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A concatenated coding scheme using a polarization transformation followed by outer sub-codes is analyzed. Achievable error exponents and upper bounds on the error rate are derived. The first bound is obtained using outer codes which are typical linear codes from the ensemble of parity check matrices whose elements are chosen independently and uniformly. As a byproduct of this bound, it determines...
Abstract-The capacity of the intensity-modulation directdetection (IM-DD) optical broadcast channel (OBC) is investigated. The OBC is modeled as a Gaussian channel with input-independent noise and both average and peak input constraints. Outer and inner bounds on the capacity region are derived. The outer bounds are based on Bergmans' approach. The inner bounds are based on superposition coding with...
We analyze the error performance of coding scheme that is found in the protocol for secret key agreement based on the Gaussian channel. The approach is regarded as the Slepian-Wolf coding or the source coding with side information at the decoder. One remarkable feature of the coding in the key agreement is that two parties may extract the set of reliable signals before Slepian-Wolf coding is performed...
In this paper our aim is to use some tight lower and upper bounds for the differential quaternary phase shift keying transmission bit error rate in order to deduce accurate approximations for the bit error rate by improving the known results in the literature. The computation of our new approximate expressions are significantly simpler than that of the exact expression.
The finite-SNR Diversity-Multiplexing Tradeoff (DMT) problem is studied in the context of spectrum aggregation, where there exist multiple noncontiguous (discrete) spectrum segments each of which has its own power limit. Firstly, we give an optimal power allocation strategy to achieve the ergodic capacity under Rayleigh fading. Secondly, two different coding schemes, i.e., coding without across sub-channels...
In FD-AWGN relay channel, the source sends the superposition of many capacity-achieving codewords. The relay decodes them using successive interference cancellation (SIC) and sends the superposition of the same codewords multiplied by random dither sequences and with a new power distribution among the codewords. The destination node decodes all code-words by removing the dithering and then applying...
We study the diversity order vs rate of an additive white Gaussian noise (AWGN) channel in the whole capacity region. We show that for discrete input as well as for continuous input, Gallager's upper bounds on error probability have exponential diversity in low and high rate region but only subexponential in the mid-rate region. For the best available lower bounds and for the practical codes one observes...
The performance of a two-way relay system with beamforming is investigated over Nakagami-m fading channels. Our analysis considers an amplify-and-forward relay system consisting of two terminals equipped with multiple antennas, and a variable-gain relay with a single antenna. Exact closed-form expressions for the outage probabilities of two unidirectional links of the two-way system are derived, respectively...
Besides the optimal but impractically complex dirty paper coding (DPC), linear precoding and vector precoding (VP) have been proposed for the vector broadcast channel (BC). Linear precoding is simple, as only a linear transform is applied to the data signals, whereas VP necessitates a closest-point search in a lattice to find the perturbation signal which reduces the necessary transmit power. In this...
In this paper, we provide a new perspective and insight into the process of finding the maximal performing method using a Cognitive Engine (CE) for link adaptation. It is found that near maximal performance can be reached relatively fast, even when a small number of the available communication methods provide adequate performance. The parameters that affect the expected number of trials are fully...
In this paper, we consider an OFDM-based cooperative diversity system where a source communicates with a destination with the help of a relay in Amplify-and-Forward relaying or Decode-and-Forward relaying. First, we propose a scheme to selecting the "best" relay to assist the transmission. And then, we present two power allocation schemes to minimize system outage probability, based on statistical...
It has been proved that when the transmit power is sufficiently large distributed space time codes can achieve the maximal diversity order in a wireless relay network. In the previous works, space time codes used in a wireless relay network are limited on unitary space time codes or orthogonal (or quasi- orthogonal) space time codes. In this paper, we apply general multi-layer full-rate space time...
The L-user additive white Gaussian noise multi-way relay channel is considered, where multiple users exchange information through a single relay at a common rate. Existing coding strategies, i.e., complete-decode-forward and compress-forward are shown to be bounded away from the cut-set upper bound at high signal-to-noise ratios (SNR). It is known that the gap between the compress-forward rate and...
Vector Perturbation Precoding (VPP) has gained recognition as a reduced-complexity method to achieve high-rates in multiuser multiple-input multiple-output (MIMO) downlink. Here we propose Space-Time VPP (STVPP), where the nonlinear lattice-based precoding operations of standard VPP are extended into the time domain. This is done by introducing temporal precoding lattices for each user, and performing...
Coding techniques for reducing peak-to-mean-envelope-power-ratio (PMEPR) have been intensively investigated for the orthogonal frequency division multiplexing (OFDM) systems adopting PSK, square QAM, and rectangular QAM constellations since the PMEPR is the crucial problem in OFDM. Recently, we designed a new coding method for reducing the PMEPR in OFDM built on star 16QAM constellations. In this...
Cooperative relay has been recognized as a promising approach for improving transmission efficiency and error performance in wireless networks. A number of realizations of cooperative relay communications, such as Amplify-and-Forward (AF), Decode-and-Forward (DF), have been proposed and the capacity gain of these replay approaches has been widely investigated. In this paper, we consider a cooperative...
The secret-key agreement problem over wiretap channels controlled by a state parameter is studied. The entire state sequence is known (non-causally) to the sender but not to the receiver and the eavesdropper. Upper and lower bounds on the secret-key capacity are established both with and without public discussion. In absence of public-discussion, our lower bound is strictly better than the best known...
A signal space diversity (SSD) scheme combined with Alamouti coding is investigated to achieve more diversity gain in fading channels. By approximating noise as a Gaussian distribution after Alamouti decoding, an exact expression for the SER for SSD schemes with Alamouti coding in Rayleigh fading channels can be derived for 4-QAM and 16-QAM. Using the formula derived by using upper bound approach,...
In this paper, we propose an efficient semi-analytical throughput evaluation strategy for an orthogonal frequency division multiple access (OFDMA) system. We compare the performance of the simulated and semi-analytical throughput values in terms of average signal to noise ratio (SNR). In the investigated system, OFDMA is combined with adaptive modulation and coding (AMC) technique based on distinct...
In this paper, we address the problem of random field estimation with wireless sensor networks in the absence of CSI at the sensor nodes. We assume that sensors encode their observations at a common and constant rate which, on the one hand, determines the quantization noise at the encoders and, on the other, the outage probability experienced in the sensor-to-fusion center fading channels. These effects,...
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