4 research outputs found
Wireless multiuser communication systems: diversity receiver performance analysis, GSMuD design, and fading channel simulator
Multipath fading phenomenon is central to the design and analysis of wireless communication systems including multiuser systems. If untreated, the fading will corrupt the transmitted signal and often cause performance degradations such as increased communication error and decreased data rate, as compared to wireline channels with little or no multipath fading. On the other hand, this multipath fading phenomenon, if fully utilized, can actually lead to system designs that provide additional gains in system performance as compared to systems that experience non-fading channels.;The central question this thesis tries to answer is how to design and analyze a wireless multiuser system that takes advantage of the benefits the diversity multipath fading channel provides. Two particular techniques are discussed and analyzed in the first part of the thesis: quadrature amplitude modulation (QAM) and diversity receivers, including maximal ratio combining (MRC) and generalized selection combining (GSC). We consider the practical case of imperfect channel estimation (ICE) and develop a new decision variable (DV) of MRC receiver output for M-QAM. By deriving its moment generating function (MGF), we obtain the exact bit error rate (BER) performance under arbitrary correlated Rayleigh and Rician channels, with ICE. GSC provides a tradeoff between receiver complexity and performance. We study the effect of ICE on the GSC output effective SNR under generalized fading channels and obtain the exact BER results for M-QAM systems. The significance of this part lies in that these results provide system designers means to evaluate how different practical channel estimators and their parameters can affect the system\u27s performance and help them distribute system resources that can most effectively improve performance.;In the second part of the thesis, we look at a new diversity technique unique to multiuser systems under multipath fading channels: the multiuser diversity. We devise a generalized selection multiuser diversity (GSMuD) scheme for the practical CDMA downlink systems, where users are selected for transmission based on their respective channel qualities. We include the effect of ICE in the design and analysis of GSMuD. Based on the marginal distribution of the ranked user signal-noise ratios (SNRs), we develop a practical adaptive modulation and coding (AMC) scheme and equal power allocation scheme and statistical optimal 1-D and 2-D power allocation schemes, to fully exploit the available multiuser diversity. We use the convex optimization procedures to obtain the 1-D and 2-D power allocation algorithms, which distribute the total system power in the waterfilling fashion alone the user (1-D) or both user and time (2-D) for the power-limited and energy-limited system respectively. We also propose a normalized SNR based GSMuD scheme where user access fairness issues are explicitly addressed. We address various fairness-related performance metrics such as the user\u27s average access probability (AAP), average access time (AAT), and average wait time (AWT) in the absolute- and normalized-SNR based GSMuD. These metrics are useful for system designers to determine parameters such as optimal packet size and delay constraints.;We observe that Nakakagami-m fading channel model is widely applied to model the real world multipath fading channels of different severity. In the last part of the thesis, we propose a Nakagami-m channel simulator that can generate accurate channel coefficients that follow the Nakagami-m model, with independent quadrature parts, accurate phase distribution and arbitrary auto-correlation property. We demonstrate that the proposed simulator can be extremely useful in simulations involving Nakagami-m fading channel models, evident from the numerous simulation results obtained in earlier parts of the thesis where the fading channel coefficients are generated using this proposed simulator
Proceedings of the Second International Mobile Satellite Conference (IMSC 1990)
Presented here are the proceedings of the Second International Mobile Satellite Conference (IMSC), held June 17-20, 1990 in Ottawa, Canada. Topics covered include future mobile satellite communications concepts, aeronautical applications, modulation and coding, propagation and experimental systems, mobile terminal equipment, network architecture and control, regulatory and policy considerations, vehicle antennas, and speech compression
Dvb-t2 performance analysis in NLOS fading environment
Π‘ΠΈΡΡΠ΅ΠΌΠΈ Π΄ΠΈΠ³ΠΈΡΠ°Π»Π½ΠΎΠ³ Π·Π΅ΠΌΠ°ΡΡΠΊΠΎΠ³ Π²ΠΈΠ΄Π΅ΠΎ Π΅ΠΌΠΈΡΠΎΠ²Π°ΡΠ° (Terrestrial Digital Video
Broadcasting Systems, DVB-T2) Ρ ΡΠ΅Π°Π»Π½ΠΈΠΌ ΡΡΠ»ΠΎΠ²ΠΈΠΌΠ° ΠΏΡΠ΅Π½ΠΎΡΠ° ΡΠ΅ΡΡΠΎ Π½Π΅ Π²ΡΡΠ΅ ΠΏΡΠ΅Π½ΠΎΡ Ρ
ΠΎΠΊΡΡΠΆΠ΅ΡΡ Π³Π΄Π΅ ΡΠ΅ ΠΏΡΠΈΡΡΡΠ½Π° ΠΎΠΏΡΠΈΡΠΊΠ° Π²ΠΈΠ΄ΡΠΈΠ²ΠΎΡΡ (LOS, line-of-sight) ΠΈ Π³Π΄Π΅ ΡΠ΅ Π²ΠΈΡΠΎΠΊ Π½ΠΈΠ²ΠΎ
ΠΎΠ΄Π½ΠΎΡΠ° ΡΠΈΠ³Π½Π°Π»-ΡΡΠΌ ΠΊΠΎΠ½ΡΡΠ°Π½ΡΠ½ΠΎ ΠΏΡΠΈΡΡΡΠ°Π½ Π½Π° ΠΏΡΠΈΡΠ΅ΠΌΡ. Π£ΡΠ»Π΅Π΄ ΡΠΎΠ³Π° ΡΠ°Π²ΡΠ° ΡΠ΅ ΠΏΠΎΡΡΠ΅Π±Π° Π·Π°
ΡΠ°Π·Π²ΠΎΡΠ΅ΠΌ ΡΡΠ°Π½Π΄Π°ΡΠ΄Π° DVB-T2 ΡΠ΅ΡΠ²ΠΈΡΠ° ΠΏΡΠ΅Π½ΠΎΡΠ° Ρ ΠΎΠΊΡΡΠΆΠ΅ΡΡ ΠΊΠ°Π΄Π° Π½ΠΈΡΠ΅ ΠΏΡΠΈΡΡΡΠ½Π° ΠΎΠΏΡΠΈΡΠΊΠ°
Π²ΠΈΠ΄ΡΠΈΠ²ΠΎΡΡ ΠΈ ΠΊΠ°Π΄ ΡΠ΅ Π½ΠΈΠ²ΠΎ SNR Π½Π° ΠΏΡΠΈΡΠ΅ΠΌΡ ΠΈΡΠΏΠΎΠ΄ ΠΏΡΠ΅Π΄Π²ΠΈΡΠ΅Π½ΠΎΠ³ ΠΏΡΠ°Π³Π°.
ΠΡΠΈΠ»ΠΈΠΊΠΎΠΌ ΡΠ°Π·Π²ΠΎΡΠ° DVB-T2 ΡΡΠ°Π½Π΄Π°ΡΠ΄Π° ΠΏΠΎΡΠ΅Π±Π½Π° ΠΏΠ°ΠΆΡΠ° ΡΠ΅ ΠΏΠΎΡΠ²Π΅ΡΠ΅Π½Π° ΡΠ΅Π°Π»ΠΈΠ·Π°ΡΠΈΡΠΈ
ΡΠ΅Ρ
Π½ΠΈΠΊΠ΅ ΠΏΡΠ΅Π½ΠΎΡΠ° ΠΎΡΡΠΎΠ³ΠΎΠ½Π°Π»Π½ΠΎΠ³ ΠΌΡΠ»ΡΠΈΠΏΠ»Π΅ΠΊΡΠ° ΠΏΠΎ ΡΡΠ΅ΠΊΠ²Π΅Π½ΡΠΈΡΠ°ΠΌΠ° (OFDM) Π½Π°ΡΠΎΡΠΈΡΠΎ ΠΊΠΎΠ΄
ΡΡΠ΅Π½Π°ΡΠΈΡΠ° ΠΏΡΠΈΡΠ΅ΠΌΠ° Π²ΠΈΠ΄Π΅ΠΎ ΡΠΈΠ³Π½Π°Π»Π° ΠΏΠΎΠΌΠΎΡΡ ΠΌΠΎΠ±ΠΈΠ»Π½ΠΈΡ
ΡΠ΅Π»Π΅ΡΠΎΠ½Π° ΠΈ Π΄ΡΡΠ³ΠΈΡ
ΠΏΠ°ΠΌΠ΅ΡΠ½ΠΈΡ
ΡΡΠ΅ΡΠ°ΡΠ°.
Π Π°Π·Π²ΠΎΡ Π½ΠΎΠ²ΠΈΡ
DVB-T2 ΡΠ΅ΡΠ²ΠΈΡΠ° ΡΠ°ΠΊΠΎΡΠ΅ Π·Π°Ρ
ΡΠ΅Π²Π° ΡΠ΅Π°Π»ΠΈΠ·Π°ΡΠΈΡΡ ΠΊΠ²Π°Π»ΠΈΡΠ΅ΡΠ½ΠΎΠ³ ΠΏΡΠ΅Π½ΠΎΡΠ° Π²ΠΈΠ΄Π΅ΠΎ
ΡΠΈΠ³Π½Π°Π»Π° Π²ΠΈΡΠΎΠΊΠ΅ Π΄Π΅ΡΠΈΠ½ΠΈΡΠΈΡΠ΅ (HD, high definition) ΠΈ ΠΈΠ½ΡΠ΅Π³ΡΠ°ΡΠΈΡΠ΅ ΡΠ° ΡΠ°Π·Π½ΠΈΠΌ ΡΠ΅ΡΠ²ΠΈΡΠΈΠΌΠ° 5G
ΡΠΈΡΡΠ΅ΠΌΠ° Π²ΠΈΠ΄Π΅ΠΎ ΠΏΡΠ΅Π½ΠΎΡΠ°. ΠΠ΅ΠΆΠΈΡΠ½Π° ΠΊΠΎΠΌΡΠ½ΠΈΠΊΠ°ΡΠΈΡΠ° ΠΈΠ·ΠΌΠ΅ΡΡ ΡΠ°Π·Π»ΠΈΡΠΈΡΠΈΡ
ΡΡΠ΅ΡΠ°ΡΠ° Ρ ΠΎΠΊΡΡΠΆΠ΅ΡΡ
ΠΊΠ°Π΄Π° Π½ΠΈΡΠ΅ ΠΏΡΠΈΡΡΡΠ½Π° ΠΎΠΏΡΠΈΡΠΊΠ° Π²ΠΈΠ΄ΡΠΈΠ²ΠΎΡΡ (NLOS) ΡΠ΅ Π·Π°ΡΠ½ΠΈΠ²Π° Π½Π° ΠΏΡΠ΅Π½ΠΎΡΡ Π²ΠΈΡΠ΅ΡΡΡΡΠΊΠΈΡ
ΠΊΠΎΠΏΠΈΡΠ°
Π΅ΠΌΠΈΡΠΎΠ²Π°Π½ΠΎΠ³ ΡΠΈΠ³Π½Π°Π»Π° ΠΊΠΎΡΠ΅ ΡΡΠΈΠΆΡ Π΄ΠΎ ΠΏΡΠΈΡΠ΅ΠΌΠ½ΠΈΠΊΠ° ΠΏΠΎΡΡΠ΅Π΄ΡΡΠ²ΠΎΠΌ ΡΠ°Π·Π»ΠΈΡΠΈΡΠΈΡ
ΠΏΡΡΠ°ΡΠ°. Π£ΡΠ»Π΅Π΄
ΡΠΎΠ³Π° ΡΠΈΠ³Π½Π°Π» Π½Π° ΠΏΡΠΈΡΠ΅ΠΌΡ ΡΠ΅ ΠΈΠ·Π»ΠΎΠΆΠ΅Π½ ΡΡΠΈΡΠ°ΡΡ ΡΠ΅Π΄ΠΈΠ½Π³Π° ΠΈ ΠΊΠΎ-ΠΊΠ°Π½Π°Π»Π½Π΅ ΠΈΠ½ΡΠ΅ΡΡΠ΅ΡΠ΅Π½ΡΠΈΡe