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Transmission parameter adaptation in a dynamic multicarrier environment is a challenging task for cognitive radio. We propose a novel adaptation method that uses binary ant colony optimization to optimize the cognitive radio parameters given a set of objectives. Simulation results show that proposed method performs better than genetic algorithm -based adaptation method in terms of convergence speed...
Automated animal monitoring with energy efficient wireless devices mounted on the animals can improve efficiency of farming industry and increase its profitability by decreasing reliance on human labor. We discuss the practical deployment of delay tolerant store and forward cattle monitoring architecture that provides data retention, detecting custom events, notification issuing, remote and in-situ...
In this paper, the performances of generalized selection combining (GSC) will be observed. Combiner has three inputs. The two strongest signals are isolated and added. For this combiner the probability density function for the output signal, characteristic function and moments for the output signals will be derived and the error probability for BPSK modulation will be determined when log-normal fading...
This paper addresses an effective early detection system of wildfires using high resolution images from low-light sensitive cameras linked to an innovative HS/RF (High Speed/Radio Frequency) communications grid. Using data compression techniques, a data-stream and signal management application, combined with OFDM data transmission, the HS/RF enables ldquobroadband speedrdquo wireless communications...
In mobile radio environment, the co-channel interference (CCI) resulting from frequency reuse is the main cause of call drops, unnecessary handoffs, compromising voice quality and channel capacity reduction. CCI is one of the most significant factors limiting the capacity and scalability of wireless networks. Various techniques such as power control, antenna down tilting, cell sectoring and multiple...
In this paper, realizing full diversity in relay channels operating in decode and forward (DF) scheme is considered. In the proposed system, the worst relay according to a chosen criterion is cancelled while the remaining ones utilize beamforming. Both theoretical analysis, and experimental comparisons in bit error rate (BER) performance are given for the proposed system and the system where all relays...
In this paper, we study the design of constellation labeling for iteratively decoded concatenated multilayer space-time error correcting codes (STECCs). We propose also an iterative receiver structure exploiting the inter-dependence between labeling bits addressing one modulation symbol. Simulations using quadratic amplitude modulation of order four (4-QAM) with two constellation labelings show the...
This paper investigates the allocation of subcarriers and power in the downlink channels of multiuser OFDM systems. The goal is to minimize the total transmit power under the constraints of user data rates and bit error rate (BER). We propose a sub-optimal algorithm to achieve the goal in this paper. We introduce a new factor which is the gain difference between the maximum and the next maximum userspsila...
Mobile networks and services have grown dramatically since digital networks were introduced in the early nineties. Now operators want to provide broadband services over the Internet to mobile and wireless users. The pressure on the transport network will increase dramatically, and more cost effective solutions for the backhaul are urgently needed. This includes both physical layer and higher protocol...
The possibility to create a wireless network through portable devices (or nodes) is getting more and more common. A community of users who use a Smartphone or a PDA can quickly establish a net everywhere. Mobile Ad hoc Networks (MANETs) are nets without a fixed infrastructure and the routing of information is left to participants. In a MANET, each device may take any type of behaviuor, but collaboration...
The increased interest in long lasting wireless sensor networks motivates to use Free Space Optics (FSO) link along with radio frequency (RF) link for communication. Earlier results show that RF/FSO wireless sensor networks has life time twice as long as RF only wireless sensor networks. However, for terrestrial applications, the effect of weather such as rain or snow on optical wireless communication...
In this paper, we propose a criterion for code selection to enhance the performance of a Time-Hopping Ultra-Wide Band (TH-UWB) system, namely the Average Collision Number (ACN) of multi-user codes. We show that the Multi-Users Interference (MUI) power depends on this criterion and the enhancement of the performance in terms of error rate could be improved if the ACN criterion is minimized. This result...
In the newly emerging body area networks (BANs), substantial demands come from both medical applications and consumer electronics (CE) applications. Due to the heterogeneous service requirements, MAC protocol design becomes a new challenge for BANs. To address this problem, a priority-guaranteed MAC protocol is proposed in this paper. In this protocol, data and control channels are split to support...
This paper presents the main features of a new IQRF wireless communications platform. The platform was designed and developed for home and industrial automation. Some basic functions of operating systems, development tools and basic modules are described. On a case study a basic home automation application is discussed. The new proprietary wireless communication platform IQRF was developed. Its advantages,...
Wireless Sensor Network security localization technologies are usually designed just for one type of attack or single step transmission for the message packets, which would be less robust in complex network environment. In this paper, we propose a novel WSN security localization algorithm: Double Guarantee Security Sensor Localization, which can enhance the reliability and security of message packets...
Informing users about new resource assignments has to be broadcast, thus generating a substantial amount of the mapping overhead that influences the system throughput. In particular, the performance of voice-over-Internet protocol (VoIP) services is seriously affected by the mapping overhead because the VoIP packet size is small. In order to reduce the mapping overhead, a semi-fixed mapping scheme...
In this contribution, four different schemes are suggested for multiple antennas multiple relays and their performances are evaluated and compared via computer simulation. At each relay, maximal ratio combining (MRC) in the receiving side and beamforming in the transmitting side are employed. Amplify and forward (AF), and estimate and forward methods (EF) used for single antenna relays are employed...
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