80-Mb/s QPSK and 72-Mb/s 64-QAM flexible and scalable digital OFDM transceiver ASICs for wireless local area networks in the 5-GHz band

Abstract

With the advent of mobile communications, voice telecommunications became wireless. Future applications, however, target multimedia, messaging, and high-speed Internet access, all expressing the need for a broadband high-speed wireless access technique. Both the domestic multimedia and the wireless local area network (WLANs) business markets are addressed. Established systems deliver 2-11 Mb/s based on spectrally inefficient spread-spectrum techniques, where scalability has reached a limit. The next generation of modems requires spectrally more efficient low-power and highly integrated solutions. We describe here the design of two digital baseband orthogonal frequency division multiplex (OFDM) signal processing ASICs, implementing respectively a quaternary phase-shift keying (QPSK)-based 80-Mb/s and a 64 quadrature amplitude modulation (QAM)-based 72-Mb/s digital inner transceiver. The latter partially matches the Hiperlan/2 and IEEE 802.11a standards. Joint development of signal processing algorithms and architectures along with on-chip data transfer, control, and partitioning leads to a low-power, yet flexible and scalable implementation. Both ASICs were designed in a unique object-oriented C++ design flow starting from algorithm level. The ASICs were successfully tested in a 5-GHz testbed both for file data transfer and web-cam multimedia transmission.