Impact of Pointing Errors on the Performance of Mixed RF/FSO Dual-Hop Transmission Systems

In this work, the performance analysis of a dual-hop relay transmission system composed of asymmetric radio-frequency (RF)/free-space optical (FSO) links with pointing errors is presented. More specifically, we build on the system model presented in [1] to derive new exact closed-form expressions for the cumulative distribution function, probability density function, moment generating function, and moments of the end-to-end signal-to-noise ratio in terms of the Meijer's G function. We then capitalize on these results to offer new exact closed-form expressions for the higher-order amount of fading, average error rate for binary and M-ary modulation schemes, and the ergodic capacity, all in terms of Meijer's G functions. Our new analytical results were also verified via computer-based Monte-Carlo simulation results.Comment: 6 pages, 3 figure

Unified Performance Analysis of Mixed Line of Sight RF-FSO Fixed Gain Dual-Hop Transmission Systems

In this work, we carry out a unified performance analysis of a dual-hop fixed gain relay system over asymmetric links composed of both radio-frequency (RF) and unified free-space optics (FSO) under the effect of pointing errors. The RF link is modeled by the Nakagami-$m$ fading channel and the FSO link by the Gamma-Gamma fading channel subject to both types of detection techniques (i.e. heterodyne detection and intensity modulation with direct detection (IM/DD)). In particular, we derive new unified closed-form expressions for the cumulative distribution function, the probability density function, the moment generation function, and the moments of the end-to-end signal-to-noise ratio of these systems in terms of the Meijer's G function. Based on these formulas, we offer exact closed-form expressions for the outage probability, the higher-order amount of fading, and the average bit-error rate of a variety of binary modulations in terms of the Meijer's G function. Further, an exact closed-form expression for the end-to-end ergodic capacity for the Nakagami-$m$-unified FSO relay links is derived in terms of the bivariate G function. All the given results are verified via Computer-based Monte-Carlo simulations

KINERJA TEKNIK PREDISTORSI PADA SISTEM KOMUNIKASI KOOPERATIF DUAL-HOP KANAL TAK SIMETRIS

Pada makalah ini akan dilakukan evaluasi penerapan teknik predistorsi baik di sumber dan di relay pada sistem transmisi kooperatif dengan protokol amplify and forward (AF). Model predistorster dan penguat daya tinggi (HPA) di sumber adalah kaskade Wiener-Hammerstein, sedang model predistorter dan HPA di relay adalah inverse Rapp dan model Rapp. Penerapan teknik predistorsi tersebut diterapkan pada kondisi kanal tak simteris, model Ricean fading dan Rayleigh fading. Evaluasi terhadap kinerja teknik predistorsi ditunjukkan dengan nilai bit error rate (BER) di tujuan. Dari hasil simulasi dapat ditunjukkan bahwa penerapan teknik predistorsi di sumber dan di relay menghasilkan kinerja paling baik. Dan penerapan pada kanal  tak simteris hasil simulasi menunjukkan bahwa kondisi kanal jalur relay-tujuan (R-D) dan sumber-tujuan (S-D) memiliki pengaruh besar terhadap sinyal yang diterima di tujuan, memberikan kinerja paling baik bila model kanal-kanal tersebut bersifat Ricean fading

Performance analysis of mixed Nakagami- m and Gamma–Gamma dual-hop FSO transmission systems

In this paper, we carry out a unified performance analysis of a dual-hop relay system over the asymmetric links composed of both radio-frequency (RF) and unified free-space optical (FSO) links under the effect of pointing errors. Both fixed and variable gain relay systems are studied. The RF link is modeled by the Nakagami-m fading channel and the FSO link by the Gamma-Gamma fading channel subject to both types of detection techniques (i.e., heterodyne detection and intensity modulation with direct detection). In particular, we derive new unified closed-form expressions for the cumulative distribution function, the probability density function, the moment generating function (MGF), and the moments of the end-to-end signal-to-noise ratio (SNR) of these systems in terms of the Meijer's G function. Based on these formulas, we offer exact closed-form expressions for the outage probability (OP), the higher order amount of fading, and the average bit error rate (BER) of a variety of binary modulations in terms of the Meijer's G function. Furthermore, an exact closed-form expression of the end-to-end ergodic capacity is derived in terms of the bivariate G function. Additionally, by using the asymptotic expansion of the Meijer's G function at the high-SNR regime, we derive new asymptotic results for the OP, the MGF, and the average BER in terms of simple elementary functions

Outage probability of Rician fading relay channels

10.1109/TVT.2007.912603IEEE Transactions on Vehicular Technology5742648-2652ITVT

Multiple antenna communication over fading channels : Performance limits and cooperative transmission strategies

Ph.DDOCTOR OF PHILOSOPH

Virtual-MIMO systems with compress-and-forward cooperation

Multiple-input multiple-output (MIMO) systems have recently emerged as one of the most significant wireless techniques, as they can greatly improve the channel capacity and link reliability of wireless communications. These benefits have encouraged extensive research on a virtual MIMO system where the transmitter has multiple antennas and each of the receivers has a single antenna. Single-antenna receivers can work together to form a virtual antenna array and reap some performance benefits of MIMO systems. The idea of receiver-side local cooperation is attractive for wireless networks since a wireless receiver may not have multiple antennas due to size and cost limitations. In this thesis we investigate a virtual-MIMO wireless system using the receiver-side cooperation with the compress-and-forward (CF) protocol. Firstly, to perform CF at the relay, we propose to use standard source coding techniques, based on the analysis of its expected rate bound and the tightness of the bound. We state upper bounds on the system error probabilities over block fading channels. With sufficient source coding rates, the cooperation of the receivers enables the virtual-MIMO system to achieve almost ideal MIMO performance. A comparison of ideal and non-ideal conference links within the receiver group is also investigated. Considering the short-range communication and using a channel-aware adaptive CF scheme, the impact of the non-ideal cooperation link is too slight to impair the system performance significantly. It is also evident that the practicality of CF cooperation will be greatly enhanced if a efficient source coding technique can be used at the relay. It is even more desirable that CF cooperation should not be unduly sensitive to carrier frequency offsets (CFOs). Thus this thesis then presents a practical study of these two issues. Codebook designs of the Voronoi VQ and the tree-structure vector quantization (TSVQ) to enable CF cooperation at the relay are firstly described. A comparison in terms of the codebook design complexity and encoding complexity is presented. It is shown that the TSVQ is much simpler to design and operate, and can achieve a favourable performance-complexity tradeoff. We then demonstrate that CFO can lead to significant performance degradation for the virtual MIMO system. To overcome it, it is proposed to maintain clock synchronization and jointly estimate the CFO between the relay and the destination. This approach is shown to provide a significant performance improvement. Finally, we extend the study to the minimum mean square error (MMSE) detection, as it has a lower complexity compared to maximum likelihood (ML) detection. A closed-form upper bound for the system error probability is derived, based on which we prove that the smallest singular value of the cooperative channel matrix determines the system error performance. Accordingly, an adaptive modulation and cooperation scheme is proposed, which uses the smallest singular value as the threshold strategy. Depending on the instantaneous channel conditions, the system could therefore adapt to choose a suitable modulation type for transmission and an appropriate quantization rate to perform CF cooperation. The adaptive modulation and cooperation scheme not only enables the system to achieve comparable performance to the case with fixed quantization rates, but also eliminates unnecessary complexity for quantization operations and conference link communication

Performance Analysis Of Full Duplex And Selective And Incremental Half Duplex Relaying Schemes

In this work we compare full-duplex (FD) and half-duplex (HD) relaying in terms of outage probability and throughput. We consider a practical FD relay model where the loop interference between transmitted and received signals is taken into account. We analyze two modes for FD transmission, block Markov encoding and multi-hop transmission without interference cancellation, and two different modes for HD transmission, which are based on selective and incremental decode-and-forward protocols. Results show that there is a tradeoff between SNR and information rate in which each scheme becomes more suitable. © 2012 IEEE.771775Laneman, J., Tse, D., Wornell, G., Cooperative Diversity in Wireless Networks: Efficient Protocols and Outage Behavior (2004) IEEE Transactions on Information Theory, 50 (12), pp. 3062-3080. , DecTannious, R., Nosratinia, A., Spectrally-efficient relay selection with limited feedback (2008) IEEE Journal on Selected Areas in Communications, 26 (8), pp. 1419-1428. , OctAlves, H., Souza, R., Selective decode-and-forward using fixed relays and packet accumulation (2011) Communications Letters, IEEE, 15 (7), pp. 707-709. , julyKramer, G., Gastpar, M., Gupta, P., Cooperative Strategies and Capacity Theorems for Relay Networks (2005) IEEE Transactions on Information Theory, 51 (9), pp. 3037-3063. , SepZhu, Y., Xin, Y., Kam, P.-Y., Outage probability of Rician fading relay channels (2008) IEEE Transactions on Vehicular Technology, 57 (4), pp. 2648-2652Riihonen, T., Werner, S., Wichman, R., Eduardo, Z., On the feasibility of full-duplex relaying in the presence of loop interference (2009) Signal Processing Advances in Wireless Communications, 2009. SPAWC '09. IEEE 10th Workshop onRiihonen, T., Werner, S., Wichman, R., Comparison of full-duplex and half-duplex modes with a fixed amplify-and-forward relay (2009) Wireless Communications and Networking Conference, 2009. WCNC 2009. IEEERiihonen, T., Werner, S., Wichman, R., Optimized gain control for single-frequency relaying with loop interference (2009) Wireless Communications, IEEE Transactions on, 8 (6), pp. 2801-2806Kwon, T., Lim, S., Choi, S., Hong, D., Optimal duplex mode for DF relay in terms of the outage probability (2010) IEEE Transactions on Vehicular Technology, 59 (7), pp. 3628-3634Khormuji, M.N., Larsson, E.G., Cooperative transmission based on decode-and-forward relaying with partial repetition coding (2009) IEEE Transactions on Wireless Communications, 8 (4), pp. 1716-1725Caire, G., Tuninetti, D., The throughput of hybrid-arq protocols for the gaussian collision channel (2001) IEEE Transactions on Information Theory, 47 (5), pp. 1971-1988Zhu, Y., Xin, Y., Kam, P.-Y., Optimal transmission strategies for rayleigh fading relay channels (2008) IEEE Transactions on Wireless Communications, 7 (2), pp. 618-628Cover, T.M., Thomas, J.M., (2006) Elements of Information Theory, , 2nd ed. Hoboken, New Jersey: Wiley-InterscienceCheng, J.-F., Coding performance of hybrid arq schemes (2006) Communications, IEEE Transactions on, 54 (6), pp. 1017-1029Papoulis, A., Pillai, S.U., (2001) Probability, Random Variables and Stochastic Processes, , McGraw-Hill Science/Engineering/Mat