Single Carrier Frequency Domain Equalization (SC-FDE) utilize Time Division multiple Access with Zero-padding under ultra-wideband¡Ait can improve Inter-Block Interference(IBI) and Multi-Access Interference(MAI) to get good performance¡AThis system even can eliminate multi-access interference. Concept of TDMA can avoid the same time to transmit different user¡¦s data with zero-padding algorithm. This method can efficiency to solve multi-access interference. In this thesis, we will utilize property of two dimension to solve multi-access interference between each others. Zero-padding have good capability the same to Cyclic prefix and can save transmitter power. In this thesis, we will not use CDMA of method because it do not need to much analysis of mathematics, moreover, we can provide low cost and low complexity for system to get low error rate. Finally we to be aimed at improve IBI and MAI to simulation under ultra-wideband, then simulation will show thesis of method is high performance than traditional of method.

Broadband wireless access systems can be used to deliver a variety of high data rate applications and services. Many of the channels being considered for such applications exhibit multipath propagation coupled with large delay spreads. Cur- rently, orthogonal frequency division multiplexing is employed in these channels to compensate the effect of dispersion. Single carrier (SC) modulation in conjunc- tion with frequency-domain equalization (FDE) at the receiver has been shown to be a practical alternate solution as it has lower peak to average power ratio and is less sensitive to frequency offsets and phase noise compared to OFDM. The effect of multipath propagation increases with increasing data rate for SC systems. This leads to larger inter-symbol-interference (ISI) spans. In addition the achievable ca- pacity of SC-broadband systems depends on their ability to accommodate multiple signal transmissions in the same frequency band, which results in co-channel inter- ference (CCI) when detecting the desired data stream. The effects of CCI and ISI are more pronounced at high data rates. The objective of this research is to investi- gate and a develop low-complexity frequency domain receiver architectures capable of suppressing both CCI and ISI and employing practical channel estimation. In this thesis, a linear and a non-linear receiver architecture are developed in the frequency domain for use in highly dispersive channels employing multiple input multiple output (MIMO) antennas. The linear receiver consists of parallel branches each corresponding to a transmit data stream and implements linear equalization and demodulation. Frequency domain joint CCI mitigation and ISI equalization is implemented based on estimated channel parameters and is called space-frequency Broadband wireless access systems can be used to deliver a variety of high data rate applications and services. Many of the channels being considered for such applications exhibit multipath propagation coupled with large delay spreads. Cur- rently, orthogonal frequency division multiplexing is employed in these channels to compensate the effect of dispersion. Single carrier (SC) modulation in conjunc- tion with frequency-domain equalization (FDE) at the receiver has been shown to be a practical alternate solution as it has lower peak to average power ratio and is less sensitive to frequency offsets and phase noise compared to OFDM. The effect of multipath propagation increases with increasing data rate for SC systems. This leads to larger inter-symbol-interference (ISI) spans. In addition the achievable ca- pacity of SC-broadband systems depends on their ability to accommodate multiple signal transmissions in the same frequency band, which results in co-channel inter- ference (CCI) when detecting the desired data stream. The effects of CCI and ISI are more pronounced at high data rates. The objective of this research is to investi- gate and a develop low-complexity frequency domain receiver architectures capable of suppressing both CCI and ISI and employing practical channel estimation. In this thesis, a linear and a non-linear receiver architecture are developed in the frequency domain for use in highly dispersive channels employing multiple input multiple output (MIMO) antennas. The linear receiver consists of parallel branches each corresponding to a transmit data stream and implements linear equalization and demodulation. Frequency domain joint CCI mitigation and ISI equalization is implemented based on estimated channel parameters and is called space-frequency

In this dissertation, the problem of symbol timing synchronization for the following three different communication systems is studied: 1) conventional single-carrier transmissions with single antenna in both transmitter and receiver; 2) single-carrier transmissions with multiple antennas at both transmitter and receiver; and 3) orthogonal frequency division multiplexing (OFDM) based IEEE 802.11a wireless local area networks (WLANs). For conventional single-carrier, single-antenna systems, a general feedforward symbol-timing estimation framework is developed based on the conditional maximum likelihood principle. The proposed algorithm is applied to linear modulations and two commonly used continuous phase modulations: MSK and GMSK. The performance of the proposed estimator is analyzed analytically and via simulations. Moreover, using the newly developed general estimation framework, all the previously proposed digital blind feedforward symbol timing estimators employing second-order statistics are cast into a unified framework. The finite sample mean-square error expression for this class of estimators is established and the best estimators are determined. Simulation results are presented to corroborate the analytical results. Moving on to single-carrier, multiple-antenna systems, we present two algorithms. The first algorithm is based on a heuristic argument and it improves the optimum sample selection algorithm by Naguib et al. so that accurate timing estimates can be obtained even if the oversampling ratio is small. The performance of the proposed algorithm is analyzed both analytically and via simulations. The second algorithm is based on the maximum likelihood principle. The data aided (DA) and non-data aided (NDA) ML symbol timing estimators and their cor- responding CCRB and MCRB in MIMO correlated ??at-fading channels are derived. It is shown that the improved algorithm developed based on the heuristic argument is just a special case of the DA ML estimator. Simulation results under different operating conditions are given to assess and compare the performances of the DA and NDA ML estimators with respect to their corresponding CCRBs and MCRBs. In the last part of this dissertation, the ML timing synchronizer for IEEE 802.11a WLANs on frequency-selective fading channels is developed. The proposed algorithm is compared with four of the most representative timing synchronization algorithms, one specically designed for IEEE 802.11a WLANs and three other algorithms designed for general OFDM frame synchronization.

Abstract This thesis focuses on advanced multi-antenna receiver and transmission techniques to improve the utilization efficiencies of radio resources in broadband single carrier communications. Special focus is devoted to the development of computationally efficient frequency domain (FD) turbo equalization techniques for single and multiuser MIMO frequency selective channels. Another special emphasis is given to transmission power optimization for single user MIMO communications, which takes into account the convergence properties of the iterative equalizer. A new iterative FD soft cancellation (SC) and minimum mean square error (MMSE) filtering based joint-over-antenna (JA) multiuser MIMO signal detection technique for multiuser MIMO uplink transmission in frequency-selective channels is proposed. The proposed FD multiuser MIMO detection technique requires significantly lower computational complexity than its time-domain counterpart. Furthermore, significant performance gains can be achieved with the proposed JA turbo receiver compared to an antenna-by-antenna (AA) turbo receiver when the total number of transmitter antennas and users is larger than the number of receiver antennas, as well as in the presence of spatial correlation. The impact of existing linear precoding techniques, e.g, maximum information rate (MaxRate) and minimum sum mean square error (MinSumMSE), on the performance of frequency domain turbo equalization is investigated by utilizing extrinsic information transfer (EXIT) chart analysis. A novel transmission power minimization framework based on an EXIT analysis of single carrier MIMO transmission with iterative FD SC-MMSE equalization is then proposed. The proposed optimization framework explicitly takes into account the convergence properties of the iterative equalizer. The proposed convergence constrained power allocation (CCPA) technique decouples the spatial interference between streams using singular value decomposition (SVD), and minimizes the transmission power while achieving the mutual information target for each stream after iterations at the receiver side. The transmission power allocation can be formulated as a convex optimization problem. A special case having only two mutual information constraints is considered, for which the Lagrange dual function is derived and its dual problem is solved. Inspired by the Lagrange duality, two CCPA based heuristic schemes are developed. The numerical results demonstrate that the proposed CCPA schemes outperform the existing power allocation schemes. / Tiivistelmä Tässä työssä tutkitaan edistyksellisten moniantennivastaanotto- ja lähetysmenetelmien käyttöä radioresurssien tehokkuuden parantamiseen laajakaistaisessa yhden kantoaallon kommunikaatiossa. Työssä keskitytään erityisesti laskennallisesti tehokkaiden taajuustasossa suoritettavien iteratiivisten kanavakorjaintekniikoiden kehittämiseen yhden ja usean käyttäjän multiple-input multiple-output (MIMO) -kommunikaatiossa taajuusselektiivisen radiokanavan yli. Toinen tutkimuksen painopiste on lähetystehon optimointi yhden käyttäjän MIMO-kommunikaatiossa, jossa iteratiivisen kanavakorjaimen konvergenssiominaisuudet otetaan huomioon. Työssä ehdotetaan uudenlaista iteratiivista taajuustasossa suoritettavaa soft-cancellation (SC) ja minimum mean square error (MMSE) -suodatukseen pohjautuvaa joint-over-antenna (JA) monen käyttäjän ilmaisumenetelmää nousevan siirtokanavan tiedonsiirtoon taajuusselektiivisessa radiokanavassa. Ehdotettu tajuustasossa suoritettava usean käyttäjän MIMO-lähetyksen ilmaisumenetelmä vaatii selvästi vähemmän laskentatehoa verrattuna aikatason menetelmään. Tämän lisäksi ehdotetulla menetelmällä voidaan saavuttaa merkittävää suorituskykyhyötyä verrattuna antenna-by-antenna (AA) -pohjaiseen iteratiiviseen vastaanottimeen kun lähetysantennien ja käyttäjien kokonaislukumäärä on suurempi kuin vastaanotinantennien. Suorituskykyhyöty pätee myös tilakorrelaation tapauksessa. Työssä tutkitaan lisäksi olemassa olevien lineaaristen esikoodaustekniikoiden, esim. maximum information rate (MaxRate) and minimum sum mean square error (MinSumMSE), vaikutusta taajuustasossa suoritettavaan iteratiivisen kanavakorjaimen konvergenssiominaisuuksiin xtrinsic information transfer (EXIT) -analyysin avulla. Työssä ehdotetaan uudenlaista EXIT-analyysi-pohjaista lähetystehon minimointimenetelmää yhden kantoaallon MIMO-lähetykseen käyttäen iteratiivista taajuustason SC-MMSE-kanavakorjainta. Menetelmä ottaa huomioon iteratiivisen kanavakorjaimen konvergenssiominaisuudet. Ehdotettu convergence constrained power allocation (CCPA) -menetelmä erottaa tilatason häiriön lähetteiden välillä hyödyntäen singular value decomposition (SVD) -tekniikkaa ja minimoi lähetystehon ja saavuttaa samalla keskinäisinformaatiotavoitteet jokaiselle lähetteelle iteraatioiden jälkeen vastaanottimessa. Lähetystehon minimointiongelma voidaan muotoilla konveksiksi optimointiongelmaksi. Kahden keskinäisinformaatiorajoitteen erityistapaukselle johdetaan Lagrangen duaalifunktio ja ratkaistaan sen duaalifunktio. Työssä kehitetään lisäksi kaksi CCPA-pohjaista heuristista menetelmää. Numeeriset tulokset osoittavat ehdotettujen CCPA-pohjaisten menetelmien suoriutuvan paremmin verrattuna olemassa oleviin menetelmiin.

Considering the communication systems with cyclic prefix (CP), such as orthogonal frequency-division multiplexing (OFDM) modulation and single-carrier cyclic prefixed (SCCP) modulation, when the length of CP is longer than the channel length, the use of cyclic prefix (CP) does not only eliminate the inter-block interference, but also convert linear convolution of the transmitted signal with the channel into circular convolution. Unfortunately, the use of CP significantly decreases the bandwidth utilization. Therefore, to reduce the length of CP is a critical issue. The thesis investigates that how to design a channel-shortening equalizer (CSE) at receiver which forces the length of the effective channel response as short as the CP length. The thesis describes the signal model as a matrix form. The effect channel response after CSE is investigated and then the coefficient of channel shortening filter is obtained using singular value decomposition method under various criterions. We further propose a novel CSE maximizing the shortening signal-to-interference ratio. In addition, it is demonstrated that the proposed CSE has the same performance as the conventional scheme but a lower computation complexity.

Les travaux de cette thèse portent sur l'égalisation des canaux de transmission pour des modulations mono-porteuses et multi-porteuses. Dans le cadre de l'égalisation, nous nous intéressons, plus précisément, à l'égalisation aveugle. Tout d'abord, nous décrivons les différents éléments constituants une chaîne de communication, et les différents types de modulations mono-porteuses et muti-porteuses (OFDM). Ensuite, nous faisons un état de l'art sur les méthodes de l'égalisation aveugle pour une modulation mono-porteuse. Nous proposons par la suite un algorithme d'égalisation aveugle en présence de perturbations bornées. Ensuite, nous fournissons une analyse de stabilité et de convergence de l'algorithme proposé. Dans le cadre de la modulation multi-porteuse, nous présentons, dans un premier temps, un état de l'art sur les techniques d'égalisation aveugle pour le système OFDM. Ensuite, nous adaptons l'algorithme proposé pour le système OFDM pour des canaux à trajets multiples, en particulier les canaux Raleigh et Rice. Les performances de l'algorithme proposé sont illustrées à travers plusieurs exemples en simulation tout au long de la thèse. / The work of this thesis deals with the equalization of the transmission channels for a single-carrier and multi-carrier modulation. In the context of equalization, we focus precisely on the blind equalization. First, we give a description of various elements constituting a communication chain, a description of different types of single-carrier modulations and a description of a multi-carrier modulation (OFDM). Then, we give an overview of the blind equalization methods for a single-carrier modulation. We propose subsequently a blind equalization algorithm in the presence of a bounded perturbation. Next, we provide stability and convergence analysis of the proposed method. In the context of multi-carrier modulation, we first present an overview of the blind equalization techniques for the OFDM system. Next, we adapt the proposed method for the OFDM system under multipath channels, especially the Raleigh and the Rice channels. Performance of the proposed algorithm have been illustrated in simulation by considering many examples throughout this thesis.

Single Carrier Frequency Division Multiple Access (SC-FDMA) is a multiple access transmission scheme that has been adopted in the 4th generation 3GPP Long Term Evolution (LTE) of cellular systems. In fact, its relatively low peak-to-average power ratio (PAPR) makes it ideal for the uplink transmission where the transmit power efficiency is of paramount importance. Multiple access among users is made possible by assigning different users to different sets of non-overlapping subcarriers. With the current LTE specifications, if an SC-FDMA system is operating at its full capacity and a new user requests channel access, the system redistributes the subcarriers in such a way that it can accommodate all of the users. Having less subcarriers for transmission, every user has to increase its modulation order (for example from QPSK to 16QAM) in order to keep the same transmission rate. However, increasing the modulation order is not always possible in practice and may introduce considerable complexity to the system. The technique presented in this thesis report describes a new way of adding more users to an SC-FDMA system by assigning the same sets of subcarriers to different users. The main advantage of this technique is that it allows the system to accommodate more users than conventional SC-FDMA and this corresponds to increasing the spectral efficiency without requiring a higher modulation order or using more bandwidth. During this work, special attentions wee paid to the cases where two and three source signals are being transmitted on the same set of subcarriers, which leads respectively to doubling and tripling the spectral efficiency. Simulation results show that by using the proposed technique, it is possible to add more users to any SC-FDMA system without increasing the bandwidth or the modulation order while keeping the same performance in terms of bit error rate (BER) as the conventional SC-FDMA. This is realized by slightly increasing the energy per bit to noise power spectral density ratio (Eb/N0) at the transmitters.

Single Carrier Frequency Division Multiple Access (SC-FDMA) is a multiple access transmission scheme that has been adopted in the 4th generation 3GPP Long Term Evolution (LTE) of cellular systems. In fact, its relatively low peak-to-average power ratio (PAPR) makes it ideal for the uplink transmission where the transmit power efficiency is of paramount importance. Multiple access among users is made possible by assigning different users to different sets of non-overlapping subcarriers. With the current LTE specifications, if an SC-FDMA system is operating at its full capacity and a new user requests channel access, the system redistributes the subcarriers in such a way that it can accommodate all of the users. Having less subcarriers for transmission, every user has to increase its modulation order (for example from QPSK to 16QAM) in order to keep the same transmission rate. However, increasing the modulation order is not always possible in practice and may introduce considerable complexity to the system. The technique presented in this thesis report describes a new way of adding more users to an SC-FDMA system by assigning the same sets of subcarriers to different users. The main advantage of this technique is that it allows the system to accommodate more users than conventional SC-FDMA and this corresponds to increasing the spectral efficiency without requiring a higher modulation order or using more bandwidth. During this work, special attentions wee paid to the cases where two and three source signals are being transmitted on the same set of subcarriers, which leads respectively to doubling and tripling the spectral efficiency. Simulation results show that by using the proposed technique, it is possible to add more users to any SC-FDMA system without increasing the bandwidth or the modulation order while keeping the same performance in terms of bit error rate (BER) as the conventional SC-FDMA. This is realized by slightly increasing the energy per bit to noise power spectral density ratio (Eb/N0) at the transmitters.

Massive MIMO communication systems have been highlighted as the main technology for physical layer of next generation communication standards, like 5G. While conventional communication between BS and its covered users is performed in orthogonal time-frequency resources, the improved interuser interference mitigation capability provided by the large number of BS antennas enables the BS to communicate with several users in the same time-frequency resource. This better usage of available but scarce spectrum elevates the spectral efficiency to very appreciable levels, and has a similar effect on energy efficiency, since the transmit power is not increased. On the other hand, if the objective is to provide a target performance for the users, the required transmit power in both direct and reverse links can be made inversely proportional to the number of BS antennas employed. In this Doctoral Thesis, several important aspects of massive MIMO systems are systematically investigated aiming to improve their energy and spectral efficiencies. We can enumerate our main contributions as follows. Considering a cellular massive MIMO network, we proposed an optimized assignment policy of training sequences to the users, which is then combined with suitable power control algorithms. We have also investigated the adoption of alternative waveforms in this scenario, such as single-carrier transmission, in order to overcome the issues of conventional OFDM. Our contributions in this topic are to derive analytical performance expressions for a time-domain single-carrier equalizer taking advantage of the large number of BS antennas, and to evaluate and compare the total energy efficiency of OFDM versus single-carrier massive MIMO systems. Finally, considering crowded massive MIMO networks, composed by both human users as well as machine-type communication devices, we proposed an improved random access protocol aiming to decrease the average number of access attempts for the users and decreasing the probability of failed access attempts. / Sistemas de comunicação de múltiplas antenas (multiple-input multiple-output - MIMO) têm se destacado como a principal tecnologia para a camada física dos padrões de comunicação da próxima geração, como o 5G. Enquanto a comunicação convencional entre a estação base (base station - BS) e seus usuários atendidos é realizada em recursos ortogonais de tempo-frequência, a grande capacidade de redução da interferência interusuários possibilitada pelo grande número de antenas da BS habilita a BS a se comunicar com diversos usuários no mesmo recurso tempo-frequência. Este melhor uso do escasso espectro disponível eleva a eficiência espectral a níveis muito apreciáveis, e tem um efeito similar na eficiência energética, pois a potência de transmissão não é aumentada. Por outro lado, se o objetivo é fornecer um desempenho desejado para os usuários, a potência de transmissão necessária em ambos os enlaces direto e reverso pode ser feita inversamente proporcional ao número de antenas na BS. Nesta Tese de Doutorado, diversos aspectos importantes de sistemas MIMO massivo são sistematicamente investigados com o objetivo de melhorar suas eficiências energética e espectral. Pode-se enumerar as principais contribuições alcançadas como se segue. Considerando uma rede celular MIMO massivo, propõe-se uma política de atribuição de sequências de treinamento aos usuários otimizada, a qual é depois combinada com apropriados algoritmos de controle de potência. Também investiga-se a adoção neste cenário de formas de onda alternativas, tal como a transmissão de portadora única, visando superar as deficiências da convencional multiplexagem por divisão de portadoras ortogonais (orthogonal frequency-division multiplexing - OFDM). As principais contribuições obtidas neste tema são derivar expressões de desempenho analíticas para um equalizador de portadora única no domínio do tempo que aproveita o grande número de antenas na BS, e avaliar e comparar a eficiência energética total de sistemas MIMO massivo OFDM versus portadora única. Finalmente, considerando redes MIMO massivo sobrecarregadas, compostas por usuários humanos bem como dispositivos de comunicação do tipo máquina, propõe-se um protocolo de acesso aleatório melhorado visando diminuir o número médio de tentativas de acesso para os usuários e diminuir a probabilidade de falhas de tentativa de acesso.

Massive MIMO communication systems have been highlighted as the main technology for physical layer of next generation communication standards, like 5G. While conventional communication between BS and its covered users is performed in orthogonal time-frequency resources, the improved interuser interference mitigation capability provided by the large number of BS antennas enables the BS to communicate with several users in the same time-frequency resource. This better usage of available but scarce spectrum elevates the spectral efficiency to very appreciable levels, and has a similar effect on energy efficiency, since the transmit power is not increased. On the other hand, if the objective is to provide a target performance for the users, the required transmit power in both direct and reverse links can be made inversely proportional to the number of BS antennas employed. In this Doctoral Thesis, several important aspects of massive MIMO systems are systematically investigated aiming to improve their energy and spectral efficiencies. We can enumerate our main contributions as follows. Considering a cellular massive MIMO network, we proposed an optimized assignment policy of training sequences to the users, which is then combined with suitable power control algorithms. We have also investigated the adoption of alternative waveforms in this scenario, such as single-carrier transmission, in order to overcome the issues of conventional OFDM. Our contributions in this topic are to derive analytical performance expressions for a time-domain single-carrier equalizer taking advantage of the large number of BS antennas, and to evaluate and compare the total energy efficiency of OFDM versus single-carrier massive MIMO systems. Finally, considering crowded massive MIMO networks, composed by both human users as well as machine-type communication devices, we proposed an improved random access protocol aiming to decrease the average number of access attempts for the users and decreasing the probability of failed access attempts. / Sistemas de comunicação de múltiplas antenas (multiple-input multiple-output - MIMO) têm se destacado como a principal tecnologia para a camada física dos padrões de comunicação da próxima geração, como o 5G. Enquanto a comunicação convencional entre a estação base (base station - BS) e seus usuários atendidos é realizada em recursos ortogonais de tempo-frequência, a grande capacidade de redução da interferência interusuários possibilitada pelo grande número de antenas da BS habilita a BS a se comunicar com diversos usuários no mesmo recurso tempo-frequência. Este melhor uso do escasso espectro disponível eleva a eficiência espectral a níveis muito apreciáveis, e tem um efeito similar na eficiência energética, pois a potência de transmissão não é aumentada. Por outro lado, se o objetivo é fornecer um desempenho desejado para os usuários, a potência de transmissão necessária em ambos os enlaces direto e reverso pode ser feita inversamente proporcional ao número de antenas na BS. Nesta Tese de Doutorado, diversos aspectos importantes de sistemas MIMO massivo são sistematicamente investigados com o objetivo de melhorar suas eficiências energética e espectral. Pode-se enumerar as principais contribuições alcançadas como se segue. Considerando uma rede celular MIMO massivo, propõe-se uma política de atribuição de sequências de treinamento aos usuários otimizada, a qual é depois combinada com apropriados algoritmos de controle de potência. Também investiga-se a adoção neste cenário de formas de onda alternativas, tal como a transmissão de portadora única, visando superar as deficiências da convencional multiplexagem por divisão de portadoras ortogonais (orthogonal frequency-division multiplexing - OFDM). As principais contribuições obtidas neste tema são derivar expressões de desempenho analíticas para um equalizador de portadora única no domínio do tempo que aproveita o grande número de antenas na BS, e avaliar e comparar a eficiência energética total de sistemas MIMO massivo OFDM versus portadora única. Finalmente, considerando redes MIMO massivo sobrecarregadas, compostas por usuários humanos bem como dispositivos de comunicação do tipo máquina, propõe-se um protocolo de acesso aleatório melhorado visando diminuir o número médio de tentativas de acesso para os usuários e diminuir a probabilidade de falhas de tentativa de acesso.