Frequency-hopping spread spectrum
About: Frequency-hopping spread spectrum is a(n) research topic. Over the lifetime, 5294 publication(s) have been published within this topic receiving 60685 citation(s).
TL;DR: A number of important multiuser DS-CDMA detectors that have been proposed are described, where information about multiple users is used to improve detection of each individual user.
Abstract: Direct-sequence code-division multiple access (DS-CDMA) is a popular wireless technology. In DS-CDMA communications, all of the users' signals overlap in time and frequency and cause mutual interference. The conventional DS-CDMA detector follows a single-user detection strategy in which each user is detected separately without regard for the other users. A better strategy is multi-user detection, where information about multiple users is used to improve detection of each individual user. This article describes a number of important multiuser DS-CDMA detectors that have been proposed.
••01 Jan 1987
TL;DR: This paper outlines those features that distinguish the High Frequency (HF) Intra Task Force (ITF) Network from other packet radio networks, and presents a design concept for this network that encompasses organizational structure, waveform design, and channel access.
Abstract: The design of a packet radio network must reflect the operational requirements and environmental constraints to which it is subject. In this paper, we outline those features that distinguish the High Frequency (HF) Intra Task Force (ITF) Network from other packet radio networks, and we present a design concept for this network that encompasses organizational structure, waveform design, and channel access. Network survivability is achieved through the use of distributed network control and frequency hopping spread-spectrum signaling. We demonstrate how the execution of the fully distributed Linked Cluster Algorithm can enable a network to reconfigure itself when it is affected by connectivity changes such as those resulting from jamming. Additional resistance against jamming is provided by frequency hopping, which leads naturally to the use of code division mutiple access (CDMA) techniques that permit the simultaneous successful transmission by several users. Distributed algorithms that exploit CDMA properties have been developed to schedule contention-free transmissions for much of the channel access in this network. Contention-based channel access protocols can also be implemented in conjunction with the Linked Cluster network structure. The design concept presented in this paper provides a high degree of survivability and flexibility, to accommodate changing environmental conditions and user demands.
•14 May 1999
Abstract: From the Publisher: Mobile radio communications technology has progressed rapidly and it is now capable of the transmission of voice, data and image signals. This new edition explains the latest techniques employed in second and third generation systems. A comprehensive all-in-one mobile communication reference work, Mobile Radio Communications, Second Edition reflects the current state-of-the-art by featuring expanded and updated sections on voice compression techniques, interleaving and channel coding methods, quaternary frequency shift keying, continuous phase modulation methods, Viterbi equalisation and slow frequency hopping as well as extended coverage of the GSM system; and three new chapters on wireless multimedia, third generation systems and on WATM respectively. As in the first edition, this edition continues to cover important topics such as radio propagation, multiple access methods and, on a higher level, cordless telecommunications and teletraffic issues. This book will prove invaluable to mobile communication engineers, designers, researchers and students in the design, operation and research of second and third generation systems and wireless LANs.
Abstract: The recent FCC frequency allocation for UWB has generated a lot of interest in UWB technologies. There is 7,500 MHz of spectrum for unlicensed use. The main limitations are provided by the low-power spectral density and by the fact that the transmit signal must occupy at least 500 MHz at whole times. IEEE 802.15.3a is being developed for high-bit-rate PAN applications, and UWB is the most promising technology to support the stringent requirements: 110, 200, and 480 Mb/s. Two UWB multiband systems, frequency hopping and Spectral Keying, have been described in this article. Both systems meet the stringent requirements provided by IEEE 802.15.
TL;DR: The authors obtain the optimum transmission ranges to maximize throughput for a direct-sequence spread-spectrum multihop packet radio network and model the network self-interference as a random variable which is equal to the sum of the interference power of all other terminals plus background noise.
Abstract: The authors obtain the optimum transmission ranges to maximize throughput for a direct-sequence spread-spectrum multihop packet radio network. In the analysis, they model the network self-interference as a random variable which is equal to the sum of the interference power of all other terminals plus background noise. The model is applicable to other spread-spectrum schemes where the interference of one user appears as a noise source with constant power spectral density to the other users. The network terminals are modeled as a random Poisson field of interference power emitters. The statistics of the interference power at a receiving terminal are obtained and shown to be the stable distributions of a parameter that is dependent on the propagation power loss law. The optimum transmission range in such a network is of the form CK/sup alpha / where C is a constant, K is a function of the processing gain, the background noise power spectral density, and the degree of error-correction coding used, and alpha is related to the power loss law. The results obtained can be used in heuristics to determine optimum routing strategies in multihop networks. >