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This work studies the design of linear precoder codebooks for N-r x N-t MIMO channels with MMSE detection at the receiver. A natural split of precoder-design is unitary precoding and non-unitary precoding. Unitary precoding is only performing rotation of the data in a way beneficial for the channel. Non-unitary precoding additionally also uses power-loading to further improve the performance. Some
Popular Abstract in Swedish Vid mitten av 1800-talet öppnades speciella institutioner i Sverige med syftet att ”rädda” prostituerade kvinnor från ett ”förtappat liv” utanför samhällets ramar. Men vilka var de kvinnor som ville rädda, bli räddare? Var deras engagemang ett uttryck för omsorg eller kan det sociala arbetet ses som en klassrelaterad maktutövning, en vilja att kontrollera och disciplineThe object of this thesis is a Swedish religious reform movement that, from mid nineteenth century to early twentieth century, undertook social work intended to ‘rescue’ female prostitutes. The purpose of the study is to illuminate the encounter between two groups of women, the rescuers and the rescued. This encounter is principally seen from the rescuer’s perspective, since it is the rescue movem
We introduce a mixed-integer optimization model for two-layer IP-over-Flexgrid networks, and present a cost study performed using the CPLEX package for the introduced model. The study concerns a generic German network with 12 nodes and 20 links in the optical layer, and a set of six IP traffic matrices with increasing demand volumes. The optimization assumes a hot-standby mechanism in the optical
The use of large-scale antenna arrays can bring substantial improvements both in energy and spectral efficiency. This paper presents an initial study of user equipment (UE) antenna performance based on prototypes for a massive MIMO test bed. Most publications in the massive MIMO area have assumed isotropic or dipole antenna behavior at the UE side. It is, however, of greatest interest to evaluate
There has been extensive research about single link multiple-input multiple-output (MIMO) channels, both simulated and measured, but only few studies have targeted multilink analysis with measured channel data. Hence, in this paper, we analyze the influence of spatial separation of user terminals and the human shadowing effect on the MIMO capacity and to the signal to interference ratio (SIR) in a
Software development organizations are continuously looking for better ways to manage their projects. An emerging approach to achieve this is Inner Source, which refers to the adoption of Open Source development practices within the confines of an organization. With an Inner Source approach, individuals, teams, and departments within an organization can start software projects, very similar to the
Cooperative content replication and request routing (C2R3) has emerged as a promising technique to enhance the efficiency of content delivery networks (CDN). Most existing approaches to C2R3 focus on efficient bandwidth usage and assume a hierarchical CDN architecture targeted towards the delivery of specific content types (e.g., video). Therefore, C2R3 problem of covering the broad range of conte
The design of a digital baseband for a low power wireless receiver in 65 nm CMOS is presented. It consists of decimation filtering, matched filters for data detection, and preamble based synchronization. The circuit was designed using low threshold devices in both low power (LP-LVT) and general-purpose (GP-LVT) domains. The fabricated circuits were functionally verified, and silicon measurements s
The ambitious goal of the upcoming IEEE 802.11ax (HEW) standard for wireless LANs (WLANs) to enhance throughput by four times (and beyond), compared with IEEE 802.11ac, demands a radical improvement of present medium access control (MAC) functionality. To this end, a promising paradigm would be a graceful migration towards new MAC protocols which incorporate higher certainty in their decisions. Ho
Video-on-Demand (VoD) and video sharing services account for a large percentage of the total downstream Internet traffic. In order to provide a better understanding of the load on these services, we analyze and model a workload trace from a VoD service provided by a major Swedish TV broadcaster. The trace contains over half a million requests generated by more than 20000 unique users. Among other
We deal with a natural integer-linear programming formulation of the routing and spectrum allocation (RSA) problem in elastic optical networks. We focus on strengthening the formulation with valid inequalities (cuts). For this purpose we apply clique inequalities that proved to be useful in other applications of this kind. We develop and combine a clique cut generation procedure with a column gene
This paper presents a detailed description of a propagation channel measurement campaign performed in a warehouse environment and provide a comprehensive channel model for this environment. Using a vector network analyzer (VNA), we explored both Line-of-sight(LOS) and Non-Line-of-sight (NLOS) scenarios over a 2-8 GHz frequency range. We extracted both small-scale and large-scale channel parameters
Governmental organisations are becoming more critically dependant on IT systems such as communication systems or patient data systems, both for their everyday tasks and their role in crisis relief activities. Therefore it is important for the organisation to analyse the reliability of these systems as part of the organisation’s risk and vulnerability analysis process. This paper presents a practic
Low-density parity-check convolutional (LDPCC) codes, also known as spatially coupled LDPC codes, can be decoded using a message passing algorithm. In order to limit decoding latency and complexity, windowed decoding can be applied. Updates within the window can be performed either in parallel or serially. However, simulation results show that uniform updating schedules do not provide the expected
In this paper, we confirm that angle and polarization diversities are indeed the dominant diversity mechanisms of a recently proposed compact six-port MIMO antenna array, as it exhibits similar effective degree-of-freedom (EDOF) performance as that of the ideal array with co-located antenna elements evaluated in propagation scenarios with different angular spreads. Furthermore, the same approach c
We find good rate 2/3 and 3/4 convolutional codes for use with iterative decoding (turbo equalization) of coded intersymbol interference with AWGN. The method is based on the input-output bit error rate characteristic of the convolutional BCJR decoder module. An analysis leads to an equivalent minimum distance under the required intrinsic subtraction, which depends on free distance and an input-ou
