This thesis proposes resource allocation algorithms for multi-input multi-output (MIMO) relay and Scalable H.264/AVC video transmission over cooperative communication networks. For MIMO relay, we explore the reception diversity with maximal ratio combining (MRC) and transmission diversity with space-time block codes (STBC) respectively. Then, a condition is proposed to maximize the overall output signal-to-noise ratio (SNR). In this condition, the ineffective relays will be excluded in sequence from the cooperation. Simulation results indicate that the effect of bit error rate (BER) through the relay selection is similar to the scheme which applies all relays, but the amounts of used relay decreased. For Scalable H.264/AVC video, by introducing frame significance analysis, the video quality dependency between coding frame and its references is investigated for temporal layers and quality layers. The proposed algorithm allocates the relay and sub-band to each layer based on channel conditions and the priority of classified video packets. Experimental results indicate that the proposed algorithm is superior to the temporal-based allocation and quality-based allocation cooperative schemes.

In this thesis, a novel iterative receiver and its improved version are proposed for relay-assisted multiuser communications, in which multiple users transmit to a destination with the help of a relay and using fast frequency-hopping modulation. Each user employs a channel encoder to protect its information and facilitate interference cancellation at the receiver. The signal received at the relay is either amplified, or partially decoded with a simple energy detector, before being forwarded to the destination. Under flat Rayleigh fading channels, the receiver at the destination can be implemented non-coherently, i.e., it does not require the instantaneous channel information to demodulate the users’ transmitted signals. The proposed iterative algorithm at the destination exploits the soft outputs of the channel decoders to successively extract the maximum likelihood symbols of the users and perform interference cancellation. The iterative method is successfully applied for both cases of amplify-and-forward and partial decode-and-forward relaying. The error performance of the proposed iterative receiver is investigated by computer simulation. Under the same spectral efficiency, simulation results demonstrate the excellent performance of the proposed receiver when compared to the performance of decoding without interference cancellation as well as the performance of the maximum likelihood multiuser detection previously developed for uncoded transmission. Simulation results also suggest that a proper selection of channel coding schemes can help to support significant more users without consuming extra system resources. In addition, to further enhance the receiver’s performance in terms of the bit error rate, an improved version of the iterative receiver is presented. Such an improved receiver invokes inner-loop iterations between the channel decoders and the demappers in such a way that the soft outputs of the channel decoders are also used to refine the outputs of the demappers for every outer-loop iteration. Simulation results indicate a performance gain of about 2.5dB by using the two-loop receiver when compared to the performance of the first proposed receiver.

Cooperative communication is a promising technique to provide spatial diversity in a virtual multi-input and multi-output (MIMO) manner. However, as application evolves toward a more practical situation, realistic constraints and issues such as channel state information (CSI) assumption must be accounted when developing appropriate cooperative schemes. In this thesis, we have addressed delay related problems in both single user pair cooperation (SUPC) and multiple user pair cooperation (MUPC) networks. In SUPC, realizing that the outdated CSI caused by delay between relay selection instant and transmission instant can impair diversity order severely, we propose an opportunistic multiple relay selection (MRS) scheme to achieve desired diversity order and combat the variation of the wireless environment. On the other hand, for multiple user pairs cooperation (MUPC), we start from one of the notable work, two hop opportunistic relaying (THOR), and analyze its the delay related problems. We propose an opportunistic pair scheduling (OPS) scheme which can get rid of the buffer requirement at the relay nodes of THOR and incurs no loss in terms of throughput scaling. Furthermore, we extend OPS to a general scheduling scheme, $L$ scheduling, which can achieve controllable throughput-and-delay trandeoffs. / Graduate

In this dissertation we consider cooperative communication systems with relay conferencing, where the relays own the capabilities to talk to their counterparts via either wired or wireless out-of-band links. In particular, we focus on the design of conferencing protocols incorporating the half-duplex relaying operations, and study the corresponding capacity upper and lower bounds for some typical channels and networks models, including the diamond relay channels (one source-destination pairs and two relays), large relay networks (one source-destination pairs and N relays), and interference relay channels (two source-destination pairs and two relays). First, for the diamond relay channels, we consider two different relaying schemes, i.e., simultaneous relaying (for which the two relays transmit and receive in the same time slot) and alternative relaying (for which the two relays exchange their transmit and receive modes alternatively over time), for which we obtain the respective achievable rates by using the decode-and-forward (DF), compress-and-forward (CF), and amplify-and-forward (AF) relaying schemes with DF and AF adopted the conferencing schemes. Moreover, we prove some capacity results under some special conditions. Second, we consider the large relay networks, and propose a "p-portion" conferencing scheme, where each relay can talk to the other "p-portion" of the relays. We obtain the DF and AF achievable rates by using the AF conferencing scheme. It is proved that relay conferencing increases the throughput scaling order of the DF relaying scheme from O(log(log(N ))) for the case without conferencing to O(log(N )); for the AF relaying scheme, it achieves the capacity upper bound under some conditions. Finally, we consider the two-hop interference relay channels, and obtain the AF achievable rates by adopting the AF conferencing scheme and two different decoding schemes at the destination, i.e., single-user decoding and joint decoding. For the derived joint source power allocation and relay combining problem, we develop some efficient iterative algorithms to compute the AF achievable rate regions. Moreover, we compare the achievable degree-of-freedom (DoF) performance of these two decoding schemes, and show that single-user decoding with interference cancellation at the relays is optimal.

The electrical grid contains protection functions to ensure a secure and efficient disconnection of faulty plant parts in accordance with Swedish law, applicable standards and industry practice. The aim with this bachelor thesis has been to develop a way of testing relay protection equipment to ensure the applicable standards are followed and at the same time show the result in a way that is easy to understand and makes it possible to use the result in E.ONs risk and vulnerable analysis. A risk and vulnerable analysis is required under regulation EIFS 2013:3. The work has consists of four stages. The first stage has been to examine the existing situation and see how the work is performed. The second stage has been to study the literature about the subject and the demands that E.ON places on the testing procedure. The third stage has been to develop a report template. The fourth stage has been to test the proposed method in reality and to guarantee the desired function of the protection. It has been discovered that the most appropriate way of reporting testing is a template where relay parameters and the testing protocol are collected into one file where an automatized assessment is done of the protection equipment. This approach also makes it possible to use the results directly in E.ONs risk and vulnerability analysis. The report contains a theoretical background of the protection equipment for electrical plants and grids. The report also shows the development of the testing plan together with the proposed reporting templates.The work shows that a periodical testing of electrical protections should consist of the following parts:• Visual inspection• Verification of tripping, blocking and signalling circuits• Verification of relay protection equipment• Measuring of operating valuesThe way of testing has been a bit simplified. This has been done by excluding those parts from the testing that are not necessary in modern protection equipment. A saving in the data handling has also been achieved when some handling has become automatic. / <p>Validerat; 20150608 (global_studentproject_submitter)</p>

Future naval ships will be all-electric, with an integrated power system that combines the propulsion power system with the rest of the ship?s electrical distribution system. Reconfiguration of the power system will increase fight-through and survivability of ships, but will also require the systems that support the power system, such as the protection system, to be automatically updated to match current power system needs. This thesis presents an adaptive relaying scheme for shipboard power systems, to automatically modify relay settings after power system topology changes. Multiple Groups of relay settings are predetermined and stored in the digital relays that are protecting the power system. The active Group of settings is automatically determined based on the open/close status of breakers and switches. The developed protection scheme is tested on two test cases by digital simulation using CAPE software and on one case by closed-loop simulation with RTDS and SEL-351S relays.

This thesis explores the application of the Virtual Test Bed (VTB) and its real-time extension, VTB-RT, for protective relay modeling, simulation, and testing. An instantaneous overcurrent relay model was developed in VTB for a transmission line protection. The same relay model was built in Matlab/Simulink for validation purposes. Both models were tested for various fault conditions on a radial power system and results were compared. Moreover, a low cost real-time Hardware-In-the-Loop (HIL) simulation platform was implemented for relay model testing using VTB-RT and public domain software packages such as Real-Time Application Interface (RTAI), Comedi, and Comedilib, and notebook computer hardware. The applicability of VTB-RT was verified through an open-loop simulation and a HIL simulation of a simple dynamic system using dSPACE as the control hardware and NI DAQCard-6062E as the input/output interface. Simulation results are presented showing the effectiveness of the VTB-RT platform for model testing.

A proteção diferencial é o esquema preferido para proteção de equipamentos e linhas de transmissão. A proteção diferencial exige que informações de todos terminais de zona sob proteção sejam usados para calcular a corrente diferencial. Se esta corrente excede um determinado limite significa que uma falta pode existir na zona protegida. Tais cálculos devem ser executados em cada terminal, consequentemente deve existir um rápido canal de comunicação entre todos os terminais de linha. Este trabalho apresenta o desenvolvimento do algoritmo de uma proteção diferencial digital de linhas de transmissão com compensação em série. O algoritmo proposto foi implementado em Matlab e foi testado com os mais diferentes tipos de faltas simuladas no programa ATP (Alternative Transients Program). Os resultados comprovam o correto funcionamento do algoritmo. O uso de tecnologias atuais de sincronização por GPS (Global Positioning System) e transmissão de dados em banda larga, resolvem antigos problemas da implementação de proteções diferenciais em linhas de transmissão. / The differential protection is the preferred scheme to protect equipment and transmission lines. The differential protection needs information from all terminals of a protected zone to be used to calculate the differential current. If the current exceeds the threshold level, it means that a fault may exist in the protected zone. These computations must be made on each terminal, consequently a fast communication channel connecting all terminals must exist. This work presents the development of a digital differential protection algorithm for series compensated transmission lines. The algorithm was implemented in Matlab and it was tested with the most different variety of faults simulated with ATP (Alternative Transients Program) software. The results proved the correct operation of the algorithm. The use of modern technologies of synchronization such as GPS (Global Positioning System) and data transmission by wide band solved old problems presented by the implementation of differential protection in transmission lines.

A proteção diferencial é o esquema preferido para proteção de equipamentos e linhas de transmissão. A proteção diferencial exige que informações de todos terminais de zona sob proteção sejam usados para calcular a corrente diferencial. Se esta corrente excede um determinado limite significa que uma falta pode existir na zona protegida. Tais cálculos devem ser executados em cada terminal, consequentemente deve existir um rápido canal de comunicação entre todos os terminais de linha. Este trabalho apresenta o desenvolvimento do algoritmo de uma proteção diferencial digital de linhas de transmissão com compensação em série. O algoritmo proposto foi implementado em Matlab e foi testado com os mais diferentes tipos de faltas simuladas no programa ATP (Alternative Transients Program). Os resultados comprovam o correto funcionamento do algoritmo. O uso de tecnologias atuais de sincronização por GPS (Global Positioning System) e transmissão de dados em banda larga, resolvem antigos problemas da implementação de proteções diferenciais em linhas de transmissão. / The differential protection is the preferred scheme to protect equipment and transmission lines. The differential protection needs information from all terminals of a protected zone to be used to calculate the differential current. If the current exceeds the threshold level, it means that a fault may exist in the protected zone. These computations must be made on each terminal, consequently a fast communication channel connecting all terminals must exist. This work presents the development of a digital differential protection algorithm for series compensated transmission lines. The algorithm was implemented in Matlab and it was tested with the most different variety of faults simulated with ATP (Alternative Transients Program) software. The results proved the correct operation of the algorithm. The use of modern technologies of synchronization such as GPS (Global Positioning System) and data transmission by wide band solved old problems presented by the implementation of differential protection in transmission lines.

International Telemetering Conference Proceedings / October 18-21, 2004 / Town & Country Resort, San Diego, California / Reliable System Services Corporation (RSS Corp.) presents the feasibility of a low cost, low power, high capacity, robust RF Communications Network using SATCOM and UAV relays. The developed architecture will be suitable for OTH Large Area Test and Training exercises as well as applications for OTH Digital Battlefield scenarios. A specific application is shown for the planned Littoral Combat Ship (LCS) missions, although the developed architecture will have broader applications for any surface combatant requiring an Over-the-Horizon (OTH) data link to distributed players and sensors. A conceptual design for the IP network radio system will implement RSS Corp. developed secure IRIDIUM global full duplex data links and Harris Corp. developed long range high bandwidth 802.11 full duplex data links. The results will be significant, and the developed system could be a cornerstone of the future digital battlefield combat communications architecture. The developed technology will also have significant use in any application for Test, Evaluation and Training Ranges requiring net centric, command/control and wide bandwidth TLM data collection from distributed remote players and sensors.