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We use the received bit information rate (RBIR) to analyze the performance of multi-layer transmission when combined with hybrid automatic repeat request (HARQ). The different layers are obtained from ordinary Gray-coded M-QAM and used for transmitting log2(M) codewords in parallel, exploiting that the different bits in Gray-coded M-QAM have very different reliability. The performance is analyzed
Stereo 3D video from surgical procedures can be highly valuable for medical education and improve clinical communication. But access to the operating room and the surgical field is restricted. It is a sterile environment, and the physical space is crowded with surgical staff and technical equipment. In this setting, unobscured capture and realistic reproduction of the surgical procedures are diffi
Typical massive multiple-input multiple-output (MIMO) architectures consider a centralized approach, in which all baseband data received by each antenna has to be sent to a central processing unit (CPU) to be processed. Due to the enormous amount of antennas expected in massive MIMO base stations (BSs), the number of connections to the CPU required in centralized massive MIMO is not scalable. In r
This work presents an approach for radio-based localization in non-line-of-sight (NLOS) environments by leveraging a dual-polarization antenna array. By estimating the polarization of the received signal, it is possible to estimate the angle of reflection of a NLOS signal. An estimate of the position of the transmitter concerning the receiver can be obtained based on a joint estimation of the refl
Context: Continuous experimentation and A/B testing is an established industry practice that has been researched for more than 10 years. Our aim is to synthesize the conducted research. Objective: We wanted to find the core constituents of a framework for continuous experimentation and the solutions that are applied within the field. Finally, we were interested in the challenges and benefits repor
Context. Continuous experimentation is used by many companies to improve their products with users data. In this study, the efficacy of continuous experimentation as used in two different types of business models (product-led or sales-led). Method. Two case companies with a product-led business model and three companies with sales-led business model were compared against each other. 14 interviewee
In this paper we consider spatial coupling in turbo equalization and demonstrate that the code design trade-off between the performance in waterfall and error floor regions can be avoided. We introduce three coupling schemes and compare their performances, where the first method introduces coupling between the encoder and the channel, while the second uses a spatially coupled (SC) code. In the thi
Testing of autonomous systems is extremely important as many of them are both safety-critical and security-critical. The architecture and mechanism of such systems are fundamentally different from traditional control software, which appears to operate in more structured environments and are explicitly instructed according to the system design and implementation. To gain a better understanding of a
We present a localization algorithm for low-power long-range Internet-of-things (IoT) networks, which exploits angle of arrival (AoA) and range information from non-coherent received signal strength (RSS) measurements. In this work, each anchor node is equipped with array antennas of known geometry and radiation patterns. The position of the target node and the path-loss exponent to each anchor ar
We present a belief propagation (BP) algorithm with probabilistic data association (DA) for detection and tracking of specular multipath components (MPCs). In real dynamic measurement scenarios, the number of MPCs reflected from visible geometric features, the MPC dispersion parameters, and the number of false alarm contributions are unknown and time-varying. We develop a Bayesian model for specul
Industrial cyber-physical system products interleave hardware, software, and communication components. System complexity is increasing simultaneously with increased demands on quality and shortened time-to-market. To effectively support the development of such systems, we present languages and tools for comprehensive integrated model-based development that cover major phases such as requirement an
This letter proposes a two-port MIMO smartphone antenna for frequency bands below 1 GHz, which is robust to user effects. The design is achieved by first analyzing the characteristic modes of a chassis that includes the large screen. Two modes predicted to be less affected by the user than other commonly used modes are selected. The modal currents and near-fields of the two desired modes then guid
Generalized low-density parity-check (GLDPC) codes are a class of LDPC codes in which the standard single parity check (SPC) constraints are replaced by constraints defined by a linear block code. These stronger constraints typically result in improved error floor performance, due to better minimum distance and trapping set properties, at a cost of some increased decoding complexity. In this paper
Internet-of-Things (IoT) systems consist of spatially distributed interacting devices. In contrast to desktop applications, IoT systems are always running and need to deal with unresponsive devices and weak connectivity. In this thesis, we propose techniques for simplifying the development of such systems. The work addresses IoT systems organised as reusable services connected by compositions. We
Efficient mitigation of power amplifier (PA) nonlinear distortion in multi-user hybrid precoding based broadband mmWave systems is an open research problem. In this article, we carry out detailed signal and distortion modeling in broadband multi-user hybrid MIMO systems, with a bank of nonlinear PAs in each subarray, while also take the inevitable crosstalk between the antenna/PA branches into acc
Multiple-input multiple-output (MIMO) is a key enabler for high data rates in mobile communications. However, it is challenging to design MIMO terminal antennas for LTE bands below 1 GHz, due to the conventional chassis offering only one resonant characteristic mode (CM). Recently, it was shown that minor structural changes can yield up to two additional resonant modes for designing two-port MIMO
We introduce a novel design of spatially coupled low density parity check codes in order to reduce the effects of error propagation in low-latency sliding window decoding for large frame lengths or streaming applications. Specifically, we employ reduced-degree check nodes spaced throughout the coupling chain, which have the effect of allowing the decoder to recover from error bursts. A simplified
In this paper, we introduce two new methods of mit- igating decoder error propagation for low-latency sliding window decoding (SWD) of spatially coupled low-density parity-check (SC- LDPC) codes. Building on the recently introduced idea of check node (CN) doping of regular SC-LDPC codes, here we employ variable node (VN) doping to fix (set to a known value) a subset of variable nodes in the coupli
