273 research outputs found

    Space-time coding techniques with bit-interleaved coded modulations for MIMO block-fading channels

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    The space-time bit-interleaved coded modulation (ST-BICM) is an efficient technique to obtain high diversity and coding gain on a block-fading MIMO channel. Its maximum-likelihood (ML) performance is computed under ideal interleaving conditions, which enables a global optimization taking into account channel coding. Thanks to a diversity upperbound derived from the Singleton bound, an appropriate choice of the time dimension of the space-time coding is possible, which maximizes diversity while minimizing complexity. Based on the analysis, an optimized interleaver and a set of linear precoders, called dispersive nucleo algebraic (DNA) precoders are proposed. The proposed precoders have good performance with respect to the state of the art and exist for any number of transmit antennas and any time dimension. With turbo codes, they exhibit a frame error rate which does not increase with frame length.Comment: Submitted to IEEE Trans. on Information Theory, Submission: January 2006 - First review: June 200

    Frequency-domain precoding for single carrier frequency-division multiple access

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    Models of Control Channels in the LTE System

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    DizertačnĂ­ prĂĄce se zabĂœvĂĄ zpracovĂĄnĂ­m signĂĄlu fyzickĂœch ƙídicĂ­ch kanĂĄlĆŻ systĂ©mu LTE a vyĆĄetƙovĂĄnĂ­m bitovĂ© chybovosti pƙi pƙenosu ƙídicĂ­ informace z vysĂ­lače do pƙijĂ­mače v zĂĄvislosti na podmĂ­nkĂĄch pƙíjmu. PrĂĄce je rozdělena do dvou hlavnĂ­ch částĂ­. PrvnĂ­ část prĂĄce je zaměƙena na simulaci pƙenosu ƙídicĂ­ informace LTE v zĂĄkladnĂ­m pĂĄsmu. Jsou zde prezentovĂĄny vytvoƙenĂ© simulĂĄtory ƙídicĂ­ch kanĂĄlĆŻ ve směru uplink i downlink. Simulace jsou provedeny pro vĆĄechny druhy nastavenĂ­ systĂ©mu a zĂĄkladnĂ­ modely pƙenosovĂ©ho prostƙedĂ­. Jsou zde popsĂĄny vĂœsledky vlivu pouĆŸitĂ­ MIMO technologiĂ­ na kvalitu pƙíjmu ƙídicĂ­ informace pƙedevĆĄĂ­m v ĂșnikovĂœch kanĂĄlech. DruhĂĄ část prĂĄce je zaměƙena na moĆŸnost nasazenĂ­ systĂ©mu LTE ve sdĂ­lenĂ©m pĂĄsmu ISM (2.4 GHz). Jsou zde pƙedstaveny zĂĄkladnĂ­ koncepce pouĆŸitĂ­, na jejichĆŸ zĂĄkladě je vytvoƙen scĂ©náƙ simulacĂ­. Kapitola dĂĄle popisuje tvorbu simulĂĄtoru koexistence LTE a systĂ©mu Wi-Fi v pƙenesenĂ©m pĂĄsmu ISM 2.4GHz. Jsou zde uvedeny vĂœsledky simulacĂ­ koexistence LTE a ruĆĄivĂ©ho systĂ©mu Wi-Fi provedenĂœch dle vytvoƙenĂ©ho scĂ©náƙe. VĂœsledky simulacĂ­ koexistence LTE a Wi-Fi jsou ověƙeny měƙenĂ­m v laboratornĂ­ch podmĂ­nkĂĄch. Toto porovnĂĄnĂ­ je dĆŻleĆŸitĂ© z hlediska optimalizace simulĂĄtoru koexistence. Dle vĂœsledkĆŻ obou typĆŻ simulacĂ­ a měƙenĂ­ jsou stanovena provoznĂ­ doporučenĂ­, kterĂĄ majĂ­ pƙispět k bezpečnĂ©mu a spolehlivĂ©mu vysĂ­lĂĄnĂ­ a pƙíjmu ƙídicĂ­ch informacĂ­ LTE i pƙi nepƙíznivĂœch podmĂ­nkĂĄch pƙíjmu.The doctoral thesis is focused on a signal processing in the LTE physical control channels and performance analysis of control information transmission according to receiving conditions. The thesis is divided into two parts. The first part deals with simulation of the transmission of control information in baseband. The created simulators for uplink and downlink are presented. The simulations are performed for all possible system settings and various channel models. The MIMO influence on a quality of control information reception under fading channels is also presented. The second part of the thesis is focused on LTE utilization in shared channel ISM (2.4 GHz). The basic LTE application concept for ISM band is presented. This concept is fundamental to created simulation scenario. The chapter also presents the LTE and Wi-Fi coexistence simulator in 2.4 GHz ISM passband. The coexistence simulation are presented according to simulation scenario and the results are shown. The simulated coexistence analysis results are verified in laboratory environment. The comparison of the simulated and the measured coexistence analysis results is crucial for further optimization of the coexistence simulator. Recommendations for optimal and reliable operation of LTE are specified according to the simulated and the measured results. Recommendations should be useful to the reliable transmission of LTE control information in bad receiving conditions.
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