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Recent advances in high-speed wireless LANs with physical layer (PHY) rates reaching 600Mbps make them ideal for multimedia applications. It has been shown that efficiency at medium access control (MAC) layer decreases with increasing the PHY rate. To achieve high efficiency, few researches have tried to use aggregation in which few packets are concatenated into a larger frame. The resultant frame...
IEEE 802.11n standard was a response to growing demands of high throughput multimedia applications over wireless networks. In spite of improvements by this protocol in physical layer rate by adding MIMO antennas to the pervious standards, some new features are mentioned in MAC layer to achieve high throughput. In this paper, we introduce an analytical model for IEEE 802.11n which analyzes different...
The WiMedia Ultra-Wide Band (UWB) specifications include physical layer and distributed Medium Access Control (MAC) layer. Physical layer offers a range of coded data rates from 53.3 Mb/s to 480 Mb/s. WiMedia MAC consists of Beacon period (BP), Distributed Reservation Protocol (DRP) and Prioritized Contention Access (PCA). DRP allows access to the medium through reservation, while PCA provides access...
With the rapidly increasing demand of traffic applications, the need to support seamless multimedia services in the Vehicular Wireless Networks and Vehicular Intelligent Transportation Systems (V-WINET/V-ITS) is growing. Several mobility support protocols such as the Mobile IPv6 (MIPv6) and the fast handover for the MIPv6 (FMIPv6) have been developed to support seamless handover. However, MIPv6 depreciates...
Effective multicast congestion control mechanism is urgently needed with the development of multimedia applications in Internet. Based on the analysis of the present layered multicast, a TCP-friendly active layered multicast congestion control mechanism with rapid self-adaptation at receivers called ALMCC is proposed. It uses active label layering and adapts to the bandwidth of network rapidly at...
To determine the potential signaling traffic reductions, the session establishment procedures are investigated. The investigation shows that, the S-CSCF (Serving Call Session Control Function) is the major bottleneck in IMS (IP Multimedia Subsystem) and the existing 3GPP (the 3rd Generation Partnership Project) Service Triggering Algorithm (3GPP STA) increases largely the end to end session setup...
IMS is a core subsystem that provides multimedia services in the next generation network. The architecture of IMS specifies a series of functional entities. In order to analyze and research the performance of IMS network and services more quickly and conveniently, an IMS simulation system model based on NS2 is proposed, the design and implementation of the key issues are given. Some simulation scenarios...
To determine the potential signaling traffic reductions, the session establishment procedures were investigated. The investigation showed that, the S-CSCF (serving call session control function) is the major bottleneck in IMS (IP multimedia subsystem) network. And then the modeling of 3GPP (3rd Generation Partnership Project) service triggering algorithm (STA) in IMS was presented. The session setup...
We propose analytic model to compute the delay of the binary exponential backoff (BEB) protocol as a collision resolution algorithm. When a packet which tries to reserve a channel collides n times, it chooses one of the next 2n frames with equal probabilities and attempts the reservation again. We derive the expected access delay until an arbitrary packet reserves a channel. Then the expected transmission...
Wireless network coding has the potential to enhance the capacity of wireless mesh networks (WMNs). However, most of the work considering the practical deployment of network coding in WMNs considers only IEEE 802.11 based medium access control (MAC) layers. The recent emergence of sophisticated MAC standards supporting WMNs (e.g. IEEE 802.16) make it necessary to view the deployment issues for network...
The traditional error control coding of channel has no long satisfied the requirement of the deep space communication, because of the long delay, great error rate, probability of packet loss, links easily interrupted and so on. The Fountain codes, used in deep space communication, has been introduced and analyzed. The coding and decoding process of LT codes of Fountain codes has been introduced and...
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