1,354,494 research outputs found
A Kalman Filter Approach for Distinguishing Channel and Collision Errors in IEEE 802.11 Networks
No full textRecognizing Video Resolution by Monitoring Memory Metrics in Mobile Clients
No full textContent delivery is one of the most successful applications in mobile networks. Mobile edge servers are significantly contributing to the improvement of this type of applications, by also performing resolution adaptations as a function of the radio link quality observed by the users. In this paper, we face the problem of dynamically tracking the perceived video resolution by mobile clients in a mobile edge environment to guarantee an agreed Service Level Agreement (SLA). To this purpose, we propose a protocol-agnostic approach, based on monitoring some memory metrics of a running video streaming process at the mobile client, for identifying the time-varying resolution of the video content
Performance Analysis of Memory Cloning Solutions in Mobile Edge Computing
No full textThis paper deals with the problem of service migration in the emerging scenarios of Mobile Edge Computing. Mobile edge computing is achieved by moving the traditional cloud infrastructures, exploited by many today applications, close to the network edge in order to reduce the response times in the so called tactile-internet. However, because of user mobility, such an application architecture may pose the problem of service migration in case of handover from one server site to another. After introducing the current solutions for dealing with service migration and, in particular, the approaches based on service decomposition into multiple layers, we quantify the migration time and the service downtime achieved under different policies (pre-copy, post-copy and hybrid-copy) for stopping and synchronizing the application between source and destination server. Numerical results are provided for RAM-intensive applications, for which a pre-copy approach can be particularly interesting
A CAPWAP Architecture for Automatic Frequency Planning in WLAN
No full textRecently, the impressive success of the IEEE 802.11 WLAN technology has dramatically changed the role of the wireless connectivity provisioning. Born as a wireless extension of small office or home networks, todays the WLANs are getting more and more popular as a large, even metropolitan, area networks. The deployment of large-scale WLANs has some critical issues, because of the lack of coordinated management functionalities among the network nodes. In this paper we briefly describe the CAPWAP architectural solution, for centralizing some control and maintenance functionalities in large scale WLAN, by guaranteeing the interoperability between network nodes provided by different vendors. We also investigate on a simple application for optimizing the wireless network resources, which is possible thanks to the centralization of some control operations. In particular, we propose an automatic frequency planning algorithm, not requiring any network administrator aids, which we tested via simulation and we implemented in an actual testbe
Remarks on IEEE 802.11 DCF Performance Evaluation, IEEE Communication Letters, Vol. 9, Issue 8, Aug 2005 pp:765 - 767
No full textThis letter presents a new approach to evaluate the throughput/delay performance of the 802.11 Distributed Coordination Function (DCF). Our approach relies on elementary conditional probability arguments rather than bidimensional Markov chains (as proposed in previous models), and can be easily extended to account for backoff operation more general than DCF's on
A CAPWAP-Compliant Solution for Radio Resource Management in Large-Scale 802.11 WLAN
No full textRecently, the impressive success of the IEEE 802.11 WLAN technology has dramatically changed the role of the wireless connectivity provisioning. Born as a wireless extension of small office or home networks, todays the WLANs are getting more and more popular as a large, even metropolitan, area networks. The deployment of large-scale WLANs has some critical issues, because of the lack of coordinated management functionalities among the network nodes. In this paper we briefly describe the CAPWAP architectural solution, for centralizing some control and maintenance functionalities in large scale WLAN, by guaranteeing the interoperability between network nodes provided by different vendors. We also investigate on a simple and efficient application for optimizing the wireless network resources, which is possible thanks to the centralization of some control operations. In particular, we propose an automatic frequency planning algorithm, not requiring any network administrator aids, which we tested via simulation and we implemented in an actual testbe
Moving RTS/CTS to the frequency domain: an efficient contention scheme for 802.11ax networks
No full textIn this paper, we propose a contention mechanism based on the execution of multiple contention rounds in the frequency domain (ReCHo), which is designed to offer high throughput performance and robustness with respect to imperfect carrier sensing. The main idea is using narrow tones as signalling messages for performing channel access contentions and allowing the Access Point (AP) to echo these signals, in order to extend the sensing capabilities to all the stations associated to the AP. In particular, we refer to the emerging IEEE 802.11ax standard, showing how our scheme can boost performance of random access with respect to the current version of IEEE 802.11ax OFDMA Back-Off (OBO), even when hidden node probability is very high
One size hardly fits all: Towards context-specific wireless MAC protocol deployment
No full textThis paper casts recent accomplishments in the field of Wireless MAC programmability into the emerging Software Defined Networking perspective. We argue that an abstract (but formal) description of the MAC protocol logic in terms of extensible finite state machines appears a convenient and viable data-plane programming compromise for modeling and deploying realistic MAC protocol logics. Our approach is shown to comply with existing control frameworks, and entails the ability to dynamically change the MAC protocol operation based on context and scenario conditions; in essence, move from the traditional idea of "one-size-fits-all" MAC protocol stack to the innovative paradigm of opportunistically on-the-fly deployed context-specific MAC stacks. With the help of selected and currently developed use cases, we report on preliminary integration activities within the CREW federated wireless testbed, and its OMF experiment control framewor
Temporal Fairness Provisioning in Multi-Rate Contention-Based 802.11e WLANs
No full textThe IEEE 802.11e extensions for QoS support in WLAN define the transmission opportunity (TXOP) concept, in order to limit the channel holding times of the contending stations in the presence of delay-sensitive traffic. We evaluate the use of TXOP for a different purpose: "temporal fairness" provisioning among stations employing different data rates. We show that the equalization of the channel access times allows each station to obtain its throughput basically (1) proportional to its transmission rate, and (2) independent of the transmitted frame length. This also improves the aggregate throughput of the overall WLAN. For a given TXOP limit, i.e., a granted channel access time, a station is required to fragment its pending frame if the TXOP limit is too short, and is allowed to transmit multiple frames back-to-back in a burst if the TXOP limit is long enough, while different fragmentation and bursting rules are possible. Based on the analytical and simulation results, we demonstrate the advantages of TXOP operations over the legacy 802.11 DCF, and compare different TXOP managing policies to find the optimal one
Breaking Layer 2: A New Architecture for Programmable Wireless Interfaces
No full textThis paper introduces a new architecture for programmable wireless interfaces, aiming at responding to the emerging request of wireless access flexibility and adaptability. Instead of implementing a specific MAC protocol stack, the proposed architecture supports a set of programmable services, devised to customize the wireless access operations according to specific network and application scenarios. The services are composed by means of simpler functions, which in turns work on system primitives (i.e. elementary non-programmable functionalities, natively provided by the system) dealing with the physical transmission and reception of the frames. Our approach significantly differs from software-radio solutions, since we argue that most practical needs for promptly adapting and customizing network features and performance may be accomplished by means of advanced and programmable interfaces exposed at a layer higher than the physical one (PHY). This choice does not rule out the possibility of using (i.e. dynamically selecting) advanced PHY mechanisms provided, as elementary primitives, by the interface manufacturers
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