Abstract
A systematic approach is presented for automatically generating variable-size FFT/IFFT soft intellectual property (IP) cores for MIMO-OFDM systems. The finite-precision effect in an FFT processor is first analyzed, and then an effective word-length searching algorithm is proposed and incorporated in the proposed IP generator. From the comparison, we show that our analysis of the finite precision effect in FFT is much more accurate than the previous work. With the flexible architecture and the effective word-length searching techniques, we can strike a good balance for the performance and the hardware cost of the generated IP cores. The generated FFT soft IP cores are portable and independent of the silicon technology, which helps to greatly reduce the design time. Experimental results demonstrate that the proposed IP generator indeed provides FFT IPs which meet the requirements and are more suitable in recent MIMO-OFDM communication standards/drafts than some conventional FFT IP generators.
Highlights
Orthogonal frequency-division multiplexing (OFDM) is one of the most popular modulation schemes in recent wireless communication systems
In this paper we propose an intellectual property (IP) generator to offer userspecific fast Fourier transform (FFT) processors targeting at the requests in recent and emerging multiple-input multipleoutput (MIMO)-OFDM communication systems
(9), reveals the reason that a shorter word-length can always be assigned for twiddle factors than the data path in an FFT processor since 2s/N 1
Summary
Orthogonal frequency-division multiplexing (OFDM) is one of the most popular modulation schemes in recent wireless communication systems. In OFDM transceivers, discrete Fourier transform (DFT) operation plays an important role to modulate data onto each subcarrier. With the fast Fourier transform (FFT) algorithm, hardware implementation of DFT, which is computation intensive and communication intensive, becomes feasible. Different OFDM systems use various FFT sizes to accommodate time-selective and/or frequency-selective channel environments. FFT operations of variable sizes are mandatory to offer the scalability for performance considerations. An extensive literature exists, which reports the lower-power/small-area/high-speed implementation of the dedicated FFT processors for certain single-input single-output (SISO) wireless communication standards/specifications [1,2,3,4,5] and for multiple-input multiple-output OFDM systems [6, 7]
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