Finite-Blocklength Bounds on the Maximum Coding Rate of Rician Fading Channels with Applications to Pilot-Assisted Transmission

We present nonasymptotic bounds on the maximum coding rate achievable over a Rician block-fading channel for a fixed packet size and a fixed packet error probability. Our bounds, which apply to the scenario where no a priori channel state information is available at the receiver, allow one to quantify the tradeoff between the rate gains resulting from the exploitation of time-frequency diversity and the rate loss resulting from fast channel variations and pilot-symbol overhead

Property Rights in Land, Agricultural Capitalism, and the Relative Decline of Pre-Industrial China

Idag skiftar industrin sitt fokus från att producera fysiska produkter till att utveckla tjänster. En ökande konkurrens på marknaden gör att företag måste använda effektiva utvecklingsprocesser för att snabbt lansera tjänster av hög kvalitet. Tjänster definieras ofta utifrån deras immateriella karaktär vilket komplicerar mätning av kvalitet. För att bestämma kvalitet kan fysiska produkter kontrolleras mot en kravspecifikation genom att testas och mätas. Tjänster däremot utgår ifrån hur väl de uppfyller kundernas och användarnas behov. För att öka tjänsters kvalitet är det viktigt att förstå kunderna och användarna och i praktiken blir det allt vanligare att involvera dem i utvecklingen. Tjänster har nyligen fått stor uppmärksamhet i industrin och i forskningen och den allmänna beskrivningen av tjänster omfattar många olika ämnesområden. Detta innebär att det inte finns en entydig definition av vad en tjänst är och det saknas en vedertagen tjänsteutvecklingsprocess som möjliggör involvering av användarna. Vidare efterfrågar forskningen studier i hur kund- och användarinvolvering bör ingå i utvecklingen av tjänster, speciellt i ett tidigare skede, och hur det påverkar tjänsters resultat. Utifrån en litteraturstudie har denna studie föreslagit en process för att involvera centrala intressenter, till exempel kunder, användare och interna intressenter, i utvecklingen av tjänster. Processen implementerades sedan i ett praktikfall där examensarbetet samarbetspartner, ett mindre IT-företag, gett i uppdrag att utveckla ett koncept av en friskvårdstjänst. Praktikfallet omfattade endast de första delarna i utvecklingen där exempelvis teknisk utveckling och lansering inte ingick. Efter att processen implementerats levererades ett färdigt koncept till samarbetspartnern och en ny justerad process presenterades baserad på analyser från empirin. Denna studie styrker dagens forskning genom att påvisa att kund- och användarinvolvering i tjänsteutvecklingen kan bidra till en effektiv process, tjänster av hög kvalitet, en ökad kundlojalitet till företaget och en ökad marknadsacceptans. Däremot är det avgörande att involveringen sker på rätt sätt med rätt intressenter. Innan utvecklingen bör syftet med intressenternas involvering definieras omsorgsfullt så att involveringsmomenten kan anpassas därefter. Efter att syftet med intressenternas involvering bestämts kan processen från denna studie med fördel implementeras i all tjänsteutveckling. Sökord: tjänsteutveckling, tjänstedesign, kundinvolvering, användarinvolvering, processToday the industry is shifting focus from producing goods to developing services. With increasing competition on the service market companies need to establish efficient development processes to quickly launch services of high quality. Services are often defined in terms of its intangible nature, which complicates the measurement of quality. Goods can be physically tested and measured to be checked against a requirement specification. On the other hand, quality in services is based on how well they meet customer and user needs. To gain quality the understanding of customers and users is crucial and in practice it is becoming increasingly common to involve customers and users in the service development. Services have recently gained attention within the industry and research. Furthermore, the general description of services includes a variety of subject areas. Because of this there is no established definition of what a service actually is and the research lack recognized processes for its development. In addition, the research request studies on how customer and user involvement should be part of the development of services, especially in the early stages, and how it affects the services’ results. Based on a literature study, this thesis has proposed a process for involving key stakeholders, including customers and users, in the development of services. The process was then implemented in a case where a small IT company commissioned to develop a concept of a wellness service. The case comprised only the first stages of the full development where, for example, technical design and launch was not included. After the process was implemented, a final concept was delivered to the business partner and a new adjusted process was presented based on the analysis of the empirical data. This study verifies today's research by demonstrating that customer and user involvement in service development can contribute to an efficient process, quality, increased customer loyalty to the company and a greater market acceptance. However, it is crucial that the right stakeholders are involved according to a purpose. Before the development, the purpose of the stakeholder involvement must be defined carefully so that activities can be designed accordingly. After this, the adjusted process presented in this study can advantageously be implemented in any service development. Keywords: Service development, Service design, Customer involvement, User involvement, Proces

Short Packets over Block-Memoryless Fading Channels: Pilot-Assisted or Noncoherent Transmission?

We present nonasymptotic upper and lower bounds on the maximum coding rate achievable when transmitting short packets over a Rician memoryless block-fading channel for a given requirement on the packet error probability. We focus on the practically relevant scenario in which there is no \emph{a priori} channel state information available at the transmitter and at the receiver. An upper bound built upon the min-max converse is compared to two lower bounds: the first one relies on a noncoherent transmission strategy in which the fading channel is not estimated explicitly at the receiver; the second one employs pilot-assisted transmission (PAT) followed by maximum-likelihood channel estimation and scaled mismatched nearest-neighbor decoding at the receiver. Our bounds are tight enough to unveil the optimum number of diversity branches that a packet should span so that the energy per bit required to achieve a target packet error probability is minimized, for a given constraint on the code rate and the packet size. Furthermore, the bounds reveal that noncoherent transmission is more energy efficient than PAT, even when the number of pilot symbols and their power is optimized. For example, for the case when a coded packet of $168$ symbols is transmitted using a channel code of rate $0.48$ bits/channel use, over a block-fading channel with block size equal to $8$ symbols, PAT requires an additional $1.2$ dB of energy per information bit to achieve a packet error probability of $10^{-3}$ compared to a suitably designed noncoherent transmission scheme. Finally, we devise a PAT scheme based on punctured tail-biting quasi-cyclic codes and ordered statistics decoding, whose performance are close ($1$ dB gap at $10^{-3}$ packet error probability) to the ones predicted by our PAT lower bound. This shows that the PAT lower bound provides useful guidelines on the design of actual PAT schemes.Comment: 30 pages, 5 figures, journa

Hur motiveras den svenska regionutvecklingen? En studie av aktuella reformförslag

This thesis deals with the Swedish regionalization process by examining the latest official report on matter, Statens regionala förvaltning – en angelägen reform (SOU 2012:81). The report contains two major propositions for reform that this study aims to understand. The first concerns where the responsibility should rest for regional development, and the second addresses the county government (Länsstyrelsen) at the regional level. The purpose is to understand the impact on the two propositions and whether they are based on democratic or economical ideas, and if they are initiated and driven from actors “above” or “below”. By using qualitative method and theories from Lennart Lundquist and Jörgen Gren, the study concludes that the first proposition on development responsibility is based on democratic ideas that people should be more included in the decision-making. The second proposition concerning county government is based on economical ideas of a more cost-effective public sector. The most interesting aspect about the findings is however that the proposals may yield more economical and “modern” regions in spite of the fact that the original purpose was to increase democracy and public involvement

Low-latency Ultra Reliable 5G Communications: Finite-Blocklength Bounds and Coding Schemes

Future autonomous systems require wireless connectivity able to support extremely stringent requirements on both latency and reliability. In this paper, we leverage recent developments in the field of finite-blocklength information theory to illustrate how to optimally design wireless systems in the presence of such stringent constraints. Focusing on a multi-antenna Rayleigh block-fading channel, we obtain bounds on the maximum number of bits that can be transmitted within given bandwidth, latency, and reliability constraints, using an orthogonal frequency-division multiplexing system similar to LTE. These bounds unveil the fundamental interplay between latency, bandwidth, rate, and reliability. Furthermore, they suggest how to optimally use the available spatial and frequency diversity. Finally, we use our bounds to benchmark the performance of an actual coding scheme involving the transmission of short packets

Malmös bostadspolitik - en snickare utan verktyg

Malmö är exempel på en kommun med ambitiösa bostadspolitiska mål. Samtidigt visar vår uppsats att bostadsbyggandet styrs alltmer av marknadskrafter och att skillnaden mellan mål och medel inom bostadspolitiken är stor. Uppsatsens syfte är dels att ta reda på vilka förutsättningar Malmö stad ges att bedriva sin bostadspolitik. För att synliggöra de bostadspolitiska förhållandena tar vi hjälp av governancteorier. Det material vi använder består främst av rapporter, lagar och en intervju Malmös bostadsförsörjningsenhet. Syftet är även att med hjälp av Lennart Lundquists uppdelning av ekonomiska och demokratiska värden undersöka konflikten mellan privat och offentligt inom bostadspolitiken, samt se vilka konsekvenser de får ur ett demokratiskt perspektiv. Vi kommer fram till att bostadspolitiken, genom nya lagar och mål, har marknadsanpassats och försvagats. Resultatet är att de ekonomiska värdena har prioriterats framför de demokratiska eftersom de demokratiska kommunerna har svårt att uppnå sina mål samt att det föreligger en diskrepans mellan nationella mål och medel

Gray coding for multilevel constellations in Gaussian noise

The problem of finding the optimal labeling (bit-to-symbol mapping) of multilevel coherent phase shift keying (PSK), pulse amplitude modulation (PAM), and quadrature amplitude modulation (QAM) constellations with respect to minimizing the bit-error probability (BEP) over a Gaussian channel is addressed. We show that using the binary reflected Gray code (BRGC) to label the signal constellation results in the lowest possible BEP for high enough signal energy-to-noise ratios and analyze what is "high enough"in this sense. It turns out that the BRGC is optimal for PSK and PAM systems whenever the target BEP is at most a few percent, which covers most systems of practical interest. New and simple closed-form expressions are presented for the BEP of PSK, PAM, and QAM using the BRGC. \ua9 2007 IEEE

Short-packet Transmission via Variable-Length Codes in the Presence of Noisy Stop Feedback

We present an upper bound on the error probability achievable using variable-length stop feedback codes, for a fixed size of the information payload and a given constraint on the maximum latency and the average service time. Differently from the bound proposed in Polyanskiy et al. (2011), which pertains to the scenario in which the stop signal is sent over a noiseless feedback channel, our bound applies to the practically relevant setup in which the feedback link is noisy. By numerically evaluating our bound, we illustrate that, for fixed latency and reliability constraints, noise in the feedback link can cause a significant increase in the minimum average service time, to the extent that fixed-length codes without feedback may be preferable in some scenarios.Comment: Submitted to a Transactions on Wireless Communication