High spectral efficiency can be achieved by a large size of transmit and receive antennas, but the BER performance of conventional linear and successive interference cancellation SIC receivers cannot be Ofdm thesis 2013 to max- imum likelihood ML receivers.
OFDM system has high utilization Ofdm thesis 2013 frequency spectrum and satisfactory capability of reducing multi-path inference.
Thus, interference awareness becomes important concept for OFDM-based systems that are excepted to be highly adaptive for coping with existing impairment.
Graduate Theses and Dissertations. However, with an increasing number of applications operating in highly mobile environments, the effect of dispersive fading caused by a combination of multi-path propagation and doppler shift is more significant.
Retrieved May 29, Identification and Separation" Normally, high data rates require shorter duration symbols, increasing the risk of ISI. Information symbols are represented in various domains of electro space such as time, frequency, and code.
Firstly, it introduces the basic principle and realization of OFDM system, and describes the system construction and model with summary of some key technologies, such as fast Fourier transform FFT and cyclic prefix CP.
Sydney, Australia November 8—12, The candidates bound can also be computed by the initial radius Ofdm thesis 2013 the updated radius to reduce the tree span as the sphere decoder does.
In practice, this means that the subchannels are allowed to partially overlap in frequency. Therefore, eye diagram in frequency domain for OFDM-based signals is introduced for visualization and identification of time varying impairments such as frequency spread and carrier frequency offset.
Retrieved May 27, Five novel techniques toward the physical layer security of wireless communications are proposed. Hence, a SIC based complex-valued sphere decoder is proposed with prob- abilistic tree pruning. Proceedings of the IEEE. The subchannels must be spaced apart in frequency just enough to ensure that their time-domain waveforms are orthogonal to each other.
In signal processing applications, discrete Fourier transforms DFTs are used to operate on real-time signal samples. Huseyin Arslan Abstract Orthogonal frequency-division multiplexing OFDM is communication technique that is robust against multipath spread, efficient in equalization implementation, and flexible in dynamic spectrum usage.
Each user may employ up to four of the available eight spatial streams. However, the initial radius and candidates bound for the union bound estimation have not been studied, which have significant influences on the search complexity.
We also propose the use of multiband channels in future wireless communication systems to alleviate the problem of radio spectrum scarcity. The broadcast nature of radio propagation, however, causes wireless communications particularly vulnerable to malicious attacks, and leads to critical challenges in securing the wireless transmission.
However, OFDM can be combined with multiple access using time, frequency or coding separation of the users.
Also, powers of corresponding interferences are estimated separately with the proposed technique. Electronic Thesis and Dissertation Repository.
Computer simulations and measurements also confirmed the effectiveness of the interference separation method. Similarly, time interleaving ensures that bits that are originally close together in the bit-stream are transmitted far apart in time, thus mitigating against severe fading as would happen when travelling at high speed.
The third and fourth techniques utilize wireless medium characteristics to enhance the built-in security of wireless communication systems, so as to prevent passive eavesdropping.
An interference spectrogram is developed in order to be able to investigate several interferences with one diagram solely. The development of 5G standards is expected to begin in The term discrete multitone modulation DMT denotes OFDM-based communication systems that adapt the transmission to the channel conditions individually for each sub-carrier, by means of so-called bit-loading.
Hence, a channel statistics based initial radius is derived based on the Rayleigh-Ritz theorem and the probability den- sity function PDF of the channel matrix.
Despite its prominent advantages, received signal quality degrades because of inter-symbol interference IS and inter-carrier interference ICI due to insufficient guard time in multipath channels and time variance as well as hardware impairments in OFDM systems. The first two techniques focus on the security risk assessment in wireless networks to enable a situation-awareness based transmission protection.
In this thesis, we propose a procedure for determining relative subchannel quality without using any traditional channel measurements.
This is accomplished without the need for additional power or bandwidth. MIMO multiplies the capacity of a radio link by transmitting multiple signals over multiple, co-located antennas.
michaelferrisjr.com THESIS ABSTRACT Sr No Area Page No 1 Power & Control 2 Signal Processing, Communications & Networks 3 Microelectronics 64 OFDM based out-of-band dedicated common control channel design for cognitive radio networks BanerjeeAdrish Sircar Pradip 9.
This is to certify that the work in the thesis entitled FPGA Implementation of Circularly Shifted PTS Technique for PAPR Reduction in OFDM by Seemanjali Sahoo is a record of an original research work carried out by her during - under my. Thesis submitted to the faculty of the Virginia Polytechnic Institute and State University in Orthogonal Frequency Division Multiplexing (OFDM) is a modulation scheme which has become Internship in the summer of Orthogonal Frequency Division Multiplexing (OFDM) plays a crucial role and reduce receiver complexity in May-June.
pp ISSN: michaelferrisjr.com | Page presence of burst errors. The interleaved are grouped together to form symbols.
The symbols are then modulated using. The authors propose something called orthogonal frequency division multiplexing (OFDM) in the downstream, and its upstream counterpart orthogonal Gallager in his Ph.D. thesis but, because of encoder and decoder complexity, it wasn’t practical to 8/19/ PM.
MAJOR PROFESSOR: Dr. Garth V. Crosby, In this thesis we proposed PSO based PTS to accomplish the lowest Peak-to-Average Power Ratio of MIMO-OFDM system.
We applied the PSO based PTS on each antenna of the system in order to find the optimal phase factors which is a straightforward method to get the minimum PAPR in such a system.Ofdm thesis 2013