Multi-user Services Research Articles

Deep Reinforcement Learning Based Joint Beam Allocation and Relay Selection in mmWave Vehicular Networks

Millimeter-wave (mmWave) can provide abundant spectrum resource in vehicular communication networks. Nevertheless, due to the high path-loss and blocking effects in mmWave propagation, and high mobility of vehicles, downlink services for vehicles would be seriously degraded. In this paper, we firstly propose a deep reinforcement learning-based joint beam allocation and relay selection (JoBARS) scheme to mitigate blocking effects and optimize the total transmission rate of the vehicular network, where the mmWave base station (mmBS) provides multi-user services. When downlinks are blocked, the mmBS can select appropriate idle vehicles as relay nodes to enhance service quality from a global perspective. We set the rate punishment restriction in JoBARS scheme to guarantee each vehicle can obtain high-quality service. Besides, a relaying incentive mechanism (RIM) is proposed to avoid vehicles being overly selected for relaying and ensure that relay vehicles have a higher chance of being served in the next round. We demonstrate that JoBARS scheme can effectively enhance the total transmission rate while alleviating transmission outages caused by severe propagation attenuation of mmWave signals. Compared with Greedy Selection scheme, the total rate and average connection probability of vehicles under JoBARS scheme are nearly 17% and 14% higher when blocking effects are severe.

Модели и методы вычисления задержек при предоставлении услуг пользователем на сервисных платформах сеансовых инфокоммуникационных услуг

The purpose of this article is to develop methods for calculating the qualitative characteristics of infocommunication services whose workloads consist of user sessions. The scope of application of these methods affects the development and maintenance of infocommunication multi-user services, in terms of ensuring a high quality of user service. The quality of service (QoS) parameters under consideration determine the characteristics of both the system as a whole and individual elements of its architecture, and for this type of service, the qualitative characteristics are the waiting time for the start of user session maintenance, the load factor of server equipment, the number of user sessions simultaneously supported by the system during its error-free operation. Multi-user services are considered from the point of view of queuing theory as a network of queuing systems, with the duration of the user session and the time of receipt of requests for services by gaming services distributed exponentially. To evaluate the parameters of the models of infocommunication multi-user services, Jackson networks were chosen as a mathematical apparatus, which allow us to consider the necessary systems of the type M/M/v. As an approbation of the results, a mathematical analysis of multi-user gaming services was proposed, since their popularity, and hence the flow of users to game servers, is increasing at a tremendous rate. As an additional tool for assessing the qualitative characteristics of the session models under consideration, simulation modeling was proposed, which allows us to evaluate the accuracy of the proposed analytical method and analyze the characteristics of complex systems with time distribution laws other than exponential, for example, long-tailed distributions (Weibull, Pareto, etc.)

Full-duplex transmission of multi-Gb/s subcarrier multiplexing and 5G NR signals in 39 GHz band over fiber and space

We propose a stable full-duplex transmission of millimeter-wave signals over a hybrid single-mode fiber (SMF) and free-space optics (FSO) link for the fifth-generation (5G) radio access networks to accelerate the Industry 4.0 transformation. For the downlink (DL), we transmit 39 GHz subcarrier multiplexing (SCM) signals using variable quadrature amplitude modulation (QAM) allocations for multi-user services. As a proof of operation, we experimentally demonstrate the transmission of 3 Gb/s SCM signals (1 Gb/s per user) over a hybrid system consisting of a 10 km SMF and 1.2 m FSO link. For the uplink (UL), satisfactory performance for the transmission of 2.4 Gb/s 5G new radio (NR) signal at 37 GHz over the hybrid system is experimentally confirmed for the first time, to the best of our knowledge. The measured error vector magnitudes for both DL and UL signals using 4/16/64-QAM formats are well below the third generation partnership project (3GPP) requirements. We also further evaluate by simulation the full-duplex transmission over the system in terms of received optical and RF powers and bit error rate performance. A wireless radio distance of approximately 200 m, which is sufficient for 5G small-cell networks, is estimated for both DL and UL direction under the heavy rain condition, based on the available data from Spain. Furthermore, simulation for the DL direction is conducted to verify the superior performance of the system using variable QAM allocation over uniform QAM allocation. Using a variable modulation allocation, up to five users (2 Gb/s per user) can be transmitted over a hybrid 10 km SMF and 150 m FSO link.

URLLC Mode Optimal Resource Allocation to Support HARQ in 5G Wireless Networks

Ultra Reliable Low Latency Communication (URLLC) mode is a promising 5G technology for various real-time applications, such as, autonomous vehicles, augmented reality, and factory automation. Several papers on URLLC exist, however, most papers only focus on ways to achieve high reliability, and lack mathematical analysis of delay related to packet errors, retransmissions, and bandwidth. In this paper, a M/G/1 queuing model is applied to analyze the erroneous transmission recovery delay of URLLC multi-user services, and using this model the minimum required bandwidth is derived and applied into an adaptive control scheme. The proposed Pollaczek-Khinchine (P-K) formula based quadratic optimization (PFQO) scheme optimizes the bandwidth requirement by controlling the maximum retransmission parameter of the hybrid automatic repeated request (HARQ) mechanism in URLLC. Simulation results show the bandwidth saving effect of the proposed PFQO scheme based on various signal to interference plus noise ratios (SINRs) and packet length distributions.

Dynamic Resource Scheduling Optimization With Network Coding for Multi-User Services in the Internet of Vehicles

For Internet of Vehicles (IoV) systems with multiple users, network coding can be introduced to provide efficient error control and throughput improvement services. However, if the heterogeneity characteristics and requirements of the end users (vehicles) are neglected, it will be difficult for an IoV system to provide each end user with fair system services, without which the advantages of network coding cannot be fully achieved and the performance of the multi-user diversity system will be degraded. In this paper, we propose a Dynamic Resource Scheduling Optimization (DRSO) algorithm, a dynamic fair scheduling algorithm combined with network coding for system resource allocation in a multi-user IoV system. We construct a general solution framework for service scheduling: first, we estimate the fairness index for each end user (vehicle) with the key information on Quality of Service (QoS). Second, we construct a service scheduling control model based on the service capability of control entities (multi-access edge computing servers), and propose a new utility evaluation function. Third, based on the fairness index, we select end users into multiple network coding sets. Network coding sets are the basic units of service scheduling. The optimization objective of the scheduling service is to maximize the total utility of all the network coding sets (the utility of the control entity). Finally, we establish a coding cache queue in the control entity based on the scheduling decision. To obtain the global optimal solution for active queue control, we combine a Quantum Particle Swarm Optimization (QPSO) algorithm with a Proportional Integral (PI) model. Then, the optimal scheduling decision can be made. Extensive simulation results show that DRSO outperforms related scheduling algorithms in varying traffic loads, demonstrating that DRSO can effectively guide service resource allocation.

Cloud Computing for Earth Surface Deformation Analysis via Spaceborne Radar Imaging: A Case Study

We present a case study on the migration to a Cloud Computing environment of the advanced differential synthetic aperture radar interferometry (DInSAR) technique, referred to as Small BAseline Subset (SBAS), which is widely used for the investigation of Earth surface deformation phenomena. In particular, we focus on the SBAS parallel algorithmic solution, namely P-SBAS, that allows the production of mean deformation velocity maps and the corresponding displacement time-series from a temporal sequence of radar images by exploiting distributed computing architectures. The Cloud migration is carried out by encapsulating the overall P-SBAS application in virtual machines running on the Cloud; moreover, the Cloud resources provisioning and configuration phases are implemented in an automatic way. Such an approach allows us to preserve the P-SBAS parallelization strategy and to straightforwardly evaluate its performance within a Cloud environment by comparing it with those achieved on a HPC in-house cluster. The results we present were achieved by using the Amazon Elastic Compute Cloud (EC2) of the Amazon Web Services (AWS) to process SAR datasets collected by the ENVISAT satellite and show that, thanks to the Cloud resources availability and flexibility, large DInSAR data volumes can be processed through the P-SBAS algorithm in short time frames and at reduced costs. As a case study, the mean deformation velocity map of the southern California area has been generated by processing 172 ENVISAT images. By exploiting 32 EC2 instances this processing took less than 17 hours to complete, with a cost of USD 850. Considering the available PB-scale archives of SAR data and the upcoming huge SAR data flow relevant to the recently launched (April 2014) Sentinel-1A and the forthcoming Sentinel-1B satellites, the exploitation of Cloud Computing solutions is particularly relevant because of the possibility to provide Cloud-based multi-user services allowing worldwide scientists to quickly process SAR data and to manage and access the achieved DInSAR results.

Theil utility based multi-device cooperation mechanism for service quality equilibrium in ubiquitous stub environments

An approach to make heterogeneous devices cooperate with each other to provide ubiquitous service remains a longstanding challenge in ubiquitous environments. In addition, when multi-user request ubiquitous services simultaneously, the arbitrariness in resource allocation process easily leads to non-equilibrium of qualities of multi-user's services. Thus, How to design an effective heterogeneous devices cooperation mechanism that meet the QoS requirements and also equilibrate QoS among multi-user's services becomes a very tough problem. In the paper, Equilibrium Index and Theil Utility function are imported to establish a multidevice equilibrium cooperation model, which is beneft for resource allocation in ubiquitous environments. Then a Theil-Equilibrium based Cooperation Mechanism for multi-service is proposed. Firstly, in order to simplify calculating, a dimensionless processing is introduced. After that, a cooperation approach with Theil-Utility Heuristic algorithm is designed to choose the best solution for the simplified model. At last, the mechanism is simulated in a smart home scenario. The simulation results show that this mechanism outperforms non-equilibrium method by improving almost 40% in internal equilibrium with just reducing 0-2% in the total utility of all the requested ubiquitous services. These data show that the proposed mechanism performs well in equilibrating qualities of multi-user's ubiquitous services.

가상 3D 콘텐츠의 실시간 방송 시스템을 위한 효율적인 어플리케이션 가상화 기법

최근 클라우드 컴퓨팅은 다양한 IT분야에서 온디맨드 방식으로 소프트웨어, 하드웨어, 데이터를 서비스처럼 제공하는 것을 가능하도록 만들었다. 본 논문은 가상 3D 콘텐츠의 실시간 방송 서비스를 위하여 이러한 클라우드 컴퓨팅 기술을 이용한다. 그러나 기존 관련 어플리케이션 가상화 솔루션들은 서비스 사용자가 증가할 때 서버의 부하가 급증가하거나 유지비용이 매우 높은 문제점들을 갖고 있다. 그래서 본 논문은 이러한 문제점을 해결할 수 있는 새로운 어플리케이션 가상화 방식을 제안한다. 제안하는 방식은 그래픽 명령어들을 서버에서 실행되는 것이 아니라 클라이언트로 전송하여 실행하기 때문에 다수 사용자들에게 안정적인 서비스를 보장한다. 성능평가는 제안한 기법이 기존 기법들보다 우수함을 보여준다. In recent, the cloud computing makes it possible to provide the on-demand provision of software, hardware, and data as a service in various IT fields. This paper uses the cloud computing techniques for the real time broadcasting service of virtual 3D contents. However, the existing related solutions have many problems that the load of the server is rapidly increased or the cost of the server is very high when the number of service users is increased. Therefore, we propose a new application virtualization method to solve these problems. It promises their stable operations in multi-user services because the proposed method does not execute the rendering commands of the application at the host server but delivers and executes them to clients via the Internet. Our performance experiments show that our proposed method outperforms the existing methods.

Evaluating extensions to IMS session setup for multicast-based many-to-many services

Telecommunication networks are converging towards an all-IP paradigm that integrates a broad set of value-added services. In this context, the IP Multimedia Subsystem (IMS) is being developed by the 3GPP as a key element to achieve the convergence. Additionally, multiparty services are nowadays acquiring an increasing interest from the industry. In this respect, network multicast provides a cost-effective solution to deliver these services to the user. Nevertheless, although network multicast is being considered as an enabler for one-to-many services (e.g. IPTV) in the IMS, the specifications for many-to-many services still follow a unicast approach (e.g. push-to-talk and conference). This paper describes extensions to the session control procedures in the IMS, to support multicast based multi-user services. The idea was first described in a prior work, but this paper presents enhancements to provide a comprehensive solution and to improve the grade of service (GOS) perceived by the users. In addition, the GOS achieved by the proposal is evaluated. First, the bandwidth utilization for the multicast-based multi-user services is analyzed and compared against the unicast scenario. Next, the GOS is evaluated using an analytical approach, by obtaining the mathematical expressions for the session and user plane setup delays. Finally, the GOS is also evaluated using an experimental approach, and the results are compared with values recommended by the ITU-T.