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In this paper, we propose a novel protection architecture of passive optical network (PON) system. Two optical line terminals (OLTs) are connected to each other as well as to the access area. This network can sustain services to access area and restores normal operation in faulty conditions. Subscribers are divided into two groups to reflect priority based bandwidth allocation. WDM access increases...
Cognitive radio network, which deals with dynamic frequency assignment, is one of the most popular research topic nowadays in the context of cellular networks, WLANs and mesh networks as well. The growing interest in the cognitive radio technology and its capability to offer more efficient spectrum usage attracts researchers to find efficient algorithms to accommodate more users and to provide better...
The persistent data ferrying problem has a naturally cascaded structure between vehicle and communication dynamics, allowing the bandwidth optimization to be encapsulated within a path planning optimization problem. This work analyzes policies that solve the inner bandwidth allocation problem quickly. Given a path and properties about the communication environment, the bandwidth allocation problem...
One of the biggest challenges in multi-hop cognitive radio networking is the dynamic change of channel availability to secondary users which could cause the breaking of routes and thus communications. To address this challenge, we propose an adaptive channel allocation and routing scheme in this paper. Our scheme is flexible so that it can react to the dynamic change of channel availability, and it...
IEEE 802.22 is the first standard to uitilize cognitive radio technology for wireless regional area networks (WRANs). It has adopted a cellular topology containing one base station (BS) and multiple customer premises equipments (CPEs) in a cell. It covers a very large area with radius ranging up to 100 km. Orthogonal frequency-division multiple access (OFDMA) system is employed and it is further slotted...
The uncertainty in channel quality due to fading and shadowing along with the unpredictability of primary user (PU) activity make channel assignment in opportunistic spectrum access (OSA) networks quite challenging. In this paper, we propose two per-link channel assignment models under channel uncertainty: a static single-stage and an adaptive two-stage. In the static model, channel assignment is...
We consider adaptive rate scheduling mechanisms used by densely deployed base station (BS) nodes in cellular wireless networks. These BS nodes share downlink channels under the employment of omnidirectional and directional antennas. We study the throughput capacity rates achieved under reuse-k scheduling schemes, for k = 1, 3, with and without the incorporation of fractional frequency reuse (FFR)...
Wi-Fi devices are popular because of low cost and easy deployment, which lead to high density of WLANs in urban areas. Due to high density, WLANs suffer performance degradation unless networks interfering with each other can allocate wireless resource reasonably. Hence, our goal is to minimize the interference caused by high density of WLANs and in turn it helps improve throughput. In this paper,...
Deadlock-free virtual channel allocation scheme should be designed to balance resources utilization, particularly for modern communication-centric interconnects networks. Dateline, proposed decades ago, is one of the most popular methods to remove cyclic dependencies within a single dimension of a torus. While the problem of virtual channel misbalance caused by these deadlock avoidance schemes brings...
Cognitive Radio Networks have changed the communication paradigm by opportunistically using available spectrum. In such networks, Secondary User vacates the channel when it detects the Primary User. The frequent channel switching degrades the throughput of Cognitive Radio Networks. Current schemes suggest only the selection of Primary Channel if there is not any licensed user available. We propose...
Multi-spot beam satellite network can achieve the power and bandwidth gain of parallel multi-beam with the appropriate resource management. The effective resource management is important not only to prevent the unnecessary resource waste but also to increase in the resource utilization efficiency in the satellite systems with limited resource environment. In this paper, we refer two resource management...
The paper introduces proactive integrated handoff management (IHM) scheme in cognitive radio mobile ad hoc networks (CR-MANETs) through an established route. This scheme considers the primary user (PU) activity, secondary user (SU) mobility and channel heterogeneity in the spectrum handoff decision. To reduce the handoff delay, handoff thresholds are used. When the spectrum handoff cannot be done...
This paper presents a study of mobile wireless LAN (WLAN) hotspots which are used to provide cellular-WiFi tethering service to personal devices. A dense deployment scenario for fixed and mobile WLAN is described and potential performance problems due to interference are identified. An analytical model for coexisting fixed and mobile WLAN hotspots with heterogeneous traffic is presented. The model...
Channel allocation has become a significant challenge in multi-channel Ad-Hoc networks due to the fast growing of wireless applications and the limitation of spectrum resource. In this paper, we assume that the demand of each user is different and alterable, which has been known by all the others. We study the problem of demand-aware channel allocation (DaChA) from a non-cooperative strategic game...
In a multi-radio multi-channel wireless mesh network, a channel assignment that is based on a fixed number of available frequency channels may cause co-channel interference, which degrades the network throughput. We address this problem by ensuring interference-free communication among the mesh nodes. The main purpose of this work is to determine the minimum number of non-overlapping frequency channels...
With the development of computer and wireless technology, cost and size of the wireless transceiver has decreased greatly. It is feasible and necessary to equip multiple radios on sensor nodes, especially on the backbone nodes having high demand on performance. The author proposed a MR-MC (Multi-radio and Multi-channel) manufacturing sensor network based on the nested cellular topology in previous...
We propose algorithms to address the channel allocation and fairness issues of multi band multiuser cognitive ad-hoc networks. Nodes in the network have unequal channel access probability and have no prior information about the offered bandwidth or number of users in the multiple access system. In that nodes use reinforcement learning algorithm to predict future channel selection probability from...
IEEE 802.11 WLANs are currently one of the most popular wireless technologies, but their immediate success results in dense deployments and high demand of user traffic. This in turn leads to decrease in throughput and poor spectrum utilization. Especially in the 2.4 GHz ISM band, where the spectrum is a very scarce resource, all available WLAN channels should be exploited in the best possible way...
In this paper we present a performance evaluation of two distributed channel assignment algorithms in a large-scale wireless multi-radio testbed. We compare the performance of a link-based approach, in which channels are assigned to existing links in the network, with an interface-based approach, in which channels are assigned to the network interfaces. Both algorithms have significantly increased...
Over the last few years, mobile wireless LANs (m-WLANs), which are characterized by portable access points (APs) and a small number of connected clients, are becoming popular. When a large number of such personal mobile APs operate close to each other, for example in crowded urban areas and conference venues, the quality of service (QoS) of the connected clients can be severely degraded due to co-channel...
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