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Ensuring a high customer satisfaction by monitoring Quality of Experience (QoE) aspects has become common practice for service providers. Such monitoring solutions, together with underlying QoE models, are mostly limited to measures captured in the core or access network and may thus neglect the QoE impact of recovery mechanisms deployed at client-side, e.g., FEC or ARQ. This limitation makes QoE...
Research and industries are recently more interesting and attracting to the Vehicular Ad hoc Networks (VANETs) development domain. They contribute to safer and more efficient roads by providing timely and accuracy information to drivers and authorities. Thus, the definition of a quality of service routing protocol for VANETs is one of their challenges. In this paper, we propose QoSBeeVanet, a new...
In this work, we propose a super-resolution blind channel modeling algorithm to characterize wide-band channels comprised of disjoint frequency subbands. Since sounding signals are not available over the frequency guard bands separating adjacent subbands, conventional channel modeling methods suffer from poor performance in modeling the channel frequency response over the guard bands. To circumvent...
Recent collapses of SIP servers in the real carrier networks indicate that the built-in SIP overload control mechanism cannot mitigate overload effectively. In this paper, we investigate the root cause of SIP server crash by studying the impact of the retransmission on the queuing delay of the overloaded server. The transient overload may introduce the excessive queuing delay, thus triggering unnecessary...
Efficient network utilization is essential towards the deployment of large scale peer-to-peer (P2P) video live streaming services on the Internet. Push-pull hybrid schemes and pull schemes provide practical solutions to P2P video live streaming, but network utilization remains unaddressed. To the best of our knowledge, a study of network utilization in the context of P2P video live streaming does...
The Bittorrent P2P (Peer-to-Peer) network is now well-known and widely used. In Europe, it is mainly used with people connected to ADSL networks. However, with the emergence of various access networks with various capabilities (bandwidth, delay, etc.), we might wonder if Bittorrent is well suited to those heterogeneous networks. Moreover, some mobile 3G network operators even forbid the use of P2P...
Ensuring timely delivery of event reports is a critical requirement in mobile sensor networks, as the effectiveness of area surveillance depends largely on the sensor network response delay. However, due to the sensor mobility and the energy limitation, fast report transportation is constrained by the intermittent wireless link connections between sensor nodes. We derive lower and upper analytical...
The present paper studies the performance of a high-speed third-generation (3.5G) networking technology (Enhanced Uplink), in collaboration with well known personal area networks (i.e. Zigbee and Bluetooth) and wireless local area network (WLAN) technology, for delivering pervasive healthcare applications. The association of personal and local area networks along with the 3.5G network is a critical...
This paper presents channel measurements for wireless body area network (WBAN) and provides performance evaluation using the model derived from measurement and the model in the final document of the IEEE802.15.6 channel modeling subcommittee. We measure the radio propagation from 3.0GHz to 5.0GHz which falls in ultra-wideband (UWB) frequency range in an anechoic chamber and give out a static model...
Scheduling schemes of wireless networks determine packet transmission opportunities for each network node by considering network parameters such as link quality, transmission rate, and delay. However, security has not been taken into account in these schemes, although it plays a critical role in network performance. In this paper a new scheduling scheme is proposed to determine packet transmissions...
Due to the massive use of parallel and distributed operations of inputs and outputs, iterative scheduling algorithms are attractive in finding a maximal size matching for an input-queued switch. For constructing a large high-speed switch, a distributed multi-chip implementation of an iterative scheduling algorithm should be followed. Since different chips may locate on different switch linecards and...
This paper adopts a time-slotted and synchronous output-queued (SS-OQ) switch, which avoids memory speedup through the use of dedicated lines connecting inputs to outputs, to show that the performance of an S-OQ switch approaches that of an ideal OQ switch, or asynchronous OQ (A-OQ) switch. An A-OQ switch forwards packets to their destined outputs at arrival but it is costly to implement as immediate...
Time asynchronism is a practical issue needs to be addressed for a general distributed two-way relay network, where two terminal nodes exchange information through multiple spatial-separated relay nodes. In this paper, we propose an analog network coding (ANC) scheme for a time asynchronous two-way relay network. In the proposed scheme, each relay node linearly transforms the received mixed asynchronous...
In the paper, we consider the end-to-end routing and link scheduling problem for multi-hop wireless sensor networks. The efficient link scheduler under our consideration is intended to assign time slots to different users so as to minimize channel usage subject to constraints on data rate, delay bound, and delay bound violation probability. We also present a coupled robust multi-path routing structure...
Virtual Output Queuing (VOQ) is widely used by input-queued (IQ) packet switches to eliminate the head-of-line (HoL) blocking problem. A lot of research has been devoted to design iterative arbitration algorithms to maximize the throughput of this architecture. Nevertheless, these approaches require either a high computation complexity or large contention resolution times for high-speed switches....
Transmission scheduling to improve the capacity in wireless mesh networks (WMNs) is challenging. One promising candidate solution is backpressure scheduling, which was shown to provide throughput optimality and queue stability. Several recent practical systems that implement approximations of backpressure scheduling show performance benefits in WMNs that are based on IEEE 802.11, which is the most...
In MIMO-OFDM communications, the channel state information (CSI) of the forward link is needed for precoder design at the transmitter to achieve the maximal performance gains. In frequency division duplex (FDD) systems, the CSI estimated at the receivers needs to be fed back to the transmitters. Because of the limited network resources, there will be CSI feedback errors due to quantization, delay...
In this paper, optimal multiple channels cooperative spectrum sensing setting in non-identical environment is investigated. In previous work on cooperative sensing, all the secondary users have the same detection threshold and the noise received is independent identically distributed random variable. Thus researchers often assume that identical sensing time is assigned to the channels for spectrum...
Adaptive modulation and coding (AMC) has been widely used to improve the spectral efficiency. In this paper, we take a different look at it from energy saving point of view. Specifically, we analyze the queuing behavior of AMC systems jointly with sleep mode where the wake-up process incurs time and energy cost. We formulate the optimization problem by jointly considering energy-efficiency, queuing...
One of the most important problems in the field of performance optimization for data networks is the problem of routing to achieve delay minimization. This becomes extremely important in the context of providing Quality of Service while satisfying demand. The problem is classical and was considered three decades ago by a number of authors primarily Gallagher, Bertsekas and Garcia-Luna-Aceves. The...
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