On Outage Probability and Diversity-Multiplexing Tradeoff in MIMO Relay Channels

Fading MIMO relay channels are studied analytically, when the source and destination are equipped with multiple antennas and the relays have a single one. Compact closed-form expressions are obtained for the outage probability under i.i.d. and correlated Rayleigh-fading links. Low-outage approximations are derived, which reveal a number of insights, including the impact of correlation, of the number of antennas, of relay noise and of relaying protocol. The effect of correlation is shown to be negligible, unless the channel becomes almost fully correlated. The SNR loss of relay fading channels compared to the AWGN channel is quantified. The SNR-asymptotic diversity-multiplexing tradeoff (DMT) is obtained for a broad class of fading distributions, including, as special cases, Rayleigh, Rice, Nakagami, Weibull, which may be non-identical, spatially correlated and/or non-zero mean. The DMT is shown to depend not on a particular fading distribution, but rather on its polynomial behavior near zero, and is the same for the simple "amplify-and-forward" protocol and more complicated "decode-and-forward" one with capacity achieving codes, i.e. the full processing capability at the relay does not help to improve the DMT. There is however a significant difference between the SNR-asymptotic DMT and the finite-SNR outage performance: while the former is not improved by using an extra antenna on either side, the latter can be significantly improved and, in particular, an extra antenna can be traded-off for a full processing capability at the relay. The results are extended to the multi-relay channels with selection relaying and typical outage events are identified.Comment: accepted by IEEE Trans. on Comm., 201

Resource Allocation and Path Selection Strategies for Cognitive Radio Multihop Networks

The next-generation cellular wireless networks will support high data rates and provide quality of service (QoS) for multimedia applications with increased network capacity. Under limited frequency resources, the conventional approach to increase network capacity is to install more base stations (BSs) to exploit spatial reuse. This solution is not very efficient because the cost of the BS transceiver is quite high. An alterna- tive approach is to employ relay stations (RSs) as intermediate nodes to establish multihop communication paths between mobile hosts and their corresponding BSs. Multihop cellular networks (MCN) can potentially enhance coverage, data rates, QoS performance in terms of call block- ing probability, bit error rate, as well as QoS fairness for different users. A number of different architectures, protocols, and analytical models for MCNs have been proposed in the literature where different system aspects were investigated. This thesis aims to present strategies of re- source allocation (RA) and path selection (PS) for cognitive radio (CR) multi-hop communications over a packet-oriented and bit-interleaved- coded OFDM transmission, employing practical modulation and coding schemes. As a promising technology, cognitive radio can be leveraged by the cellular network to increase the overall spectral efciency by allowing additional users in an already crowded spectrum. Here, we assume that a secondary transmitter (ST) adapt his parameters for transmitting to a secondary receiver (SR) or to a relay, over sections of spectrum owned by licensed or primary users (PUs), without harming the quality of service of the latter. This approach is known as underlay. The performance of the system are evaluated in terms of goodput (GP), which is defined as the number of information bits delivered in error free packets per unit of time. It is able to quantify the trade-off between data rate and link reliability, and it is a more suitable metric to quantify the actual perfor- mance of packet-oriented systems, employing practical modulation and coding schemes, respect to the capacity for example. A generic trans- mitter of the network is able to optimize the GP by a proper selection of the transmission parameters, if the channel state information (CSI) are perfect. In most wireless networks, because of channel estimation errors and channel feedback delay, this CSI will not be perfect there- fore any transmitting node only has outdated and imperfect CSI and the channel prediction and as a consequence, a predicted GP (PGP), will be optimized. GP depends on PER that is not easy to calculate for a multi-carrier system and so will be use kESM technique. From here a Local-RA (L-RA) technique and a Sub-Optimal PS (Sub-PS) strategies are formulated for non-cooperative CR multi-hop communications, ex- ploiting xed decode-and-forward (DF) relay nodes (RNs). With these strategies we are able to reduce the signaling over the feedback channel and the computational complexity, compared to the Optimal-RA with Optimal-PS method, paying a very little reduction of GP. Finally we will evaluate whether the increase of the number of relays corresponds to a performance increase

Sobre a capacidade-soma e a probabilidade de bloqueio em canais de múltiplos usuários equipados com múltiplas antenas

Orientadores: Gustavo Fraidenraich, Behnaam AazhangTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de ComputaçãoResumo: O uso de múltiplas antenas em comunicações sem fio permitiu, inicialmente, garantir que um sinal transmitido fosse recebido com maior energia, o que diretamente aumenta a probabilidade de sucesso na recuperação dos dados transmitidos. Posteriormente, foi possível aumentar a capacidade de uma comunicação sem fio utilizando múltiplas antenas transmitindo e recebendo ao mesmo tempo. Atualmente, os dispositivos móveis como telefones celulares e computadores pessoais já são equipados com múltiplas antenas garantindo uma flexibilidade entre taxas maiores, quando as condições são favoráveis, ou aumento da confiabilidade de recepção, em condições menos favoráveis. Além dos graus de liberdade trazidos com a utilização de múltiplas antenas para uma comunicação ponto-a-ponto, os benefícios para uma rede onde um ou mais elementos façam uso destas é notável. Neste trabalho, apresentamos um estudo sobre o impacto do uso de múltiplas antenas em diversos tipos de redes compostas por múltiplos usuários fazendo uso do canal sem fio ao mesmo tempo. Como será visto, em algumas situações o objetivo será reduzir a probabilidade de que ocorra uma falha na comunicação, havendo ou não interferência. Em outras situações, faremos um estudo da capacidade soma de vários usuários ao transmitirem ao mesmo tempo. Em todos os casos, o conhecimento ou não do canal no transmissor é fator determinante para decidir como os sinais serão distribuídos nas múltiplas antenas do transmissor e se estes estarão sujeitos a uma probabilidade de bloqueio ou uma determinada capacidade. Em todos os casos, para uma dada configuração da rede (número de transmissores, receptores), iremos obter a métrica adequada em função da relação sinal ruído e apresentaremos uma modelagem teórica do problema comparando os resultados propostos com simulações de forma a validar estes resultadosAbstract: The first use of multiple antennas in wireless communications aimed to the improvement of the reliability of a transmission by improving the signal to noise ratio at receiver. More energy of the desired signal means that the receiver has higher probability to correctly decode the transmitted signal. Later, it was possible to increase the capacity of a wireless communication by the use of multiple antennas to transmit and receive at the same time. Nowadays, even the inexpensive mobile devices such as smartphones and personal computers are equipped with multiple antennas that provide flexibility between more data rate in favourable channel situations and more reliability in poor channel conditions. Besides the degrees of freedom that multiple antennas provide in single user communication, it dramatically increases the network data rate. In this work, we study the impact of multiple antennas in several multi-user scenarios with concurrent transmission. Whenever is possible, we provide closed-form expressions or approximations for outage probability or sum capacity depending on the type of network. The derived expressions allow us to quantify the impact of the number of users and number of antennas in the performance of the network. We quantify either outage or sum capacity in terms of signal-to-noise ratio for channels under fading conditionsDoutoradoTelecomunicações e TelemáticaDoutor em Engenharia Elétrica10714/14-6CAPESBE

Outage Probability For Mimo Relay Channel

The channel capacity for the multiple-input multiple-output (MIMO) relay channel is still an open problem. In view of this gap, upper and lower bounds were found by Wang et al., 2005. This paper presents an extensive study of mutual information and outage probability of Rayleigh fading MIMO relay channels based on the eigenvalues distribution for the sum of complex Wishart matrices. Interestingly, for certain scenarios, upper and lower bounds are coincident providing the real channel capacity. To compute outage probability, a Gaussian approximation for mutual information has been used. Furthermore, it was proposed an equivalent distribution for the sum of Wishart matrices, which proves to be excellent in all scenarios. Closed-form expressions for probability density function and outage probability have been found for the general case of any number of antennas and any SNR values. Analytical expressions have been validated by means of Monte Carlo simulations.621137913800Wang, B., Zhang, J., Host-Madsen, A., On the capacity of MIMO relay channels (2005) IEEE Trans. Inf. Theory, 51 (1), pp. 29-43. , JanRappaport, T.S., Wireless Communications: Principles and Practice, , Upper Saddle River, NJ, USA: Prentice-Hall, 2002, ser. Prentice Hall Communications Engineering and Emerging Technologies SeriesTelatar, E., Capacity of multi-antenna Gaussian channels (1999) Eur. Trans. Telecommun., 10 (6), pp. 585-595. , NovDohler, M., Li, Y., (2010) Cooperative Communications, , Chichester U.K.: Wiley, FebSklar, B., Digital Communications: Fundamentals and Applications, , Upper Saddle River, NJ, USA: Prentice-Hall, 2001, ser. Prentice Hall Communications Engineering and Emerging Technologies SeriesWang, Z., Giannakis, G., Outage mutual information of spacetime MIMO channels (2004) IEEE Trans. Inf. Theory, 50 (4), pp. 657-662. , AprFan, Y., Thompson, J., MIMO configurations for relay channels: Theory and practice (2007) IEEE Trans. Wireless Commun., 6 (5), pp. 1774-1786. , MayChalise, B., Vandendorpe, L., Outage probability analysis of a MIMO relay channel with orthogonal space-time block codes (2008) IEEE Commun. Lett., 12 (4), pp. 280-282. , AprJayasinghe, L.K.S., Rajatheva, N., Dharmawansa, P., Latva-Aho, M., Noncoherent amplify-and-forward MIMO relaying with OSTBC over Rayleigh Rician fading channels (2013) IEEE Trans. Veh. Technol., 62 (4), pp. 1610-1622. , MayLoyka, S., Levin, G., On outage probability and diversity-multiplexing tradeoff in MIMO relay channels (2011) IEEE Trans. Commun., 59 (6), pp. 1731-1741. , JunHe, W., Georghiades, C., Computing the capacity of a MIMO fading channel under PSK signaling (2005) IEEE Trans. Inf. Theory, 51 (5), pp. 1794-1803. , MayGirnyk, M.A., Vehkapera, M., Rasmussen, L.K., Large-system analysis of the K-hop AF MIMO relay channel with arbitrary inputs (2013) Proc. IEEE Int. Symp. Inf. Theory, Jul., pp. 439-443Marzetta, T., Hochwald, B., Capacity of a mobile multiple-antenna communication link in Rayleigh flat fading (1999) IEEE Trans. Inf. Theory, 45 (1), pp. 139-157. , JanGoodman, N.R., Statistical analysis based on a certain multivariate complex Gaussian distribution (an introduction) (1963) Ann. Math. Statist., 34 (1), pp. 152-177. , MarJames, A.T., Distributions of matrix variates and latent roots derived from normal samples (1964) Ann. Math. Statist., 35 (2), pp. 475-501. , JunSimon, M., Alouini, M., Digital Communication over Fading Channels, , Hoboken, NJ, USA: Wiley, 2005, ser. Wiley series in telecommunications and signal processingPapoulis, A., Pillai, S.U., Probability Random Variables, Stochastic Processes, , Noida, India: Tata McGraw-Hill, 2002, ser. McGraw-Hill series in electrical engineering: Communications and signal processingNadarajah, S., Kotz, S., Exact distribution of the max/min of two Gaussian random variables (2008) IEEE Trans. Very Large Scale Integr. (VLSI) Syst., 16 (2), pp. 210-212. , FebEaton, M., Multivariate Statistics: AVector Space Approach, , Beachwood, OH, USA: Inst. Math. Statist. 1983, ser. Lecture Notes-Monograph SeriesParis, J.F., Lopez-Martinez, F.J., Martos-Naya, E., On the connection between Gaussian Q-functions and a class of hypergeometric functions: Application to LCR of lognormal processes (2013) IEEE Commun. Lett., 17 (8), pp. 1493-1496. , AugGradshteyn, I., Ryzhik, I., (2007) Table of Integrals, Series, Products, , New York, NY, USA: Academi

Outage Probability Of Dual-hop Decode And Forward Mimo Relay With Co-channel Interference

In this paper, the mutual information outage probability (P) for dual-hop decode-and-forward multiple-input multiple-output (MIMO) relay channel is obtained. Rayleigh distribution is used to model MIMO channels, and both full-duplex and half-duplex modes are investigated. Co-channel interference at relay and destination nodes has been considered.Wang, Z., Giannakis, G., Outage mutual information of space time MIMO channels (2004) IEEE Transactions on Information Theory, 50 (4), pp. 657-662. , AprYacoub, M., (1993) Foundations of Mobile Radio Engineering, , Taylor & FrancisTelatar, E., Capacity of multi-antenna gaussian channels (1999) European Transactions on Telecommunications, 10 (6), pp. 585-595. , NovDohler, M., Li, Y., (2010) Cooperative Communications, , Chichester UK: John Wiley & Sons, Ltd, FebSklar, B., (2001) Digital Communications: Fundamentals and Applications, ser, , Prentice Hall Communications Engineering and Emerging Technologies Series. Prentice-Hall PTRJin, S., McKay, M.R., Zhong, C., Wong, K.-K., Ergodic capacity analysis of amplify-and-forward MIMO dual-hop systems (2010) IEEE Transactions on Information Theory, 56 (5), pp. 2204-2224. , MayWu, H., Wang, L., Wang, X., You, X., Asymptotic and non-asymptotic analysis of uplink sum rate for relay-assisted MIMO cellular systems (2014) IEEE Transactions on Signal Processing, 62 (6), pp. 1348-1360. , MarChen, S., Wang, W., Zhang, X.X., Peng, M., Li, Y., Ergodic and outage capacity analysis of amplify-and-forward MIMO relay with OSTBCs (2010) 2010 IEEE Wireless Communication and Networking Conference, pp. 1-6. , AprLoyka, S., Levin, G., On outage probability and diversity-multiplexing tradeoff in MIMO relay channels (2011) IEEE Transactions on Communications, 59 (6), pp. 1731-1741. , JunDing, H., He, C., Jiang, L., Performance analysis of fixed gain MIMO relay systems in the presence of co-channel interference (2012) IEEE Communications Letters, 16 (7), pp. 1133-1136. , JulKamruzzaman, M.M., Effect on performance of wireless uplink for placing decode and forward MIMO relay at different position between source and destination (2014) 2013 International Conference on Electrical Information and Communication Technology (EICT), pp. 1-6. , FebGao, Y., Ge, J., Jin, M., Outage performance analysis of transmit an-tenna selection in MIMO decode-and-forward relaying over Nakagami-m fading channels (2012) 2012 International Conference on Wireless Communications and Signal Processing (WCSP) IEEE, pp. 1-5. , OctHa, D.-B., Nguyen, T.-D., Performance analysis of decode-and-forward MIMO relay networks with keyhole and Nakagami-m fading effects (2013) 2013 International Conference on Computing, Management and Telecommunications (ComManTel), pp. 17-21. , JanSagias, N., Tombras, G., Peppas, K., Datsikas, C., Dual-hop multi-input multi-output relay systems over spatially correlated Nakagami-m fading channels (2011) IET Communications, 5 (15), pp. 2106-2115. , OctFan, Z., Guo, D., Zhang, B., Zhang, H., Outage probability and power allocation for MIMO AF two-way relaying over Rician fading (2012) Proceedings of 2012 2nd International Conference on Computer Science and Network Technology IEEE, pp. 1723-1727. , DecBao, V.N.Q., Performance analysis of TAS/SC-based MIMO decode-and-forward relaying for multi-hop transmission over Rayleigh fading channels (2012) 2012 Fourth International Conference on Communications and Electronics (ICCE) IEEE, pp. 150-155. , AugHuang, Y., Outage analysis of MIMO DF relay systems with partial Nth-best relay selection scheme in the presence of co-channel interference (2013) 2013 International Conference on Wireless Communications and Signal Processing IEEE, pp. 1-6. , OctHerath, P., Gunawardana, U., Liyanapathirana, R., Rajatheva, N., Outage probability analysis of two-hop MIMO relay networks with interference at the relay (2011) 2011 Australian Communications Theory Workshop IEEE, pp. 89-93. , JanZhang, J., Roemer, F., Haardt, M., Relay assisted physical resource sharing: Projection based separation of multiple operators (probasemo) for two-way relaying with mimo amplify and forward relays," Signal Processing (2012) IEEE Transactions on, 60 (9), pp. 4834-4848. , SeptRiihonen, T., Werner, S., Wichman, R., Hamalainen, J., Outage probabilities in infrastructure-based single-frequency relay links (2009) 2009 IEEE Wireless Communications and Networking Conference. 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