Sun, 27 Jul 2008 07:39:30 BST CiteULike: dcastro's A10 http://www.citeulike.org/user/dcastro/author/A10 CiteULike.org en-gb Copyright © 2004-2008 citeulike.org http://www.citeulike.org/user/dcastro/article/2176491 <i>Communications Magazine, IEEE, Vol. 42, No. 9. (2004), pp. 80-89.</i><br /><br />In recent years, there has been an upsurge of interest in multihop-augmented infrastructure-based networks in both the industry and academia, such as the seed concept in 3GPP, mesh networks in IEEE 802.16, and converge extension of HiperLAN/2 through relays or user-cooperative diversity mesh networks. This article, a synopsis of numerous contributions to the working group 4 of the wireless world research forum and other research work, presents an overview of important topics and applications in the context of relaying. It covers different approaches to exploiting the benefits of multihop communications via relays, such as solutions for radio range extension in mobile and wireless broadband cellular networks (trading range for capacity), and solutions to combat shadowing at high radio frequencies. Furthermore, relaying is presented as a means to reduce infrastructure deployment costs. It is also shown that through the exploitation of spatial diversity, multihop relaying can enhance capacity in cellular networks. We wish to emphasize that while this article focuses on fixed relays, many of the concepts presented can also be applied to systems with moving relays. Relay-based deployment concepts for wireless and mobile broadband radio Relay-based deployment concepts for wireless and mobile broadband radio R Pabst R Pabst BH Walke BH Walke DC Schultz DC Schultz P Herhold H Yanikomeroglu S Mukherjee H Viswanathan M Lott W Zirwas M Dohler A10 H Aghvami A11 DD Falconer A12 GP Fettweis A13 doi:10.1109/MCOM.2004.1336724 Communications Magazine, IEEE, Vol. 42, No. 9. (2004), pp. 80-89. 2007-12-28T05:38:41-00:00 2004 Communications Magazine, IEEE 42 9 80 89 broadband mobile radio http://www.citeulike.org/user/dcastro/article/2822750 <i>Microwave Theory and Techniques, IEEE Transactions on, Vol. 53, No. 4. (2005), pp. 1451-1461.</i><br /><br />In this paper, a new approach for the development of planar metamaterial structures is developed. For this purpose, split-ring resonators (SRRs) and complementary split-ring resonators (CSRRs) coupled to planar transmission lines are investigated. The electromagnetic behavior of these elements, as well as their coupling to the host transmission line, are studied, and analytical equivalent-circuit models are proposed for the isolated and coupled SRRs/CSRRs. From these models, the stopband/passband characteristics of the analyzed SRR/CSRR loaded transmission lines are derived. It is shown that, in the long wavelength limit, these stopbands/passbands can be interpreted as due to the presence of negative/positive values for the effective /spl epsiv/ and /spl mu/ of the line. The proposed analysis is of interest in the design of compact microwave devices based on the metamaterial concept. Equivalent-circuit models for split-ring resonators and complementary split-ring resonators coupled to planar transmission lines JD Baena J Bonache F Martin RM Sillero F Falcone T Lopetegi MAG Laso J Garcia-Garcia I Gil I Gil MF Portillo A10 M Sorolla A11 doi:10.1109/TMTT.2005.845211 Microwave Theory and Techniques, IEEE Transactions on, Vol. 53, No. 4. (2005), pp. 1451-1461. 2008-05-22T10:30:36-00:00 2005 Microwave Theory and Techniques, IEEE Transactions on 53 4 1451 1461 metamaterial planar srr tl http://www.citeulike.org/user/dcastro/article/2801377 <i>Spoken Language, 1996. ICSLP 96. Proceedings., Fourth International Conference on, Vol. 3 (1996), pp. 1676-1679 vol.3.</i><br /><br />We report on the architectural design issues and experiences gained while building and demonstrating an experimental interpreting video phone (IVP) system. The IVP system has been demonstrated in an Internet home shopping simulation simultaneously before live audiences in Japan and the US. An American shop assistant and a Japanese customer engaged in task directed dialogues using their native languages. In addition to their direct audio/visual contact by ISDN video phone, each participant heard a translation of the remote speaker's utterances in a synthetic voice in real time. Each site used a medium size vocabulary, a continuous speech recognition system and a text to speech synthesis (TTS) system for the local language. Recognition results were transmitted over the Internet to the remote site, where the corresponding translated sentence was spoken by TTS in the listener's native language. All of the speech and language processing software components of the system were independently developed proprietary technologies of the authors' laboratories which were integrated using commercially available hardware and communication media. Difficulties encountered in developing the system, the accommodations which were made, and other experiences gained through the process are reported An experimental Japanese/English interpreting video phone system M Karaorman TH Applebaum T Itoh M Endo Y Ohno M Hoshimi T Kamai K Matsui K Hata K Hata S Pearson A10 JC Junqua A11 doi:10.1109/ICSLP.1996.607948 Spoken Language, 1996. ICSLP 96. Proceedings., Fourth International Conference on, Vol. 3 (1996), pp. 1676-1679 vol.3. 2008-05-15T11:34:57-00:00 1996 Spoken Language, 1996. ICSLP 96. Proceedings., Fourth International Conference on 3 1676 1679 vol.3 phone system video http://www.citeulike.org/user/dcastro/article/2762226 <i>Microwave Symposium Digest, 1998 IEEE MTT-S International, Vol. 1 (1998), pp. 327-330 vol.1.</i><br /><br />This paper presents several power amplifier approaches that promise to significantly improve efficiency, while meeting the linearity requirements of advanced, spectrally efficient wireless systems. The approaches include: a) use of active integrated antenna structures that provide harmonic terminations for high efficiency Class F amplifiers; b) integrated dc-dc converters for power conditioning and envelope restoration; c) switching mode amplifiers based on bipolar transistors with controlled saturation; and d) the use of band-pass delta-sigma modulators to tailor input signals Device and circuit approaches for improved linearity and efficiency in microwave transmitters PM Asbeck T Itoh Y Qian MF Chang L Milstein G Hanington PF Chen V Schultz DW Lee DW Lee J Arun A10 doi:10.1109/MWSYM.1998.689385 Microwave Symposium Digest, 1998 IEEE MTT-S International, Vol. 1 (1998), pp. 327-330 vol.1. 2008-05-06T18:30:58-00:00 1998 Microwave Symposium Digest, 1998 IEEE MTT-S International 1 327 330 vol.1 efficiency microwave transmitter http://www.citeulike.org/user/dcastro/article/2762106 <i>Proceedings of the IEEE, Vol. 84, No. 2. (1996), pp. 268-298.</i><br /><br />Optical phased arrays represent an enabling new technology that makes possible simple affordable, lightweight, optical sensors offering very precise stabilization, random-access pointing programmable multiple simultaneous beams, a dynamic focus/defocus capability, and moderate to excellent optical power handling capability. These new arrays steer or otherwise operate on an already formed beam. A phase profile is imposed on an optical beam as it is either transmitted through or reflected from the phase shifter array. The imposed phase profile steers, focuses, fans out, or corrects phase aberrations on the beam. The array of optical phase shifters is realized through lithographic patterning of an electrical addressing network on the superstrate of a liquid crystal waveplate. Refractive index changes sufficiently large to realize full-wave differential phase shifts can be effected using low (<10 V) voltages applied to the liquid crystal phase plate electrodes. High efficiency large-angle steering with phased arrays requires phase shifter spacing on the order of a wavelength or less; consequently addressing issues make 1-D optical arrays much more practical than 2-D arrays. Orthogonal oriented 1-D phased arrays are used to deflect a beam in both dimensions. Optical phased arrays with apertures on the order of 4 cm by 4 cm have been fabricated for steering green, red, 1.06 μm, and 10.6 μm radiation. System concepts that include a passive acquisition sensor as well as a laser radar are presented Optical phased array technology PF Mcmanamon TA Dorschner DL Corkum LJ Friedman DS Hobbs M Holz S Liberman HQ Nguyen DP Resler DP Resler RC Sharp A10 EA Watson A11 doi:10.1109/5.482231 Proceedings of the IEEE, Vol. 84, No. 2. (1996), pp. 268-298. 2008-05-06T17:19:28-00:00 1996 Proceedings of the IEEE 84 2 268 298 array optical phased http://www.citeulike.org/user/dcastro/article/2709696 <i>Selected Areas in Communications, IEEE Journal on, Vol. 17, No. 3. (1999), pp. 399-410.</i><br /><br />This paper deals with the measurement and modeling of multipath delay on fixed wireless paths at 1.9 GHz in suburban environments. The primary focus is on the delay profile, which is the normalized plot of received power versus delay in response to an RT “impulse.” We describe measurement campaigns in the western suburbs of Chicago, IL, and in suburban north-central New Jersey. Our analysis of the data suggests to us that, for directive terminal antennas, the delay profile can be modeled as having a “spike-plus-exponential” shape, i.e., a strong return (“spike”) at the lowest delay, plus a set of returns whose mean powers decay exponentially with delay. This delay profile can be characterized by just two parameters (both variable over the terrain), namely, the ratio (K₀) of the average powers in the “spike” and “exponential” components and the decay time constant (τ₀) of the “exponential” component. No such simple structure appears to apply for delay profiles using omnidirectional antennas. For a directive antenna with a 32° beamwidth, we find that: (1) the statistical correlation between the profile parameters K₀ and τ₀ is negligible; (2) these parameters are relatively insensitive to antenna height and path length; and (3) over each measured region (Illinois and New Jersey), K₀ and τ₀ have median values close to 8 dB and just below 0.2 μs, respectively. Moreover, we have found simple probability distributions that accurately portray the variability of K₀ and τ₀ over the terrain A model for the multipath delay profile of fixed wireless channels V Erceg DG Michelson SS Ghassemzadeh LJ Greenstein AJ Rustako PB Guerlain MK Dennison RS Roman DJ Barnickel DJ Barnickel SC Wang A10 RR Miller A11 doi:10.1109/49.753726 Selected Areas in Communications, IEEE Journal on, Vol. 17, No. 3. (1999), pp. 399-410. 2008-04-23T18:12:48-00:00 1999 Selected Areas in Communications, IEEE Journal on 17 3 399 410 channel delay multipath profile wireless http://www.citeulike.org/user/dcastro/article/2674775 <i>Personal Communications, IEEE [see also IEEE Wireless Communications], Vol. 8, No. 6. (2001), pp. 48-57.</i><br /><br />Broadband wireless communication is the key technology to a new generation of products in the consumer market. The emerging standards for the 5 GHz band will form the basis for many applications requiring a high communication bandwidth. Low cost and low power dissipation will be a prerequisite for most mobile applications. One way to realize low-cost systems is to reduce the system complexity and deploy highly integrated components. The work presented in this article discusses aspects of implementing a complete Hiperlan/2 and IEEE 802.11a compliant modem, including the physical layer as well as the data link control layer, into a single chip On the single-chip implementation of a Hiperlan/2 and IEEE 802.11a capable modem E Grass K Tittelbach-Helmrich U Jagdhold A Troya G Lippert O Kruger J Lehmann K Maharatna KF Dombrowski KF Dombrowski N Fiebig A10 R Kraemer A11 P Mahonen A12 doi:10.1109/98.972168 Personal Communications, IEEE [see also IEEE Wireless Communications], Vol. 8, No. 6. (2001), pp. 48-57. 2008-04-15T18:16:17-00:00 2001 Personal Communications, IEEE [see also IEEE Wireless Communications] 8 6 48 57 80211 wifi wlan http://www.citeulike.org/user/dcastro/article/2648124 <i>Aerospace Conference, 2005 IEEE (2005), pp. 1266-1285.</i><br /><br />The National Aeronautics and Space Administration (NASA) Exploration Systems Mission Directorate is planning a series of human and robotic missions to the Earth's Moon and to Mars. These missions will require telecommunication and navigation services. This paper sets forth presumed requirements for such services and presents strawman lunar and Mars telecommunications network architectures to satisfy the presumed requirements. The paper suggests that a modest ground network would suffice for missions to the near-side of the Moon. A constellation of three Lunar Telecommunications Orbiters connected to a modest ground network could provide continuous redundant links to a polar lunar base and its vicinity. For human and robotic missions to Mars, a pair of areostationary satellites could provide continuous redundant links between a mid-latitude Mars base and Deep Space Network antennas augmented by large arrays of 12-m antennas. Integrated network architecture for sustained human and robotic exploration GK Noreen RJ Cesarone LJ Deutsch CD Edwards JA Soloff T Ely BM Cook DD Morabito H Hemmati H Hemmati S Piazzolla A10 R Hastrup A11 DS Abraham A12 MK Sue A13 F Manshadi A14 doi:10.1109/AERO.2005.1559417 Aerospace Conference, 2005 IEEE (2005), pp. 1266-1285. 2008-04-10T06:29:59-00:00 2005 Aerospace Conference, 2005 IEEE 1266 1285 architecture integrated mars network plancom http://www.citeulike.org/user/dcastro/article/2355171 <i>Position, Location, And Navigation Symposium, 2006 IEEE/ION (2006), pp. 883-892.</i> MBOC: The New Optimized Spreading Modulation Recommended for GALILEO L1 OS and GPS L1C GW Hein JA Avila-Rodriguez S Wallner AR Pratt J Owen J Issler JW Betz CJ Hegarty S Lenahan S Lenahan JJ Rushanan A10 AL Kraay A11 TA Stansell A12 Position, Location, And Navigation Symposium, 2006 IEEE/ION (2006), pp. 883-892. 2008-02-08T23:57:44-00:00 2006 Position, Location, And Navigation Symposium, 2006 IEEE/ION 883 892 galileo gps mboc modulation