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Wireless sensor networks (WSN) are used in many fields such as industrial control, building automation, environmental monitoring, etc. IEEE 802.15.4 standard defines the features of MAC layer and physical layer for WSN. Many analytical models studied the performance of the multihop IEEE 802.15.4 networks under the assumption of ideal wireless channel, and they did not consider the effect of imperfect...
There are advantages to retrieve information from the Wireless Sensor Network (WSN) for UAVs (Unmanned Aerial Vehicles). However, the UAV-WSN system has some differences with conventional WSN system. So it is important to design an appropriate scheme to control the transmission in a UAV-WSN system. In this paper we proposed a protocol called A-OAloha (Adaptive-Opportunistic Aloha) for UAV-UAV-WSN...
In this paper we exploit cooperative relaying for energy savings in narrowband short range communication scenarios. The nodes can operate under cooperative decode-and-forward with repetition coding (RC) or with parallel coding (PC), and cooperative amplify-and-forward (AF) protocols. The system is constrained by maximum packet loss and end-to-end throughput requirements. Our results show that, when...
We consider a time slotted cognitive radio (CR) network under Rayleigh fading where multiple secondary users (SUs) contend for spectrum usage over available primary users' channels. In the contention, all SUs use common access probabilities to decide whether they access one of available channels. We focus on the throughput performance of an arbitrary SU. To improve the throughput performance of SUs,...
To better exploit the spectrum resources a wireless sensor network can be used to assists a secondary cognitive radio network by providing information about the current primary spectrum occupancy. In this paper we study the performance of the secondary network when it is co-located with and having similar cell size as a mobile primary network that uses a cellular reuse pattern with seven frequencies...
A Sensor Network Aided Cognitive Radio Network uses the concept of a wireless sensor network that assists a cognitive radio network by providing information about the current primary spectrum occupancy. In this paper we study the performance of the cognitive network for various cell sizes and transmit power levels when deployed co-located with a mobile primary system that uses a cellular reuse pattern...
A major challenge for cooperative communication in distributed networks is to coordinate relay transmissions without introducing too much overhead. Targeting a clustered network, we propose a novel cooperative communication scheme including channel quality based relay selection and distributed space-time code allocation in this paper. Both analysis and simulations are carried out to investigate the...
In this paper we analyze the energy efficiency of single-hop, multi-hop and incremental decode-and-forward in wireless sensor networks composed of multiple nodes. The energy efficiency analysis is constrained by a target outage probability and an end-to-end throughput, while the Nakagami-m distribution is used to model the small scale fading. Our results show that in most scenarios the cooperative...
The evaluation of wireless research is challenging because signals traveling through the ether are affected by the physical environment, including movement by people and objects. As a result, testbed experiments are hard to control and are non-repeatable. We have developed a wireless networking testbed based on digital signal propagation emulation that provides control over the signal propagation...
Wireless multicast can exploit broadcast nature of wireless communication. It is sufficient to transmit information only once to reach a group of users. But some users may fail to receive it due to channel fading etc. Thus, we have to find a proper threshold of scheduling and retransmit in order to reduce the packet loss. In this paper, the multicast scheduling problem with packet loss and delay constraints...
Energy efficiency is a considerable criterion in design of wireless sensor networks. MIMO technology has the potential of supporting a higher data rate under a lower power budget and bit-error-rate, which makes cooperative MIMO in WSNs a popular research topic. This paper investigates a cluster-based time division cooperative MIMO communication system for WSNs. An optimum algorithm for the power and...
The low rate wireless personal network (LR-WPAN) is a new standard uniquely designed for low data rates and low energy consumption. LR-WPAN researchers are focusing extensively on the wireless technology and energy consumption, but many papers do not cover channel characterization and link quality assessment in LR-WPANs, even though we could reasonably surmise that the network performance will be...
The concept of cooperative diversity promises to offer the benefits of spatial diversity gains to handheld wireless devices with single antennas. So far the research has focused on special modulation or space-time coding in order to allow the cooperating terminals transmit simultaneously during the relay phase. In this paper, we proposed a joint relay selection and ARQ scheme in the cooperative diversity...
We study sensor networks with energy harvesting nodes. The generated energy at a node can be stored in a buffer. A sensor node periodically senses a random field and generates a packet. These packets are stored in a queue and transmitted using the energy available at that time at the node. For such networks we develop efficient energy management policies. First, for a single node, we obtain policies...
In this paper, we present a performance analysis of user scheduling over independent and non-identically distributed Nakagami-m fading channels for multiuser MIMO systems exploiting the multiuser and antenna diversities while maintaining fairness among the users. We consider different scheduling schemes including absolute SNR-based scheduling, and normalized SNR-based scheduling schemes for heterogeneous...
We consider the problem of characterizing per node throughput scaling in arbitrary extended wireless networks. Recently, Ozgur, Leveque, and Tse (2007) obtained a complete characterization of throughput scaling for random extended networks (i.e., nodes are placed in a square region uniformly at random) under a fast fading channel model. They proposed a hierarchical cooperative communication scheme...
Rate adaptation is the determination of the optimal data transmission rate most appropriate for current wireless channel conditions. It consists of assessing channel conditions and accordingly adjusting the rate. Rate adaptation is fairly challenging due to wild channel conditions fluctuations. In the last decade, rate adaptation for IEEE 802.11 networks has been extensively investigated. This paper...
As evidenced by measurement data, channel fading and co-channel interference occur on the same time scales, and it is therefore difficult to determine if packet losses are due to interference change or channel variation. The coupling between the timescales of fading and interference at the MAC layer calls for a unified PHY/MAC design. Using optimal stopping theory, we first devise channel aware distributed...
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