alamouti apos s transmit diversityscheme for ofdm systems
A Study of Channel Estimation for OFDM Systems and System Capacity for MIMO-OFDM Systems
... 2: OFDM systems and MIMO systems Since the thesis studies the channel estimation for OFDM systems and system capacity for MIMO -OFDM systems, this chapter briefly introduces the background of OFDM ... 2.2 OFDM systems 20 2.2.1 Basic principles and characteristics for OFDM systems 21 2.2.2 Peak-to-Average (PAR) of OFDM systems 30 2.2.3 Channel estimation for OFDM systems ... of OFDM system operation This section summarized the process of OFDM systems Fig 2.17 depicts the discrete baseband OFDM system model The baseband transmitted OFDM signals can be written as N...
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Báo cáo hóa học: "Channel length assisted symbol synchronization for OFDM systems in multipath fading channels" potx
... length assisted symbol synchronization algorithm Section IV discusses in detail the design issues Section V demonstrates simulation results Finally, Section VI draws conclusions II OFDM signal ... length assisted synchronization scheme based on the properties of OFDM signals Only simple operations, such as the multiplication and addition operations, are necessary Simulation results demonstrate ... performance of symbol synchronization, the channel length is used explicitly in this work This work presents a new synchronization algorithm, assisted by channel length information, for OFDM systems...
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Báo cáo hóa học: "Research Article Low-Complexity Estimation of CFO and Frequency Independent I/Q Mismatch for OFDM Systems" pdf
... dB for gain mismatch and [0, 4◦ ] for phase mismatch System performance versus SNR for coded and uncoded systems is shown in Figures and respectively, where CFO is uniformly distributed over ... and I/Q mismatch estimation in OFDM systems In Section 3, the proposed CFO and I/Q mismatch estimation schemes are developed Simulation results are presented in Section Section concludes the paper ... frequency offest estimation for OFDM systems with I/Q imbalance,” in Proceedings of the 47th IEEE Midwest Symposium on Circuits and Systems (MWSCAS ’04), vol 2, pp 633–636, Cincinnati, Ohio, USA, July...
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Báo cáo hóa học: " Research Article Degenerated-Inverse-Matrix-Based Channel Estimation for OFDM Systems" pdf
... under the specifications that we assumed for 4G mobile systems Our conclusions are given in Section System Description Figure shows the frame format for OFDM signals The data symbols are time-multiplexed ... where N is the size of the fast Fourier transform (FFT) used in the system Consider the OFDM system shown in Figure 2, where xn are the transmitted symbols, g(t) is the channel impulse response (CIR), ... gDIM is reformed by zero-padding all the discarded samples Zeropadding also has the function of suppressing residual noise 4.1 System Parameters The main simulation parameters assumed for a broadband...
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Báo cáo hóa học: "Research Article A Fast LMMSE Channel Estimation Method for OFDM Systems" ppt
... comparison We study two cases One case is the MSE analysis for matched SNR, that is, the designed SNR is equal to the true SNR, and the other one is the MSE analysis for mismatched SNR Secondly, ... by conclusion in Section System Model The OFDM system model with pilot signal (i.e., training sequence) assisted is shown in Figure For N subcarriers in the OFDM system, the transmitted signal ... tap for NMST OFDM symbols, PLS (k), by formula (15) Then, we choose the L most significant taps from PLS (k) and reserve it as PMST (k), by formula (18) Step Obtain the estimate of SNR, SNR, by formula...
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Báo cáo hóa học: " Research Article Opportunistic Scheduling for OFDM Systems with Fairness Constraints" docx
... systems such as TDMA However, the same is not the case for multiplechannel systems In this paper, we propose an opportunistic scheduling framework for multiuser OFDM systems We build on Liu s ... problem (U, S, E, w), where U represents the set of all users, S represents the set of all subcarriers, and E represents the set of all the feasible choices for specific users to select specific subcarriers ... channels from all mobile users The scheduling decision made by the scheduler is conveyed to the OFDM transmitter The transmitter then assigns different transmission rates to scheduled users on corresponding...
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Báo cáo hóa học: " Research Article Opportunistic Scheduling for OFDM Systems with Fairness Constraints" pdf
... systems such as TDMA However, the same is not the case for multiplechannel systems In this paper, we propose an opportunistic scheduling framework for multiuser OFDM systems We build on Liu s ... problem (U, S, E, w), where U represents the set of all users, S represents the set of all subcarriers, and E represents the set of all the feasible choices for specific users to select specific subcarriers ... channels from all mobile users The scheduling decision made by the scheduler is conveyed to the OFDM transmitter The transmitter then assigns different transmission rates to scheduled users on corresponding...
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Báo cáo hóa học: " Research Article Carrier Frequency Offset Estimation and I/Q Imbalance Compensation for OFDM Systems" pot
... burst-mode transmission systems It 10 should be mentioned that the proposed technique can easily be extended for applications in other communication systems as long as those systems have a similar ... OFDM systems, ” IEEE Transactions on Wireless Communications, vol 2, no 4, pp 822–839, 2003 [4] N Lashkarian and S Kiaei, “Class of cyclic-based estimators for frequency-offset estimation of OFDM systems, ” ... OFDM frame is assumed to contain 10 short symbols followed by 10 OFDM symbols The I/Q imbalance is assumed as g = dB and θ = 15◦ Figure shows the BER-SNR plots of a BPSK OFDM system with and...
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Báo cáo hóa học: " Research Article Channel Impulse Response Length and Noise Variance Estimation for OFDM Systems with Adaptive Guard Interval" docx
... important OFDM system parameters for simulations are listed as follows: 0.5 0 L Proposed method Larsson s method (c) Figure 8: Comparison results of the PDF obtained by Larsson s and proposed methods, ... has been shown by simulation results that this method provides reliable estimation results in terms of the CIR length and the noise variance, even though the OFDM systems suffer from the presence ... estimate is significantly less than a second It calls for a new class of OFDM systems with adaptive GI length, which optimizes the GI length according to the transmission environment Our future research...
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Báo cáo hóa học: " Low-Complexity Banded Equalizers for OFDM Systems in Doppler Spread Channels" ppt
... spreads CONCLUSIONS In this paper, we have designed banded MMSE equalizers for OFDM systems in high Doppler spread channels Thanks to a band LDL factorization algorithm, these MMSE equalizers ... Computations, Johns Hopkins University Press, Baltimore, Md, USA, 3rd edition, 1996 [18] L Tong, B M Sadler, and M Dong, “Pilot-assisted wireless transmissions,” IEEE Signal Processing Magazine, ... fast TV scenarios, channel estimation as well as its effect on the BER performance has to be considered Recently, several authors [7, 14–16] proposed pilot-assisted channel estimation techniques...
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Báo cáo hóa học: " A Low-Complexity KL Expansion-Based Channel Estimator for OFDM Systems" pptx
... 40 SNR (dB) SNR (dB) Simulation results: SNR design = 10 dB Theoretical results: SNR design = 10 dB Simulation results: SNR design = 30 dB Simulation results: SNR design = 30 dB Simulation results: ... in Figure describes the conventional OFDM system We consider an OFDM system with K subcarriers for the transmission of K parallel data symbols Thus, the information stream X(n) is parsed into K-long ... estimator s sensitivity to the channel statistics in terms of average MSE and SER performance measures, respectively As it can be seen from Figures and 7, only small performance loss is observed for...
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Transmit and receive techniques for MIMO OFDM systems
... channels can also be used to exploit diversity gains and improve the robustness of wireless communication systems against fading This is achieved by transmitting spacetime coded signals through ... systems transfers the spatial diversity to frequency diversity by making use of the linear algebraic model of OFDM systems • Proposed a two-dimensional linear pre-transformed MIMO -OFDM system structure ... Signal to Noise Ratio SS spatial spreading ST Space-Time STBC Space Time Block Code(d) STC Space Time Code(d) STFP Space-Time-Freq(uency)-Precoding STSR single -transmit single-receive STTC Space Time...
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Semi-blind signal detection for mimo and mimo-ofdm systems
... method is proposed for quasisynchronous MIMO systems operating in multi-path channels The proposed technique consists of three steps The first step separates the multi-user multi-path signal vector ... Rake-based multi-user detection technique is proposed for quasi-synchronous MIMO systems The first step separates the multi-user multi-path signal vector into multi-user single-path signal vectors ... Moulines, 1997; Liu and Xu, 1997; Hua, An and Xiang, 2003] for synchronous MIMO systems can be used to separate the users’ signals into multi-user single-path signals Unlike CDMA systems where...
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oracle9i administrator's reference for unix systems aix-based systems, compaq tru64 unix, hp 9000 series hp-ux, linux intel, and sun solaris
... Intimate Shared Memory (Solaris Only) On Solaris systems, Oracle9i uses Intimate Shared Memory (ISM) for shared memory segments because it shares virtual memory resources among Oracle processes On Solaris ... Configuration Assistant Summary window appears, users must change the SYS and SYSTEM account passwords You cannot use the default CHANGE_ON_INSTALL and MANAGER passwords For security reasons, the Database ... Administrator s Reference System Global Area Note: The process name for the oradism utility is ora_dism_sid, where sid is the system identifier When using DISM, this process is started during instance...
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oracle9i administrator's reference for unix systems aix-based systems, compaq tru64 unix, hp 9000 series hp-ux, linux intel, and sun solaris
... Intimate Shared Memory (Solaris Only) On Solaris systems, Oracle9i uses Intimate Shared Memory (ISM) for shared memory segments because it shares virtual memory resources among Oracle processes On Solaris ... Configuration Assistant Summary window appears, users must change the SYS and SYSTEM account passwords You cannot use the default CHANGE_ON_INSTALL and MANAGER passwords For security reasons, the Database ... Administrator s Reference System Global Area Note: The process name for the oradism utility is ora_dism_sid, where sid is the system identifier When using DISM, this process is started during instance...
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oracle9i administrator's reference for unix systems aix-based systems, compaq tru64 unix, hp 9000 series hp-ux, linux intel, and sun solaris
... Intimate Shared Memory (Solaris Only) On Solaris systems, Oracle9i uses Intimate Shared Memory (ISM) for shared memory segments because it shares virtual memory resources among Oracle processes On Solaris ... Configuration Assistant Summary window appears, users must change the SYS and SYSTEM account passwords You cannot use the default CHANGE_ON_INSTALL and MANAGER passwords For security reasons, the Database ... Administrator s Reference System Global Area Note: The process name for the oradism utility is ora_dism_sid, where sid is the system identifier When using DISM, this process is started during instance...
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Báo cáo hóa học: " Precoding and Transmitter-Side processing techniques for multiuser MIMO OFDM systems with special emphasis on the PAPR problem" pdf
... and Luis A Paredes-Hernandez as well as “Low PAPR space frequency block coding for multiuser MIMO SC-FDMA systems: Specific issues for users with different spectral allocations“ by Cristina Ciochina, ... al.: Precoding and Transmitter-Side processing techniques for multiuser MIMO OFDM systems with special emphasis on the PAPR problem EURASIP Journal on Advances in Signal Processing 2011 2011:59 ... phase shifts within context of PTS technique is presented Space-time-frequency block coded system are analyzed for PAPR reduction in “PAPR Reduction in SFBC MIMO MC-CDMA Systems via User Reservation“...
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Báo cáo hóa học: " Preamble and pilot symbol design for channel estimation in OFDM systems with null subcarriers" pdf
... MIMO -OFDM as well as the SISO -OFDM systems Like PEP, our proposed method can be easily adopted in the design of the disjoint pilot symbols for MIMO -OFDM systems For MIMO -OFDM systems that utilizes ... referred as PEP in this article, is discussed in [13] The algorithm in [13] is novel as it can be employed to design pilot symbols for both the MIMO -OFDM as well as SISO -OFDM systems Furthermore, ... proposed design to be a candidate for pilot symbols design in OFDM systems with null subcarriers VII Conclusion We have addressed the design of optimal preamble as well as suboptimal pilot symbols...
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Báo cáo hóa học: " Particle swarm optimization for pilot tones design in MIMO-OFDM systems" pot
... 127 for the system which has 128 subcarriers, and and 63 for the system which has 64 subcarriers All the possible combinations of particle positions are tested using fitness R function that is ... coded (STBC) OFDM system are investigated to get optimal solution of MMSE algorithm In this article, LS channel estimation algorithm for MIMO -OFDM systems based on comb-type pilot tones is described ... tones using PSO that is in Figure (d) Optimized both power and location of pilot tones using PSO If fitness (p) better than fitness (pbest) then pbest=p Set best of pBests as gBest Update the position...
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Báo cáo hóa học: " Research Article Automatic IP Generation of FFT/IFFT Processors with Word-Length Optimization for MIMO-OFDM Systems" doc
... power consumption is estimated from the synthesized results at 1-V supply voltage Usually it is pessimistic compared to the measurement results Other designs of 64-point FFT processors for 802.11a, ... various OFDM systems than previous works Although we not address issues for power reduction, such as dynamic voltage and frequency scaling in [7] and thus the power consumption seems larger, the system-level ... the use of sleep transistors or multiple-threshold transistors, especially in nanotechnology Besides, in large-size FFT processors, instead of shift registers, the delay buffers are usually implemented...
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