QoE-driven resource allocation for D2D underlaying NOMA cellular networks

Device-to-device (D2D) communication can significantly improve network coverage and spectral efficiency. Meanwhile, non-orthogonal multiple access (NOMA) has recently been integrated with D2D communication to further improve connection density and satisfy explosive data rate requirements of end users. Considering quality of experience (QoE) has become an important indicator from the user perspective, in this paper, we study the QoE-driven resource allocation problem in a device-to-device (D2D) underlaying NOMA cellular network coexisting with D2D pairs and NOMA-based cellular users (CUs). Our target is to maximize the sum mean opinion scores (MOSs) of all users while guaranteeing the minimum QoE requirement of each CU and D2D pair, by jointly optimizing subchannel assignment and power allocation at CUs and D2D pairs. Since this problem is mixed-integer and non-convex, we first transform it into an equivalent yet more tractable form. Then, a two-stage iterative algorithm based on the alternating optimization framework and constrained concave-convex procedure technique is proposed to optimize subchannel assignment and power allocation alternately. Simulation results show that the proposed scheme outperforms the orthogonal multiple access solution and three NOMA based benchmark schemes in terms of QoE performance.acceptedVersionPeer reviewe

Cellular Digital Post-Distortion : Signal Processing Methods and RF Measurements

In this paper, we study the feasibility of digital post-distortion (DPoD) based mitigation of transmitter nonlinear distortion in cellular networks. With specific emphasis on downlink, we describe a computationally efficient one-shot method to estimate and mitigate the cascaded multipath channel and transmitter nonlinear distortion effects at terminal receiver, building on demodulation reference symbols (DMRSs). We also describe a DMRS boosting approach to match the envelope characteristics of the DMRS and the actual data-bearing multicarrier symbols such that accurate mitigation is feasible. We provide RF measurement results with a state-of-the-art 28 GHz active antenna array and 256-QAM data modulation, demonstrating larger performance enhancements in received signal error vector magnitude (EVM) compared to existing computationally expensive iterative methods.Peer reviewe

Second-line therapy for patients with steroid-refractory aGVHD: systematic review and meta-analysis of randomized controlled trials

ObjectiveSteroids-refractory (SR) acute graft-versus-host disease (aGVHD) is a life-threatening condition in patients undergoing allogeneic hematopoietic stem cell transplantation (allo-HSCT), but the optimal second-line therapy still has not been established. We aimed to perform a systematic review and meta-analysis of randomized controlled trials (RCTs) to compare the efficacy and safety of different second-line therapy regimens.MethodsLiterature search in MEDLINE, Embase, Cochrane Library and China Biology Medicine databases were performed to retrieve RCTs comparing the efficacy and safety of different therapy regimens for patients with SR aGVHD. Meta-analysis was conducted with Review Manager version 5.3. The primary outcome is the overall response rate (ORR) at day 28. Pooled relative risk (RR) and 95% confidence interval (CI) were calculated with the Mantel-Haenszel method.ResultsEight eligible RCTs were included, involving 1127 patients with SR aGVHD and a broad range of second-line therapy regimens. Meta-analysis of 3 trials investigating the effects of adding mesenchymal stroma cells (MSCs) to other second-line therapy regimens suggested that the addition of MSCs is associated with significantly improvement in ORR at day 28 (RR = 1.15, 95% CI = 1.01–1.32, P = 0.04), especially in patients with severe (grade III–IV or grade C–D) aGVHD (RR = 1.26, 95% CI = 1.04–1.52, P = 0.02) and patients with multiorgan involved (RR = 1.27, 95% CI = 1.05–1.55, P = 0.01). No significant difference was observed betwwen the MSCs group and control group in consideration of overall survival and serious adverse events. Treatment outcomes of the other trials were comprehensively reviewed, ruxolitinib showed significantly higher ORR and complete response rate at day 28, higher durable overall response at day 56 and longer failure-free survival in comparison with other regimens; inolimomab shows similar 1-year therapy success rate but superior long-term overall survial in comparison with anti-thymocyte globulin, other comparisons did not show significant differences in efficacy.ConclusionsAdding MSCs to other second-line therapy regimens is associated with significantly improved ORR, ruxolitinib showed significantly better efficacy outcomes in comparison with other regimens in patients with SR aGVHD. Further well-designed RCTs and integrated studies are required to determine the optimal treatment.Systematic review registrationhttps://www.crd.york.ac.uk/PROSPERO/, identifier CRD42022342487

A meaningful exploration of ofatumumab in refractory NMOSD: a case report

ObjectiveTo report the case of a patient with refractory neuromyelitis optica spectrum disorder (NMOSD), who, despite showing poor response or intolerance to multiple immunosuppressants, was successfully treated with Ofatumumab.Case presentationA 42-year-old female was diagnosed with NMOSD in the first episode of the disease. Despite treatment with intravenous methylprednisolone, immunoglobulin, rituximab and immunoadsorption, together with oral steroids, azathioprine, mycophenolate mofetil and tacrolimus, she underwent various adverse events, such as abnormal liver function, repeated infections, fever, rashes, hemorrhagic shock, etc., and experienced five relapses over the ensuing four years. Finally, clinicians decided to initiate Ofatumumab to control the disease. The patient received 9 doses of Ofatumumab over the next 10 months at customized intervals. Her symptoms were stable and there was no recurrence or any adverse events.ConclusionOfatumumab might serve as an effective and safe alternative for NMOSD patients who are resistant to other current immunotherapies

Reconfigurable Signal Processing and DSP Hardware Generator for 5G Transmitters

To impose the reconfigurability and reusability of digital circuits for millimeterwave transmitter architectures, high-speed digital signal processing architectures are explored. The digital front-end of these next-generation transmitters can be implemented up to the maximum operating frequency to meet the requirements of the 5G NR FR2 frequency bands. This paper presents an efficient implementation of a reconfigurable digital signal processor (DSP) that contains programmable multistage multirate filters, operable up to 4 GHz, and a flexible generator for polar, outphasing, and multilevel outphasing modulation. The system achieves an excellent ACLR of 42 dB and EVM degradation of 1.61% with a 7-bit phase signal at a sampling frequency of 4 GHz for outphasing modulation. Digital synthesis of the circuit in a 22 nm FDSOI process results in a core area of 0.12 mm2and an estimated power consumption of 142 mW for a 200 MHz bandwidth 5G NR baseband signal.acceptedVersionPeer reviewe

QoE-Aware Resource Allocation for Non-Orthogonal Multiple Access Enhanced HetNets

Non-orthogonal multiple access (NOMA) has drawn significant attention due to its high spectral efficiency. Invoking NOMA in heterogeneous networks (HetNets) can support ubiquitous connectivity and satisfy the growing demand for mobile data traffic. Existing studies on NOMA-enhanced HetNets mainly focus on network’s quality of service (QoS) metrics such as delay, throughput, coverage, etc. However, these parameters are not sufficient for evaluating the quality of experience (QoE) perceived by users. To that end, we propose a QoE-aware resource allocation framework for NOMA-enhanced HetNets under web browsing and video services. Specifically, a unified QoE-aware joint subchannel and power allocation optimization problem is formulated to maximize the sum mean opinion scores (MOSs) of all users, while guaranteeing the QoE requirement of each user. However, this problem is mixed-integer, non-convex, and intractable. To solve it, a penalty-based iterative algorithm is proposed. In particular, binary constraints on subchannel assignment variables are equivalently transformed into equality constraints via penalty method. Then, subchannel assignment and power allocation are alternately optimized in each iteration by leveraging block coordinate descent method and sequential parametric convex approximation techniques. Extensive numerical results show that the proposed scheme could achieve competitive QoE performance compared to existing NOMA and orthogonal multiple access schemes.acceptedVersionPeer reviewe