Data Link Research Articles

IF NOT, ELSE: STANDARDS, PROTOCOLS, NETWORKS AND HOW THEY MAKE A DIFFERENCE

The contemporary Internet's "network of networks" has become infrastructural to our lives. The Internet is a stack of physical, data link, network, transport, and application layers which all have unique rules and roles. While many see Internet infrastructure as a foregone conclusion, Paris, Cath and Myers West (2023) write “Internet infrastructure is built slowly, over time, protocol by protocol, in response to many different technical, social, political, environmental, and economic imperatives”. Even as the particular model of the Internet we are all accustomed to has become the standard, other attempts proliferated and eventually failed, as did the Soviet Internet (Peters 2016), and as this panel highlights, the Internet is still ever-evolving. The project of this panel is to trace alternative, parallel, and emergent network models, standards and protocols, theorize their impact as they appear in different places, spaces, and contexts, and gesture towards how the Internet might be different. As critical internet studies have since the early 2000s shown, computational standards, protocols, and network diagrams are more than technical details, they have the power to shape and structure the conditions for our socio-cultural lifeworlds (Galloway 2006; Chun 2008; Bratton 2016). As Gehl (2014) puts it: “interfaces, database structures, mechanisms of connection all shape social activities”. Change an element in the stack and a different connectivity, a different future becomes possible. The papers of this panel introduce and discuss five different and potentially revolutionary network technologies that manage and organize our online lives. The first paper represents a media genealogy of ActivityPub – a protocol that enables the Fediverse, a collection of social media sites that can communicate with one another. The author argues that ActivityPub was not produced through an instrumental process, but was the result of accidents and coincidences. The accidental nature of the protocol, coupled with its being authored by self-identified queer and trans developers, has put it on a collision course with both the “standard” approach to standards production as well as mainstream, corporate social media. The second paper focuses on the design of the Interplanetary Internet and the idea of delay-tolerant networking fundamental to operating in outer space. The author maintains that when delays are central to a network model, we are forced to rethink how our connections are maintained and organized in the future. Delay-tolerant networking is thus not only a technical solution for a communications system but a control protocol through which interplanetary life can be managed. The third paper is also focused on the temporality of networks. The third paper examines how time is enacted as a design ideology in the course of the development of a future internet architecture protocol project: named data networking (NDN). This work locates aspects of the sociomateriality of time in the processes of building Internet infrastructure and demonstrates how it binds together cultural, economic, and discursive power. The paper argues that thinking through time as a design ideology can be useful in projects imagining how the Internet might be built to engender and support different values than market ideology. The fourth paper is about the organizational culture of the Internet Engineering Task Force (IETF), a key internet standards and protocol organization. The paper argues that the organization is guided by a culturally inflected anti-political engineering ethos, whose depoliticizing tendencies hampers the organization’s functioning and its ability to rise above narrow industry-interest and pursue a public interest internet. The fifth paper looks to the Crypto Wars of the 1990s as a moment where things could have been otherwise; comparing the examples of PGP and RSA encryption software and how they shaped the nature of our networked systems. It argues that a combination of regulatory and commercial interests influenced the development and use of cryptography in ways that facilitated the development of e-commerce, but left private messaging in dubious legal status. Collectively the papers investigate alternative and emergent trends behind the Internet and its network models, standards, and protocols. The protocols and rules for network connection, standards bodies, and modes of governance are critical to maintaining and upkeeping a network. Their impact, however, is not merely technical but potentially world-changing. The papers direct their critical gaze towards the development of these technologies and what their introduction to our world potentially entails. By focusing on projects of past, present, and future and by exploring the Internet’s deepest sociotechnical layers, the panel critically dismantles the commonly-held idea that the Internet is a monolith and illustrates that the history of the Internet is still being written.

The Use of Technology as the Indonesia's Strategy to Counter China's Gray Zone Operations in the North Natuna Sea

Ever since the end of World War II, the Republic of China (ROC), led by the Kuomintang Party and continued by the People’s Republic of China (PRC) led by the Communist Party, with its Eleven Dash Line (EDL), has claimed almost 90% of the South China Sea (SCS) waters, including the Spratly Islands, Paracel Islands, and all sea structures in that area. In 1953, the EDL was renamed to the Nine Dash Line (NDL) because China gave the area of the Tonkin Gulf to North Vietnam, led by Ho Chi Minh, which was still at war against the French and South Vietnam. China’s NDL claim has overlapped with Brunei’s claim, specifically Louisa Reef located on its continental shelf, Malaysia’s claim covering a portion of SCS in northern Kalimantan (Borneo), which includes at least 12 maritime structures in the Spratly Islands, among others, the coral reefs Swallow, Adraiser, and Marivelles. Additionally, the Philippines' claim includes the northernmost part of the Spratly Islands and Scarborough Shoal, known as Kalayaan in the Philippines. Vietnam's claim encompasses the Paracel and Spratly Islands, including 25 rock and sand formations and islands such as Spratly Island, Namyit Island, and Barque Canada Reef. The overlapping claims, which also occurred between Brunei and Vietnam, Malaysia and the Philippines, and Malaysia and Vietnam, have increased tension and incidents in the SCS, particularly between the Philippines, Malaysia, Vietnam against China due to China’s actions forcefully imposing its claim. This has made the situation more complex and fragile, leading the international community to term the overlapping claims as the South China Sea (SCS) Dispute. has no claim in the SCS, and no other country has a claim over Indonesia. However, in 2009, when China registered its new map of NDL claim with the United Nations (UN), it included part of Indonesia’s Exclusive Economic Zone (EEZ) in the North Natuna Sea (NNS). The UN rejected this claim since it was not based on international law, particularly the United Nations Convention on the Law of the Sea (UNCLOS 1982). Indonesia firmly denied that claim as it goes against Indonesia’s law and UNCLOS 1982. Due to increasing Chinese actions in imposing its claim on part of the IEEZ in the NNS, including Gray Zone Operations (GZO) maneuvers, Indonesia has risen to defend its sovereign rights in the NNS. According to UNCLOS 1982, in the IEEZ at the NNS, as a coastal state, Indonesia "has sovereign rights for the purpose of exploring and exploiting, conserving and managing the natural resources, whether living or non-living resources, of the waters superjacent to the sea-bed and off the sea bed and its subsoil, and with regard to other activities for the economic exploitation and exploration of the zone such as the production of energy from water, currents, and winds" (Article 56; 1 a). To overcome any disturbance and threat toward Indonesia’s sovereign rights in its EEZ in the NNS, Indonesia needs to convince China to nullify its IEEZ NNS’ claim. Indonesia needs to launch total diplomacy toward China, including cultural diplomacy, economic diplomacy, and defense diplomacy combined with and supported by defense capability. In this regard, Indonesia should increase its defense capability, particularly in the NNS, to guard the works, personnel, and equipment of the activities of natural resources exploration and exploitation. The enlargement of defense capability, including the quality and quantity of equipment and weaponry such as patrol boats, troopships, warships, hunter jets, fighter jets, radar systems, and Geographic Information Systems (GIS), should be done by optimizing the use of advanced technology. Determining the performance strategy, as well as the use of technology and interoperability systems in developing the defense equipment platform, information and communications technology such as Big Data and Data Links, can be a solution to increase and integrate the defense system, capability, and operational implementation. In this case, particularly by the Indonesia Navy and Air Force, by integrating various defense equipment owned and used. This study provides a comprehensive analysis of Indonesia’s strategy to counter China’s Gray Zone Operations in the North Natuna Sea.

MSdeCIpher: A Tool to Link Data from Complementary Ionization Techniques in High-Resolution GC-MS to Identify Molecular Ions.

Electron ionization (EI) and molecular ion-generating techniques like chemical ionization (CI) are complementary ionization methods in gas chromatography (GC)-mass spectrometry (MS). However, manual curation effort and expert knowledge are required to correctly assign molecular ions to fragment spectra. MSdeCIpher is a software tool that enables the combination of two separate datasets from fragment-rich spectra, like EI-spectra, and soft ionization spectra containing molecular ion candidates. Using high-resolution GC-MS data, it identifies and assigns molecular ions based on retention time matching, user-defined adduct/neutral loss criteria, and sum formula matching. To our knowledge, no other freely available or vendor tool is currently capable of combining fragment-rich and soft ionization datasets in this manner. The tool's performance was evaluated on three test datasets. When molecular ions are present, MSdeCIpher consistently ranks the correct molecular ion for each fragment spectrum in one of the top positions, with average ranks of 1.5, 1, and 1.2 in the three datasets, respectively. MSdeCIpher effectively reduces candidate molecular ions for each fragment spectrum and thus enables the usage of compound identification tools that require molecular masses as input. It paves the way towards rapid annotations in untargeted analysis with high-resolution GC-MS.

DIVERSE ENVIRONMENTAL CONTEXTS AND LINKS TO LATER-LIFE WELL-BEING

Abstract The places older adults spend time have profound impacts on their well-being. As new sources of data and methods become available it is imperative to refine work in this area to guide development of interventions with the precision necessary to address persistent disparities in well-being. This symposium brings together four complementary papers that focus on diverse environmental contexts and well-being using multiple methodological approaches. Perzynski, Berg, and Dalton discuss the potential of Digital Twin Neighborhoods, i.e., digital replicas of real communities, to address health inequalities. They present findings from engagement sessions with community members about priorities, preferences, and concerns with regard to use of digital twins. Sol, Clarke and Zahodne link data from the Detroit-area Michigan Cognitive Aging Project with data from the National Neighborhood Data Archive to examine the association between neighborhood disadvantage and cognitive reserve. They show how this association differs between Black and White participants. Cho, Dunkle, and Smith use data from the Health and Retirement Study (HRS) to examine the association between later life relocation and contact frequency with adult children. They illustrate the importance of proximity and mode of contact in this association. Morris and colleagues also use HRS data to examine the extent to which stressors operating at multiple levels (interpersonal, community, and society) explain racial disparities in memory. They show these contexts together explain 11% of the racial disparity in baseline memory. These papers will be discussed by Markus Schafer who will provide an outlook for future research in this area.

Analisis Link Aggregated Group Interface Pada Switch Untuk Sistem Link Redudancy Di Universitas Widyatama

Widyatama University is a Legal Entity Private Higher Education Institution under the main institution of the Ministry of Education, Culture, Research and Technology (Kemendikbudristek). Providing superior private universities is one of the results of performance, management and maintaining service quality. Link Redundancy is one of the technologies in the network that is used to maintain the stability of a network connection by using several physical network paths simultaneously. Link Redundancy is needed for performance and services to run well. Link Aggregation Group (LAG) is one of the link redundancy models whose way of working is to combine several physical interfaces into a single interface at the Layer 2 network layer (Data Link Layer). Implementation of Link Aggregation Group (LAG) makes network connections more secure by increasing bandwidth, dividing bandwidth loads, increasing network path availability, and having a minimal risk of data duplication of data errors.

Data Link Effectiveness Evaluation Method Based on Improved ADC Model

Aiming at the problem of innumerable data link effectiveness evaluation bases, the battlefield environment adaptability is introduced into the ADC model to improve the accuracy of the ADC evaluation method based on the analysis of the ADC model. According to the mission and using mode of data link equipment, the evaluation index system and calculation method of data link equipment effectiveness are proposed, and the quantitative evaluation of data link system effectiveness is realized. The validity and scientificity of the model are verified by the example analysis, which provides an effective method for the effectiveness evaluation of data link equipment.

Long-Range Remote Control Based on LoRa Transceivers

Abstract Within this paper, the possibility of using advanced LoRa technology in the field of long-range remote control was considered. For testing purposes, a one-way point-to-point LoRa remote control link was implemented based on the LoRa Ra-02 SX1278 transceiver and the corresponding 32-bit Cortex-M3 microcontroller. The remote control application software is developed in the Arduino development environment. The implemented link was tested experimentally to check the range, data transfer speed and link stability. Test results show that LoRa transceiver modules can be used in the field of long-range remote control.

The Trends, Challenges, and Key Technologies of Beam-Space Multiplexing in the Integrated Terristrial-Satellite Communication for B5G and 6G

Along with the development of beam-space multiplexing theory, multi-layer beamforming has been applied successfully in 4G and 5G terrestrial wireless communication systems to increase the system capacity. For the future Integrated Terrestrial-Satellite Communication (ITSC), beam-space multiplexing is also expected to improve beamforming gain, wireless link quality and data transmission rate. This paper explores beam-space multiplexing in the ITSC towards B5G and 6G, including its application scenarios, evolution trends, technical challenges and key technologies. Based on the analysis of system capacity, performance evaluation is obtained by the simulation of several scenarios, and exposed the promising gain of beam-space multiplexing of the ITSC.

Operational and Performance Experience with uMI550 Digital PET-CT during Routine Quality Control Procedures.

Introduction The quality control (QC) procedures for positron emission tomography (PET) scanners are covered by National Electrical Manufacturers Association and International Electrotechnical Commission. QC must be carried out at regular intervals according to the specifications of the scanner manufacturer. Daily and weekly QC plays a valuable role in monitoring positron emission tomography (PET) scanner performance changes. This study shares operational and performance experience of QC procedures that do not require a radioactive Ge-68 source to perform daily QC and experience with fluorodeoxyglucose F18 ( 18 F-FDG) as a substitute for germanium-68/sodium-22 (Ge-68/Na-22) source for weekly QC. Method This study was performed on an uMI550 digital positron emission tomography-computed tomography (PET-CT) scanner. In this scanner daily QC checks system temperature and humidity, system count rate, data link status, and voltage. QC was performed at the console control, the position of the scanner table was in the home position pulled out from the gantry, and the room was closed during the quick QC. Weekly full QC check items include look-up table drift, energy drift, time-of-flight status, C-map status, temperature and humidity, and voltage. Weekly full QC was performed with a 18 F-FDG source in a rod phantom source. Results Over 200 daily QC tests without a radioactive source Ge-68 phantom and 50 full weekly QC tests using a 18 F-FDG rod phantom were performed with this scanner according to the manufacturer's instructions and a test report was generated. No daily QC errors or warnings were observed during this period. Conclusion The new approach for the daily PET QC does not expose operators to radiation. This translates into commercial and operational merits with consistent performance and results. Implications for Practice Reduction in radiation exposure to operating staff during QC procedure in PET-CT scanner.

StarFront: Cooperatively Constructing Pervasive and Low-Latency CDNs Upon Emerging LEO Satellites and Clouds

Internet content providers (ICPs) typically exploit content distribution networks (CDNs) to provide wide-area data access with high availability and low latency. However, our analysis on a large-scale trace collected from seven major CDN operators has revealed that: from a global perspective, there are still a large portion of users suffering from high user-perceived latency due to the insufficient deployment of terrestrial cloud infrastructures, especially in remote or rural areas where even the closest available cache server is too far away. This paper presents, a cost-effective content distribution framework to optimize global CDNs and enable low content access latency anywhere. collaboratively builds CDNs upon emerging low earth orbit (LEO) constellations and existing cloud platforms to satisfy the low latency requirements while minimizing the operational cost. Specifically, exploits a key insight that emerging mega-constellations will consist of thousands of LEO satellites which can be equipped with high-speed data links and storage, and thus can potentially work as “cache in space” to enable pervasive and low-latency data access. judiciously places replicas on either LEO satellite caches or terrestrial cloud caches, and dynamically assigns user requests to proper cache servers based on different constellation parameters, cloud/user distributions and pricing policies. We have implemented a prototype in our testbed, and extensive trace-driven evaluations covering multiple geo-distributed vantage points have demonstrated that can effectively reduce the global content access latency with acceptable operational cost under representative CDN traffic.

Manifold Structure Analysis of Tactical Network Traffic Matrix Based on Maximum Variance Unfolding Algorithm

As modern weapons and equipment undergo increasing levels of informatization, intelligence, and networking, the topology and traffic characteristics of battlefield data networks built with tactical data links are becoming progressively complex. In this paper, we employ a traffic matrix to model the tactical data link network. We propose a method that utilizes the Maximum Variance Unfolding (MVU) algorithm to conduct nonlinear dimensionality reduction analysis on high-dimensional open network traffic matrix datasets. This approach introduces novel ideas and methods for future applications, including traffic prediction and anomaly analysis in real battlefield network environments.

A compact SiGe D-band power amplifier for scalable photonic-enabled phased antenna arrays

To address the rising demand for high-speed wireless data links, communication systems operating at frequencies beyond {100},hbox {GHz} are being targeted. A key enabling technology in the development of these wireless systems is the phased antenna array. Yet, the design and implementation of such steerable antenna arrays at frequencies over {100},hbox {GHz} comes with a multitude of challenges. In particular, the cointegration of active electronics at each antenna element poses a major hurdle due to the inherent space constraints in the array. This article proposes a novel scalable concept for opto-electronic phased antenna arrays operating at 140 GHz. It details the system architecture of a transmitter that enables the implementation of large scale, wideband, 2D steerable phased antenna arrays and presents the design and measurement of a compact SiGe power amplifier (PA) chip to be used as one of its key building blocks. The amplifier achieves a gain of 20 dB at 135 GHz, features a P_{1dB} of 14.6 dBm and can support data rates up to 45 Gbps in a limited footprint of only 540μm × 550μm. This makes it one of the fastest, most powerful D-band power amplifiers in literature with a footprint compatible with frac{lambda }{2}-spaced phased array integration.

Digital Resource Management and Sharing for Teaching and Learning in Higher Education by Integrating Multiple Data Chain Networks

Abstract In this paper, we construct a GCCP multivariate datalink network for teaching and learning resource sharing through the Generalized Control Chaining Primary Protocol (GCCP) combined with mutual cooperative services among the physical, data link and network layers for resource sharing. The solution set is mapped to the distributed dynamic self-organizing network data links through Nash equilibrium. Attribute descriptions for the necessary digital teaching resources are provided in a P2P system for sharing resources in large-scale heterogeneous teaching environments. Finally, simulations are conducted under the Group Service Control Protocol (GCCP) for teaching resource sharing to verify the effectiveness of the scheduling and management model for digital teaching resources. According to the results, the system with a multivariate datalink network maintains an average cluster size of 5 nodes. The response time of the system increases significantly with the increase of scale when RP(k)C-Grid takes k as 10,20,30,40,50 respectively. This paper effectively manages and maintains the entire digital resource management system for teaching and learning in universities, making it more stable and efficient.

Research on Data Link Channel Decoding Optimization Scheme for Drone Power Inspection Scenarios

With the rapid development of smart grids, the deployment number of transmission lines has significantly increased, posing significant challenges to the detection and maintenance of power facilities. Unmanned aerial vehicles (UAVs) have become a common means of power inspection. In the context of drone power inspection, drone clusters are used as relays for long-distance communication to expand the communication range and achieve data transmission between patrol drones and base stations. Most of the communication occurs in the air-to-air channel between UAVs, which requires high reliability of communication between drone relays. Therefore, the main focus of this paper is on decoding schemes for drone air-to-air channels. Given the limited computing resources and battery capacity of a drone, as well as the large amount of power data that needs to be transmitted between drone relays, this paper aims to design a high-accuracy and low-complexity decoder for LDPC long-code decoding. We propose a novel shared-parameter neural-network-normalized minimum sum decoding algorithm based on codebook quantization, applying deep learning to traditional LDPC decoding methods. In order to achieve high decoding performance while reducing complexity, this scheme utilizes codebook-based weight quantization and parameter sharing methods to improve the neural-network-normalized minimum sum (NNMS) decoding algorithm. Simulation experimental results show that the proposed method has a better BER performance and low computational complexity. Therefore, the LDPC decoding algorithm designed effectively meets the drone characteristics and the high channel decoding performance requirements. This ensures efficient and reliable data transmission on the data link between drone relays.

Smart Optimization Solution for Channel Access Attack Defense Under UAV-Aided Heterogeneous Network

6G-based wireless communication system is poised to redefine the next-generation network landscape by enabling novel services and applications such as intelligent link establishment, power control, data collection, transmission, and distribution. However, security issues, particularly recently revealed Channel Access Attack (CAA), present significant challenges to performance optimization tasks in the heterogeneous wireless networks of 6G, namely, Age of Information (AoI) Oriented Network (AoN), Throughput Oriented Network (ToN), and Latency Oriented Network (LoN). To address these challenges, this paper presents a game theory-based smart optimization solution to enable Unmanned Aerial Vehicles (UAV) to resist CAA within a 6G-based heterogeneous network. Our methodology begins by outlining the advantages and challenges associated with UAV usage, followed by the design of performance indicators and intelligent resource allocation schemes under the influence of CAA. Subsequently, we introduce definitions and categories within game theory, encompassing the concept and equilibrium of three typical game models. The efficacy of our proposed framework is validated through simulation results, which demonstrate the achievement of optimal AoI, enhanced throughput, and reduced latency compared with baseline methodologies when countering CAA in a UAV-assisted heterogeneous network.

Energy Efficient Beamforming for Millimeter-Wave Massive MIMO Systems Under User-Wise Asymmetric Uplink–Downlink Traffic

In this paper, a beamforming scheme that aims to support user-wise asymmetric uplink-downlink (UL-DL) traffic in a more energy-efficient manner is proposed for time-division duplex (TDD) millimeter-wave massive multiple-input-multiple-output (MIMO) systems. Assuming that proper data links have been established during the initial access stage for DL or UL traffic, we consider the beamforming problem for UL or DL whose payload traffic is much lighter than the other link. Such asymmetric traffic allows part of the massive MIMO array to be deactivated in order to achieve a higher energy efficiency (EE) while still meeting the spectrum efficiency (SE) requirements for UL or DL. To deal with such a problem, we propose the corresponding phase shifter (PS) deactivation strategies based on different SE constraints for individual mobile stations or users independently, which select the PSs to be deactivated accordingly with low computational complexity. We then propose a novel codebook design method, which relies on the iteratively updated average main beam gain, in order to pursue a flatter beam under asymmetric DL-UL traffic that interacts with the corresponding PS deactivation strategy. The proposed codebook not only offers flexible beam width and flat main beam gain, but also can generate some good candidate codewords to account for the need of beam refinements, after some of the PSs have been deactivated. Simulation results demonstrated the superiority of the proposed energy efficient PS deactivation approach and the corresponding codebook design.

Adaptive Multi-Path Routing Protocol in Autonomous Vehicular Networks

Vehicular ad hoc networks consist of self-organizing nodes using multi-hop wireless links for communication without any infrastructure support. Traditionally, ad hoc routing protocols use the minimum hop count for their routing metric since a smaller number of transmissions is typically equivalent to a higher throughput, lower delay, and minimal power consumption. However, with the muti-rate capability of emerging radio interfaces, e.g., 802.11ax/be standards, the min-hop metric no longer results in high throughput. For instance, if the higher data rate links are selected for the route, it could result in a higher throughput even if the route takes more hop counts. In this paper, we propose a high throughput routing scheme, called MARV, which makes two key contributions. MARV searches for high throughput paths using an on-demand route searching algorithm so that the routing overhead is smaller compared to other multi-rate-aware routing schemes. MARV also searches for multiple paths to maintain both min-hop and high-throughput paths to select the adequate path depending on the data packet size. We conduct simulations to demonstrate that MARV outperforms not only min-hop path metrics but also previously proposed high-throughput metrics.

Analysis and application research on key issues of channel coding

Channel coding plays a crucial role in enhancing the reliability and efficiency of communication systems, particularly when transmission channels are disrupted by noise and interference. This paper presents an in-depth review of various channel coding techniques, their applications, and future research directions. Key topics discussed include prevalent channel coding methods, such as repetition codes, convolutional codes, LDPC codes, turbo codes, and polar codes. The paper also delves into the selection of suitable channel coding parameters and their applications in digital TV, mobile and satellite communications, unmanned aerial vehicle data links, speech communication, and underwater acoustic channels. Moreover, the paper explores the performance analysis and comparison of different channel coding techniques, shedding light on their strengths and weaknesses. Lastly, the paper identifies emerging trends and challenges in channel coding research, providing valuable insights for researchers and practitioners in the field of communication systems. By examining these techniques and future directions, this comprehensive overview aims to contribute to the development of more robust and efficient channel coding schemes for a wide range of communication applications.

High-Resolution Rainfall Maps from Commercial Microwave Links for a Data-Scarce Region in West Africa

Abstract We present high-resolution rainfall maps from commercial microwave link (CML) data in the city of Ouagadougou, Burkina Faso. Rainfall was quantified based on data from 100 CMLs along unique paths and interpolated to achieve rainfall maps with a 5-min temporal and 0.55-km spatial resolution for the monsoon season of 2020. Established processing methods were combined with newly developed filtering methods, minimizing the loss of data availability. The rainfall maps were analyzed qualitatively both at a 5-min and aggregated daily scales. We observed high spatiotemporal variability on the 5-min scale that cannot be captured with any existing measurement infrastructure in West Africa. For the quantitative evaluation, only one rain gauge with a daily resolution was available. Comparing the gauge data with the corresponding CML rainfall map pixel showed a high agreement, with a Pearson correlation coefficient > 0.95 and an underestimation of the CML rainfall maps of ∼10%. Because the CMLs closest to the gauge have the largest influence on the map pixel at the gauge location, we thinned out the CML network around the rain gauge synthetically in several steps and repeated the interpolation. The performance of these rainfall maps dropped only when a radius of 5 km was reached and approximately one-half of all CMLs were removed. We further compared ERA5 and GPM IMERG data with the rain gauge and found that they had much lower correlation than data from the CML rainfall maps. This clearly highlights the large benefit that CML data can provide in the data-scarce but densely populated African cities. Significance Statement In this study, we investigate the possibility of deriving accurate high-resolution rainfall maps from commercial microwave link (CML) data in West Africa. The main challenges are the lack of reference data in this area and the adoption of existing processing tools without reference data. We show CML rainfall maps for Ouagadougou, Burkina Faso, with a resolution of 5 min and 0.55 km, which is unprecedented in this region. The comparison with the only available rain gauge, which provides data only at a daily resolution, yields a Pearson correlation of >0.95. An analysis of synthetically thinned-out networks shows that this accuracy is valid for the whole domain. Comparing reanalysis and satellite data with the rain gauge and CML data showed a poor performance of these gridded reference datasets. Also, a high coincidence of temporal dynamics between CML rainfall maps and satellite products was observed. Overall, these findings support the potential of CMLs for future hydrometeorological applications in West Africa.

Modeling and analysis for group delay mismatch effect on wideband adaptive spatial interference cancellation

The adaptive interference cancellation technique has been widely utilized in radar, GPS, data link, etc., systems to address challenges from external interference, such as co-site and hostile interference. Since the anti-jamming performance of the adaptive interference cancellation technique is sensitive to group delay mismatch between channels, the group delay mismatch becomes one of the main factors that limit the system’s anti-jamming capability. However, the traditional adaptive interference cancellation system’s mathematical model cannot quantitatively characterize the group delay mismatch effect on the wideband interference cancellation performance. In this paper, the mathematical model of the wideband adaptive spatial interference cancellation (ASIC) system is established, which considers the group delay mismatch, to quantitatively analyze the impact of group delay mismatch on the hostile interference cancellation. The mathematical model utilizes the weighted multi-tone signals to fit the wideband interference, and then, delay differences are attached to each tone signal to simulate the group delay mismatch. Then, the analytic expressions of weight and interference cancellation ratio are derived, which consider the interference bandwidth and group delay mismatch, to quantitatively analyze the group delay mismatch effect on the anti-jamming performance of the wideband ASIC system. Simulation results indicate that the theoretical analysis based on the mathematical model of wideband ASIC system are accurate, which can achieve the quantitative analysis of the group delay mismatch effect on the WIC performance.