Passive Intermodulation Research Articles

Practical Characterization of the Effect of the Transmission Carrier Phases in Passive Intermodulation

Practical Characterization of the Effect of the Transmission Carrier Phases in Passive Intermodulation

A Novel Passive Intermodulation Model of Coaxial Cable Assemblies With Distributed and Point-Source Nonlinearities

A Novel Passive Intermodulation Model of Coaxial Cable Assemblies With Distributed and Point-Source Nonlinearities

Automated PIM Detection in Wireless Networks via Smart Data-Driven Techniques

As the number of base stations keeps increasing due to ever-growing wireless services and pervasive connectivity, the operational costs for network service providers rises proportionally. In addition, with the evolution of wireless technologies and the development of next generation networks such as 5G and 6G, network operators are inevitably expected to encounter more complex challenges. One such network issue is the Passive Intermodulation (PIM) problem that is observed in both 4G and 5G networks. It degrades the user experience and radio resource efficiency while leading to an operational overhead for detecting and mitigating it on the operator side. Although there is a significant body of work regarding PIM detection and cancellation methods, the majority of such studies depends on hardware solutions and manual investigation by network engineers, which is costly in terms of time and labor. In this paper, we propose two methods using unsupervised and semi-supervised Machine Learning (ML) approaches, namely a time-series-based anomaly detection technique and an autoencoder-based one, for identifying PIM problems in network sites. The proposed solutions utilize a set of Key Performance Indicator (KPI) data of base stations obtained from network management systems for a significantly long time interval and detect possible PIM problems without the need for a human in the loop. We measure and analyze the performance of our solutions, with the guidance of experienced network engineers, on our collected dataset.

Modeling of Spectral Regrowth Effects of Passive Intermodulation With Broadband Signal Excitation

Modeling of Spectral Regrowth Effects of Passive Intermodulation With Broadband Signal Excitation

Testing and Analysis of PIM Performance in a Passive DAS Network - Experimental Approach

Passive intermodulation (PIM) poses a significant challenge in telecommunication networks, with potentially severe impacts on network performance and signal integrity if not addressed during the initial deployment phase. This study investigates PIM levels within a passive distributed antenna system (DAS) network for cellular mobile radio communication across multiple floors of a building. The network comprises coaxial cables, connectors, splitters, combiners, and antennas structured in a systematic plan. This work used the experimental method to test for PIM in the network used for this investigation. Designed as a multicarrier system, it handles RF signals across frequencies of 700/850MHz, 1900MHz, 2100MHz, and 2600MHz. On-site PIM testing was conducted during the network deployment phase to analyze the behavior of high-power RF signals. Utilizing Kaelus iQA-1921C and iQA 850C series PIM analyzers, tests were conducted following known industry codes and standards. High RF power was preset to 43dBm for full band, 35dBm for high bands, and 25dBm for low band. The test equipment was calibrated on high PIM load and low PIM load. Test points were selected at both vertical and horizontal subsystem cabling structures, focusing on riser cables. The standard baseline performance PIM levels was set to -150dBc. The analysis focused on examining the characteristics of PIM signals captured via time-domain PIM traces, investigating the impact of altering the frequency of the two-tone signal on the IM3 frequency component, and highlighting the importance of selecting an appropriate frequency for the two-tone signal that is not positioned near the edges. Results were based on pass or fail test, and resolution measures were taken to mitigate interference.

Passive Intermodulation in Metal-to-Metal Contacts Caused by Tunneling Current

Passive Intermodulation in Metal-to-Metal Contacts Caused by Tunneling Current

Modeling of Passive Intermodulation Induced by Concentrated Current Density in Bent Coaxial Connectors

Modeling of Passive Intermodulation Induced by Concentrated Current Density in Bent Coaxial Connectors

System Residual Noise Reduction for Non-Contact Passive Intermodulation Measurements of Array Antennas Using Multiple Testers

System Residual Noise Reduction for Non-Contact Passive Intermodulation Measurements of Array Antennas Using Multiple Testers

Digital cancellation of multi-band passive inter-modulation based on Wiener-Hammerstein model

Utilizing multi-band and multi-carrier techniques enhances throughput and capacity in Long-Term Evolution (LTE)-Advanced and 5G New Radio (NR) mobile networks. However, these techniques introduce Passive Inter-Modulation (PIM) interference in Frequency-Division Duplexing (FDD) systems. In this paper, a novel multi-band Wiener-Hammerstein model is presented to digitally reconstruct PIM interference signals, thereby achieving effective PIM Cancellation (PIMC) in multi-band scenarios. In the model, transmitted signals are independently processed to simulate Inter-Modulation Distortions (IMDs) and Cross-Modulation Distortions (CMDs). Furthermore, the Finite Impulse Response (FIR) filter, basis function generation, and B-spline function are applied for precise PIM product estimation and generation in multi-band scenarios. Simulations involving 4 carrier components from diverse NR frequency bands at varying transmitting powers validate the feasibility of the model for multi-band PIMC, achieving up to 19 dB in PIMC performance. Compared to other models, this approach offers superior PIMC performance, exceeding them by more than 5 dB in high transmitting power scenarios. Additionally, its lower sampling rate requirement reduces the hardware complexity associated with implementing multi-band PIMC.

Determination of Optimal Sample Length for Passive Intermodulation Measurements in Microstrip Lines with Non-Contact Connections

Determination of Optimal Sample Length for Passive Intermodulation Measurements in Microstrip Lines with Non-Contact Connections

External Passive Intermodulation Suppression by Near-Field Downlink Beamforming

External Passive Intermodulation Suppression by Near-Field Downlink Beamforming

Quantitative analysis of passive intermodulation and surface roughness

AbstractWe explore the relationship between rough surface conductors and the phenomenon of passive intermodulation. The underlying surface is taken to be the boundary of a Lipschitz domain, and a characteristic angle of the domain is used to track boundary dependence on the various fields. To model electro‐thermal passive intermodulation in particular, we consider a specific type of temperature‐dependent conductivity and determine conditions on the conductivity under which one can use fixed point arguments to solve an induction heating and Joule heating problem on a Lipschitz domain. In the latter problem, we also consider a time‐dependent permittivity function . Finally, weak solutions to a magneto‐quasi‐static problem are obtained when the permeability µ is temperature dependent and is allowed to degenerate in a certain way. An interesting effect of the rough surface is the inherently limited Sobolev regularity of the electric field, which can be improved if one assumes additional constraints on the boundary.

A Piecewise Linear Model for Passive Intermodulation Distortion

A Piecewise Linear Model for Passive Intermodulation Distortion

High-Precision Localization of Passive Intermodulation Source in Radio Frequency Transmission Lines Based on Dual-Frequency Signals

With the development of communication technology, the interference from passive intermodulation to the communication system has become increasingly severe. Locating the source of passive intermodulation and then repairing or replacing the device experiencing passive intermodulation is a reliable method. Therefore, this paper proposes a dual-frequency signal localization method based on the principle of phase ranging to accurately locate the passive intermodulation sources in RF cables. This method switches the test signal frequency to obtain the phase of passive intermodulation signals at different frequencies to localize the passive intermodulation source. This paper analyzes the principle of the passive intermodulation localization method based on dual-frequency signals, establishes a localization system for experiments, and finally, analyzes the experimental error to propose an optimization strategy. Through experimental verification, this method can stabilize the positioning error of a passive intermodulation source in a transmission line less than 0.06 m. Meanwhile, this method has high positioning accuracy and the advantages of slight computational complexity, fast positioning speed, and only a small number of requirements on hardware resources. It can work in communication scenarios like satellite and base stations, providing a new technical solution for localizing passive intermodulation interference sources in 5G and 6G communication systems.

Passive Intermodulation on Microstrip Induced by Microstructured Edge

Passive Intermodulation on Microstrip Induced by Microstructured Edge

Full-Wave Simulation of Contact-Nonlinearity-Induced Passive Intermodulation Using a Nonlinear Interface Boundary Model

Full-Wave Simulation of Contact-Nonlinearity-Induced Passive Intermodulation Using a Nonlinear Interface Boundary Model

Modeling of Passive Intermodulation in Coaxial Connectors With Ideal and Nonideal Contacts

Modeling of Passive Intermodulation in Coaxial Connectors With Ideal and Nonideal Contacts

Practical Determination of Passive Intermodulation From Modulated Signals in Satellite Applications

Practical Determination of Passive Intermodulation From Modulated Signals in Satellite Applications

Phase Effects on Combined Passive Intermodulation From Multiple Sources

Phase Effects on Combined Passive Intermodulation From Multiple Sources

Novel Coupling Coaxial Adapter for Portable Passive Intermodulation Test of Coaxial Cable

Novel Coupling Coaxial Adapter for Portable Passive Intermodulation Test of Coaxial Cable