The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
IEEE 802.11e hybrid coordination function (HCF) provides quality of service (QoS) in 802.11 networks, which proposed a simple HCF scheduler to take the QoS requirements into account. However, such scheduling algorithm is only efficient for constant bit rate (CBR) traffic. A simple and effective scheduling scheme is proposed to support both variable bit rate (VBR) traffic and CBR traffic in this paper,...
We studied three types of retransmission scheme for turbo-MIMO packet: Chase combining, soft information combining and incremental redundancy, which are suitable for different situations. The channel in each retransmission is correlated in temporal dimension, the simulation result shows using different interleavers in retransmission is very effective in correlated channel. We also find coding gain...
An effective scheduler is proposed to improve the performance of IEEE 802.11e wireless local area networks (LANs), which adaptively adjusts the ratio of enhanced distributed channel access (EDCA) duration to controlled access phase (CAP) duration by tracking the amounts of variable bit rate (VBR) and constant bit rate (CBR) traffics in a real-time manner. Simulation results show that the proposed...
An effective adaptive scheme is proposed to improve the performance of IEEE 802.11 wireless local area networks (LANs) to support real-time traffic. In order to accurately estimate system status, the scheme employs a bi-dimensional Markovian model and a point coordination function (PCF) model to depict distributed coordination function (DCF) and PCF respectively. The scheme adaptively adjusts the...
In this paper, focusing on the problem of improving quality of service (QoS) in a mixed enhanced distributed channel access (EDCA) and hybrid coordination function (HCF) controlled channel access (HCCA) scenario, a dynamic adaptive scheduler called DAS located at the QoS-enhanced access point (QAP) is proposed, which schedules traffics to transmit frames in appropriate mode by monitoring the statuses...
This paper presents an analysis of two algorithms for processing requests for connections in a centralized wireless network. These algorithms are called bandwidth packing algorithms. Each call request comes with a bandwidth demand. A demand can be met only if there is sufficient bandwidth available during allocation, and requests with demands not met are held in a queue. We use the measure of bandwidth...
In computer communication network, the term frame is used widely (e.g. the basic unit in the highspeed switch fabric or media access control layer), which may be of variable size or of fixed-size. We focus on the fixed-size frame because of its advantages for real-time data. Since user information couldn't be exactly the multiple of the frame size, part of bandwidth resource will be lost. In this...
Channel estimation is very important in wireless communication system. On discussing the signal model of variable spread spectrum gain multirate DS-CDMA system, this paper proposed a multirate subspace-based blind channel estimation algorithm. To overcome the high-complexity shortage of this algorithm, a modified approach is devised that offers tradeoff between performance and complexity. Finally...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.