Learning-Based Admission Control for Low-Earth-Orbit Satellite Communication Networks

Satellite communications has been regarded as an indispensable technology for future mobile networks to provide extremely high data rates,ultra-reliability,and ubiquitous coverage.However,the high dynamics caused by the fast movement of low-earth-orbit(LEO)satellites bring huge challenges in designing and optimizing satellite communication systems.Especially,admission control,deciding which users with diversified service requirements are allowed to access the network with limited resources,is of paramount importance to improve network resource utilization and meet the service quality requirements of users.In this paper,we propose a dynamic channel reservation strategy based on the Actor-Critic algorithm(AC-DCRS)to perform intelligent admission control in satellite networks.By carefully designing the longterm reward function and dynamically adjusting the reserved channel threshold,AC-DCRS reaches a long-run optimal access policy for both new calls and handover calls with different service priorities.Numerical results show that our proposed AC-DCRS outperforms traditional channel reservation strategies in terms of overall access failure probability,the average call success rate,and channel utilization under various dynamic traffic conditions.

A Combining Call Admission Control and Power Control Scheme for D2D Communications Underlaying Cellular Networks

As device-to-device(D2D) communications usually reuses the resource of cellular networks, call admission control(CAC) and power control are crucial problems. However in most power control schemes, total data rates or throughput are regarded as optimization criterion. In this paper, a combining call admission control(CAC) and power control scheme under guaranteeing QoS of every user equipment(UE) is proposed. First, a simple CAC scheme is introduced. Then based on the CAC scheme, a combining call admission control and power control scheme is proposed. Next, the performance of the proposed scheme is evaluated. Finally, maximum DUE pair number and average transmitting power is calculated. Simulation results show that D2 D communications with the proposed combining call admission control and power control scheme can effectively improve the maximum DUE pair number under the premise of meeting necessary QoS.

Joint Resource Allocation and Admission Control in Sliced Fog Radio Access Networks

Network slicing based fog radio access network(F-RAN) has emerged as a promising architecture to support various novel applications in 5 G-and-beyond wireless networks. However, the co-existence of multiple network slices in F-RANs may lead to significant performance degradation due to the resource competitions among different network slices. In this paper, the downlink F-RANs with a hotspot slice and an Internet of Things(Io T) slice are considered, in which the user equipments(UEs) of different slices share the same spectrum. A novel joint resource allocation and admission control scheme is developed to maximize the number of UEs in the hotspot slice that can be supported with desired quality-of-service, while satisfying the interference constraint of the UEs in the Io T slice. Specifically, the admission control and beamforming vector optimization are performed in the hotspot slice to maximize the number of admitted UEs, while the joint sub-channel and power allocation is performed in the Io T slice to maximize the capability of the UEs in the Io T slice tolerating the interference from the hotspot slice. Numerical results show that our proposed scheme can effectively boost the number of UEs in the hotspot slice compared to the existing baselines.

MODELING MULTI-TRAFFIC ADMISSION CONTROL IN OFDMA SYSTEM USING COLORED PETRI NET

Call Admission Control (CAC) is one of the key traffic management mechanisms that must be deployed in order to meet the strict requirements for dependability imposed on the services provided by modern wireless networks. In this paper, we develop an executable top-down hierarchical Colored Petri Net (CPN) model for multi-traffic CAC in Orthogonal Frequency Division Multiple Access (OFDMA) system. By theoretic analysis and CPN simulation, it is demonstrated that the CPN model is isomorphic to Markov Chain (MC) assuming that each data stream follows Poisson distribution and the corresponding arrival time interval is an exponential random variable, and it breaks through MC's explicit limitation, which includes MC's memoryless property and proneness to state space explosion in evaluating CAC process. Moreover, we present four CAC schemes based on CPN model taking into account call-level and packet-level Quality of Service (QoS). The simulation results show that CPN offers significant advantages over MC in modeling CAC strategies and evaluating their performance with less computational complexity in addition to its flexibility and adaptability to different scenarios.

QoS awared power and admission controls based on non-cooperative game theory in wireless networks

In order to better accommodate heterogeneous quality of service (QoS) in wireless networks, an algorithm called QoS-aware power and admission controls (QAPAC) is proposed. The system is modeled as a non-cooperative game where the users adjust their transmit powers to maximize the utility, thus restraining the interferences. By using adaptive utility functions and tunable pricing parameters according to QoS levels, this algorithm can well meet different QoS requirements and improve system capacity compared with those that ignore the QoS differences.

Downlink call admission control with power allocation and rate scheduling for IDMA-based multi-beam satellite systems

Considering the advantage of interleave-division multiple-access(IDMA) technique and the technical bottlenecks in the existing satellite systems,IDMA is introduced into satellite communication networks.To further validate the IDMA into satellite systems,an effective call admission control(CAC) is proposed to maximize the resource utilization.After establishing the multi-beam satellite system model based on variable spreading gain(VSG) IDMA,the power allocation scheme based on SINR evolution technique and transmission rate adaptation for nonreal time interactive traffic are designed as integrated parts of the CAC,working together to improve the system performance in terms of power efficiency and throughput.Further,the analysis and simulation results show that IDMA under the proposed scheme can provide better QoS,in terms of the blocking/dropping probability,outage probability as well as delay performance.

Joint Optimization of Admission Control and Rate Adaptation for Video Sharing over Multirate Wireless Community Cloud

Emerging wireless community cloud enables usergenerated video content to be shared and consumed in a social context. However, the nature of shared wireless medium and timevarying channels seriously limits the quality of service(QoS), partially owing to the lack of mechanisms for effectively utilizing multi-rate channel resources. In this paper, the joint optimization of admission control and rate adaptation is proposed, resulting in a bandwidth-aware rate-adaptive admission control(BRAC) scheme to provide bandwidth guarantee for sharing social multimedia contents. The analytical approach leads to the following major contributions:(1) a bandwidth-aware rate selection(BRS) algorithm to optimally meet the bandwidth requirement of the data session and channel conditions at the physical layer;(2) a routing-coupled rate adaption and admission control algorithm to admit data sessions with bandwidth guarantee. Moreover, extensive numerical simulations suggest that BRAC is efficient and effective in meeting the bandwidth requirements for sharing social multimedia contents. These insights will shed light on communication system implementation for multimedia content sharing over multirate wireless community cloud.

COMBINED ADMISSION CONTROL AND SCHEDULING IN MULTI-SERVICE NETWORKS

Providing the required metrics for different service respectively is a basic characteristic in multi-service networks. The different service can be accessed and forwarded differently to provide the different transmission performance. The state information between admission control and scheduling can be exchanged each other by the defined correlation coefficient to adjust the flow distribution in progress. The priority queue length measured by scheduler implicitly can describe the priority flows load. And the fair rate can describe the non-priority flows load. Different admission decision will be made according to the state of scheduler to assure the time-delay upper threshold for the priority flows under heavy load and the fairness for elastic flows in light load, respectively. The stability condition was conduced and proved. Simulation results show the policy can ensure both the delay for the priority flows and the minimal throughput for non-priority flows.

Resource and Admission Control in NGN

After the separation of service control from transport function in the Next Generation Network (NGN), a concept of the Resource and Admission Control (RAC) was introduced to ensure the Quality of Service (QoS). It hides the details of transport network to the service layer to support the separation of service control from transport function. It detects the resource status of transport network to secure a correct and reasonable usage of transport network resources. This accordingly ensures there are sufficient resources available to guarentee the appropriate level of QoS and avoid bandwidth and service stealing. The functional architecture, the entity involved and reference point, the access type and terminal, the resource control mode, the selection mechanism between functional entities, the interconnection between different domains, and the interaction between other transport control functions are the core study content of RAC. The RACS of the Telecoms & Internet Converged Services & Protocols for Advanced Networks (TISPAN) and the Resource and Admission Control Function (RACF) of the International Telecommunication Union Telecommunication Standardization Sector (ITU-T) differ in research focus. Consequently, the unification of Architecture, defined by different organizations, becomes the central issue of future research for each organization.

Joint Routing and Admission Control in Wireless Mesh Network

Wireless Mesh Network is a promising technology with many challenges yet to be addressed. Novel and efficient algorithms need to be developed for routing and admission control with the objective to increase the acceptance ratio of new calls without affecting the Quality of Service (QoS) of the existing calls and to maintain the QoS level provided for the mobile calls. In this paper, a novel Markov Decision-based Admission Control and Routing (MDACR) algorithm is proposed. The MDACR algorithm finds a near optimal solution using the value iteration method. To increase the admission rate for both types of calls, a multi-homing admission and routing algorithm for handoff and new calls is proposed. This algorithm associates the user with two different access points which is beneficial in a highly congested network and proposes a new routing metric to assure seamless handoff in the network. Our proposed algorithm outperforms other algorithms in the literature in terms of handoff delay, blocking probability, and number of hard handoff.

Lesson Learned from COVID-19 Retrospective Study: An Entropy-Based Clinical-Interpretable Scorecard for Mortality Risk Control at ICU Admission

With severe acute respiratory syndrome coronavirus 2 spreading globally and causing 2019 coronavirus disease(COVID-19),a challenge that we unprepared for was about how to optimally plan and distribute limited top-medical resources for patients in need of urgent care.To address this challenge,physicians desperately needed a scientific tool to methodically differentiate between cases with varying severity.In this study,the unique data of COVID-19 intensive care unit(ICU)patients provided by the national medical team in Wuhan were classified into discrete and continuous variable types.All continuous data were discretized using an entropy-based method and transformed into serial information margins,in which each information margin is related to a specific symptom or clinical meaning.Finally,all these native and processed discrete data were used to configure a readable scorecard through logistic regression,which is the desired scientific tool aforementioned.A total of 322 ICU patients(age:[median:64,interquartile range:54-75],males:178[55.28%],and death:72[22.36%])were included in the study.Probabilities of mortality in COVID-19 patients can be evaluated using a scorecard model(calibration slope:1.343,Brier:0.048,Dxy=0.972,and population stability index=0.071),with desired model performances(accuracy=0.948,area under curve=0.99,sensitivity=1,and specificity=0.939).This new model can interpret clinical meanings from complex data,and compare it with existing machine learning methods through a black-box mechanism.This new data-information model answers a critical question of how a computing algorithm produces clinically meaningful results that will help physicians logically allocate medical resources for COVID-19 patients.Notably,this tool has limitations,giving that this research is a retrospective study.Hopefully,this tool will be tested further and optimized for adaptation to similar clinical cases in the future.

融合的蜂窝网络/无线局域网中资源管理的性能分析(英文)

Wireless Local Area Network(WLAN) with high data bit rates can be used with cellular network to achieve higher level of Quality of Service(QoS) by sharing their total resources efficiently.The integration between cellular and WLAN networks should be ensured considering different channel-allocation strategies of both networks and efficient resource management techniques should be developed.In this paper,we propose a new call admission scheme to use the coupled resource effectively.The proposed scheme,by taking the different resource sharing strategies for two access networks,limits the new,horizontal and vertical handoff voice and data call arrivals with respect to their call-level QoS requirements.Numerical results show that the proposed integrated cellular/WLAN network model uses the resources more effectively and achieves all upper bound QoS requirements for voice and data users as compared with the non-integrated network model.

Optimal control and cost-effective analysis of an agestructured emerging infectious disease model

Emerging infectious diseases are one of the global public health problems which may lead to widespread epidemics and potentially life-threatening infection.Integrated vaccination and physical distancing interventions are two elementary methods for preventing infectious diseases transmission.In this paper,we construct a continuous age-structured model for investigating the transmission dynamics of an emerging infection disease during a short period.We derive the basic regeneration number R 0,the spectral radius of the next generation operator K,which determines the disease outbreak or not.Furthermore,we propose an optimal control problem to take account for the cost-effectiveness of social distancing intervention and vaccination.We rigorously obtain sufficient conditions for a L1 control problem.Numerical simulations show that coupling integrated vaccination and physical distancing intervention could effectively eliminate the infection,and such control strategy is more sensitive for people aged 10e39 and over 60.

Admission Control Scheme for Handover Service in High-Speed Train Communication System

Admission control in high-speed train communication system is quite different from admission control in traditional cellular networks. Conventional admission control strategies cannot be directly applied to this special communication scenario. In this paper, the problem of admission control for handover service is investigated in high-speed train communication environment. An admission control scheme considering bit error rate(BER)and bandwidth borrowing strategy is proposed. On the basis of admission control decision rule taking BER into account, a part of bandwidth obtained by compressing variable rate service in the networks is provided for handover services. The admission control scheme can admit handover services as more as possible while it guarantees the lowest data rate of different services in the networks. Simulation results show that the proposed admission control scheme has a better performance than existing admission control schemes.

EMSC:a joint multicast routing,scheduling,and call admission control in multi-radio multi-channel WMNs

This paper deals with the problem of joint multicast routing,scheduling,and call admission control in multiradio multi-channel wireless mesh networks.To heuristically solve this problem,we propose a cross-layer algorithm named“extended MIMCR with scheduling and call admission control phases(EMSC)”.Our model relies on the on-demand quality of service(QoS)multicast sessions,where each admitted session creates a unique tree with a required bandwidth.The proposed scheme extends the MIMCR algorithm to fairly schedule multiple non-interfering transmissions in the same time slot.It also exploits a call admission control mechanism to protect the QoS requirements of the multicast traffics.EMSC reduces the number of occupied time slots,with consideration of spatial reuse,both Intra-flow and Inter-flow interferences,and selecting the minimum-interference minimum-cost paths.This subsequently leads to better radio resource utilization and increases the network throughput.Simulation results show that the proposed algorithm outperforms the other algorithms and improves the network performance.

Joint admission control algorithm in access network

To deal with long probing delay and inaccurate probing results in the endpoint admission control method,a joint local and end-to-end admission control algorithm is proposed,which introduces local probing of access net-work besides end-to-end probing.Through local probing,the algorithm accurately estimated the resource status of the access network.Simulation shows that this algorithm can improve admission control performance and reduce users’average waiting time when the access network is heavily loaded.

DEMONSTRATING THE SYNERGY BETWEEN CAC AND SCHEDULING IN WIRELESS NETWORKS

Wireless technology is now an integral part of communication network infrastructure.From their first beginnings,such as connection-oriented General System Mobile networks for voice traffic only and connectionless wireless local area networks for data traffic,new generation wireless networks are connection-oriented and provide differentiated services to the user.With the arrival of more sophisticated services and mobility,have arisen the need for Connection Admission Control and traffic scheduling in the network to enhance the quality of experience(QoE)of the user and optimizing the revenue in dynamic workload environments.A great deal of research effort has gone into the study of the performance of one such network standard,namely the IEEE 802.16 networks.Most optimization studies focus on scheduling(a very mature subject in computing)and ignore connection admission(a very mature subject in telephone engineering)or vice versa.In this paper we claim that one should not study the two in isolation and provide empirical evidence to prove our claim.

A novel approach for radio resource management in multi-dimensional heterogeneous 5G networks

A GRA-BKP(Grey Relational Analysis-Bounded Knapsack Problem)scheme was proposed for the radio resource management of the 5G networks.It consists of two steps,access selection and admission control.The former step was executed via GRA,whereas the latter problem was formulated as a bounded knapsack problem.Accordingly,an optimal solution of the BKP was given for access selection a greedy algorithm,GRA-Greedy,was proposed for admission control.The simulation results show that the GRA-BKP scheme can effectively increase system profit and decrease the drop-ping probability compared with the existing scheme.In addition,GRA-Greedy achieves comparable perform-ance with the optimal solution GRA-DP,but its computational complexity is much lower than that of the latter.