892 research outputs found

    Optimization of high-definition video coding and hybrid fiber-wireless transmission in the 60 GHz band

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    This paper was published in OPTICS EXPRESS and is made available as an electronic reprint with the permission of OSA. The paper can be found at the following URL on the OSA website: http://dx.doi.org/10.1364/OE.19.00B895. Systematic or multiple reproduction or distribution to multiple locations via electronic or other means is prohibited and is subject to penalties under law[EN] The paper addresses the problem of distribution of highdefinition video over fiber-wireless networks. The physical layer architecture with the low complexity envelope detection solution is investigated. We present both experimental studies and simulation of high quality high-definition compressed video transmission over 60 GHz fiberwireless link. Using advanced video coding we satisfy low complexity and low delay constraints, meanwhile preserving the superb video quality after significantly extended wireless distance. © 2011 Optical Society of America.This work has been partly funded by the European Commission under FP7 ICT-249142 FIVER project and by the by the Spanish Ministry of Science and Innovation under the TEC2009-14250 ULTRADEF project.Lebedev, A.; Pham, T.; Beltrán Ramírez, M.; Yu, X.; Ukhanova, A.; Llorente Sáez, R.; Monroy, I.... (2011). Optimization of high-definition video coding and hybrid fiber-wireless transmission in the 60 GHz band. Optics Express. 19(26):895-904. https://doi.org/10.1364/OE.19.00B895S8959041926Stockhammer, T., Hannuksela, M. M., & Wiegand, T. (2003). H.264/AVC in wireless environments. IEEE Transactions on Circuits and Systems for Video Technology, 13(7), 657-673. doi:10.1109/tcsvt.2003.815167Yong, S. K., & Chong, C.-C. (2006). An Overview of Multigigabit Wireless through Millimeter Wave Technology: Potentials and Technical Challenges. EURASIP Journal on Wireless Communications and Networking, 2007(1). doi:10.1155/2007/7890

    Shuttle/TDRSS Ku-band downlink study

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    Assessing the adequacy of the baseline signal design approach, developing performance specifications for the return link hardware, and performing detailed design and parameter optimization tasks was accomplished by completing five specific study tasks. The results of these tasks show that the basic signal structure design is sound and that the goals can be met. Constraints placed on return link hardware by this structure allow reasonable specifications to be written so that no extreme technical risk areas in equipment design are foreseen. A third channel can be added to the PM mode without seriously degrading the other services. The feasibility of using only a PM mode was shown to exist, however, this will require use of some digital TV transmission techniques. Each task and its results are summarized

    Study and simulation of low rate video coding schemes

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    The semiannual report is included. Topics covered include communication, information science, data compression, remote sensing, color mapped images, robust coding scheme for packet video, recursively indexed differential pulse code modulation, image compression technique for use on token ring networks, and joint source/channel coder design

    A FEASIBILITY STUDY ON C-RAN

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    Now a days the number of users of mobile phone are increasing exponentially, so it will cause jamming in the network  and require  large bandwidth So among promising technology candidates to overcome this problem, cloud radio access network (C-RAN) used.C-RAN, having one baseband unit (BBU) communicates with users through distributed Remote Radio Heads (RRHs) .RRH  are connected to the BBU via high capability, low latency fronthaul links and performs soft relaying. The architecture of C-RAN imposes a shortage of fronthaul bandwidth because raw I/Q  samples are exchanged between the RRHs and the BBU.In BBU different algorithms are used to improve the capacity,joint decompression and decoding(JDD) and wynerziv coding

    Second year technical report on-board processing for future satellite communications systems

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    Advanced baseband and microwave switching techniques for large domestic communications satellites operating in the 30/20 GHz frequency bands are discussed. The nominal baseband processor throughput is one million packets per second (1.6 Gb/s) from one thousand T1 carrier rate customer premises terminals. A frequency reuse factor of sixteen is assumed by using 16 spot antenna beams with the same 100 MHz bandwidth per beam and a modulation with a one b/s per Hz bandwidth efficiency. Eight of the beams are fixed on major metropolitan areas and eight are scanning beams which periodically cover the remainder of the U.S. under dynamic control. User signals are regenerated (demodulated/remodulated) and message packages are reformatted on board. Frequency division multiple access and time division multiplex are employed on the uplinks and downlinks, respectively, for terminals within the coverage area and dwell interval of a scanning beam. Link establishment and packet routing protocols are defined. Also described is a detailed design of a separate 100 x 100 microwave switch capable of handling nonregenerated signals occupying the remaining 2.4 GHz bandwidth with 60 dB of isolation, at an estimated weight and power consumption of approximately 400 kg and 100 W, respectively
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