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Although COPS-PR is a policy management protocol already found in commercial network equipments, the IETF has been also working on the standardization of the NETCONF protocol, which can be seen as a competing solution when employed for QoS management. NETCONF seems to have the potential to become a feasible alternative to the established management protocols (e.g., SNMP), but few is known about its...
Sleep-based topology control is an important technique used in wireless sensor networks (WSNs) to reduce the energy consumption of the individual node platforms and, as a consequence, sleep-based topology control is useful to increase the functional lifetime of the networks. While in the literature there are several schemes that address sleep-based topology control in WSNs, there is no proposal that...
We deal with the split-channel MAC where total bandwidth splits into one control channel for RTS/CTS dialogue and several data sub-channels for data packet transmission. We consider the with-reservation scheme which allows successful RTS/CTS dialogue to be stored in a virtual queue for future transmission when all of the data sub-channels are occupied. We obtain the throughput of the split-channel...
Wireless video streaming Quality of Service (QoS) support has got a lot of attention recently. Due to error-prone nature of wireless media, one of the main challenges is to improve wireless video streaming reliability, remaining within strict throughput/delay constraints of video applications. In the paper, we focus on video stream buffering as a tool for reliability improvement and compare different...
In this paper we propose a new method to recover images corrupted with salt and pepper noise. The proposed method uses ordered statistics filtering and soft-decisioning in successive approximations to find the locations and amplitudes of all the impulses. In our method we use soft-decision to generate a mask which is based on histogram distributions in local windows to distinguish impulsive noise...
The ubiquitous use of mobile phones motivates the idea of dasiaparticipatory sensingpsila with a cell-phone based sensor network. In our work, we consider a layered architecture for a query-based urban monitoring application using mobile phones. The key contribution of the paper is a Data-Aware Layered Waiting (DA-LW) time aggregation protocol in cell-phone based wireless sensor networks. To motivate...
We consider IEEE 802.11s multi-hop wireless mesh network under multi-channel and multi-radio environments. We decompose the mesh network into disjoint zones by using multiple channels and multiple radios such a way that (i)mesh nodes in a zone are within one-hop distance and compete with other nodes to access the channel using IEEE 802.11e EDCA, (ii) neighbor zones use different channels, (iii) each...
Amplitude phase-shift keying (APSK), especially 16APSK and 32APSK modulations, have been efficiently applied into satellite broadcasting and communications, such as DVB-S2, which endows the system with high spectrum efficiency and transmission rate. However, fewer design about the trellis coding and modulation based on APSK has been reported so far. In this paper, the symmetric and asymmetric TCM...
Pervasive applications and in particular Wireless Sensors Networks have very strict requirements in terms of power consumption. It is well known that radio activity is very expensive in terms of energy; we show here that intensive processing activities (as security) represent a major contribution to power budget. In this paper we extend our methodology for analyzing the impact of security related...
This paper presents some of the results obtained by the application of Ethernet layer 2 quality of service in IP networks. IP networks traditionally provide quality of service in Layer 3. However, since there is an enormous existing Layer 2 infrastructure, todaypsilas networks could benefit from the deployment of Layer 2 quality of service and the cooperation between layer 2 quality of service and...
In recent years, the upgrade of access networks to broadband networks together with the P2P technology has brought many new applications to the Internet. P2P applications have quickly become the biggest consumer of network resources. ISPs of access networks as well as backbone networks are all wondering how to better manage their network resources. We explore the idea of uplink pricing as a way to...
In this paper, we propose a self-protected spanning tree (SST) construction algorithm and the corresponding single link switching mechanism (SLSM) for tree-based recovery schemes. Using SLSM, an SST can recover from any single link failure without the help of the other trees. When some link fails, SLSM transforms an SST into another spanning tree by only replacing the failed link in the tree with...
In order to migrate toward 4G, studies on 3G LTE (Long Term Evolution) have been announced recently in the 3GPP(3rd Generation Partnership Project) and standardization is under way. Therefore, 3G LTE (Long Term Evolution) systems have been designed and developed over many countries. We also have been developing a 3G LTE testbed system at ETRI. 3G LTE system is adopting OFDM (Orthogonal Frequency Division...
Wireless mesh networks (WMNs) are an emerging technology which provides broadband wireless access services. One of the challenges that still faces high performance WMNs is the capacity reduction due to interference of wireless links. In this paper, we address the problem of assigning channels to nodes in WMNs. For this, we introduce the cluster channel assignment (CCA) approach with the objective...
We introduce MarkMax a new flow-aware active queue management algorithm for additive increase multiplicative decreases protocols (like TCP). MarkMax sends a congestion signal to a selected connection whenever the total back-log reaches a given threshold. The selection mechanism is based on the state of large flows. Using a fluid model we derive some bounds that can be used to analyze the behavior...
Efficient mechanisms for broadcasting of service advertisements to Mobile Terminals (MTs) over Wireless Billboard Channels (WBC) are of significant importance for the emerging Ubiquitous Consumer Wireless World (UCWW). Reducing the MT access time and tuning time are the main goals of these broadcasting mechanisms. The challenge is to define reasonable WBC data management algorithm. Diverse from previous...
Wireless channels are prone to transmission errors. Loss of IP packets due to imperfect local error concealment strategy implemented at the data-link layer is the major reason for TCP performance degradation in wireless networks. These losses are misinterpreted by TCP senders as congestion indications and subsequently lead to decrease of the sending rate. In addition to wireless losses IP packets...
IMT-advanced wireless systems will require very high spectrum efficiencies in order to achieve the required data rates of 1 Gbit/s and more. In 3GPP, there is broad agreement that enhanced multicarrier based MIMO will be the key to achieve those targets. In particular, higher numbers of antennas than standardized for 3GPP long term evolution (LTE) will be applied. At the node B, we have more freedom...
Experimental results are typically envisioned as the ultimate validation reference for any theoretical and/or simulation modelling assumptions. However, in the case of Wireless LANs, the situation is not nearly as straightforward as it might seem. In this paper, we discuss to what (large) extent measurement results may depend on proprietary undocumented algorithms implemented in the vendor-specific...
The problem of data aggregation for binary event detection using wireless sensor networks has been considered in the present work. We propose a novel multibit adaptive aggregation scheme (MAAS) which combines the merits of both multibit and adaptive aggregation schemes. Firstly, being adaptive, the proposed scheme does not require knowledge of the performance indices of sensor nodes as required by...
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