273 research outputs found
Space-time coding techniques with bit-interleaved coded modulations for MIMO block-fading channels
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
Models of Control Channels in the LTE System
DizertaÄnĂ prĂĄce se zabĂœvĂĄ zpracovĂĄnĂm signĂĄlu fyzickĂœch ĆĂdicĂch kanĂĄlĆŻ systĂ©mu LTE a vyĆĄetĆovĂĄnĂm bitovĂ© chybovosti pĆi pĆenosu ĆĂdicĂ informace z vysĂlaÄe do pĆijĂmaÄe v zĂĄvislosti na podmĂnkĂĄch pĆĂjmu. PrĂĄce je rozdÄlena do dvou hlavnĂch ÄĂĄstĂ. PrvnĂ ÄĂĄst prĂĄce je zamÄĆena na simulaci pĆenosu ĆĂdicĂ informace LTE v zĂĄkladnĂm pĂĄsmu. Jsou zde prezentovĂĄny vytvoĆenĂ© simulĂĄtory ĆĂdicĂch kanĂĄlĆŻ ve smÄru uplink i downlink. Simulace jsou provedeny pro vĆĄechny druhy nastavenĂ systĂ©mu a zĂĄkladnĂ modely pĆenosovĂ©ho prostĆedĂ. Jsou zde popsĂĄny vĂœsledky vlivu pouĆŸitĂ MIMO technologiĂ na kvalitu pĆĂjmu ĆĂdicĂ informace pĆedevĆĄĂm v ĂșnikovĂœch kanĂĄlech. DruhĂĄ ÄĂĄst prĂĄce je zamÄĆena na moĆŸnost nasazenĂ systĂ©mu LTE ve sdĂlenĂ©m pĂĄsmu ISM (2.4 GHz). Jsou zde pĆedstaveny zĂĄkladnĂ koncepce pouĆŸitĂ, na jejichĆŸ zĂĄkladÄ je vytvoĆen scĂ©nĂĄĆ simulacĂ. Kapitola dĂĄle popisuje tvorbu simulĂĄtoru koexistence LTE a systĂ©mu Wi-Fi v pĆenesenĂ©m pĂĄsmu ISM 2.4GHz. Jsou zde uvedeny vĂœsledky simulacĂ koexistence LTE a ruĆĄivĂ©ho systĂ©mu Wi-Fi provedenĂœch dle vytvoĆenĂ©ho scĂ©nĂĄĆe. VĂœsledky simulacĂ koexistence LTE a Wi-Fi jsou ovÄĆeny mÄĆenĂm v laboratornĂch podmĂnkĂĄch. Toto porovnĂĄnĂ je dĆŻleĆŸitĂ© z hlediska optimalizace simulĂĄtoru koexistence. Dle vĂœsledkĆŻ obou typĆŻ simulacĂ a mÄĆenĂ jsou stanovena provoznĂ doporuÄenĂ, kterĂĄ majĂ pĆispÄt k bezpeÄnĂ©mu a spolehlivĂ©mu vysĂlĂĄnĂ a pĆĂjmu ĆĂdicĂch informacĂ LTE i pĆi nepĆĂznivĂœch podmĂnkĂĄch pĆĂjmu.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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