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High computational cost is the main obstacle to adapting globally optimal branch-and-bound algorithms to intensity-based registration. Existing techniques to speed up such algorithms use a multiresolution pyramid of images and bounds on the target function among different resolutions for rigidly aligning two images. In this paper, we propose a dual algorithm in which the optimization is done in th

Although surface integral equations (SIEs) have been extensively used in solving electromagnetic problems of penetrable objects, there are still open issues relating to their application to the Theory of Characteristic Modes. This work demonstrates that when an SIE is used to solve for the characteristic modes (CMs) of a dielectric or magnetic object, the resulting eigenvalues are unrelated to the

We consider a case where K closely located users communicate with a base station in the uplink of a wireless communication system. Each user has a certain number of assigned time-frequency slots at its disposal. At a small cost, which we in this paper consider as negliable, the users can communicate with each other and share their data. Thus, they can cooperate in the uplink in order to save trans

We consider optimal channel shortener design for reduced-state soft-output Viterbi equalizer (RS-SOVE) in singlecarrier (SC) systems. To use RS-SOVE, three receiver filters need to be designed: a prefilter, a target response and a feedback filter. The collection of these three filters are commonly referred to as the “channel shortener”. Conventionally, the channel shortener is designed to transfor

We investigate the ability of Massive multiple-input multiple-output (MIMO) systems to spatially separate up to eighteen users located close to one another in line-of-sight (LOS) propagation conditions, in both indoor and outdoor environments. For that, we use fully-synchronous measured channels at 2.6 GHz of single-antenna users moving within a small area and concurrently communicating with a bas

In this paper, we study sliding window decoding of braided convolutional codes (BCCs) in the context of a streaming application, where decoder error propagation can be a serious problem. A window extension algorithm and a resynchronization mechanism are introduced to mitigate the effect of error propagation. In addition, we introduce a soft bit-error-rate stopping rule to reduce computational comp

In this letter, we analyze cluster characteristics in mm wave channel characteristics, based on an indoor channel measurement campaign at 28 GHz. The spatial characteristics of clusters are analyzed, and we investigate the CDFs of the intra cluster angular spreads and the number of clusters. Also we introduce the Random Cluster Number (RCN) feature to the primary module of IMT-2020 channel model,

The overall system performance of massive MIMO is improved by equipping user terminals with multiple antennas. In this paper, we investigate transceiver designs for the case of a single downlink stream and in particular, we study the uplink pilot design. Moreover, we study the consequences of channel estimation errors at the base-station, and to what extent a dual-antenna terminal can get access t

In this paper, we introduce a novel hybrid multiuser multiple-input multiple-output (MU-MIMO) architecture, with an emphasis on aggressive millimeter-wave (mmWave) hardware reduction methods, omitting the beam selection stage. We propose a simplification in a 28 GHz Rotman lens, where the number of beam-ports are reduced relative to the array ports resulting in the removal of a bank of RF switches

Favorable propagation (FP) and channel hardening are desired properties in massive multiple-input and multiple-output (MIMO) systems, where nearly optimal performance is achieved with linear processing techniques, such as maximal-ratio combining. To date, these properties have primarily been analyzed for statistical channel models, or ray-based models with very specific angular parameters and dist

The performance of linear multi-user multiple-input multiple-output (MU-MIMO) systems has been extensively studied for classical statistical channel models. In contrast, there is little analysis for ray-based models, which are physically motivated, feature prominently in standards and have been experimentally validated. Thus, we present a novel analysis framework for zero forcing (ZF) and maximal

At the same time as our dependence on IT systems increases, the number of reports of problems caused by failures of critical IT systems has also increased. Today, almost every societal system or service, e.g., water supply, power supply, transportation, depends on IT systems, and failures of these systems have serious and negative effects on society. In general, public organizations are responsibl

The non line-of-sight (NLOS) scenario in urban intersections is critical in terms of traffic safety—a scenario where Vehicle-to-Vehicle (V2V) communication really can make a difference by enabling communication and detection of vehicles around building corners. A few NLOS V2V channel models exist in the literature but they all have some form of limitation, and therefore further research is need. I

Connected autonomous vehicles and industry 4.0 productions scenarios require ultra-reliable low-latency communication links. The varying positions of transmitter, reflecting objects and receiver cause a non-stationary time- and frequency-selective fading process. In this paper, we present the necessary hardware architecture and signal processing algorithms for a real-time geometry-based channel em

In this paper, we consider a wireless communication system where a large intelligent surface (LIS) is deployed comprising a number of small and distributed LIS-Units. Each LIS-Unit has a separate signal process unit (SPU) and is connected to a central process unit (CPU) that coordinates the behaviors of all the LIS-Units. With such a LIS system, we consider the user assignments both for sum-rate a

The work at hand is a selection of topics in efficient wireless communication system design, with topics logically divided into two groups.One group can be described as hardware designs conscious of their possibilities and limitations. In other words, it is about hardware that chooses its configuration and properties depending on the performance that needs to be delivered and the influence of exte

The performance of baseband beamforming in multi-user multiple-input multiple-output (MU-MIMO) systems has been extensively studied for simplified statistical channel models where no angular parameters are taken into account. In contrast, there is little performance analysis with ray-based models, which are more physically motivated, feature prominently in standardization and have been experimenta