Abstract
Wireless personal area network (WPAN), currently under development by IEEE 802.15.3c Task Group, targets to provide multi-giga bits per second (multi-Gbps) data rate for the short-distance and ultra-high speed communication technology in the next generation. The high-speed interface (HSI) mode defined in this standard adopts orthogonal frequency division multiplexing (OFDM), which, with great bandwidth efficiency and invulnerability to non-ideal channel, is regarded as a prospective modulation strategy. Its specifications, however, impose a great challenge on the design of its key component, a long-length and high-throughput-rate Fast Fourier Transform (FFT) processor with acceptable hardware cost. In this thesis, we proposed a high throughput-rate and hardware-efficient 2048-point FFT/IFFT processor, in which the number of parallel paths is extended from four to eight.Besides, an efficient memory-accessing scheme and a novel constant-based multiplier unit are also proposed to reduce both area and power consumptions resulted from doubled data-path numbers. Also, a new multi-data scaling method is proposed, which can be easily integrated with multi-path delay-feedback (MDF) architecture using relatively simple control logic. The proposed FFT/IFFT processor is implemented in UMC 90-nm 1P9M process, whose core area is 1.18 mm2 and power consumption is 127 mW at 300MHz operating frequency. Compared with previous four-path architecture, the proposed processor has only 21.6% more area cost and provides up to 2.4G sample/s throughput rate at only 8.5% more power consumption. Moreover, a test chip of 128-point FFT processor is fabricated using UMC 90-nm 1P9M process to verify the high throughput-rate and hardware-efficiency of our architecture. This test chip has a core area of 0.53 mm2, a power consumption of 6.8 mW at 52 MHz operating frequency, and a maximum throughput rate of 2.08G sample/s. Therefore, the proposed 2048-point FFT/IFFT processor is a promising solution to the realization of OFDM-based WPAN systems in the future.