Esquemas distribuídos para seleção de múltiplas antenas em redes com retransmissores do tipo amplifica-e-encaminha

Orientador: José Cândido Silveira Santos FilhoTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de ComputaçãoResumo: A seleção de antena na transmissão tem sido apresentada como uma estratégia promissora para explorar os benefícios do uso de múltiplas antenas em sistemas de comunicações com retransmissores. No entanto, essa abordagem pode exigir um montante considerável de estimações de canal, transmissões de realimentação e atraso, dado que a sua implementação ótima e centralizada requer o monitoramento do estado do canal de todos os enlaces. Para aliviar essas deficiências, este trabalho propõe e analisa um conjunto de esquemas subótimos de seleção de antena na transmissão para sistemas com retransmissores do tipo amplifica-e-encaminha, os quais podem ser implementados de uma forma distribuída. Nos esquemas propostos, a antena é selecionada com base na informação local do estado de canal que está disponível na fonte, requerendo, portanto, um atraso e uma carga de realimentação pequenos e constantes. Tal abordagem é considerada em uso conjunto com diferentes técnicas, incluindo métodos de combinação de diversidade (combinação por máxima razão e combinação por seleção) no destino, protocolos de ganho fixo ou variável no relay, e transceptores com múltiplas antenas no relay. Além disso, para o caso particular em que o retransmissor tem ganho fixo e uma única antena, considera-se também o uso de um mecanismo de seleção de enlace na fonte. Para cada caso, o desempenho do sistema é avaliado em termos de probabilidade de outage, eficiência espectral e/ou vazão. O foco principal é direcionado à probabilidade de outage, para a qual são deduzidas expressões exatas e limitantes de desempenho. Uma análise assintótica é também efetuada para enriquecer a compreensão do comportamento do sistema quando operando sob alta relação sinal-ruído. Finalmente, como contribuição isolada, uma estratégia subótima e simples de alocação de potência é elaborada para um sistema com múltiplos retransmissores do tipo decodifica-e-encaminha, considerando-se enlaces com erros e codificação de fonte distribuídaAbstract: Transmit-antenna selection has been presented as a promising strategy for exploiting the benefits of multiple antennas in relaying communication systems. However, this approach may demand a considerable amount of channel estimations, feedback transmissions, and delay, since its optimal centralized implementation requires monitoring the channel state of all links. To alleviate those impairments, this work proposes and analyzes a set of suboptimal transmit-antenna selection schemes for amplify-and-forward relaying systems, which can be implemented in a distributed manner. In the proposed schemes, the antenna is selected based on the local channel-state information that is available at the source, thus requiring a low and constant delay/feedback overhead. Such an approach is considered along with different techniques, including diversity combining methods (maximal-ratio combining and selection combining) at the destination, fixed- and variable-gain protocols at the relay, and multi-antenna transceivers at the relay. A link-selection mechanism at the source is also considered for the special case of a single-antenna fixed-gain relay. For each case, the system performance is assessed in terms of outage probability, spectral efficiency, and/or throughput. The main focus is placed on the outage probability, for which exact or bound expressions are derived. An asymptotic analysis is also performed to provide further insights into the system behavior at high signal-to-noise ratio. Finally, as an isolated contribution, a simple suboptimal power allocation strategy is designed for a decode-and-forward multi-relay system with lossy intra-links and distributed source codingDoutoradoTelecomunicações e TelemáticaDoutora em Engenharia ElétricaCAPE

Distributed Suboptimal Schemes For Tas/sc And Tas/ls In Fixed-gain Af Relaying Systems

We design and analyze two distributed suboptimal schemes for transmit-antenna selection and link selection in a dual-hop, fixed-gain, amplify-and-forward relaying system, composed by one multi-antenna source, one single-antenna destination, and one single-antenna relay. The proposed schemes share the same antenna-selection policy, but differ from each other in the way the direct or relaying link is selected for communication. In a first scheme, the link is selected after transmission, at the destination; in a second scheme, it is selected before transmission, at the source. A great advantage of the proposed schemes over the optimal centralized solution is their low and constant delay/feedback overhead, regardless of the number of transmit antennas. In addition, the second scheme brings an improved spectral efficiency, once it saves one time slot when selecting the direct link. We derive analytical lower and upper bounds for the outage probability of the first scheme, in single-fold integral form, and exact closed-form expressions for the outage probability and mean spectral efficiency of the second scheme. We also perform an asymptotic analysis, showing that the first scheme achieves full diversity order, whereas the second scheme achieves full diversity order minus one, as a penalty for its improved spectral efficiency.131160416053Li, E., Yang, S., Wu, H., A source-relay selection scheme in two-way amplify-and-forward relaying networks (2012) IEEE Commun. Lett, 16 (10), pp. 1564-1567. , OctBao, V.N.Q., Phuong, B.P.L., Thanh, T.T., Performance analysis of TAS/SC-based MIMO decode-and-forward relaying for multi-hop transmission over Rayleigh fading channels (2012) Proc. ICCE, Santander, Spain, pp. 150-155. , Jul. 1-6Yeoh, P., Elkashlan, M., Yang, N., Da Costa, D.B., Duong, T., MIMO multi-relay networks with TAS/MRC and TAS/SC inWeibull fading channels (2012) Proc. IEEE Int. Symp. PIMRC, pp. 2314-2318. , Sydney, Australia, Sep. 9-12Suraweera, H., Smith, P., Nallanathan, A., Thompson, J., Amplify-andforward relaying with optimal and suboptimal transmit antenna selection (2011) IEEE Trans. Wireless Commun, 10 (6), pp. 1874-1885. , JunDing, H., Ge, J., Da Costa, D.B., Tsiftsis, T., A novel distributed antenna selection scheme for fixed-gain amplify-and-forward relaying systems (2012) IEEE Trans. Veh. Technol, 61 (6), pp. 2836-2842. , JulAmarasuriya, G., Tellambura, C., Ardakani, M., Performance analysis framework for transmit antenna selection strategies of cooperative MIMO AF relay networks (2011) IEEE Trans. Veh. Technol, 60 (7), pp. 3030-3044. , SepChen, Z., Yuan, J., Vucetic, B., Analysis of transmit antenna selection/maximal-ratio combining in Rayleigh fading channels (2005) IEEE Trans. Veh. Technol, 54 (4), pp. 1312-1321. , JulSimon, M.K., Alouini, M., (2000) Digital Communication over Fading Channels: A Unified Approach to Performance Analysis, , New York NY USA: WileyKaraevli, I.L., Altunbas, I., Karabulut Kurt, G., Performance analysis of cooperative relaying scheme applying TAS/SC (2010) Proc. ISCC, Riccione, pp. 127-132. , Italy, Jun 2-25Karaevli, I.L., Karabulut Kurt, G., Altunbas, I., Analysis of cooperative MIMO transmission system with transmit antenna selection and selection combining (2012) Wireless Commun. Mobile Comput, 12 (14), pp. 1266-1275. , OctYilmaz, A., Kucur, O., Performance of joint transmit and receive antenna selection in dual hop amplify-and-forward relay network over Nakagami-m fading channels (2014) Wireless Commun. Mobile Comput, 14 (1), pp. 103-114. , JanYilmaz, A., Kucur, O., End-to-end performance of transmit antenna selection and generalized selection combining in dual-hop amplify-andforward relay network in the presence of feedback errors (2014) Wireless Commun. Mobile Comput, 14 (7), pp. 689-703. , MaySanayei, S., Nosratinia, A., Antenna selection in MIMO systems (2004) IEEE Commun. Mag, 42 (10), pp. 68-73. , OctYeoh, P.L., Elkashlan, M., Collings, I., Selection relaying with transmit beamforming: A comparison of fixed and variable gain relaying (2011) IEEE Trans. Commun, 59 (6), pp. 1720-1730. , JunDing, H., Ge, J., Da Costa, D.B., Jiang, Z., Link selection schemes for selection relaying systems with transmit beamforming: New and efficient proposals from a distributed concept (2012) IEEE Trans. Veh. Technol, 61 (2), pp. 533-552. , FebDing, H., Ge, J., Da Costa, D.B., Jiang, Z., Diversity and coding gains of fixed-gain amplify-and-forward with partial relay selection in Nakagami-m fading (2010) IEEE Commun. Lett, 14 (8), pp. 734-736. , AugXu, F., Lau, F., Yue, D.-W., Diversity order for amplify-and-forward dual-hop systems with fixed-gain relay under Nakagami fading channels (2010) IEEE Trans. Wireless Commun, 9 (1), pp. 92-98. , JanGradshteyn, I.S., Ryzhik, M.I., (2007) Table of Integrals, Series, Products, , 7th ed San Diego, CA, USA: Academi