Novel DDS Based OFDM Transmitter Structure without IFFT and Interpolation Filter

The traditional orthogonal frequency divi-sion multiplexing(OFDM)transmitter is implemented by inverse fast Fourier transform(IFFT),up-sampling and low pass shaping filter(LPSF),which occupy a large number of hardware resources and have long la-tency.To further meet the 5G and future 6G commu-nication requirements,this paper proposes a novel di-rect digital synthesis(DDS)based OFDM transmitter structure that can replace these modules.Due to the strong parallelism of the system structure,it is very suitable for implementation on field programable gate array(FPGA)platform.After making two special sim-plifications to the primary structure,the refined struc-ture becomes very simple compared with the tradi-tional structures.Most attractively,the proposed struc-ture has the following three advantages that i)the data transformation from frequency domain to time domain has zero latency,ii)the transformation length does not need to be an integer power of 2 and iii)the struc-ture does not even need to use any multiplier,thus leading to low implementation complexity and high speed.Comparative experiments are carried out on Intel FPGA platform which show that our DDS based structure can save more than half of the resources com-pared with the traditional structures and can provide the same bit error rate(BER)performance under the condition without using any LPSF.