Combining coded signals with arbitrary modulations in orthogonal relay channels

We consider a relay channel for which the following assumptions are made. (1) The source-destination and relay-destination channels are orthogonal (frequency division relay channel). (2) The relay implements the decode-and-forward protocol. (3) The source and relay implement the same channel encoder, namely, a onvolutional encoder. (4) They can use arbitrary and possibly different modulations. In this framework, we derive the best combiner in the sense of the maximum likelihood (ML) at the destination and the branch metrics of the trellis associated with its channel decoder for the ML combiner and also for the maximum ratio combiner (MRC), cooperative-MRC (C-MRC), and the minimum mean-square error (MMSE) combiner

Generalizing the Sampling Property of the Q-function for Error Rate Analysis of Cooperative Communication in Fading Channels

This paper extends some approximation methods that are used to identify closed form Bit Error Rate (BER) expressions which are frequently utilized in investigation and comparison of performance for wireless communication systems in the literature. By using this group of approximation methods, some expectation integrals, which are complicated to analyze and have high computational complexity to evaluate through Monte Carlo simulations, are computed. For these integrals, by using the sampling property of the integrand functions of one or more arguments, reliable BER expressions revealing the diversity and coding gains are derived. Although the methods we present are valid for a larger class of integration problems, in this work we show the step by step derivation of the BER expressions for a canonical cooperative communication scenario in addition to a network coded system starting from basic building blocks. The derived expressions agree with the simulation results for a very wide range of signal-to-noise ratio (SNR) values.Comment: 5 pages, 5 figures, Submitted to IEEE International Symposium on Information Theory, ISIT 2013, Istanbul, Turke

Архитектурные решения ретрансляции в сети LTE-Advanced

Побудовані математичні моделі запропонованих архітектурних рішень однонаправленої, двонаправленої ретрансляцій та ретрансляції типу «зі спільною РС» в мережі LTE-Advanced. При координації БС пропускна здатність на 119% перевищує пропускну здатність моделі без ретрансляції чи координації. При ретрансляції «зі спільною РС» досягається 60% результатів системи з координацією. Однонаправлена ретрансляція перевищує на 15% пропускну здатність традиційної передачі, в той час як двостороння передача гірше традиційної.The mathematical models of the proposed one-way relaying, two-way relaying and shared relaying architectures of LTE-Advanced were described. Base station coordination gives the highest downlink sum rates, a roughly 119% increase over a conventional architecture with no relaying or coordination. The shared relaying achieves approximately 60% of the gains of base station coordination. The one-way architecture only give a roughly 15% increase in the rate relative to a conventional system, whereas two-way relaying performs worse than conventional.Построены математические модели предложеных архитектурных решений однонаправленной, двухнаправленной ретрансляций и ретрансляции типа «с общей РС» в сети LTE-Advanced. При координации БС пропускная способность на 119% превышает пропускную способность модели без ретрансляции или координации. При ретрансляции «с общей РС» достигается 60% результатов системы с координацией. Однонаправленная ретрансляция превышает на 15% пропускную способность традиционной передачи, в тот момент, когда духсторонняя передача хуже традиционной

Comparison of Cooperative Diversity Protocols in Various Relay Locations through Network Coding

In this paper, the performance of Network Coded (NC) based cooperative network for various relay location over Rayleigh fading channels is studied. Comparisons of Amplify and Forward (AAF), Detect and Forward (DTF) and Decode and forward (DCF) protocols for the proposed system are shown. The performance of relays in AAF, DTF and DCF is analyzed in terms of bit error rate (BER) vs signal to noise ratio (SNR). Matlab is used to build Monte-Carlo link level simulation. The effect of relays at different position is studied

Error Rate Analysis of GF(q) Network Coded Detect-and-Forward Wireless Relay Networks Using Equivalent Relay Channel Models

This paper investigates simple means of analyzing the error rate performance of a general q-ary Galois Field network coded detect-and-forward cooperative relay network with known relay error statistics at the destination. Equivalent relay channels are used in obtaining an approximate error rate of the relay network, from which the diversity order is found. Error rate analyses using equivalent relay channel models are shown to be closely matched with simulation results. Using the equivalent relay channels, low complexity receivers are developed whose performances are close to that of the optimal maximum likelihood receiver.Comment: 28 pages, 10 figures. This work has been submitted to the IEEE for possible publication. Copyright may be transferred without notice, after which this version may no longer be accessibl