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Routing in wireless mesh networks based on cognitive radio environment is a challenge due to dynamic channel selection. When nodes look for routing and schedule channels, channel allocation seems unbalanced sometimes. To increase the utility of unlicensed bands and increase the throughput with the learning mechanism, a route tree-based channel assignment algorithm, which is based on channel statics...
In this paper, we present a cooperative MAC protocol called automatic relay cooperative MAC (ARC-MAC) for wireless Ad Hoc networks. ARC-MAC develops the 802.11 DCF to five handshakes, which is suitable for cooperative transmission. According to the channel condition, neighbors decide whether it is a relay by itself, and the relay helps the source transmitting packets with a definite probability. An...
By development and the spread of a wireless technology,the mobile ad hoc network (Manet) that can be easily constructed only with mobile nodes is getting much attention.However, it is difficult to control the performance of the entire network appropriately, as a network consists of individual communication nodes operating autonomously and there is no device that controls the entire network. Recently,...
In this paper, a new delay-enabled EDCF for the transport of real-time traffic over an IEEE802.11e wireless LAN is proposed. The proposed technique will drop any packet belonging to a conversational class when a maximum queueing delay is reached. The packets belonging to an interactive or a background class are not dropped due to the queuing delay. The performance of this new technique is evaluated...
Cognitive radio (CR) is an emerging technology in wireless access, aiming at vastly improving the way radio spectrum is utilized. Its basic idea is that a secondary user (unlicensed user) can be permitted to use licensed spectrum, provided that it does not interfere with any primary users (licensed users). CR technology enables the development of an intelligent and adaptive wireless communication...
The increase in network traffic has lead to the concept of congestion in computer networks. The problem of network congestion control remains a major issue in today's computer networks. Despite various methods and algorithms that has been proposed, however due to the dynamic nature of computer networks, no universal control method has been widely accepted. This paper reviews various conventional methods...
We propose a novel view on efficient packet forwarding in wireless mesh networks based on a molecular analogy in which mesh routers are either nuclei or electrons in an atom that corresponds to a 802.11 cell. In this view, a mesh network appears as a collection of spatially distributed 802.11 cells operating on different channels. We define molecular MAC that uses dynamic channel switching at neighbor...
We propose and evaluate a novel improvement to a previously published, unreliable covert channel based on the network traffic of multiplayer, first person shooter online games (FPSCC). Covert channels typically embed themselves within pre-existing (overt) data transmissions in order to carry hidden messages. FPSCC encodes covert bits as slight, yet continuous, variations of a player's character's...
Wireless mesh networking (WMN), the static mesh routers (MRs) cooperatively relay each other packets to the Internet Gateway (IGW). The routing protocols assume all the nodes in the network to be non-malicious. However, the open architecture of WMNs paves way to malicious attackers who can exploit hidden loopholes in the routing protocol. In this paper, we mainly focus on the vulnerability of the...
Unlike in IEEE 802.11, the CSMA/CA traffic conditions in IEEE 802.15.3 are typically unsaturated. This paper presents an extended analytical model based on Bianchi's model in IEEE 802.11, by taking into account the device suspending events, unsaturated traffic conditions, as well as the effects of error-prone channels. Based on this model we re-derive a closed form expression of the average service...
Rapid and reliable resolution of the collisions caused by multiple RFID tags during identification is a key factor for the proliferation application of RFID system. In this paper, an enhanced query tree protocol for memoryless passive RFID tags is proposed, in which the binary identifiers stored in the RFID tags and the binary query strings broadcasted by the RFID reader are mapped to real numbers...
In this paper, we study the capacity of cognitive networks. We focus on the network model consisting of two overlapping ad hoc networks, called the primary ad hoc network (PaN) and secondary ad hoc network (SaN), respectively. PaN and SaN operate on the same space and spectrum. For PaN (or SaN resp.) we assume that primary (or secondary resp.) nodes are placed according to a Poisson point process...
In this paper, a new frame size adjusting method is proposed for framed slotted ALOHA algorithm in RFID system. This method does not predict the number of tags. The reader just use the current frame size and the total number of successful slots, idle slots and collision slots in current frame to select a more appropriate frame size to continue the inventory of tags in a new frame. The proposed adjusting...
Recently, there has been much renewed interest in developing compact data structures for packet processing functions such as longest prefix-match for IP lookups. This has been motivated by several factors: (1) The advent of 100 Gbps interfaces necessitating correspondingly fast packet processing algorithms with a compact memory footprint; (2) network virtualization leading to virtualization of physical...
This paper aims at improving the throughput of the wireless sensor networks (WSNs), particularly to overcome the so-called funneling effect for WSNs with converge-cast patterns. Due to the disproportionate larger number of packets accumulated in the sensors that are closer to the sink, there is a need to decrease the collisions and increase the throughput around the sink area as well as the nodes...
With the increasing concern for global warming, the impact of Internet power consumption is gaining interest. In this paper, we explore, for the first time, the relationship between network robustness, performance and Internet power consumption. We first discuss such a relationship based on data collected from Internet sources. Next, we propose a modeling framework to size that relationship. It is...
Synchronous dataflow graphs (SDFGs) are widely used to model streaming applications such as signal processing and multimedia applications. These are often implemented on resource-constrained embedded platforms ranging from PDAs and cell phones to automobile equipment and printing systems. Trade-off analysis between resource usage and performance is critical in the life cycle of those products, from...
A new hardware efficient, low power postprocessor architecture is presented in this paper to correct the mismatch errors in time interleaved ADCs. The Least Mean Squares (LMS) algorithm is utilized as correction algorithm to identify the offset and gain mismatches. The proposed architecture uses one processing core for calibrating all parallel channels output codes with reference channel. Increasing...
This paper studies the importance of accounting for a neglected facet of overall workload behavior, the pattern of task arrival. A stochastic characterization is formulated that defines regularity in the task arrival pattern. This characterization is used as the basis for a quantitative evaluation of the importance of accurately accounting for the task arrival behavior in the design of the processing...
This paper considers a communication system where m synchronized transmitters access a shared medium independently of each other with probability p, and upon access each user transmits a signal subject to an average power constraint P. A common receiver observes the sum of the signals transmitted by the active users corrupted by additive Gaussian noise. Let the throughput denote the sum of the achievable...
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