The advanced signal processing systems of today require extreme data throughput and low power consumption. The only way to accomplish this is to use parallel processor architecture. The aim of this thesis was to evaluate the use of parallel processor architecture in baseband signal processing. This has been done by implementing three demanding algorithms in LTE on Ambric Am2000 family Massively Parallel Processor Array (MPPA). The Ambric chip is evaluated in terms of computational performance, efficiency of the development tools, algorithm and I/O mapping. Implementations of Matrix Multiplication, FFT and Block Interleaver were performed. The implementation of algorithms shows that high level of parallelism can be achieved in MPPA especially on complex algorithms like FFT and Matrix multiplication. Different mappings of the algorithms are compared to see which best fit the architecture.

Long Term Evolution (LTE) είναι το όνομα που έδωσε το 3GPP στο πρόγραμμα εξέλιξης των κινητών συστημάτων επικοινωνιών τρίτης γενιάς UMTS, με στόχο την αντιμετώπιση των μελλοντικών απαιτήσεων της αγοράς των κινητών δικτύων. Βασικοί στόχοι του νέου προτύπου LTE αποτελούν η αυξημένη απόδοση, το μικρότερο κόστος υλοποίησης, η μείωση της πολυπλοκότητας λειτουργίας και η παροχή νέων εξελιγμένων υπηρεσιών, κάνοντας χρήση νέων φασμάτων λειτουργίας. Οι προσδοκίες από το LTE είναι ιδιαίτερα υψηλές και βασίζονται στην παροχή υπηρεσιών απαλλαγμένων από τις απώλειες. Συνεπώς, η επιτυχία του LTE θα καθοριστεί από την ικανότητα παροχής κινητών συσκευών και ασύρματης υποδομής που θα ανταποκρίνονται στα πρότυπα του 3GPP και θα είναι ιδιαίτερα ανθεκτικά στις απώλειες της ασύρματης μετάδοσης, ώστε να προσφέρονται βελτιωμένες υπηρεσίες υψηλής απόδοσης. Μία βασική πτυχή των προδιαγραφών του συστήματος LTE είναι η ενίσχυση της υπηρεσίας Multimedia Broadcast/Multicast Services, όπου το ίδιο περιεχόμενο μεταδίδεται σε πολλαπλούς χρήστες που βρίσκονται σε μία συγκεκριμένη περιοχή μετάδοσης της υπηρεσίας. Η υπηρεσία MBMS πρωτοπαρουσιάστηκε σαν ένα νέο χαρακτηριστικό στην έκδοση 6 του 3GPP, ώστε να προσφέρει broadcast και multicast μετάδοση πολυμεσικού περιεχομένου σε κινητούς χρήστες μέσω MBMS ασύρματων φορέων μετάδοσης. Η υπηρεσία MBMS παρέχει δύο διαφορετικές μεθόδους διανομής περιεχομένου, τη μέθοδο download και τη μέθοδο streaming. Για να υποστηρίξει την αποδοτική διανομή MBMS περιεχομένου, το 3GPP συμπεριέλαβε ένα μηχανισμό Forward Error Correction στο επίπεδο εφαρμογών (AL-FEC). Το FEC είναι μία μέθοδος που προσφέρει έλεγχο λαθών κατά τη μετάδοση δεδομένων, η οποία χρησιμοποιείται για να υποστηρίξει ή να αντικαταστήσει άλλες μεθόδους παροχής αξιοπιστίας. Στο FEC, ο αποστολέας εισάγει πλεονάζουσα πληροφορία στη μετάδοση δεδομένων. Αυτή η πληροφορία επιτρέπει στο δέκτη να ανακατασκευάσει τα αρχικά δεδομένα. Τέτοια σχήματα αναπόφευκτα προσθέτουν ένα σταθερό overhead στα μεταδιδόμενα δεδομένα με αποτέλεσμα να είναι υπολογιστικά ακριβά. Παρόλα αυτά στα multicast πρωτόκολλα, η χρήση FEC τεχνικών προσφέρει πολύ ισχυρά κίνητρα. Η κωδικοποίηση μπορεί να εξαλείψει τις ανεξάρτητες απώλειες στους διαφορετικούς δέκτες. Επιπρόσθετα, η δραματική μείωση του ρυθμού απώλειας πακέτων μειώνει κατά ένα μεγάλο μέρος την ανάγκη επαναποστολής των χαμένων πακέτων από τον αποστολέα. Επομένως, οι FEC τεχνικές είναι πολύ εύκολο να εκπληρώσουν έναν πρωταρχικό σκοπό των multicast κινητών υπηρεσιών, που είναι η προσαρμοστικότητα σε εφαρμογές με μεγάλο αριθμό δεκτών. Αυτός είναι ο λόγος που το 3GPP συνιστά τη χρήση του AL-FEC για την υπηρεσία MBMS και πιο συγκεκριμένα, υιοθετεί τη χρήση των συστηματικών κωδίκων Raptor. Λαμβάνοντας υπόψιν τα παραπάνω, στόχος της παρούσας μεταπτυχιακής διπλωματικής εργασίας είναι η μελέτη της απόδοσης του AL-FEC πάνω σε υπηρεσίες MBMS, εστιάζοντας στην υπηρεσία της streaming μεθόδου παράδοσης δεδομένων. Προς αυτή την κατεύθυνση, στην παρούσα εργασία μελετάμε την εφαρμογή του μηχανισμού AL-FEC πάνω σε multicast streaming υπηρεσίες των LTE, διερευνώντας πως το ποσό της πλεονάζουσας πληροφορίας ποικίλλει σε πολλαπλούς χρήστες χρησιμοποιώντας ρεαλιστικά περιβάλλοντα προσομοίωσης. Επίσης, εξετάζουμε την απόδοση του AL-FEC για διάφορες διατάξεις του δικτύου ασύρματης πρόσβασης, διάφορα μοντέλα κινητικότητας των χρηστών καθώς και διάφορες παραμέτρους της FEC κωδικοποίησης. / Long Term Evolution (LTE) is the name given to a project within the Third Generation Partnership Project (3GPP) to improve the UMTS 3G mobile system standard to cope with future requirements. Goals include improving efficiency, lowering cost, reducing complexity and improving services, making use of new spectrum opportunities. Expectations are high for LTE and are based on the premise of fault-free performance. Therefore, LTE’s initial success will be determined by the ability of handset and radio infrastructure manufacturers to deliver products that conform to 3GPP standards and are robust enough to allow operators to introduce improved services. A key aspect of LTE specifications is the enhancement of Multimedia Broadcast/Multicast Services (MBMS), where the same content is transmitted to multiple users located in a specific service area. MBMS was firstly standardized as a new feature in 3GPP Release 6, in order to broadcast and multicast multimedia content to mobile terminals via MBMS radio bearer. The MBMS provides two different delivery methods, the download delivery and the streaming delivery method. To support efficient download and streaming delivery, 3GPP has included Application Layer Forward Error Correction (AL-FEC) in the MBMS standard. FEC is a method for error control for data transmission that is used to augment or replace other reliability methods. In FEC, the sender introduces redundant information in the data transmitted. This information allows the receiver to reconstruct the source data. Such schemes inevitably add a constant overhead in the transmitted data and are computationally expensive. In multicast protocols however, the use of FEC techniques has very strong motivations. The encoding eliminates the effect of independent losses at different receivers. This makes these schemes able to scale irrespectively of the actual loss pattern at each receiver. Additionally, the dramatic reduction in the packet loss rate largely reduces the need for retransmission of lost data from the sender. FEC schemes are therefore so simple as to meet a prime objective for mobile multicast services, which is scalability to applications with thousands of receivers. This is the reason why 3GPP recommends the use of AL-FEC for MBMS and, more specifically, adopts the use of systematic Raptor code. After taking into account the above analysis, objective of this master thesis is the study of AL-FEC in MBMS, focusing on the streaming delivery method. To this direction, in this work we study the application of AL-FEC for the streaming delivery method over LTE networks. We investigate how the amount of FEC overhead varies at multiple receivers using realistic simulation scenarios and we investigate the performance of AL-FEC overhead considering different cell deployments, user mobility models and FEC encoding parameters.

abstract: As wireless communication enters smartphone era, more complicated communication technologies are being used to transmit higher data rate. Power amplifier (PA) has to work in back-off region, while this inevitably reduces battery life for cellphones. Various techniques have been reported to increase PA efficiency, such as envelope elimination and restoration (EER) and envelope tracking (ET). However, state of the art ET supply modulators failed to address high efficiency, high slew rate, and accurate tracking concurrently. In this dissertation, a linear-switch mode hybrid ET supply modulator utilizing adaptive biasing and gain enhanced current mirror operational transconductance amplifier (OTA) with class-AB output stage in parallel with a switching regulator is presented. In comparison to a conventional OTA design with similar quiescent current consumption, proposed approach improves positive and negative slew rate from 50 V/µs to 93.4 V/µs and -87 V/µs to -152.5 V/µs respectively, dc gain from 45 dB to 67 dB while consuming same amount of quiescent current. The proposed hybrid supply modulator achieves 83% peak efficiency, power added efficiency (PAE) of 42.3% at 26.2 dBm for a 10 MHz 7.24 dB peak-to-average power ratio (PAPR) LTE signal and improves PAE by 8% at 6 dB back off from 26.2 dBm power amplifier (PA) output power with respect to fixed supply. With a 10 MHz 7.24 dB PAPR QPSK LTE signal the ET PA system achieves adjacent channel leakage ratio (ACLR) of -37.7 dBc and error vector magnitude (EVM) of 4.5% at 26.2 dBm PA output power, while with a 10 MHz 8.15 dB PAPR 64QAM LTE signal the ET PA system achieves ACLR of -35.6 dBc and EVM of 6% at 26 dBm PA output power without digital pre-distortion (DPD). The proposed supply modulator core circuit occupies 1.1 mm2 die area, and is fabricated in a 0.18 µm CMOS technology. / Dissertation/Thesis / Doctoral Dissertation Electrical Engineering 2017

In recent years, the advent of Long Term Evolution (LTE) technology as a prominent component of 4G networks and future 5G networks, has paved the way for fast and new mobile web access and application services. With these advantages come some security concerns in terms of attacks that can be launched on such networks. This thesis focuses on the impact of the mobile botnet on LTE networks by implementing a mobile botnet architecture that initiates a Distributed Denial of Service (DDoS) attack. First, in the quest of understanding the mobile botnet behavior, a correlation between the mobile botnet impact and different mobile device mobility models, is established, leading to the study of the impact of the random patterns versus the uniform patterns of movements on the mobile botnet’s behavior under a DDoS attack. Second, the impact of two base transceiver station selection mechanisms on a mobile botnet behavior launching a DDoS attack on a LTE network is studied, the goal being to derive the effect of the attack severity of the mobile botnet. Third, an epidemic SMS-based cellular botnet that uses an epidemic command and control mechanism to initiate a short message services (SMS) phishing attack, is proposed and its threat impact is studied and simulated using three random graphs models. The simulation results obtained reveal that (1) in terms of users’ mobility patterns, the impact of the mobile botnet behavior under a DDoS attack on a victim web server is more pronounced when an asymmetric mobility model is considered compared to a symmetric mobility model; (2) in terms of base transceiver station selection mechanisms, the Distance-Based Model mechanism yields a higher threat impact on the victim server compared to the Signal Power Based Model mechanism; and (3) under the Erdos-and-Reyni Topology, the proposed epidemic SMS-based cellular botnet is shown to be resistant and resilient to random and selective cellular device failures. / Graduate

Single-carrier frequency division multiple access (SC-FDMA) has become a popular alternative to orthogonal frequency division multiple access (OFDM) in multi-user communication on LTE uplink systems. This is primarily due to the low peak-to-average power ratio (PAPR) of SC-FDMA compared to that of OFDM. Long-term evolution (LTE) uses SC-FDMA on the uplink to exploit this PAPR advantage to reduce transmit power amplifier (PA) back-off in mobile user terminals. However, the latest generation of communication systems requires high power efficiency and a large quantity of capacity in transmitting mobile data, bringing out some other critical problems: 1) the nonlinearity of Radio Frequency (RF) power amplifiers inevitably affects the power efficiency. Working beyond the saturation point is the main reason for power amplifiers having nonlinear properties; 2) In order to obtain adequate capacity, wide bandwidth is applied to the latest communication systems. Since in previous systems the pre-distorter would focus on memory-less distortion with relatively narrow bandwidth, this change makes memory distortion become a serious issue, degrading the transmission quality in the wireless communication systems. The intent of this thesis is to present nonlinear analysis of the SC-FDMA Spectrum with the RF power amplifier. Relevant mathematical models were considered and applied to the RF power amplifier in terms of intermodulation products and the third-order intercept point. The equivalent mathematical model is applied for the first time to SC-FDMA signals and with the previous formulation of the PA model, the derivation of the expressions for spectrum regrowth of amplified SC-FDMA signals was first established and finally simulated with Matlab software. The digital pre-distortion (DPD) technology was also applied to SC-FDMA signals for the first time in this thesis. An inverse intermodulation and Autoregressive Moving-Average (IM-ARMA) model was introduced to linearize the PA distortion with memory in the LTE uplink system. The DPD was finally implemented by Matlab R2010b. Conclusions are drawn that amplified power emission levels can be expressed by the form of third-order intercept point (IP_3). The expressions for spectrum regrowth of amplified SC-FDMA signals have been verified for the first time with the comparison of simulation, measurement and calculation results. The effects of third order intermodulation have a greater impact than higher order components with respect to out-of-band emission power levels. Furthermore, the DPD algorithm reduced the spectrum regrowth of SC-FDMA signals by 12 dB. The proposed pre-distorter can effectively solve the distortion problem caused by the memory effect in RF power amplifier.

The demand for higher data rates for indoor and cell-edge users led to evolution of small cells. LTE femtocells, one of the small cell categories, are low-power low-cost mobile base stations, which are deployed within the coverage area of the traditional macro base station. The cross-tier and co-tier interferences occur only when the macrocell and femtocell share the same frequency channels. Open access (OSG), closed access (CSG), and hybrid access are the three existing access-control methods that decide users' connectivity to the femtocell access point (FAP). We define a network performance function, network productivity, to measure the traffic that is carried successfully. In this dissertation, we evaluate call mobility in LTE integrated network and determine optimized network productivity with variable call arrival rate in given LTE deployment with femtocell access modes (OSG, CSG, HYBRID) for a given call blocking vector. The solution to the optimization is maximum network productivity and call arrival rates for all cells. In the second scenario, we evaluate call mobility in LTE integrated network with increasing femtocells and maximize network productivity with variable femtocells distribution per macrocell with constant call arrival rate in uniform LTE deployment with femtocell access modes (OSG, CSG, HYBRID) for a given call blocking vector. The solution to the optimization is maximum network productivity and call arrival rates for all cells for network deployment where peak productivity is identified. We analyze the effects of call mobility on network productivity by simulating low, high, and no mobility scenarios and study the impact based on offered load, handover traffic and blocking probabilities. Finally, we evaluate and optimize performance of fractional frequency reuse (FFR) mechanism and study the impact of proposed metric weighted user satisfaction with sectorized FFR configuration.

La demande de transmissions à débits de plus en plus élevés s'accentue davantage avec l'essor de nouveaux services dans les réseaux de communication sans fils. Pour répondre à cette demande, une solution consiste à augmenter la capacité de transmission du canal radiofréquence entre la station de base et le terminal portatif. Ceci peut être réalisé en augmentant le nombre d'éléments rayonnant impliqués à l'émission et à la réception de cette liaison radiofréquence : on parle alors de technique MIMO (Multiple Input, Multiple Output). Cette thèse porte principalement sur la conception, l'optimisation et la caractérisation de systèmes multi-antennaires pour techniques de diversité et MIMO en bandes LTE (Long Term Evolution). Trois prototypes multi-bandes sont proposés dont deux systèmes planaires et un système d'antennes IFAs compactes. De nouvelles solutions multi-bandes et l'influence de la position de l'antenne sur le plan de masse sont étudiées pour réaliser de la diversité spatiale, de polarisation et de diagramme de rayonnement avec une faible corrélation entre les signaux reçus sur chaque antenne mais surtout une bonne efficacité totale. Une ligne de neutralisation est utilisée pour isoler les antennes et un fonctionnement multi-bande est réalisé. L'impédance d'entrée des antennes est étudiée avec la méthode de Youla & Carlin afin d'améliorer la bande passante de la structure compacte de type IFA. Les performances en diversité et en MIMO de ces systèmes sont évaluées dans différents environnements de propagation. Elles montrent que ces systèmes peuvent être utilisés efficacement pour des applications en diversité et MIMO.

This research is the array processing help wireless communication techniques to increase the signal accuracy. This technique has an important part of prevalent applications. The wireless communication system, radar, and sonar. Beamforming is one of methods in array processing that filters signals based on their capture time at each element in an array of antennas spatially. Numerous studies in adaptive array processing have been proposed in the last several decades, which are divided in two parts. The first one related to non-adaptive beamforming techniques and the next one related to digitally adaptive Beamforming methods. The trade-off between computational complexity and performance make them different. In this thesis, we concentrate on the expansion of array processing algorithms in both non-adaptive and adaptive ones with application of beamforming in 4G mobile antenna and radar systems. The conventional and generalized side-lobe canceller (GSC) structures beamforming algorithms were employed with a phase array antenna that changed the phase of arrivals in array antenna with common phased array structure antennas. An eight-element uniform linear array (ULA), consisting of di-pole antennas, represented as the antenna array. An anechoic chamber measures the operation of beamforming algorithms performance. An extended modified Kaiser weighting function is proposed to make a semi-adaptive structure in phased array beamforming. This technique is extended to low complexity functions like hyperbolic cosine and exponential functions. Furthermore, these algorithms are used in GSC beamforming. The side-lobe levels were so lower than other algorithms in conventional beamforming around -10 dB. On the other hand, a uniform linear arrays for smart antenna purposes designed to utilize in implementing and testing the proposed algorithms. In this thesis, performance of smart antenna with rectangular aperture coupled microstrip linear array which experimental investigations carried out for obtaining X-band operation of rectangular microstrip antenna by using aperture coupled feeding technique. Frequency range set at approximately 8.6 to 10.9 GHz, by incorporating frequency range of the antenna resonates for single wideband with an impedance bandwidth of 23%. The enhancement of impedance bandwidth and gain does not affect the nature of broadside radiation characteristics. This thesis describes the design, operation, and realization of the beamforming such as Sidelobe level (SLL) control and null forming array antenna are examined with the prototype. An antenna radiation pattern beam maximum can be simultaneously placed towards the intended user or Signal of interest (SOl), and, ideally nulls can be positioned towards directions of interfering signals or signals not of interest (SNOIs). Finally, we focused on the adaptive digitally algorithms in compact antenna that faces with mutual coupling. The variable step-size normalized lease mean square (VS-NLMS) algorithm is implemented in beamforming. This algorithm utilizes continuous adaptation. The weights are attuned that the final weight vector to the most satisfied result. The gradient vector can be achieved by iterative beamforming algorithm from the available data. This algorithm is compared with LMS, NLMS, VSS-NLMS algorithms, it is determined that the VSS-NLMS algorithm is better performance to other algorithms. Finally, we introduced novel adaptive IP-NNLMS beamformer. This beamformer reaches to faster convergence and lower error floor than the previous adaptive beamformers even at low SNRs in presence of mutual coupling. The experimental results verified the simulation results that the proposed technique has better performance than other algorithms in various situations. / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2016. / FAU Electronic Theses and Dissertations Collection

Ericsson Brasil / Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / Em um mundo onde as pessoas contam com smartphone, smartwatch, tablet e outros dispositivos para mantÃ-las conectadas onde quer que vÃo, t odos esperam que seus aplicativos sejam executados sem problemas, tais como cham adas abandonadas, download lento e vÃdeos com saltos. Neste contexto, comunicaÃÃo dispositivo-a-dispositivo ( do inglÃs, Device-to-Device (D2D)) constitui uma tecnologia promissora, pois à um tipo de comun icaÃÃo direta e utiliza baixa potÃncia entre dispositivos prÃximos, permitindo-se desv iar o trÃfego da rede mÃvel, aumentar a eficiÃncia espectral e de potÃncia. Do ponto de vista do assi nante, D2D significa usar aplicaÃÃo sem problemas e aumentar o tempo de vida da bateria do celular. No entanto, a fim de realizar os ganhos potenciais das comunic aÃÃes D2D, algumas questÃes-chave devem ser abordadas, pois as comunicaÃÃes D 2D podem aumentar a interferÃncia co-canal e comprometer a qualidade do enlace das comunicaÃÃes celulares. Esta dissertaÃÃo foca em tÃcnicas de Gerenciamento de Recur sos de RÃdio (do inglÃs, Radio Resource Management (RRM)) para mitigar a interferÃncia co -canal para comunicaÃÃes D2D que se baseiam na EvoluÃÃo de Longo Prazo (do inglÃs, Long Ter m Evolution (LTE)), visando a reduÃÃo da interferÃncia intra- e inter-celular e na melho ria da eficiÃncia energÃtica. Os principais esquemas de Controle de PotÃncia (do inglÃs, Pow er Control (PC)) (e.g. OLPC,CLPC e SDPC) e um esquema hÃbrido (CLSD) sÃo calibrados e utilizad os no cenÃrio macro ou micro multicelular, usando diferentes cargas e InformaÃÃo do Est ado do Canal (do inglÃs, Channel State Information (CSI)) perfeita ou imperfeita. AlÃm diss o, o impacto da inclinaÃÃo da antena ( downtilt ) à analisado, que à usada para ajustar o raio de cobertura de u ma Evolved Node B (eNB) e reduzir a interferÃncia co-canal, aumentando o iso lamento de cÃlulas. Os resultados numÃricos indicam que os regimes de controle d e potÃncia e inclinaÃÃo da antena, devidamente calibrados, podem fornecer ganhos p ara a comunicaÃÃo celular e D2D. Em outras palavras, a tecnologia D2D pode ser utilizada para aumentar ainda mais a eficiÃncia de espectro e a eficiÃncia energÃtica se algoritm os de RRM forem utilizados adequadamente / In a world where people count on their smartphone, smartwatch, tablet and other devices to keep them connected wherever they go, they expect its application to run without problems, such as dropped calls, slow download and choppy videos. In this context, Device-to-Device (D2D) communication represents a promising technology, because it is a direct and low-power communication between devices close, allowing to offload the data transport network, increase spectral and power efficiency. From the subscriber point of view, D2D means to use applications without problem and increase battery life. However, in order to realize the potential gains of D2D communications, some key issues must be tackled, because D2D communications may increase the co-channel interference and compromise the link quality of cellular communications. This masterâs thesis focuses on Radio Resource Management (RRM) techniques, especially Power Control (PC) schemes, to mitigate the co-channel interference for D2D communications underlaying a Long Term Evolution (LTE) network, aiming at the reduction of the intra- and inter- cell interference and at the improvement of energy efficiency. The main PC schemes (e.g. OLPC, CLPC and SDPC) and a hybrid scheme (CLSD) are calibrated and used in macro- or micro- multicell scenario, using different loads and imperfect Channel State Information (CSI). In addition, the impact of downtilt is analyzed, which is used to adjust the coverage radius of an Evolved Node B (eNB) and reduce co-channel interference by increasing cell isolation. The numerical results indicate that PC schemes and downtilt, duly calibrated, can provide gains to cellular and D2D communications. In other words, D2D technology can be used to further increase the spectral and energy efficiency if RRM algorithms are used suitably.

A tablet computer antenna array for WWAN/LTE and LTE MIMO operations is proposed. The antenna array comprises a main antenna and an auxiliary antenna. The main antenna is an eight-band coupled-fed antenna, which can cover the GSM850/900/1800/1900/UMTS and LTE700/2300/2700 operations. The auxiliary antenna is a three-band antenna, which can cover the LTE700/2300/2500 operation and occupies a small size. Acceptable isolation between the main and auxiliary antennas has also been obtained, which makes it promising for the main and auxiliary antennas to perform LTE MIMO operation in the LTE700/2300/2500 bands. Effects of the internal tablet computer antenna on the user¡¦s body are also studied. The obtained results show that the antenna can meet the 1-g body SAR specification of less than 1.6 W/kg by selecting a proper distance between the antenna and the flat phantom. Also, since the user¡¦s body is a lossy material, a decrease in the antenna¡¦s radiation efficiency is observed when the user¡¦s body is in the vicinity of the internal antenna.