Frequency-hopping spread spectrum

About: Frequency-hopping spread spectrum is a research topic. Over the lifetime, 5294 publications have been published within this topic receiving 60685 citations.

Wireless video distribution

Abstract: A system and method for providing interactive multimedia services to subscriber premises utilizing wireless distribution within the subscriber premise. The service is provided via a communications link delivering to the subscriber premises broad band digital information including video and audio from a plurality of information providers and control signals in a multiplexed form. This multiplexed signal is then separated and processed on premise and distributed in a two-way fashion using frequency hopping code division multiple access (CDMA) spread spectrum using radio frequency signals preferably at UHF. Upstream control signals from the user installation are communicated from the individual user terminals in the same wireless manner.

Jamming-resistant Key Establishment using Uncoordinated Frequency Hopping

Abstract: We consider the following problem: how can two devices that do not share any secrets establish a shared secret key over a wireless radio channel in the presence of a communication jammer? An inherent challenge in solving this problem is that known anti-jamming techniques (e.g., frequency hopping or direct-sequence spread spectrum) which should support device communication during the key establishment require that the devices share a secret spreading key (or code) prior to the start of their communication. This requirement creates a circular dependency between antijamming spread-spectrum communication and key establishment, which has so far not been addressed. In this work, we propose an uncoordinated frequency hopping (UFH) scheme that breaks this dependency and enables key establishment in the presence of a communication jammer. We perform a detailed analysis of our UFH scheme and show its feasibility, both in terms of execution time and resource requirements.

Throughput Analysis in Multihop CSMA Packet Radio Networks

Abstract: In this paper, we use a Markov model to develop a product form solution to efficiently analyze the throughput of arbitrary topology multihop packet radio networks that employ a carrier sensing multiple access (CSMA) protocol with perfect capture. We consider both exponential and nonexponential packet length distributions. Our method preserves the dependence between nodes, characteristic of CSMA, and determines the joint probability that nodes are transmitting. The product form analysis provides the basis for an automated algorithm that determines the maximum throughput in networks of size up to 100 radio nodes. Numerical examples for several networks are presented. This model has led to many theoretical and practical extensions. These include determination of conditions for product form analysis to hold, extension to other access protocols, and consideration of acknowledgments.

Wireless positioning technologies and applications

Abstract: At last--here's a comprehensive book that puts full details on all short-range wireless-positioning methods at your command for instant access and use. This one-stop resource surveys each technique's theory of operation, advantages and disadvantages, applicability in different domains, implementation procedures, and accuracy to help you select the right technology for any application and ensure the best results possible. Real-life examples together with 161 diagrams help bring all options into sharp focus. After introducing wireless positioning fundamentals along with various personal, commercial, and industrial applications, the book guides you step by step through radio signal time of flight methods, the signal strength method, the angle of arrival system, and the geometric use of distance measurement to determine location. It discusses location awareness applications and implementations using cellular networks. You are brought up to speed on fast-developing techniques involving local area networks (WLANs), personal area networks (WPANs), and radio frequency ID (RFID). Moreover, you find coverage of the distance measurement features in the new IEEE 802.15.4a spec for low rate wireless personal area networks. This practical resource offers detailed guidance on how to implement important technologies, including direct sequence spread spectrum, frequency hopping spread spectrum, and ultrawideband (UWB). The book also explores ways to counteract accuracy impairments caused by noise, multipath and fading, and limitations of antenna directivity and time measurement precision.

Signaling strategies for dual-function radar communications: an overview

Abstract: The last decade witnessed a growing demand on radio frequency that is driven by technological advances benefiting the end consumer but requiring new allocations of frequency bandwidths. Further, higher data rates for faster communications and wireless connections have called for an expanded share of existing frequency allocations. Concerns for spectrum congestion and frequency unavailability have spurred extensive research efforts on spectrum management and efficiency [1]-[4] within the same type of service and have led to cognitive radio [5] and cognitive radar [6]. On the other hand, devising schemes for coexistence among different services have eased the competition for spectrum resources, especially for radar and wireless communication systems [7]-[14]. Both systems have been recently given a common portion of the spectrum by the Federal Communications Commission.