Channel allocation schemes

About: Channel allocation schemes is a research topic. Over the lifetime, 10656 publications have been published within this topic receiving 182117 citations.

Defeating Primary User Emulation Attacks Using Belief Propagation in Cognitive Radio Networks

Abstract: Cognitive radio (CR) is a promising technology for future wireless spectrum allocation to improve the usage of the licensed bands. However, CR wireless networks are susceptible to various attacks and cannot offer efficient security. Primary user emulation (PUE) is one of the most serious attacks for CR networks, which can significantly increase the spectrum access failure probability. In this paper, we propose a defense strategy against the PUE attack in CR networks using belief propagation, which avoids the deployment of additional sensor networks and expensive hardware in the networks used in the existing literatures. In our proposed approach, each secondary user calculates the local function and the compatibility function, computes the messages, exchanges messages with the neighboring users, and calculates the beliefs until convergence. Then, the PUE attacker will be detected, and all the secondary users in the network will be notified in a broadcast way about the characteristics of the attacker's signal. Therefore, all SUs can avoid the PUE attacker's primary emulation signal in the future. Simulation results show that our proposed approach converges quickly, and is effective to detect the PUE attacker.

Channel hopping in a radio communications system

Abstract: The invention relates to a method and to an arrangement for effecting base orthogonal channel hopping between mobile stations (MS1-MS3) and a base station in a radio communications system. Connections (F1-F3) having low attenuation are allotted a number of channels having high interference I (channel, t). Connections (F1-F3) that have higher attenuation are allocated a number of channels that have lower interference I (channel, t). A channel allocation means (211) in the base station functions to produce channel hopsequences which are transferred to hopsequence lists (204-206) in the mobile stations (MS1-MS3), via a control channel SACCH. The channel hopsequences are also transferred to corresponding hopsequence lists (201-203) in the base station. Attenuation of the connections (F1-F3) and interference on the channels I (channel, t) are measured continuously in the channel allocating means (211), wherein the best channels with respect to interference are used. The channel allocation means creates the channel hop sequences in accordance with the principle that the better a connection with respect to attenuation, the poorer the channels with respect to interference that are allocated to the connection.

The impact of channel bonding on 802.11n network management

Abstract: The IEEE 802.11n standard allows wireless devices to operate on 40MHz-width channels by doubling their channel width from standard 20MHz channels, a concept called channel bonding. Increasing channel width should increase bandwidth, but it comes at the cost of decreased transmission range and greater susceptibility to interference. However, with the incorporation of MIMO (Multiple-Input Multiple-Output) technology in 802.11n, devices can now exploit the increased transmission rates from wider channels at a reduced sacrifice to signal quality and range. The goal of our work is to understand the characteristics of channel bonding in 802.11n networks and the factors that influence that behavior to ultimately be able to predict behavior so that network performance is maximized. We discuss the impact of channel bonding choices as well as the effects of both co-channel and adjacent channel interference on network performance. We discover that intelligent channel bonding decisions rely not only on a link's signal quality, but also on the strength of neighboring links and their physical rates.

Channel Allocation in 802.11-Based Mesh Networks

Abstract: IEEE 802.11 (WiFi) has been used beyond its original intended purpose of a tether-free LAN. In this paper, we are interested in the use of 802.11 in mesh networks. Specifically, we consider those which involve directional antennas and longdistance point-to-point links. In recent work, the 2P MAC protocol has been designed to suit such a network architecture. In this paper, we assume the use of the 2P MAC protocol in the links of the network, and consider the problem of link channel allocation. We first formulate the problem of minimizing the mismatch between link capacities desired by the network operator and that achieved under a channel allocation. We show that this problem is NP-hard. We then explore several heuristics for channel allocation and find a set of heuristics that achieve the optimal allocation in most scenarios.

Fair bandwidth sharing among adaptive and non-adaptive flows in the Internet

Abstract: The problem of fair bandwidth sharing among adaptive (TCP) and non-adaptive (i.e. CBR-UDP) flows at an Internet gateway is considered. An algorithm that drops packet preventively, in an attempt to actively penalize the non-adaptive traffic that attempts to "steal" buffer space, and therefore bandwidth from the adaptive traffic flows, is presented. The algorithm maintains minimal flow state information and is therefore scalable. The performance of the algorithm is compared with other gateway algorithms and it is shown that, in the presence of non-adaptive traffic, it achieves a more balanced bandwidth allocation among the different flows. The behavior of a flow subjected to the given algorithm has also been analysed in detail.