Unmanned Aerial Vehicles (UAVs) for Integrated Access and Backhaul (IAB) Communications in Wireless Cellular Networks

An integrated access and backhaul (IAB) network architecture can enable flexible and fast deployment of next-generation cellular networks. However, mutual interference between access and backhaul links, small inter-site distance and spatial dynamics of user distribution pose major challenges in the practical deployment of IAB networks. To tackle these problems, we leverage the flying capabilities of unmanned aerial vehicles (UAVs) as hovering IAB-nodes and propose an interference management algorithm to maximize the overall sum rate of the IAB network. In particular, we jointly optimize the user and base station associations, the downlink power allocations for access and backhaul transmissions, and the spatial configurations of UAVs. We consider two spatial configuration modes of UAVs: distributed UAVs and drone antenna array (DAA), and show how they are intertwined with the spatial distribution of ground users. Our numerical results show that the proposed algorithm achieves an average of 2.9× and 6.7× gains in the received downlink signal-to-interference-plus-noise ratio (SINR) and overall network sum rate, respectively. Finally, the numerical results reveal that UAVs cannot only be used for coverage improvement but also for capacity boosting in IAB cellular networks

Toward cm-Level Accuracy: Carrier Phase Positioning for IIoT in 5G-Advanced NR Networks

High-precision positioning accuracy is among the key features of the future fifth-generation (5G-advanced) cellular networks to enable a wide variety of commercial, critical, and consumer use cases. 5G new radio (NR) systems have relied on (1) cellular temporal/angular-based positioning methods to provide the indoor environments with a moderate positioning accuracy that is well below the positioning requirements of these future use cases and (2) highly precise satellite carrier phase/code-based positioning methods for the outdoor deployments that are limited by the availability of the satellite coverage. This paper defines the relevant standard mechanisms and algorithms to use the carrier phase cellular-based measurements as a potential solution to achieve a high-precision positioning estimation accuracy in 5G-advanced NR networks. The presented positioning technique is evaluated using high-fidelity system-level simulations for indoor factory (InF) deployment scenarios. The numerical results demonstrate that the presented technique can significantly improve the positioning accuracy compared with the state-of-the-art NR positioning methods. Our findings in this paper also show that the carrier phase method not only provides an indoor complement to the outdoor satellite positioning but also provides an outdoor alternative to the high-precision satellite methods.Comment: in Proc. IEEE International Symposium on Personal, Indoor and Mobile Radio Communications (IEEE PIMRC), Sep. 202

High resolution computed tomography and pulmonary function tests in childhood systemic lupus erythematosus and juvenile rheumatoid arthritis

Background: Alveolar and airway injury represent one of the most common features of rheumatological diseases and is believed to have a significant impact on the course of these diseases. Objective: This work aimed at evaluating airway and alveolar involvement in children with systemic lupus erythematosus (SLE) and juvenile rheumatoid arthritis (JRA). Methods: Thirty four children (21 with SLE and 13 with JRA) were assessed by pulmonary function tests (PFTs) namely spirometry and carbon monoxide diffusion capacity (DLCO) in comparison to 10 healthy controls, as well as by plain roentgenography and high resolution computed tomography (HRCT) of the chest. Results: The studied patients had significantly lower mean PFT values as compared to controls. A restrictive pattern of PFTs was more common as it was detected in 62% of patients with SLE and 23% of those with JRA whereas an obstructive pattern was detected in 14% and 8% respectively. Significantly lower FEF 25-75% values were detected in symptomatic patients. Low values of DLCO (less than 80% of predicted) were recorded in 60% of the studied patients. Chest HRCT was abnormal in 68% of studied patients. In SLE, ground glass appearance and pleural irregularity were the most common findings whereas in JRA, bronchial wall thickening, mosaic appearance and air trapping were prominent. Abnormal findings were detected in 5/9 of asymptomatic patients. Conclusion: airway and alveolar abnormalities are frequently encountered in children with SLE (95%) and JRA (85%) even if they are asymptomatic. HRCT and pulmonary function tests including diffusion studies are recommended as useful tools for the diagnosis and early detection of pulmonary involvement in these patients.Keywords: JRA, SLE, HRCT, PFTs, DLCOEgypt J Pediatr Allergy Immunol 2004; 2(1): 8-1