Real‐time support for HCCA function in IEEE 802.11e networks: a performance evaluation

Proceedings of the 15th ACM International Conference on Modeling, Analysis and Simulation of Wireless and Mobile Systems

Mastropaolo

et al. 2012

Self Cite

IEEE 802.11e HCCA reference scheduler guarantees Quality of\ud Service only for Constant Bit Rate traffic streams, whereas its as-\ud signment of scheduling parameters (transmission time TXOP and\ud polling period) is too rigid to serve Variable Bit Rate (VBR) traffic.\ud This paper presents a new scheduling algorithm, Dynamic TXOP\ud HCCA (DTH). Its scheduling scheme, integrated with the central-\ud ized scheduler, uses both a statistical estimation of needed trans-\ud mission duration and a bandwidth reclaiming mechanism with the\ud aim of improving the resource management and providing an in-\ud stantaneous dynamic Transmission Opportunity (TXOP), tailored\ud to multimedia applications with variable bit rate. Performance evaluation through simulation, confirmed by the scheduling analysis, shows that DTH is suitable to reduce the transmission queues length.\ud This positively impacts on the delay and on packets drop rate experienced by VBR traffic streams

Section: Resultsmentioning

confidence: 99%

“…Hence, many alternative scheduling algorithms have been proposed to improve the HCCA QoS provisioning [12,14,26,33], but the support of the real-time requirements has been investigated only by few studies [4]. In the following, at the best of our knowledge, we summarize some significant HCCA real-time schedulers.…”

Section: Related Workmentioning

confidence: 99%

Dynamic TXOP HCCA reclaiming scheduler with transmission time estimation for IEEE 802.11e real-time networks

Proceedings of the 15th ACM International Conference on Modeling, Analysis and Simulation of Wireless and Mobile Systems

Mastropaolo

et al. 2012

Self Cite

“…For instance, EDF-based algorithms are suitable to efficiently manage only CBR traffic, whereas they are under-performing in the case of VBR TSs [4].…”

Section: Immediate Dynamic Txop Hccamentioning

confidence: 99%

“…Furthermore numerous theoretical and simulative studies about the HCCA reference scheduler [8], [13], [23], [28] shown that it is suitable to serve only Constant Bit Rate (CBR) traffic, whereas it is unable to efficiently manage Variable Bit Rate (VBR) TSs, since all different TSs are polled with the same period and are served with the same computation time. Hence many scheduling algorithms alternative to the reference one have been proposed to improve the HCCA QoS provisioning [10], [11], [22], [28], but the support of real-time guarantees due to temporal requirements has been investigated only by few works [4].…”

Section: Introduction and Related Workmentioning

confidence: 99%

Providing variable TXOP for IEEE 802.11e HCCA real-time networks

2012 IEEE Wireless Communications and Networking Conference (WCNC)

Mastropaolo

et al. 2012

Self Cite

Quality of Service (QoS) provided by the IEEE 802.11e amendment and by the proposed HCF Controlled Channel Access (HCCA) reference scheduler is tailored for Constant Bit Rate traffic streams. Moreover the numerous alternative scheduling algorithms are not suitable to serve Variable Bit Rate (VBR) traffic streams with the required QoS and real-time guarantees.This paper presents Immediate Dynamic TXOP HCCA (IDTH), a new scheduling algorithm based on a bandwidth reclaiming mechanism suitable to cooperate with a HCCA real-time scheduler. IDTH recovers the portion of the transmission time unused by the scheduled stations to provide a further capacity for the next variable bit rate traffic streams. The transmission opportunity of the next scheduled station is assigned considering the available spare resources and the previously used ones. The scheduling analysis and the simulations results show that IDTH is suitable to reduce the delay experienced by VBR traffic streams, to efficiently deal with the variability of multimedia traffic and to avoid waste of resources.

“…As a consequence the reference scheduler results tailored for Constant Bit Rate (CBR) TSs, whereas it is underperforming in the case of Variable Bit Rate (VBR) TSs; see [19] and the cited works herein. However, when data rate rapidly changes its profile, providing a variable transmission time tailored for multimedia traffic streams is a challenging task also for many of the existing HCCA scheduling algorithms [19][20][21][22][23][24][25] introduced to improve the QoS, including those with variable . Many algorithms have been proposed in order to improve the QoS support as provided by the reference HCCA scheduler, and different techniques have been investigated to compute variable .…”

Section: Introduction and State Of The Artmentioning

confidence: 99%

Elastic QoS Scheduling with Step-by-Step Propagation in IEEE 802.11e Networks with Multimedia Traffic

Wireless Communications and Mobile Computing

Castoldi

2019

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The spreading diffusion of wireless devices and the crowded coexistence of multimedia applications greedy of bandwidth and with strict requirements stress the service provisioning offered by wireless technologies. WiFi is a reference for wireless connectivity and it requires a continuous evolution of its mechanism in order to follow increasingly demanding service needs. In particular, despite the evolution of physical layer, some critical contexts, such as industrial networks, telemedicine, telerehabilitation, and virtual training, require further refined improvements in order to ensure the respect of strict real-time service requirements. In this paper an in-depth analysis of Dynamic TXOP HCCA (DTH) MAC enhanced centralized scheduler is illustrated and it is further refined introducing a new improvement, DTH with threshold. DTH and DTH with threshold can be integrated with preexisting centralized schedulers in order to improve their performances, without any overprovisioning that can negatively impact on the admission control feasibility test. Indeed, without modifying the centralized scheduler policy, they combine together the concepts of reclaiming transmission time and statistical estimation of the traffic profile in order to provide, at each polling, an instantaneous transmission time tailored to the variable traffic requirements, increasing, when necessary, the service data rate. These mechanisms can coexist with advanced physical layer-based solutions, providing the required service differentiation. Experimental results and theoretical analysis, based on elastic scheduler theory, show that they are effective especially in the case of Variable Bit Rate traffic streams in terms of transmission queues length, packets loss, delay, and throughput.