Guard Band Research Articles

Determination of Total Sulfur Content in Fuels: A Comprehensive and Metrological Review Focusing on Compliance Assessment.

Sulfur-containing compounds are naturally found in crude oil, and they can be partially removed during the refining process. The wide use of fossil fuels has a significant contribution to sulfur emissions into the atmosphere, and Governments are striving to reduce the amount of the fuels by environmental regulations. The reduction of sulfur levels in diesel and other transportation fuels is beneficial from economic and environmental points, but meeting this standard represents a major operational and economic challenge for the oil and gas industry. Quantitative measurement of the sulfur amount must be taken along the oil refining chains guided by standards of measurement and recommended analytical methods such as various American Society for Testing and Materials methods (ASTM D2622, ASTM D5453, ASTM D7039, and ASTM D7220). Advancement in the refining processes and environmental regulations also require reliable measurements and well-defined criteria for compliance assessment. This work presented a brief review of the ASTM Standards used in the laboratories of the Brazilian oil and gas industry to determine the total sulfur content in fuels. We also presented an approach based on the reproducibility of the measurement methods and the guard band concept to evaluate the conformity statement.

Metamaterial inspired electromagnetic bandgap filter for ultra-wide stopband screening devices of electromagnetic interference

Presented here is a reactively loaded microstrip transmission line that exhibit an ultra-wide bandgap. The reactive loading is periodically distributed along the transmission line, which is electromagnetically coupled. The reactive load consists of a circular shaped patch which is converted to a metamaterial structure by embedded on it two concentric slit-rings. The patch is connected to the ground plane with a via-hole. The resulting structure exhibits electromagnetic bandgap (EBG) properties. The size and gap between the slit-rings dictate the magnitude of the reactive loading. The structure was first theoretically modelled to gain insight of the characterizing parameters. The equivalent circuit was verified using a full-wave 3D electromagnetic (EM) solver. The measured results show the proposed EBG structure has a highly sharp 3-dB skirt and a very wide bandgap, which is substantially larger than any EBG structure reported to date. The bandgap rejection of the single EBG unit-cell is better than − 30 dB, and the five element EBG unit-cell is better than − 90 dB. The innovation can be used in various applications such as biomedical applications that are requiring sharp roll-off rates and high stopband rejection thus enabling efficient use of the EM spectrum. This can reduce guard band and thereby increase the channel capacity of wireless systems.

Spectrally stitched WDM nonlinear frequency division multiplexed transmission system

We present the concept and design of a 100 GHz PIC-based nonlinear frequency division multiplexed transmission system in which four b-modulated spectrally overlapping channels are spectrally stitched without frequency guard bands to obtain a continuous spectrum. Neural network-based equalizers are used at the receiver for improved performance. Simulations show that the proposed system alleviates the problem of nonlinear interaction between neighboring channels, that would, otherwise, be out of reach even for neural network equalization to solve on its own. The system achieves a 960 km transmission distance with a raw data rate of 333 Gbps per polarization and a BER well below the SD-FEC limit for every subcarrier.

Inter-Numerology Interference in Mixed Numerology OFDM Systems in Time-Varying Fading Channels With Phase Noise

Mixed numerology has been adopted in the orthogonal frequency division multiplexing-based physical layer of 5G new radio (NR) to serve diverse use cases and services. Since the subcarriers of different numerologies have different bandwidths and symbol durations, they interfere with each other despite being centered at different frequencies. We analyze the inter-numerology interference (INI) encountered by these systems in wideband time-varying channels in the presence of phase noise. We derive novel expressions for the fading-averaged INI power at each subcarrier as a function of the channel’s power delay profile. These lead to insightful, tight bounds for the bandwidth-averaged INI power, which bring out the combined impact of Doppler spread and phase noise. Our comprehensive approach applies to the entire family of numerologies of 5G NR, and accounts for partial subcarrier loading, guard bands, and non-line-of-sight and line-of-sight channels. Our results show that INI affects high-rate modulation and coding schemes (MCSs). To mitigate its impact, we propose a novel statistical square root power allocation scheme that exploits the variation in the average INI powers across the subcarriers. It achieves a lower block error rate than uniform power allocation, which is used in 5G NR.

Metrics Related to Confusion Matrix as Tools for Conformity Assessment Decisions

Conformity assessment refers to activities undertaken to check whether some product, service or process meets certain criteria and specifications given by internationally accepted standards. The decision on whether a property of interest is aligned with the set standards is made based on measurement. However, uncertainty associated with the measurement results may lead to incorrect decisions. Measurement results may be falsely rejected as non-conforming, although they meet specifications. This is referred to as the producer’s risk. If the measurement result that does not meet the required specifications is accepted as conforming, this is referred to as the consumer’s risk. This paper covers calculations of global consumer's and producer's risk using the Bayesian approach and deals with the application of metrics related to confusion matrices in conformity assessments. These techniques have been used to assess the conformity of the bearing ring diameter with the given specifications. Based on the behavior of these metrics, the optimal length of the guard band was determined with the aim of minimizing the global consumer’s and producer’s risk.

Increasing the power and spectral efficiencies of an OFDM-based VLC system through multi-objective optimization.

The nonlinearity induced by light-emitting diodes in visible light communication (VLC) systems presents a challenge to the parametrization of orthogonal frequency division multiplexing (OFDM). The goal of the multi-objective optimization problem presented in this study is to maximize the transmitted power (superimposed LED bias-current and signal amplification) for both conventional and constant envelope (CE) OFDM while also maximizing spectral efficiency. The bit error rate (BER) metric is used to evaluate the optimization using the non-dominated sorting genetic algorithm II. Simulation results show that for a BER of 1×10-3, the signal-to-noise ratio (SNR) required decreases with the guard band due to intermodulation distortions. In contrast to SNR values of approximately 13 and 25dB achieved by traditional OFDM-based systems, the VLC system with CE signals achieves a guard band of 6% of the signal bandwidth with required SNR values of approximately 10.8 and 24dB for 4-quadrature amplitude modulation (QAM) and 16-QAM modulation orders, respectively.

Demonstration of Turbulence-Resilient Self-Homodyne 12-Gbit/s 16-QAM Free-Space Optical Communications Using a Transmitted Pilot Tone

Free-space optical (FSO) communication links can benefit from recovering both amplitude- and phase-encoded data (e.g., quadrature-amplitude-modulation, QAM) by mixing a local oscillator (LO) with a received data beam in a coherent detector. However, atmospheric turbulence can cause power coupling from a fundamental Gaussian mode of the data beam to higher-order modes, resulting in a significantly degraded mixing efficiency between the data and a fundamental Gaussian LO. Previously, a turbulence-resilient pilot-assisted self-coherent FSO QAM link has been demonstrated by transmitting a frequency-offset Gaussian pilot beam along with the Gaussian data beam. The pilot and data beams experienced similar modal coupling and thus can efficiently mix in a self-heterodyne detector. However, a frequency guard band was used to avoid signal-signal beating interference, thereby reducing the utilization efficiency of the detector's bandwidth. To increase the detector's bandwidth utilization, we experimentally demonstrate in this paper a turbulence-resilient 12-Gbit/s 16-QAM FSO link using pilot-assisted self-homodyne detection. The pilot beam is located at the same center optical frequency as the data channel but on an orthogonal polarization. At the receiver, we utilize self-homodyne detection to achieve the efficient mixing of the data and pilot. Compared to self-heterodyne, our approach has ∼2X the utilization efficiency of the detector's bandwidth. Compared to conventional LO-based coherent (homodyne or intradyne) detection, the pilot-assisted self-homodyne link shows up to ∼20-dB improvement of optical-to-electrical mixing efficiency under a turbulence strength of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$2{{\bm{w}}}_0/{\bm{\ }}{{\bm{r}}}_0 = \ \sim 7.5$</tex-math></inline-formula> . The turbulence resilience of the link is demonstrated with a bit-error rate below the 7% forward error correction limit for 400 different turbulence realizations.

Laser Sharing Uplink Polarization Division Multiplexing FBMC Passive Optical Network

In this paper, we proposed and experimentally demonstrated a laser sharing filter bank multicarrier passive optical network (FBMC-PON) uplink architecture, to provide high spectrum efficiency frequency division multiple access (FDMA) to the optical network terminals (ONTs) with aggregated uplink data rate of up to 100 Gb/s/λ for each optical network unit (ONU), in a fiber to the frontage (FTTF) scenario utilizing existing copper infrastructure. Intensity modulation (IM) and heterodyne detection are implemented, combined with polarization division multiplexing (PDM) to double the system capacity. The uplink performance of FBMC-PON is emulated with two asynchronous ONT bands in transmission over 20 km single mode fiber (SMF). FBMC with prototype filters (PFs) PHYDYAS, extended Gaussian filter (EGF) and isotropic orthogonal transform algorithm (IOTA) is discussed in comparison with orthogonal frequency division multiplexing (OFDM) in terms of frequency guard band and multiple access interference (MAI). The laser from an external cavity laser (ECL) is split and shared among ONTs. The experimental results show that FBMC can achieve significant improved receiver sensitivity compared to OFDM in the asynchronous uplink. FBMC with PHYDYAS can avoid MAI with frequency guard interval of one time the subcarrier spacing. With optical receiving power (ROP) of −23 dBm, to support 2, 4 and 8 ONTs, the required optical power of the narrow linewidth laser is respectively 10, 16 and 22 dBm with bit error rate (BER) at the hard decision forward error correction (HD-FEC) threshold.

A Max-Min Scheduling Algorithm Based on TAS Mechanism

In order to solve the problem of too many guard bands and gate control lists (GCL) caused by time triggered (TT) flow scheduling per flow, this paper proposes a maximum minimum cycle scheduling algorithm based on time aware shaping (TAS) mechanism. At the same time, a period shift algorithm is proposed to overcome the excessive super period of TT flow. The results show that compared with the conventional scheduling methods, this method can ensure the deterministic transmission requirements of TT flows, and reduce the number of protection bands and GCLs.

Guard band protection for coexistence of 5G base stations and satellite earth stations

In this paper, the coexistence between fifth generation (5G) network and fixed satellite service (FSS) is investigated. To reduce the interference between 5G base stations (BSs) and FSS earth station (ES), a guard band protection method is proposed. Additionally, the distance and angular protection methods are amalgamated. The performances are evaluated by simulation in realistic 3GPP. Also, the impacts of four antenna types are analysed for a 5G BS. The numerical results show that the guard band protection can solve the interference for the 5G/FSS coexistence, when the distance protection is combined. In addition, when the hybrid protection method is employed, the coexistence between 5G BS and FSS ES is guaranteed.

Determining the Zero-Temperature-Coefficient Point From Device Simulation to Circuit for Improving Temperature Variation Immunity

Thermal issue emerges as one of the critical reliability concerns in integrated circuit design, especially for advanced technology. To improve the temperature immunity and reduce the thermal-related timing guard bands in digital circuits, in this work, we offer a new insight into the zero-temperature-coefficient (ZTC) based design strategy featuring minimizing the temperature-induced delay variation. An effective current-based method to facilitate the ZTC point ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${V}_{\text {ZTC}}$ </tex-math></inline-formula> ) determination for standard cells is developed, which is demonstrated on advanced gate-all-around (GAA) nanosheet (NS) FETs from 300 to 425 K using the calibrated TCAD simulation. The <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${V}_{\text {ZTC}}$ </tex-math></inline-formula> dependencies on the signal input slew rate, output capacitance, and self-heating effects (SHEs) are further investigated from the perspective of the effective current by tracing the voltage trajectory. The mixed-mode TCAD simulation results show that the frequency variation of ring oscillator (RO) reduces nearly ten times when operating near <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${V}_{\text {ZTC}}$ </tex-math></inline-formula> and great power-performance trade-offs can also be achieved. The <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${V}_{\text {ZTC}}$ </tex-math></inline-formula> determination for standard cells combined with the compensation effect among different standard cells benefits selecting the optimal zero-temperature-delay (ZTD) point in the target path, thereby helping to implement a robust digital design against temperature variation.

Time Domain Analysis of NB-IoT Signals

The NB-IoT (NarrowBand-Internet of Things) radio technology is now widely implemented by mobile phone network operators to support the communication of IoT devices such as smart meters, insurance black boxes for cars, network connected waste bins, smart bicycles. In the present work, some LTE800 cells of different mobile phone network operators implementing the NB-IoT technology in the guard band mode have been investigated. The signals, consisting of a PRB (Physical Resource Block) 180 kHz wide, have been analyzed and characterized in the time domain by means of a narrow band instrumental chain equipped with a Rohde &amp; Schwarz FSH8 spectrum analyzer. Time domain analysis allows us to identify, within the transmission frame, the position of the NB-IoT signaling channels such as the Narrowband Reference Signal (NRS), the primary (NPSS) and secondary (NSSS) synchronization signals and the broadcast channel (NPBCH), but, above all, to measure the power received during the transmission of the NRS. This value has been compared with that measured by the NB-IoT decoding module supplied on the same analyzer, in order to verify the equivalence of these measurement methods. This would allow use of a more diffuse and cheaper instrumentation rather than more expensive vector analyzers, currently required to assess electric fields due to the NB-IoT signals through the extrapolation techniques set by Italian CEI 211-7/E technical standard.

Urine concentrations of vilanterol and its metabolites, GSK932009 and GW630200, after inhalation of therapeutic and supratherapeutic doses.

The 2023 Prohibited List issued by the World Anti-Doping Agency (WADA) permits athletes to inhale the beta2 -agonist vilanterol at a standard dose of 25 μg daily. However, given limited data on urine pharmacokinetics, vilanterol has no urinary threshold or decision limit to discriminate therapeutic from supratherapeutic use. We investigated urine concentrations of vilanterol and its main metabolites GSK932009 and GW630200 over 0-72 h following inhalation of therapeutic (25 μg) or supratherapeutic (100 μg) doses and repeat-dose administration for 7 days of 25 or 100 μg·day-1 in 25 trained men and women. Vilanterol administration was followed by 1 h of exercise. GW630200 urine concentrations were low and insufficient for threshold purposes, and while GSK932009 had higher urine concentrations, it could not discriminate between therapeutic and supratherapeutic use. Mean (range) maximum urine concentrations of parent vilanterol were 1.2 (0.2-4.1) and 6.2 (1.4-14.3)ng·ml-1 for single-dose 25 and 100 μg vilanterol, respectively, and 2.0 (0.3-4.8) and 22.4 (6.4-42.1)ng·ml-1 for repeat-dose 25 and 100 μg·day-1 vilanterol. In 333 samples collected 6 h post-administration and considering WADA TD2022DL, a 3.1 ng·ml-1 vilanterol cut-off showed 30% sensitivity in detecting supratherapeutic use at 100 μg versus therapeutic use at 25 μg. Considering inter- and intra-individual variability and guard bands in doping analysis, a 6 ng·ml-1 decision limit, which could be shifted upwards in samples with specific gravity >1.018, appears sufficiently high to minimize risk of samples exceeding the decision limit after therapeutic use of vilanterol, while demonstrating the ability to detect supratherapeutic use at 100 μg.

Ultra-wideband discrete Raman amplifier optimization for single-span S-C-L-band coherent transmission systems.

We experimentally compare the performance of two key ultra-wideband discrete Raman amplifier structures, a cascaded dual-stage structure and an in-parallel dual-band structure, in fully loaded S-C-L band coherent transmission systems over 70 km of single-mode fiber. Our results show that dual-band discrete Raman amplifier with minimized backreflections can effectively avoid unstable random distributed feedback lasing, reduce the noise figure, and therefore improve the transmission performance for signals at shorter wavelengths, versus the cascaded dual-stage structure. The average noise figure for S-band signals is 6.8 dB and 7.2 dB for the dual-band structure and cascaded dual-stage structure, respectively, while the average S-band Q2 factor is similarly improved by 0.6 dB. Moreover, the cascaded dual-stage discrete Raman amplifier requires guard bands around the 1485-nm and 1508-nm pumps as the signal and pump wavelengths overlap, which results in a bandwidth loss of ∼10 nm and reduces the potential net data throughput to 28.6 Tb/s for 30-GBaud DP-16QAM signals. However, the dual-band structure can utilize the bandwidth more effectively, which leads to a higher estimated net data throughput of 31.2 Tb/s.

Spectral Efficiency of OTFS Based Orthogonal Multiple Access With Rectangular Pulses

In this paper, we consider Orthogonal Time Frequency Space (OTFS) modulation based multiple-access (MA). We specifically consider Orthogonal MA methods (OMA) where the user terminals (UTs) are allocated non-overlapping physical resource in the delay-Doppler (DD) and/or time-frequency (TF) domain. Well known OMA methods include, i) Guard Band (GB) based MA (GBMA), ii) Interleaved Delay Doppler MA (IDDMA), iii) Interleaved Time Frequency MA (ITFMA). The spectral efficiency (SE) performance of these OMA methods has <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">only</i> been studied for <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ideal</i> transmit and receive pulses. <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">With ideal pulses</i> , IDDMA and ITFMA are free from multi-user interference (MUI) and unlike GBMA they <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">do not</i> use guard bands in the DD/TF domain. Since ideal pulses are not realizable, in this paper we study the SE performance of these OMA methods with <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">practical rectangular pulses</i> . For these OMA methods, we derive the expression for the received DD/TF domain symbols at the base station (BS) receiver and the effective DD domain channel matrix when rectangular pulses are used. Study of these expressions reveals the presence of MUI when rectangular pulses are used, although the amount of MUI in IDDMA is observed to be significantly smaller than that in ITFMA. We also derive the expression for the achievable sum SE. Through simulations, for practical values of the received signal-to-noise ratio, we observe that with rectangular pulses the sum SE achieved by the IDDMA method is significantly higher than that achieved by the ITFMA and GBMA methods.

Optimal Embedding of Heterogeneous RAN Slices for Secure and Technology-Agnostic RANaaS

A key challenge related to Radio Access Network (RAN) slicing is deciding how to efficiently map radio resources from the physical radio to realise RAN slices, known as the virtual wireless network embedding problem. To the best of our knowledge, this is the first paper to model and derive an analytical solution for embedding heterogeneous RAN slices with different waveforms, numerologies and Radio Access Technologies (RATs) with resources isolated down to the Physical (PHY) layer, ultimately enabling secure technology-agnostic RAN as a Service (RANaaS). First, we assess how current virtual wireless network embedding solutions model the allocation of radio resources to realise RAN slices. Then, we propose a graph-based model for embedding heterogeneous RAN slices that considers the guard bands required to ensure isolation in the frequency domain. This approach is transparent to the type and granularity of radio resources of each RAN slice, and can be extended to support RAN slices with new waveforms, numerologies and RATs. Next, we introduce a resource management optimisation problem solved at the Network Provider (NP) to determine the optimal embedding of RAN slices that maximises the total useful bandwidth occupied by tenants; and we propose three different heuristic algorithms to obtain solutions in near real-time. We compare their performance against the analytical solution using different metrics, and our results show that the best heuristic depends on the NP’s business model, e.g., using the Greedy Algorithm (GA) to increase resource utilisation or the Nearest Neighbour Algorithm (NNA) to increase the number of allocated RAN slices.

Dual-Carrier-Assisted Phase Retrieval for Polarization Division Multiplexing

Phase retrieval (PR) schemes based on modified Gerchberg-Saxton (GS) algorithm using pilot symbol or pilot tone have recently attracted great attentions in self-coherent systems. In this work, we propose a dual-carrier-assisted phase retrieval (D-CAPR) algorithm and further fulfill a dual-polarization carrier-assisted PR (DP-CAPR) scheme. The polarization diversity is realized by transmitting a polarization-division-multiplexed (PDM) signal with orthogonal offset carriers, and the dual-polarization optical fields are recovered by the proposed D-CAPR algorithm. The D-CAPR scheme is able to directly retrieve the phases of optical field given the prior phase information of two carriers on each polarization without the use of any frequency guard band. We numerically characterize the performance of proposed DP-CAPR and experimentally demonstrate it for 30 GBaud dual-polarization-32-ary quadrature amplitude modulation (DP-32-QAM) transmission over 80 km single-mode fiber. The impacts of polarization rotation, polarization mode dispersion, and electrical noise on DP-CAPR have been investigated. Moreover, we compare the electrical bandwidth requirement, optical signal-to-noise ratio (OSNR) sensitivity, and hardware complexity of the DP-CAPR scheme with previously reported DP field recovery schemes.

Compliance assessment when radioactive discharges are close to exemption levels in nuclear medicine facilities

Nuclear Medicine has applied radiopharmaceuticals to diagnose and treat several diseases for decades. The decay of the radionuclide inserted in the drug needs to be monitored and controlled to avoid unnecessary impact on the environment, as well as on the general public. Gamma-ray spectrometry is the technique usually selected to identify and quantify these gamma emitters radionuclides. When radionuclides' active concentrations are close to upper limit specifications, doubts are raised about whether they meet the regulatory body's definitions. A different and innovative approach to assessing compliance in these situations is the use of guard band, interval between the boundary and the end of the acceptance zone. The study presented aimed the evaluation of the guard bands' effect on the disposal limits of some radionuclides commonly used in a medical facility. A relatively small increase in the activity concentration could be observed when the guard bands approach was used for the detector's uncertainty. However, these values can be used when activity concentrations are on the boundary of the exemption level. According to the results achieved with this study, guard bands can be seen as an alternative approach to the current one that do not use an in-depth metrological study. For the biota study, and under the described conditions, it was verified that the guard band approach did not show significant damage.

Design and Study of the Performance of Patch Antenna with Double C Slot for MIMO-OFDM Based Communications Systems for Media Technology

Mobile phones, server stacks, and other high-bitrate devices demand greater bandwidth from antennas. More bandwidth means higher bitrates and more data sent. MIMO antennas simultaneously deliver and receive data. MIMO antennas can broadcast data to unreachable places with little noise. Multiple data streams and multipath propagation boost performance and data quality. Many antennas allow MIMO systems to send and receive data at regular intervals. These antennas can perform beamforming and determine a signal's 3-D route. OFDM increases bitrates at the same frequency by multiplexing without guard bands. Multiple orthogonal carrier frequencies increase data in the same bandwidth and avoid carrier distortion. Air gaps, parasitic patches, and substrate modifications are methods to increase bandwidth and beam width for patch antennas. The conventional patch pattern has been modified and refined for maximum success. This article proposes a patch antenna with double C slots. This new design features a large bandwidth, wide beamwidth, and multidirectional transmission pattern. The gain, VSWR, and reflection coefficient of this patch antenna meets the MIMO-OFDM systems with 5G standard. Hence the proposed antenna design is recommended to employ in the MIMO-OFDM system for 5G applications.

Quality control of lifetime drift effects

Electrical parameters of semiconductor devices are specified in their product data sheets. These parameters have to stay within their specified ranges over lifetime. The lifetimes of semiconductor devices are simulated by accelerated stress tests. In the course of these stress tests, electrical parameters are checked for any change in their values. This change can occur at semiconductor devices and is called lifetime drift. In order to avoid that electrical parameters drift out of their specified limits, the devices are tested with tighter limits at the end of the production line. These limits are referred to as test limits. The differences between test limits and specification limits are called guard bands. Guard bands are optimized to reduce yield losses and ensure compliance with the product data sheets over lifetime.In this paper, a simplified lifetime drift model for continuous electrical parameters is introduced. The drift calculation is faster compared to existing models, requires less memory resources, and is suitable for edge devices. It is tailored to the needs of semiconductor manufacturers and their development and production flows. It considers additional information on the stress test data. With this model, one can detect and quantify lifetime drift, calculate typical drift patterns, and optimize guard bands based on quality targets. Thus, this model enables fast, efficient, and accurate calculations of test limits.