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.
In this paper, we propose a new QAPM scheme for improving power efficiency. A proposed QAPM scheme is build on QAM. And BER performance of QAPM is better than existing PSSK because BER performance of QAM is better than PSK. In this paper, we find the BER performance closed form of QAPM modulation. Also, we compare to PSSK and QAPM with regard to BER performance and throughput in AWGN channel.
This paper takes into account the uncertainty of the primary users' locations and transmission power in designing an optimal downlink scheduling scheme for cognitive radio cellular networks (CogCells). Localization technique is exploited to estimate the position and transmission power of the primary user (PU) transmitting on specific channel. The objective of our scheduling scheme is to maximize the...
Current medium access control mechanisms are based on collision avoidance and collided packets are discarded. The recent work on ZigZag decoding departs from this approach by recovering the original packets from multiple collisions. In this paper, we view each collision as a linear combination of the original packets at the senders. The transmitted, colliding packets may themselves be a coded version...
The exact Markov modeling analysis of erasure networks with finite buffers is an extremely hard problem due to the large number of states in the system. In such networks, packets are lost due to either link erasures or blocking by the full buffers. In this paper, we propose a novel method that iteratively estimates the performance parameters of the network and more importantly reduces the computational...
In this paper we develop a discrete and distributed optimization framework that maximizes the overall spectral efficiency of heterogeneous networks while ensuring a minimum fairness among users. We split the problem into two subproblems: the first one is handled by the users and consists in a transmission by each user of a minimum rate requirement to the base stations and the second is the resource...
In this paper, we evaluate the saturation throughput for an IEEE 802.11 based wireless network considering capture effect at the receiver, while nodes transmit with random powers. In this respect, we consider a scenario consisting of a specific number of wireless nodes. Then, we derive the transmission as well as collision probabilities with respect to the perfect capture effect. In order to maximize...
Hierarchical modulation is a means to better use the overall resources of a given system by superposing, in terms of modulation, a user with better radio conditions on one with inferior radio conditions so as to advantageously transfer some resources from the latter to the former. This in turn impacts the overall performance of the system, which we consider in this work at the flow level, for a realistic...
The advent of fourth generation technologies in wireless networks and the rapid growth of 3G have heralded an era that will require researchers to find reliable and easily implement-able solutions to the problem of poor TCP performance in the wireless environment. Since a large part of the Internet is TCP-based, solving this problem will be instrumental in determining if the move from wired to wireless...
Dynamic spectrum access can enable secondary network users to access unused spectrum, or whitespace, which is found between the transmissions of primary users in a wireless network. The main design objectives for secondary user access strategy are to be able to "scavenge" spatio-temporally fragmented whitespace opportunities while limiting the amount of interference caused to the primary...
We consider new queueing model describing the operation of cyclic polling systems in very hight throughput wireless mesh-networks. Queues are cyclically polled by two servers. Some of queues are served by both servers, the rest are served just by one of them. To investigate the model, we apply the mean value analysis to derive the mean waiting times in queues and provide the numerical examples.
Dynamic spectrum access can enable secondary network users to access unused spectrum, or whitespace, which is found between the transmissions of primary users in a wireless network. The main design objectives for secondary user access strategy are to be able to ??scavenge?? spatio-temporally fragmented whitespace opportunities while limiting the amount of interference caused to the primary users....
Many models for TCP throughput prediction were proposed in the literature. However, the first ones only considered the most common networks at that time: wired networks. Thus, these models could not predict the behavior of a network that included wireless links. Also, different link layer protocols had to be considered, resulting in different modifications of the former throughput prediction models...
Ubiquitous communication indeed requires a seamless networking deployment enable user access the Internet and receive particular service at anytime. However, the deployment of wireless device and service source for ubiquitous communication is a dynamic complex problem which a typical multiple objectives decision problem. In this research, a general model is proposed to deal with such ubiquitous networking...
Automatic repeat request (ARQ) protocols deal with the situations where the selected data rate is not supported by the current channel realization. The inappropriate selection is motivated by the limited channel state information at the transmitter (CSIT). This work looks into how the ARQ protocols are applied to the half-duplex relay-assisted transmission with decode-and-forward relays by exploiting...
In this paper, we study the problem of multi-user channel selection in multi-channel wireless networks. Specifically, we study the case in which the autonomous users deploy delay-sensitive applications. Existing centralized approaches result in efficient allocations, but require intensive message exchanges among the users (i.e. they are not informationally efficient). Current distributed approaches...
An analytical model has been developed to determine the suitable value of the fold k of a k-fold multicast network with different traffic loads under Poisson traffic with finite queue. We have derived stationary probability distribution for the network states and then derived expressions for the throughput, blocking probability and the probability of delayed service of the network. It has been found...
Energy management is the key issue in the design and operation of wireless network applications like sensor networks, pervasive computing and ubiquitous computing where the network is primarily driven by battery-powered embedded devices. This paper studies network coding as an energy minimization technique. Network coding reduces the energy consumption by minimizing the number of transmissions required...
In this paper we propose a cross-layer handoff ordering scheme. The frame success rate (FSR) is adopted as the basis of prioritization. Different quality of service (QoS) requirements of various applications would result in different FSR requirements. In order to indicate how critical a handoff request is, both the FSR requirement from the application layer and the FSR measurement from the medium...
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.