Low Complexity OFDM Modulator and Demodulator Based on Discrete Hartley Transform

Sembiring, Zakaria; Malek, Mohd Fareq Abd; Rahim, Hasliza A.

doi:10.1109/ams.2011.54

Cited by 6 publications

(2 citation statements)

References 8 publications

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“…Поряд із широким застосуванням швидких перетворень Фур'є, у системах зв'язку з використанням OFDM технології інтенсивно досліджують використання перетворень у базисі функцій Хартлі [14], косинусних [3], синусних функцій та ін. Так, у роботі [16] проводять аналіз і порівняння OFTDM-мультиплексування на базі швидких перетворень Фур'є та швидких косинусних перетворень.…”

Section: ʑ˔˕˖˒unclassified

Fast Transforms of Fourier Class in Ofdm Technology of Wireless Transmission Systems

Prots'ko¹

2019

UJIT

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The main modifications and standards of OFDM technology that provide high quality communication in multipath transmission of the transmitted signal are highlighted. It is analyzed in the structure of the transmitter of the communication system based on OFDM technology of execution of fast transforms of Fourier class. The orthogonal frequency division multiplexing / demultiplexing function is assigned to the fast computer of transform, and the precoder is used to reduce the high peak factor inherent in OFDM technology. The basic elements and requirements for the computers that perform fast transforms in the structural scheme of implementation of OFDM technology are determined. The relation between the number of subcarriers and the size of basic transform of OFDM technology is considered. The possibility of using Fourier, Hartley transforms and cosine transforms in the precoder has been found out. The basic stages of the method of constructing the structural scheme of fast Fourier transforms based on cyclic convolutions are formulated. The identified steps include: building a hashing array, determining a simplified hashing array supplemented by an array of signs, constructing and analyzing a generalized structure of the basis matrix, building blocks of input data integration, building blocks of cyclic convolutions, building blocks of combining results of cyclic convolutions whose outputs are results of direct/indirect transforms of Fourier class based on cyclic convolutions. The stages of constructing and analyzing the generalized structure of the basic matrix are performed on the basis of a hashing array, a simplified hashing array, and an array of signs. The tabular assignment of the block-cyclic structure of the basic matrix specifies the coordinates of the placement of the sign and the simplified value of the first elements of the cyclic submatrices. An example for the ішяу N=16 of determining the hashing array, the simplified hashing array and the sign array, the block-cyclic structure of the basis matrix used in constructing the structural scheme of the computer is considered. An example of a structural scheme of a DHT-I of size N=20, containing four blocks of execution of a 4-point cyclic convolution. The technique of constructing the structure scheme of computers using cyclic convolution blocks can be used to efficient perform discrete transforms of Fourier class in OFDM-based communication systems. The possibility of using structural construction technique to automate the process of constructing structural schemes the transforms of Fourier class based on cyclic convolutions has been established.

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Section: ʑ˔˕˖˒unclassified

Fast Transforms of Fourier Class in Ofdm Technology of Wireless Transmission Systems

Prots'ko¹

2019

UJIT

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“…Many researches were proposed to improve the performance of the OFDM system such as channel equalization [7][8][9] and ICI reduction using pre-coding for self-cancelation [10][11][12][13][14] and using wideband OFDM with spectrum losses [15,16]. In [17][18][19] a DHT based OFDM system is proposed similarly as the conventional system except the FFT is replaced by the DHT to improve system performance. In this paper a suitable solution is proposed to improve system performance through the splitting of OFDM spectrum into multi-orthogonal bands where each band is designed to carry local OFDM symbol and all local symbols form the global OFDM symbol.…”

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confidence: 99%

Design and Simulation of Hartley based Multi Orthogonal Band OFDM

Shaheen¹

2013

IJCA

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Recent advances in wireless communication systems have made use of OFDM technique to achieve high data rate transmission. The sensitivity to frequency offset between the carrier frequencies of the transmitter and the receiver is one of the major problems in OFDM systems. This frequency offset introduces inter-carrier interference in the OFDM symbol and then the BER performance reduced. In this paper a MultiOrthogonal-Band MOB-OFDM system based on the Discrete Hartley Transform (DHT) is proposed to improve the BER performance. The OFDM spectrum is divided into equal subbands and the data is divided between these bands to form a local OFDM symbol in each sub-band using DHT. The global OFDM symbol is formed from all sub-bands together using the (IDHT). The BER performance of the proposed system is simulated and compared with the conventional OFDM in different channel conditions to show the gain in SNR achieved by the proposed system.

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