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Chapter 25 - An 802.11g WLAN System on a Chip
- from Part X - 802.11 Hardware Design
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- By Srenik Mehta, Atheros Communications, David Weber, Atheros Communications, Manolis Terrovitis, Atheros Communications, Keith Onodera, Atheros Communications, Michael MacK, Atheros Communications, Brian Kaczynski, Atheros Communications, Hirad Samavati, Atheros Communications, Steve Jen, Atheros Communications, Weimin Si, Atheros Communications, MeeLan Lee, Atheros Communications, Kalwant Singh, Atheros Communications, Suni Mendis, Atheros Communications, Paul Husted, Atheros Communications, Ning Zhang, Atheros Communications, Bill McFarland, Atheros Communications, David Su, Atheros Communications, Teresa Meng, Stanford University, Bruce Wooley, Stanford University
- Edited by Benny Bing, Georgia Institute of Technology
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- Book:
- Emerging Technologies in Wireless LANs
- Published online:
- 10 December 2009
- Print publication:
- 05 November 2007, pp 551-562
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- Chapter
- Export citation
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Summary
A single-chip IEEE 802.11g compliant wireless LAN system-on-a-chip (SoC) that implements all RF, analog, digital PHY and MAC functions has been integrated in a 0.18-µm CMOS technology. The IC transmits 0 dBm EVM-compliant output power for a 64 QAM OFDM signal. The overall receiver sensitivities are better than -92 dBm and - 73 dBm for data rates of 6 Mbps and 54 Mbps, respectively.
Introduction
The IEEE 802.11g specification which was only ratified in June 2003, has become the most widely deployed wireless local area network (WLAN) standard today. Its popularity is due in large part to its support for higher data rates while maintaining backwards compatibility to legacy IEEE 802.11b WLANs. An IEEE 802.11g device achieves the higher data rate when communicating with other 802.11g devices by using orthogonal frequency division multiplexing (OFDM) modulation. When communicating with legacy 802.11b devices, it will revert back to either direct sequence spread spectrum (DSSS) or complementary code keying (CCK) modulation. The standard uses 83.5-MHz of available spectrum in the 2.4-GHz band and allows for three non-overlapping channels. The data rates range from 1-2 Mbps using DSSS modulation, 5.5-11 Mbps using CCK modulation, and 6-54 Mbps using OFDM modulation. As in the IEEE 802.11a specification the OFDM in 802.11g uses 52 sub-carriers, each of which can be modulated with BPSK, QPSK, 16-QAM or 64-QAM.
The rapid adoption of IEEE 802.11g WLANs and their growing popularity in portable applications such as PDAs and cellphones highlighted the need for a low-cost, small form factor solution.