Sequential design of a 8192 complex point FFT in OFDM receiver

In this paper we propose an implementation method for a single-chip 8192 complex point FFT in terms of sequential data processing. In order to reduce the required chip area for the sequential processing of 8 K complex data, a DRAM-like pipelined commutator architecture is used. The 16-point FFT is a basic building block of the entire FFT chip, and the 8192-point FFT consists of the cascaded blocks with six stages of radix-4 and one stage of radix-2. Since each stage requires rounding of the resulting bits while maintaining the proper S/N ratio, the convergent block floating point (CBFP) algorithm is used for the effective internal bit rounding. As a result the proposed structure brings about the 55% chip size reduction compared with conventional approach.