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Industrial networks based on IEEE 802.15.4 are spreading, even though the joint requirement on predictability and reliability from industrial applications is hard to fulfil in wireless networks, and the data rate of IEEE 802.15.4 is rather low. With the goal of providing real-time guarantees, with increased reliability and throughput, we propose two multichannel network architectures based on IEEE...
The IEEE 802.15.4 is the most widespread used protocol for Wireless Sensor Networks (WSNs) and it is being used as a baseline for several higher layer protocols such as ZigBee, 6LoWPAN or Wireless HART. Its MAC (Medium Access Control) supports both contention-free (CFP, based on the reservation of guaranteed time-slots GTS) and contention based (CAP, ruled by CSMA/CA) access, when operating in beacon-enabled...
In this paper, we propose a new 802.16 Qos scheduling architecture based on GPSS, integrating some kinds of existing scheduling algorithms. Then we design a simulation experiment to validate the effectiveness of the Qos scheduling architecture using Anylogic. The simulation results prove the new QoS architecture is effective, which can not only meet the delay requirement of real time applications,...
In VoIP over WLAN (known as VoWLAN) transmission, one of the main problems is that the supported voice channel capacity is relatively low. As an improvement to IEEE 802.11 MAC layer Carrier Sense Multi-Access/Collision Avoidance (CSMA/CA) algorithm, this paper presents Prediction/Collision Avoidance (P/CA) mechanism based on service attribute and cross-layer control. Under this mechanism, there is...
In order to become truly ubiquitous, the Internet of Things (IoT) has to evolve to provide connectivity anytime, any place, for any thing. IEEE 802.15.4-based wireless personal area networks (WPANs) is a preferable communication method for IoT. Wireless personal area networks (WPANs) are used to convey information over relatively short distances. Connections effected via WPANs involve little or no...
In this paper, an improved IEEE802.11 WLAN analytical model under unsaturated traffic conditions was proposed. It adapts Distributed Coordination Function (DCF) models to describe all the states. Compared with other MAC models, two special states were added for this model. One is D state meaning whether the medium is sensed to be available for a time interval greater than DIFS, so the sender can transmit...
The primary concern of broadband wireless technologies is to provide the end-to-end Quality of Service (QoS) for integrated real-time and non real-time applications. The main focus of the IEEE 802.16d/e MAC layer is to manage the radio recourse in an efficient way. The basic functional blocks of the QoS model are addressed by the standards to support five different types of service classes. However,...
The IEEE 802.16/WiMAX mesh network, which is dynamically self-organized and self-configured, is a promising solution for wireless broadband access in metropolitan scale with a cost-effective deployment. As in most wireless multi-hop networks, traffic scheduler in MAC is one of most important factor for the performance of 802.16 mesh networks. Two scheduling modes, centralized scheduling and distributed...
Long registration delay and signaling cost restrict the practical deployment of MIP. Proxy Mobile IPv6 has been proposed to overcome limitation of Mobile IP, which can avoid tunneling overhead and support of hosts in the mobility management. In this paper, we propose an extension protocol based on Proxy Mobile IPv6 to reduce the overhead of Local Mobile Anchor and decrease handoff delay. When the...
Delay-constrained video applications have stringent bandwidth, delay and loss requirements, which is a great challenge to support such real-time applications in wireless ad hoc networks. In this paper, to minimize the distortion of video received at the decoder, we propose a cross layer design (CLD) approach which combines the network layer and MAC layer to meet the stringent requirements by dynamically...
Multi-hop wireless ad hoc networks suffer from temporary link error due to fading. In order to improve packet transmission reliability and achieve efficient transmission in fading environment, this paper proposes an integrated dynamic multi-hopping scheme based on a cross-layer approach and cognitive behavior of local nodes. The scheme provides two important functions, temporary bypassing and dynamic...
It is difficult to provide QoS guarantees for streams in wireless network based on IEEE802.11 DCF because of limited bandwidth. Taking CBR traffic as example, we studied the traffic performance with different parameters in this paper. The results show that for an overloaded network, the traffic with longer packet size has greater throughput. Since the MAC layer performs the same competitive algorithm,...
This paper presents a Model of Quality of Service (QoS) for Next Generation Networks (NGN), that consist of a tower of five defined layers such as the Model Layer of QoS, Control of Admission, QoS in the Routing, QoS in the Signaling, and MAC QoS. In addition, the model raises a method based on the concept of segregation of functions defining two functional networks along with the tasks of QoS. Then,...
In ad hoc networks, performance objectives are often in contention with each other. Indeed, due to the transmission errors incurred over wireless channels, it is difficult to achieve a high rate of transmission in conjunction with reliable delivery of data and low latency. In order to obtain favorable throughput and delay performances, the system may choose to compromise on its reliability and have...
Guaranteeing quality of service is a key problem to multimedia stream in mobile Ad Hoc networks. The related works study the channel delay and bandwidth based on the MAC layer; however, there is little focus on queue delay. In a mobile environment, the changing of queue is quite different from those in static conditions. How to calculate the queue delay is a challenging question in mobile Ad Hoc networks...
The IEEE 802.16 is a well known set of standards, which have been developed for global deployment of Metropolitan Area Networks (MANs) in order to provide broadband wireless accesses supporting the integrated transmission of multimedia applications with different Quality of Service (QoS) requirements. In order to achieve the QoS requirements of multimedia applications, the IEEE 802.16 standards offers...
Current passive RFID systems face the challenges to locate mobile objects in real time in indoor environments, including the realization of low delay as well as effective cooperation among readers and accurate ranging ability in the physical layer. In order to overcome these challenges, this paper presents a low delay multi-reader passive RFID system using ultra high frequency (UHF) radio as the forward...
Wireless Networks are the most popular networks now a days due to their less cost and easy deployment anywhere. The carrier sense multiple access with collision avoidance (CSMA/CA) protocol is a random access protocol that is used to avoid collisions in wireless local area networks (WLANs). In this paper, a detailed performance evaluation of IEEE 802.11 medium access control (MAC) protocol is presented...
Proposed a modified WLAN MAC protocol, to lower real-time data access delay of control system. Data transported through the control system of WLAN included: burst real-time data (BRD), periodical real-time date (PRD) and non-real-time data (NRD). Priority ranged from the high level to the low level and distinguished them by different inter frame space (IFS). Presents boundary backoff and polling algorithm...
A new MAC and a new routing protocol are introduced for ad hoc sea surface sensor networks. These protocols are resilient against continuous changes in over sea surface RF channel conditions. The MAC protocol is contention based and does not need RTS-CTS signaling. It has three modes: unreliable, delay sensitive reliable, bandwidth sensitive reliable. The routing protocol adapts the continuous changes...
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