11,698 research outputs found
Energy-efficient wireless communication
In this chapter we present an energy-efficient highly adaptive network interface architecture and a novel data link layer protocol for wireless networks that provides Quality of Service (QoS) support for diverse traffic types. Due to the dynamic nature of wireless networks, adaptations in bandwidth scheduling and error control are necessary to achieve energy efficiency and an acceptable quality of service. In our approach we apply adaptability through all layers of the protocol stack, and provide feedback to the applications. In this way the applications can adapt the data streams, and the network protocols can adapt the communication parameters
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A connection-level call admission control using genetic algorithm for MultiClass multimedia services in wireless networks
Call admission control in a wireless cell in a personal communication system (PCS) can be modeled as an M/M/C/C queuing system with m classes of users. Semi-Markov Decision Process (SMDP) can be used to optimize channel utilization with upper bounds on handoff blocking probabilities as Quality of Service constraints. However, this method is too time-consuming and therefore it fails when state space and action space are large. In this paper, we apply a genetic algorithm approach to address the situation when the SMDP approach fails. We code call admission control decisions as binary strings, where a value of â1â in the position i (i=1,âŚm) of a decision string stands for the decision of accepting a call in class-i; a value of â0â in the position i of the decision string stands for the decision of rejecting a call in class-i. The coded binary strings are feed into the genetic algorithm, and the resulting binary strings are founded to be near optimal call admission control decisions. Simulation results from the genetic algorithm are compared with the optimal solutions obtained from linear programming for the SMDP approach. The results reveal that the genetic algorithm approximates the optimal approach very well with less complexity
Energy-efficient adaptive wireless network design
Energy efficiency is an important issue for mobile computers since they must rely on their batteries. We present an energy-efficient highly adaptive architecture of a network interface and novel data link layer protocol for wireless networks that provides quality of service (QoS) support for diverse traffic types. Due to the dynamic nature of wireless networks, adaptations are necessary to achieve energy efficiency and an acceptable quality of service. The paper provides a review of ideas and techniques relevant to the design of an energy efficient adaptive wireless networ
Adaptive Quality Of Service Call Admission Control With User Mobility Prediction For Multimedia Traffic Over Wireless Networks
Multimedia traffic is expected to be supported in the next generation wireless
networks. As in wireline networks, the wireless network must also be capable
of providing guaranteed quality of service (QoS) over the lifetime of mobile
connections. Some challenging problems that appear in multimedia wireless
networks, such as user mobility and shortage of bandwidth, influence the
QoS provisioning for the users.
In this thesis, we propose a new framework called Adaptive quality of service
(AdQoS) to guarantee the QoS of multimedia traffic. The objectives that
AdQoS framework tries to accomplish are minimum new call blocking and
handoff dropping rates. The key feature of this framework is the bandwidth reallocation scheme. This scheme is developed to control the bandwidth
operation of ongoing connections when the system is overloaded.
The other key feature is the bandwidth reservation scheme incorporating a
user mobility prediction to manage the QoS of the networks. Based on the
mobility prediction, bandwidth is reserved to guarantee the uninterrupted
hand off process. A comparison between existing user mobility prediction and
the proposed scheme is also presented.
An integrated system, which combines the Bandwidth Allocation Level
technique and the user mobility prediction, is also proposed. The proposed
user mobility prediction algorithm integrates the Received Signal Strength
(RSS) measurements for the mobile terminal's intra-cell movement and
aggregate history of mobile terminals for inter-cell movement.
When compared with the conventional scheme proposed in the literature, the
simulation results show that our proposed scheme reduces the new call
blocking probabilities, the handoff dropping probabilities and reduces
significantly the probability of terminating calls while still maintaining
efficient bandwidth usage
A Dynamic Multimedia User-Weight Classification Scheme for IEEE_802.11 WLANs
In this paper we expose a dynamic traffic-classification scheme to support
multimedia applications such as voice and broadband video transmissions over
IEEE 802.11 Wireless Local Area Networks (WLANs). Obviously, over a Wi-Fi link
and to better serve these applications - which normally have strict bounded
transmission delay or minimum link rate requirement - a service differentiation
technique can be applied to the media traffic transmitted by the same mobile
node using the well-known 802.11e Enhanced Distributed Channel Access (EDCA)
protocol. However, the given EDCA mode does not offer user differentiation,
which can be viewed as a deficiency in multi-access wireless networks.
Accordingly, we propose a new inter-node priority access scheme for IEEE
802.11e networks which is compatible with the EDCA scheme. The proposed scheme
joins a dynamic user-weight to each mobile station depending on its outgoing
data, and therefore deploys inter-node priority for the channel access to
complement the existing EDCA inter-frame priority. This provides efficient
quality of service control across multiple users within the same coverage area
of an access point. We provide performance evaluations to compare the proposed
access model with the basic EDCA 802.11 MAC protocol mode to elucidate the
quality improvement achieved for multimedia communication over 802.11 WLANs.Comment: 15 pages, 8 figures, 3 tables, International Journal of Computer
Networks & Communications (IJCNC
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