Novel Radio Link Buffer Management Schemes for End-User Multi-class Traffic in High Speed Packet Access Networks

The requirement to provide multimedia services with QoS support in mobile networks has led to standardization and deployment of high speed data access technologies such as the High Speed Downlink Packet Access (HSDPA) system. HSDPA improves downlink packet data and multimedia services support in WCDMA-based cellular networks. As is the trend in emerging wireless access technologies, HSDPA supports end-user multi-class sessions comprising parallel flows with diverse Quality of Service (QoS) requirements, such as real-time (RT) voice or video streaming concurrent with non real-time (NRT) data service being transmitted to the same user, with differentiated queuing at the radio link interface. Hence, in this paper we present and evaluate novel radio link buffer management schemes for QoS control of multimedia traffic comprising concurrent RT and NRT flows in the same HSDPA end-user session. The new buffer management schemes—Enhanced Time Space Priority (E-TSP) and Dynamic Time Space Priority (D-TSP)—are designed to improve radio link and network resource utilization as well as optimize end-to-end QoS performance of both RT and NRT flows in the end-user session. Both schemes are based on a Time-Space Priority (TSP) queuing system, which provides joint delay and loss differentiation between the flows by queuing (partially) loss tolerant RT flow packets for higher transmission priority but with restricted access to the buffer space, whilst allowing unlimited access to the buffer space for delay-tolerant NRT flow but with queuing for lower transmission priority. Experiments by means of extensive system-level HSDPA simulations demonstrates that with the proposed TSP-based radio link buffer management schemes, significant end-to-end QoS performance gains accrue to end-user traffic with simultaneous RT and NRT flows, in addition to improved resource utilization in the radio access network.     

基于无线Mesh网络的分布式协调功能的研究

随着无线mesh网络的迅速发展和实时多媒体业务的日益增长,要求无线网络不仅能提供简单的连通性,还需要提供非常有效的QoS保证机制,针对这一问题,以时分多址/时分双工(TDMA/TDD)技术为基础,提出一种基于无线mesh网络的分布式协调功能,信道存取与数据传输发生在不同的时隙中,能够为端到端数据流公平的分配带宽,并且保证了实时服务传输的QoS.仿真及分析表明该协调功能可提高系统吞吐量并降低端到端延迟,有着更好的QoS性能.     

Proportional delay differentiation provision by bandwidth adaptation of class‐based queue scheduling

Supporting quality of service (QoS) over the Internet is a very important issue and many mechanisms have already been devised or are under way towards achieving this goal. One of the most important approaches is the so‐called Differentiated Services (DiffServ) architecture, which provides a scalable mechanism for QoS support in a TCP/IP network. The main concept underlying DiffServ is the aggregation of traffic flows at an ingress (or egress) point of a network and the marking of the IP packets of each traffic flow according to several classification criteria. Diffserv is classified under two taxonomies: the absolute and the relative. In absolute DiffServ architecture, an admission control scheme is utilized to provide QoS as absolute bounds of specific QoS parameters. The relative DiffServ model offers also QoS guarantees per class but in reference to the guarantees given to the other classes defined. In this paper, relative proportional delay differentiation is achieved based on class‐based queueing (CBQ) scheduler. Specifically, the service rates allocated to the classes of a CBQ scheduler are frequently adjusted in order to obtain relative delay spacing among them. The model presented can also be exploited in order to meet absolute delay constraints in conjunction with relative delay differentiation provision. Simulation experiments verify that our model can attain relative as well as absolute delay differentiation provided that the preconditions posed are satisfied. Copyright © 2004 John Wiley & Sons, Ltd.     

Mobile flow-aware networks for mobility and QoS support in the IP-based wireless networks

As the volume of mobile traffic consisting of video, voice, and data is rapidly expanding, a challenge remains with the mobile transport network, which must deliver data traffic to mobile devices without degrading the service quality. Since every Internet service holds its own service quality requirements, the flow-aware traffic management in fine granularity has been widely investigated to guarantee Quality of Service (QoS) in the IP networks. However, the mobile flow-aware management has not been sufficiently developed yet because of the inherent constraints of flow routing in the mobile networks regarding flow-aware mobility and QoS support. In this paper, we propose a flow-aware mobility and QoS support scheme called mobile flow-aware network (MFAN) for IP-based wireless mobile networks. The proposed scheme consists of dynamic handoff mechanisms based on QoS requirements per flow to reduce the processing overhead of the flow router while ensuring QoS guarantee to mobile flows. The performance analyses of the proposed scheme demonstrate that MFAN successfully supports the mobile flow traffic delivery while satisfying the QoS requirement of flows in the wireless mobile IP networks.     

Managing QoS requirements for video streaming: from intra‐node to inter‐node

Streaming video over IP networks has become increasingly popular; however, compared to traditional data traffic, video streaming places different demands on quality of service (QoS) in a network, particularly in terms of delay, delay variation, and data loss. In response to the QoS demands of video applications, network techniques have been proposed to provide QoS within a network. Unfortunately, while efficient from a network perspective, most existing solutions have not provided end‐to‐end QoS that is satisfactory to users. In this paper, packet scheduling and end‐to‐end QoS distribution schemes are proposed to address this issue. The design and implementation of the two schemes are based on the active networking paradigm. In active networks, routers can perform user‐driven computation when forwarding packets, rather than just simple storing and forwarding packets, as in traditional networks. Both schemes thus take advantage of the capability of active networks enabling routers to adapt to the content of transmitted data and the QoS requirements of video users. In other words, packet scheduling at routers considers the correlation between video characteristics, available local resources and the resulting visual quality. The proposed QoS distribution scheme performs inter‐node adaptation, dynamically adjusting local loss constraints in response to network conditions in order to satisfy the end‐to‐end loss requirements. An active network‐based simulation shows that using QoS distribution and packet scheduling together increases the probability of meeting end‐to‐end QoS requirements of networked video. Copyright © 2005 John Wiley & Sons, Ltd.     

A QoS-enabled resource management scheme for F-HMIPv6 micro mobility approach

In the near future, wireless networks will certainly run real-time applications with special Quality of Service (QoS) requirements. In this context micro mobility management schemes such as Fast Handovers over Hierarchical Mobile IPv6 (F-HMIPv6) will be a useful tool in reducing Mobile IPv6 (MIPv6) handover disruption and thereby to improve delay and losses. However, F-HMIPv6 alone does not support QoS requirements for real-time applications. Therefore, in order to accomplish this goal, a novel resource management scheme for the Differentiated Services (DiffServ) QoS model is proposed to be used as an add-on to F-HMIPv6. The new resource management scheme combines the F-HMIPv6 functionalities with the DiffServ QoS model and with network congestion control and dynamic reallocation mechanisms in order to accommodate different QoS traffic requirements. This new scheme based on a Measurement-Based Admission Control (MBAC) algorithm is effective, simple, scalable and avoids the well known traditional resource reservation issues such as state maintenance, signaling overhead and processing load. By means of the admission evaluation of new flows and handover flows, it is able to provide the desired QoS requirements for new flows while preserving the QoS of existing ones. The evaluated results show that all QoS metrics analyzed were significantly improved with the new architecture indicating that it is able to provide a highly predictive QoS support to F-HMIPv6.     

面向带宽碎片最小化和QoS保障的数据中心网络流量调度算法

随着数据中心网络流量的迅速增长,如何提高数据中心网络性能和服务质量成为了研究热点。然而现有的流量调度算法在网络负载加大时,一方面会导致网络带宽碎片化从而使得网络吞吐量降低,另一方面忽视了流量应用需求导致网络服务质量较差。为此,该文提出一种面向带宽碎片最小化和QoS保障的动态流量调度算法,算法综合考虑了带宽敏感的大流、时延与丢包敏感的小流的不同需求,首先根据待调度流的源地址和目的地址建立最短路径集,其次从中筛选出满足待调度流的带宽需求的所有路径,然后根据路径剩余带宽信息和小流应用需求情况为每条路径建立权重函数,最后根据权重函数值利用轮盘赌算法选择转发路径。实验仿真结果显示,与其它算法相比,所提算法降低了小流的丢包率和时延,同时在网络负载较大时提升了网络吞吐量。     

QoS-driven multicast routing in sparse-splitting optical networks

This paper investigates the quality-of-service (QoS)-driven multicast routing problem in a sparse-splitting optical network. The main objective is to minimize the total cost of wavelength channels utilized by the light-tree while satisfying required QoS parameters. In this paper, both the optical-layer constraints (e.g., optical signal power) and application-layer requirements (e.g., end-to-end delay and inter-destination delay variation) are considered as the QoS parameters. First, integer linear programming (ILP) formulations to solve the optimal multicast routing problem with the given QoS parameters are presented. Solving the ILP formulations for large-scale networks can easily overwhelm the capabilities of state-of-the-art computing facilities, and hence, a heuristic algorithm is proposed to construct a feasible light-tree that satisfies the required QoS parameters in large-scale networks. Simulation results demonstrate the performance of the proposed heuristic algorithm in terms of the cost of utilized wavelength channels.     

Quality of service-aware coexistence in unlicensed 5G new radio based on time-domain virtualization

The deployment of mobile systems is facing several challenges. Precisely, the lack of available licensed bands limits the network capacity, affecting the quality of service (QoS). Consequently, there has been significant interest in utilizing the unlicensed spectrum for mobile data traffic. 3GPP proposed and improved the coexistence of LTE and Wi-Fi in the unlicensed band starting in Release 13 and the following releases, such as LTE-LAA and 5G NR-U. This will cause significant interference and drastically affects the Wi-Fi users' QoS. To that end, we propose the use of time-domain virtualization between 5G NR-U and Wi-Fi systems. In particular, a scheduling algorithm is proposed, where the sharing mechanism is allocated in time slots rather than allocating a subband frequency for each technology. 5G use cases have different QoS requirements and our proposed solution aims at meeting these requirements. Accordingly, the performance is evaluated by studying the impact of resource virtualization and the coexistence configuration. Simulation results confirm that the minimum rate and maximum delay constraints are met. Moreover, it is shown that resource virtualization improves the throughput in both technologies. Furthermore, the delay performance is displayed for both 5G NR-U and Wi-Fi to show any impact of time-sharing coexistence.     

QoS routing in networks with inaccurate information: theory andalgorithms

This paper investigates the problem of routing flows with quality-of-service (QoS) requirements through one or more networks, when the information available for making such routing decisions is inaccurate. Inaccuracy in the information used in computing QoS routes, e.g., network state such as link and node metrics, arises naturally in a number of different environments that are reviewed in the paper. The goal is to determine the impact of such inaccuracy on the ability of the path-selection process to successfully identify paths with adequate available resources. In particular, we focus on devising algorithms capable of selecting path(s) that are most likely to successfully accommodate the desired QoS, in the presence of uncertain network state information for the purpose of the analysis, we assume that this uncertainty is expressed through probabilistic models, and we briefly discuss sample cases that can give rise to such models. We establish that the impact of uncertainty is minimal for flows with only bandwidth requirements, but that it makes path selection intractable when end-to-end delay requirements are considered. For this latter case, we provide efficient solutions for special cases of interest and develop useful heuristics     

Efficient Radio Resource Management in Integrated WLAN/CDMA Mobile Networks

The complementary characteristics of wireless local area networks (WLANs) and wideband code division multiple access (CDMA) cellular networks make it attractive to integrate these two technologies. How to utilize the overall radio resources optimally in this heterogeneous integrated environment is a challenging issue. This paper proposes an optimal joint session admission control scheme for multimedia traffic that maximizes overall network revenue with quality of service (QoS) constraints over both WLANs and CDMA cellular networks. WLANs operate under IEEE 802.11e medium access control (MAC) protocol, which supports QoS for multimedia traffic. A cross-layer optimization approach is used in CDMA networks taking into account both physical layer linear minimum mean square error (LMMSE) receivers and network layer QoS requirements. Numerical examples illustrate that the network revenue earned in the proposed joint admission control scheme is significantly more than that when the individual networks are optimized independently.     

QoS-oriented packet scheduling for wireless multimedia CDMA communications

In the third-generation (and beyond) wireless communication systems, there will be a mixture of different traffic classes, each having its own transmission rate characteristics and quality-of-service (QoS) requirements. In this paper, a QoS-oriented medium access control (MAC) protocol with fair packet loss sharing (FPLS) scheduling is proposed for wireless code-division multiple access (CDMA) communications. The QoS parameters under consideration are the transmission bit error rate (BER), packet loss, and delay requirements. The MAC protocol exploits both time-division and code-division statistical multiplexing. The BER requirements are guaranteed by properly arranging simultaneous packet transmissions and controlling there transmit power levels, whereas the packet loss and delay requirements are guaranteed by proper packet scheduling. The basic idea of FPLS is to schedule the transmission of multimedia packets in such a way that all the users have a fair share of packet loss according to their QoS requirements, which maximizes the number of the served users under the QoS constraints. Simulation results demonstrate effectiveness of the FPLS scheduler, in comparison with other previously proposed scheduling algorithms.     

QoS routing in networks with uncertain parameters

We consider the problem of routing connections with quality of service (QoS) requirements across networks when the information available for making routing decisions is inaccurate. Such uncertainty about the actual state of a network component arises naturally in a number of different environments. The goal of the route selection process is then to identify a path that is most likely to satisfy the QoS requirements. For end-to-end delay guarantees, this problem is intractable. However, we show that by decomposing the end-to-end constraint into local delay constraints, efficient and tractable solutions can be established. Moreover, we argue that such decomposition better reflects the interoperability between the routing and reservation phases. We first consider the simpler problem of decomposing the end-to-end constraint into local constraints for a given path. We show that, for general distributions, this problem is also intractable. Nonetheless, by defining a certain class of probability distributions, which includes typical distributions, and restricting ourselves to that class, we are able to establish efficient and exact solutions. We then consider the general problem of combined path optimization and delay decomposition and present efficient solutions. Our findings are applicable also to a broader problem of finding a path that meets QoS requirements at minimal cost, where the cost of each link is some general increasing function of the QoS requirements from the link     

RSVP and integrated services in the Internet: a tutorial

The growing use of multimedia communication applications, with specific bandwidth and real-time delivery requirements has created the need for an integrated services Internet in which traditional best-effort datagram delivery can coexist with additional enhanced quality of service (QoS) delivery classes. Such classes provide data flows with QoS commitments with regard to bandwidth, packet loss, and delay through the reservation of network resources along the data path, which can be done using the Resource Reservation Protocol (RSVP). This article is a tutorial on how RSVP can be used by end applications to ensure that they receive the end-to-end QoS that they require     

Cross-Layer Scheduling with QoS Support over a Distributed Queuing MAC for Wireless LANs

Distributed Queuing Collision Avoidance (DQCA) is an efficient MAC protocol designed for infrastructure Wireless LANs. In this paper, four algorithms are proposed that alter the FIFO scheduling order of DQCA in order to meet specific network requirements. The proposed schemes combine the efficiency of opportunistic scheduling with the QoS provisioning through service differentiation. The opportunistic policy encourages transmissions at higher rates when the channel condition is good and is implemented through a cross-layer dialogue between the PHY and the MAC layers. The key idea of service differentiation is to assign priorities to traffic flows with different requirements in order to provide QoS guarantees. The throughput, delay and jitter performance of the proposed schemes has been evaluated through simulations for a scenario with heterogeneous traffic of voice, video, best-effort and background data traffic flows.     

一种基于QoS的选播路由算法研究

随着计算机和网络技术的迅猛发展,对网络服务质量的要求越来越高,因此选播成为了IPv6中的一种标准通信模型。在提出了一种新的解决多种限制条件下QoS路由问题的启发式算法,在该算法中,综合考虑了时延、带宽和费用的限制条件,主要采用了网络链路信息预先处理和改进的宽度优先搜索等方法。实验结果表明,该算法具有良好的性能指标,能够有效解决多种限制条件下的QoS路由问题,并且较好的平衡网络负载和服务器负载。     

Cross-layer resource allocation over wireless relay networks for quality of service provisioning

The authors propose a physical-datalink cross-layer resource allocation scheme over wireless relay networks for quality-of-service (QoS) guarantees. By integrating information theory with the concept of effective capacity, the proposed scheme aims at maximizing the relay network throughput subject to a given delay QoS constraint. This delay constraint is characterized by the so-called QoS exponent thetas, which is the only requested information exchanged between the physical layer and the datalink layer in our cross-layer design based scheme. Over both amplify-and-forwards (AF) and decode-and-forward (DF) relay networks; the authors develop the associated dynamic resource allocation algorithms for wireless multimedia communications. Over DF relay network, the authors also study a fixed power allocation scheme to provide QoS guarantees. The simulations and numerical results verify that our proposed cross-layer resource allocation can efficiently support diverse QoS requirements over wireless relay networks. Both AF and DF relays show significant superiorities over direct transmissions when the delay QoS constraints are stringent. On the other hand, the results demonstrate the importance of deploying the dynamic resource allocation for stringent delay QoS guarantees.     

Downlink scheduling of multiuser MIMO systems with transmit beamforming

This article deals with downlink scheduling for multiuser multiple-input multiple-output （MIMO） systems, where the base station communicates with multiple users simultaneously through transmit beamforming. Most of the existing transmission schemes for multiuser MIMO systems focus on optimizing sum rate performance of the system. The individual quality of service （QoS） requirements （such as packet delay and minimum transmission rate for the data traffic） are rarely considered. In this article, a novel scheduling strategy is proposed, where we try to optimize the global system performance under individual QoS constraints. By performing scheduling into two steps, namely successive user selection and power allocation, the scheduler can achieve efficient resource utilization while maintaining the QoS requirements of all users. Extensive simulations and analysis are given to show the effectiveness of the proposed scheduler.     

MMSPEED: multipath Multi-SPEED protocol for QoS guarantee of reliability and. Timeliness in wireless sensor networks

In this paper, we present a novel packet delivery mechanism called Multi-Path and Multi-SPEED Routing Protocol (MMSPEED) for probabilistic QoS guarantee in wireless sensor networks. The QoS provisioning is performed in two quality domains, namely, timeliness and reliability. Multiple QoS levels are provided in the timeliness domain by guaranteeing multiple packet delivery speed options. In the reliability domain, various reliability requirements are supported by probabilistic multipath forwarding. These mechanisms for QoS provisioning are realized in a localized way without global network information by employing localized geographic packet forwarding augmented with dynamic compensation, which compensates for local decision inaccuracies as a packet travels towards its destination. This way, MMSPEED can guarantee end-to-end requirements in a localized way, which is desirable for scalability and adaptability to large scale dynamic sensor networks. Simulation results show that MMSPEED provides QoS differentiation in both reliability and timeliness domains and, as a result, significantly improves the effective capacity of a sensor network in terms of number of flows that meet both reliability and timeliness requirements up to 50 percent (12 flows versus 18 flows).     

Downlink scheduling in a cellular network for quality-of-service assurance

We consider the problem of scheduling data in the downlink of a cellular network over parallel time-varying channels, while providing quality-of-service (QoS) guarantees to multiple users in the network. We design simple and efficient admission control, resource allocation, and scheduling algorithms for guaranteeing requested QoS. In our design, a joint Knopp and Humblet (K&H)/round robin (RR) scheduler, composed of K&H scheduling and RR scheduling, utilizes both multiuser and frequency diversity to achieve capacity gain when delay constraints are loose or moderate. However, for tight delay constraints, an additional reference channel scheduler is required to obtain additional frequency diversity gain. The key advantage of our formulation is that the desired QoS constraints can be explicitly enforced by utilizing the concept of effective capacity.