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.
This paper considers a two-tier femto-macro overlay network architecture, where groups of femtocells are overlaid by macrocells. The capacity of the femtocells is limited, thus redirection of blocked femto calls to the overlaid macrocell is used as a QoS assurance strategy. Similar overflow approaches have been used in telephony; however, extension of this approach to capacity-constrained femto-macro...
In recent years, the femtocell plays an important role in wireless networks not only for its spectrum reuse but also for its low power consumption. However, there exists several critical issues that need to be investigated, especially for the interferences between the macrocells and the femtocells. Two major access policies are considered in the femtocell network, including the closed access mode...
Femtocells are expected as the surest way to increase the system capacity with higher-quality links and more spatial reuse in future networks. In spite of their great potential, the system capacity is highly susceptible to network density because a large portion of users are exposed to inter-cell interference (ICI). In this work, we proposed a dynamic interference avoidance scheme in densely deployed...
Restoring connectivity subjected to the failure of mobile node(s) is an important research challenge in mobile ad hoc networks. To achieve this objective, a Connectivity Restoration Strategy (CRS) is developed, aiming at restoring the connectivity of mobile network whenever it is partitioned from multiple simultaneous node failures. The proposed strategy is fully distributed and requires only local...
We consider several fading channel models for which we aim to maximize ergodic capacity assuming that channel state information (CSI) is available at both the receiver and the transmitter. We characterize the optimal power allocation structure in the single-input-single-output (SISO), multiple-input- single-output (MISO), and multiple-input-multiple-output (MIMO) models subject to both long-term and...
In this paper we address the problem of multicasting individual and common information from a single transmitter (source) to multiple receivers (destinations). We consider the general case where a separate message could be intended for any subset of destinations. We call this problem multicasting in broadcast channel. We derive an achievable rate region for this setup when the `deterministic channel...
This paper addresses the linear processing issues for two way non-regenerative MIMO relay systems with multiple antennas at each node. Based on theoretical derivation, we first propose an optimal joint iterative linear processing scheme for the relay node and receiving source nodes, aiming to minimize the total mean squared error (MSE). The convergence of this iterative algorithm is proved in terms...
In this paper, we are interested in blind and semi-blind identification of multiple-input multiple-output (MIMO) channel for orthogonal frequency division multiplexing (OFDM) systems. Using the sparsity property of wireless channel impulse response, we propose an iterative method which minimizes a cost function to result from the combination of blind or semi-blind criterion and the lp norm. This norm...
Applicability of the concept of Flow-Aware Networking (FAN) for QoS assurance in wireless networks is studied in the paper. The link utilization efficiency for six versions of the TCP protocol in the FAN environment is investigated and compared. The second contribution of the paper is a new congestion control mechanism for FAN, referred to as RAMAF (Remove and Accept Most Active Flows), that fulfills...
In this work, we propose an adaptive distributed network-channel coding for a cooperative multiple access channel where M users cooperatively communicate with a common base station. The scheme is based on the recently proposed generalized dynamic-network codes (GDNC), in which the network code design that maximizes the diversity order was recognized as equivalent to the design of linear block codes...
The MIMO wireless channel offers a rich ground for quality of service analysis. In this work, we present a stochastic network calculus analysis of a MIMO system, operating in spatial multiplexing mode, using moment generating functions (MGF). We quantify the spatial multiplexing gain, achieved through multiple antennas, for flow level quality of service (QoS) performance. Specifically we use Gilbert-Elliot...
Traditional techniques for navigation such as the Kalman filter cannot capture the nonlinear and non-Gaussian models appearing in wireless localization systems deployed in harsh environments. Nonparametric filters as particle filters can cope with such models at the expense of a computational complexity beyond the reach of low-cost navigation devices. In this paper, we establish a general framework...
In this paper, we investigate various cooperative transmission techniques for hybrid and/or integrated satellite and terrestrial systems, where satellite and terrestrial components cooperates to provide high quality services. It has been reported that cooperative diversity techniques combined with space time and/or error correction coding schemes could provide appreciable diversity and additional...
By supporting advanced multimedia applications and multitasking, recent Smartphone operation systems offer great flexibility to the users but make these devices even more difficult to serve. Now, operators of cellular networks face a situation where many applications and services generate highly heterogeneous and bursty traffic patterns. To cope with this challenge, we introduce Context-Aware Resource...
Aiming at improving the QoS performance over fading channels, this paper presents an analysis of the effective capacity for a relay-assisted communication system which utilizes a cooperative packet retransmission protocol at the link-layer in conjunction with AMC-based multi-rate transmission at the physical layer. In the considered model, a source (S) node employs AMC to transmit delay-constrained...
Network throughput of the best-effort networks as typified by the Internet and wireless networks is often insufficient for multimedia communication, and it spoils the quality of communication. Therefore, it is important to analyze a dynamic characteristics of the throughput when multimedia traffic is injected. We point out that the dynamics of the throughput has the viscosity and the elasticity because...
This paper introduces a batch scheduling algorithm for OBS networks which has linear computational complexity. A transformation of the problem formulation is applied to allow the modeling of the problem as a job scheduling with identical machine type of problem. The proposed algorithm was compared to several other heuristic. Results show that it produces a lower bound to the blocking probability of...
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.