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One recent method to approach the capacity of a channel is Turbo Coding. However, a major concern with the implementation of a Turbo Code is the overall complexity and real-time throughput of the digital hardware system. The salient design problem of Turbo Coding is the iterative decoder, which must perform calculations over all possible states of the trellis. Complex computations such as exponentiations, logarithms and division are explored as part of this research to compare the complexity of the traditionally avoided maximum a-posteriori probability (MAP) decoder to that of the more widely accepted and simplified Logarithm based MAP decoder (LOG-MAP). This research considers the fine grained implementation and processing of MAP, LOG-MAP and a hybrid LOG-MAP-Log Likelihood Ratio (LLR) based Turbo Codes on a Xilinx Virtex 4 PGA. Verification of the Turbo Coding system performance is demonstrated on a Xilinx Virtex 4 ML402SX evaluation board with the EDA of the Xilinx System Generator utilizing hardware co-simulation. System throughput and bit error rate (BER) are the performance metrics that are evaluated as part of this research. An efficient system throughput is predicated by the parallel design of the decoder and BER is determined by data frame size, data word length and the number of decoding iterations. Furthermore, traditional and innovative stopping rules are evaluated as part of this research to facilitate the number of iterations required during decoding. / Engineering

<p> The goal of this thesis is the development of a computationally-efficient coded system that enables communication over the non-coherent Multiple-Input Multiple-Output (MIMO) fiat-fading wireless channel at high data rates. The proposed signalling technique applies the principles of Bit-Interleaved Coded Modulation (BICM) with Iterative Demapping and Decoding (IDD) to non-coherent MIMO communication systems. </p> <p> The principle of BICM is applied to a constellation that mimics the non-coherent capacity achieving distribution at high signal to noise ratios. The capacity achieving distribution is in the form of isotropically distributed unitary matrices, and the constellation can be represented by points on a Grassmannian manifold. A mapping technique that exploits the Grassmannian geometry is proposed. This mapping technique is based on the partitioning of the constellation into two subsets. The Grassmannian geometry also gives rise to an efficient list-based demapping algorithm that substantially reduces the computational complexity of the receiver while incurring some degradation in performance. For example, at a bit error rate (BER) of 10-4 the signal to noise ratio (SNR) performance degradation with respect to full constellation demapping is approximately 1. 75 dB. A technique by which the decoder can augment the demapping list is proposed, and it is shown that the performance degradation of the efficient algorithm can be rendered insignificant (approximately 0.2 dB at a BER of 10-4). </p> <p> Finally, the performance of the proposed BICM-IDD using the Grassmannian constellation will be compared to that of a corresponding training-based BICM-IDD scheme. These simulations show that the proposed scheme can provide better performance at high data rates; e.g., for a data rate of 5/3 bits per channel use, the performance gap is almost 1 dB at BER of 10^(-4). </p> / Thesis / Master of Applied Science (MASc)

Yes / The quasi-orthogonal space time block coding (QO-STBC) over orthogonal frequency division multiplexing (OFDM) is investigated. Traditionally, QO-STBC does not achieve full diversity since the detection matrix of QO-STBC scheme is not a diagonal matrix. In STBC, the decoding matrix is a diagonal matrix which enables linear decoding whereas the decoding matrix in traditional QO-STBC does not enable linear decoding. In this paper it is shown that there are some interfering terms in terms of non-diagonal elements that result from the decoding process which limit the linear decoding. As a result, interference from the application of the QO-STBC decoding matrix depletes the performance of the scheme such that full diversity is not attained. A method of eliminating this interference in QO-STBC is investigated by nulling the interfering terms towards full diversity for an OFDM system. It was found that the interference reduction technique permits circa 2dB BER performance gain in QO-STBC. The theoretical and simulation results are presented, for both traditional QO-STBC and interference-free QO-STBC applying OFDM

Att folk inte förstår vad man säger beror på flera olika anledningar. En självklar orsak till att detta är till exempel givetvis om man inte talar samma språk. Men även om man skulle begripa varandra i en konversation betyder inte det att sändarens budskap tolkas på önskat sätt av mottagaren. Kommunikationen är avgörande för att en förståelse mellan två parter ska kunna skapas. Stuart Hall (1973) problematiserar kommunikationsprocessen och kedjan från det att meddelandet produceras till dess distribution och slutliga konsumtion. Kommunikationen mellan kodare och avkodare är aldrig given i sin överenskommelse. Att man talar samma språk betyder följaktligen inte att man förstår varandra fullt ut. Det finns många andra faktorer som påverkar hur meddelandet avkodas av mottagaren. Vi har valt att undersöka hur två hockeyklubbar kommunicerar med sina supportrar. Studiens syfte är att göra en jämförelse mellan de två varumärkena. I respektive varumärkes identitet och image söks likheter och olikheter. Den eventuella varumärkeskongruensen studeras ur ett kommunikativt perspektiv.   Intentionen är att ta reda på hur kommunikativa processer kan påverka varumärkens identitet och image och relationen mellan dem. Det teoretiska ramverk som använts består av marknadskommunikation, encoding och decoding och varumärkesteori. Under varumärkesteorin följer kompletteringar om sport och varumärken, varumärkesidentitet och varumärkesimage. Studien baseras på en kvalitativ och en kvantitativ metod. Den kvalitativa metoden består av gruppintervjuer som utförts för att fastställa varumärkenas identiteter medan den kvantitativa metoden utgörs av enkäter som identifierar varumärkenas image. En av de slutsatser som presenteras i studien är att det både finns kongruens och skillnader angående överensstämmelsen mellan varumärkesidentitet- och image. Sammanfattningsvis går det att konstatera att resurser utgör den stora skillnaden klubbarna mellan i förutsättningen för att mottagarna ska kunna tillgodoses på ett bra sätt. / The reason people don’t understand what others are saying can depend on a lot of things. One obvious reason would be that two individuals don’t speak the same language. Even if the two individuals would understand the words in a conversation, it’s not certain that the meaning of the message reaches the receiver the intended way. The communication settles the agreement for understanding between two parts. Stuart Hall (1973) problematizes the communication process and the chain from when the message is created and coded with meaning, through its distribution until its consumption. The communication between an encoder and a decoder are not ever certain. To not speak the same language is the same as not understanding each other. There are many other factors that influence how the receiver decodes a message.   This thesis aims to identify the brand congruence related to two Swedish ice hockey brands. The intention is to examine how communicative processes can influence the differences between how the brand identity and brand image are interpreted. The theory frame used in the thesis concludes of the following theories; Marketing Communication, Encoding and Decoding and Brand Theory. The Brand Theory is specified within the areas of Sports and Brands, Brand Identity and Brand Image.  The thesis includes both a qualitative and a quantitative method. The qualitative interviews are used to establish the brand identities while the quantitative questionnaire study aims to define the brand images. One of the major conclusions is that there are both congruence and differences in the comparison within both of the brands. Another conclusion is that the differences in how substantial the congruence is relates to resources and the brands background.

The unifying theme of this dissertation is the development of new solutions for decoding and inference problems based on convex optimization methods. Th first part considers the joint detection and decoding problem for low-density parity-check (LDPC) codes on finite-state channels (FSCs). Hard-disk drives (or magnetic recording systems), where the required error rate (after decoding) is too low to be verifiable by simulation, are most important applications of this research. Recently, LDPC codes have attracted a lot of attention in the magnetic storage industry and some hard-disk drives have started using iterative decoding. Despite progress in the area of reduced-complexity detection and decoding algorithms, there has been some resistance to the deployment of turbo-equalization (TE) structures (with iterative detectors/decoders) in magnetic-recording systems because of error floors and the difficulty of accurately predicting performance at very low error rates. To address this problem for channels with memory, such as FSCs, we propose a new decoding algorithms based on a well-defined convex optimization problem. In particular, it is based on the linear-programing (LP) formulation of the joint decoding problem for LDPC codes over FSCs. It exhibits two favorable properties: provable convergence and predictable error-floors (via pseudo-codeword analysis). Since general-purpose LP solvers are too complex to make the joint LP decoder feasible for practical purposes, we develop an efficient iterative solver for the joint LP decoder by taking advantage of its dual-domain structure. The main advantage of this approach is that it combines the predictability and superior performance of joint LP decoding with the computational complexity of TE. The second part of this dissertation considers the matrix completion problem for the recovery of a data matrix from incomplete, or even corrupted entries of an unknown matrix. Recommender systems are good representatives of this problem, and this research is important for the design of information retrieval systems which require very high scalability. We show that our IMP algorithm reduces the well-known cold-start problem associated with collaborative filtering systems in practice.

During the last decade new attention has been paid to reading fluency. One reason might be that training studies often have failed to provide growth in reading rate in spite of the fact that the accuracy problem was remediated. Recent research has also indicated that, in languages with a consistent mapping between graphemes and phonemes, automatization of decoding processes are more difficult to reach than aquiring accurate decoding skills. Several studies have found that computer-based flashcard training seems to be a productive way to develop reading fluency. The aims of this thesis are partly to replicate some of the previous studies with time pressured exposure and partly to examine whether the condition with time pressure is more effective than the flashcard condition with fixed exposure duration. In the time pressure condition, the exposure duration was varied as a function of accuracy. This thesis reports one main study and two case studies. The participants in the main study were 17 males and 11 females between the ages of 11 and 17. All of them were poor readers, scoring below the 11th percentile on standardized reading test for their age group. The two participants of the first case study were the poorest readers of all. Their decoding strategies differed greatly. The younger of them, a slow reader in the fourth grade, can be seen as “a speller” with most impairment in the orthographic processing and the older, a quick reader in the fifth grade, can be seen as “a guesser” with most impairment in the phonological processing. The four participants in the second case study were moderately poor readers between the ages of 12 and 14. Each participant practiced the two different conditions of the computer-based flashcard training with spelling response in sessions about twenty minutes long twice to three times a week during three to four months. Teacher-controlled tuition was only given in some pre-sessions. According to the online results, all participants in both of the exposure conditions were capable of keeping the accuracy at a high level, i.e. fluent reading was expected to be developed. A battery of silent and oral reading tests and spelling-to-dictation tests was used in pre-, middle- and posttest. Both accuracy and rate were measured in reading. Except for “the speller” in the first case study, significant improvements were found on all tests for both conditions. The best progress was during the first training period independent of condition. Positive effects were found for both trained and untrained material and for words and pseudo-words. The reading progress has in general been better than the average student usually develops during the same time. The students reported the time pressured condition as being more effective and motivating but no significant difference was found between the two conditions in the pre- to posttests.

In this thesis, we consider the problem of designing space-time block codes that have low maximum-likelihood (ML) decoding complexity. We present a unified framework for determining the worst-case ML decoding complexity of space-time block codes. We use this framework to not only determine the worst-case ML decoding complexity of our own constructions, but also to show that some popular constructions of space-time block codes have lower ML decoding complexity than was previously known. Recognizing the practical importance of the two transmit and two receive antenna system, we propose the asymmetric golden code, which is designed specifically for low ML decoding complexity. The asymmetric golden code has the lowest decoding complexity compared to previous constructions of space-time codes, regardless of whether the channel varies with time. We also propose the embedded orthogonal space-time codes, which is a family of codes for an arbitrary number of antennas, and for any rate up to half the number of antennas. The family of embedded orthogonal space-time codes is the first general framework for the construction of space-time codes with low-complexity decoding, not only for rate one, but for any rate up to half the number of transmit antennas. Simulation results for up to six transmit antennas show that the embedded orthogonal space-time codes are simultaneously lower in complexity and lower in error probability when compared to some of the most important constructions of space-time block codes with the same number of antennas and the same rate larger than one. Having considered the design of space-time block codes with low ML decoding complexity on the transmitter side, we also develop efficient algorithms for ML decoding for the golden code, the asymmetric golden code and the embedded orthogonal space-time block codes on the receiver side. Simulations of the bit-error rate performance and decoding complexity of the asymmetric golden code and embedded orthogonal codes are used to demonstrate their attractive performance-complexity tradeoff.