on belief propagation algorithm, utilizes the correlation between adjacent network coded symbols to minimize the error propagation problem significantly, compared with previous methods. In case of increasing degree of asynchrony, disjoint decoding exhibits poorer error...
Coded cooperation is an attractive user cooperation scheme for wireless systems, where different parts of a coded packet are transmitted over different channels. In this paper, we propose a new approach to improve the performance of coded cooperation. We present cooperative maximum-ratio combining (C-MRC) based coded cooperation to guarantee full diversity even if the inter-user link is not ideal...
In this paper, we study the performance of network-coded cooperative wireless networks with channel coding over each wireless links. As a case study, the two-source two-relay network is considered and the performance vs. energy-efficiency trade-off of various network code designs (offering both equal and unequal error protection capabilities) over fast- and slowly-varying fading channels is studied...
To facilitate practical implementation of a dynamic decode-&-forward (DDF) for type-2 user equipment (UE) relay defined in 3GPP which is being considered for next-generation cellular standards (e.g., LTE-Advanced), we propose “Modified Dynamic DF (M-DDF)” to realize fast jump-in relaying and decoding scheme for cooperative transmission. More specifically, subframe based sequential decoding is...
In infrastructure-based wireless networks, installing multiple antennas on fixed relay stations provides an effective and low-cost solution to increase network capacity and combat hostile fading channels. Previous work on multi-antenna relays either assumes that only one relay available in the network without benefiting from relay cooperation or all relays are used to assist the source transmission...
Recently, substantial attention has been paid to improve the spectral efficiency of communication setups using different spectrum sharing techniques. This paper studies the ergodic achievable rate of spectrum sharing channels in the case where the primary licensed user is equipped with a sequential decoder, while there is no connection between the transmitters. Assuming Rayleigh block-fading channels,...
In this paper, we propose a novel cooperative multi-hop transmission protocol (NCMT). In the proposed protocol, cooperative communication is used to decrease the end-to-end outage probability and reduce the number of transmissions due to the skipped hops. The performances are evaluated via theoretical analyses and Monte Carlo simulations.
We consider the transmission of a memoryless Gaussian source over a power-constrained Rayleigh fading channel with additive white Gaussian noise. We propose the use of low-delay joint source-channel mappings and consider optimizing the non-parametric mappings through an iterative process. A design algorithm for joint source-channel mapping is proposed and numerically evaluated for 2:1, 3:1, and 4:1...
Consider the composite relay channel (CRC) where the channel is randomly drawn from a set of conditional distributions with index θ ∊ Θ, which represents the vector of channel parameters. The specific draw • is assumed to be unknown at the source, fully known at the destination and only partly known at the relay. In this setting, the coding would commonly be chosen regardless of the channel measurement...
This short note gives an overview of the concept of integer-forcing architectures for MIMO systems. Such architectures employ a linear receiver structure, i.e., a static linear transform followed by separate single-stream decoders, thus enjoying a significant complexity advantage over joint decoding of all streams. In standard linear receivers, the component single-stream decoders each decode one...
We propose a scheme of utilizing multilevel space-time signal-based turbo code (MST-SB-TC) for wireless communication systems with multiple antennas over very rapidly Rayleigh block fading channels where the fading coefficients changes independently for every transmitted signal. No channel state information (CSI) is available and even unitary space-time signals fail to operate. We give an effective...
A dynamic decode-&-forward (DDF) is redesigned to meet the crucial requirements for type-2 user equipment (UE) relays which are being considered for next-generation cellular standards (e.g., LTE-Advanced). Toward this, the proposed modified DDF (M-DDF) realizes a fast jump-in relaying and sequential decoding where a subframe decoding is employed to yield a combination of energy/information/mixed...
Though opportunistic relaying coded cooperation is known as an efficient cooperation scheme for cooperative multi-relay networks, the existing works have the disadvantage of low resource utilization or high system complexity. In this paper, we focus on how to achieve a balance between resource utilization and system complexity by proposing an novel opportunistic relaying coded cooperation with selective...
Bi-directional relaying (BDR) in which two users wish to exchange independent information in presence of a relay is one of the fundamental wireless network coding applications that attracted intense interests recently. In this paper, maximum likelihood (ML), cooperative maximal ratio combining (CMRC) and soft information relaying (SIR) schemes proposed to combat error propagation in wireless relay...
In this paper, we propose an orthogonal space-time block coding (STBC) for continuous phase modulation (CPM) over frequency-selective channels. The new method maintains the constant envelope and the phase continuity of the CPM waveforms by inserting three blocks of data-dependent symbols in addition to a cyclic prefix (CP). At the transmitter, the data blocks are precoded and transmitted in two antennas...
In this paper, we investigate the outage performance of relay-assisted free-space optical (FSO) networks which build upon the combinations of serial and parallel relaying. We assume log-normal atmospheric turbulence channels and derive outage probability expressions for multi-hop parallel relaying scheme under consideration. Our outage probability analysis demonstrates substantial performance improvements...
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