wlan testing basics发展到下一代无线连接测试局域网解决方案应用工程师.pdf

Evolve to the next generation in Wireless Connectivity test Agilent WLAN Solution Zhao Xinxiang Application Engineer WLAN Measurement Basics WLAN Overview - Standards Test Requirements Making N4010A Measurements - Meeting the Standards Test Requirements Good Measurement Practice Troubleshooting - OFDM Troubleshooting - RF Measurements Test Solutions - Golden Radio v’s One Box Testers WLAN Standards System Modulation 802.11 Chapter Data Rates IEEE802.11 2-GFSK or 4-GFSK FHSS 14 1 or 2 Mbps DBPSK or DQPSK DSSS 15 IEEE802.11b CCK, PBCC 18 5.5 or 11 Mbps IEEE802.11g 64 OFDM + BPSK, 19 6, 9, 12, 18, 24, QPSK, 16 QAM, 64 QAM 36, 48, 54 Mbps System Modulation Data Rates IEEE802.11a 64 OFDM + BPSK, 6, 9, 12, 18,24, 36, (Chapter 17) QPSK, 16QAM, 64 QAM 48, 54 Mbps • Japan – 802.11j (Appendix I) • Europe– 802.11h (Chapter 17) Standard IEEE 802.11b Packet Structure LONG Standard IEEE 802.11b Packet Structure SHORT Standard IEEE 802.11g PSDU (MPDU) – DSSS- OFDM •Same PLCP Preamble and Header as b, then •the PSDU uses (g-mode) OFDM format. Standard IEEE 802.11a 802.11g PSDU (MPDU) Orthogonal Frequency Division Multiplexing •Closelyspaced carriers overlap •Nulls in each carrier’s spectrum land at the center of all other carriers for Zero Inter-Carrier Interference Structure of OFDM Frame Short Training Chan. Estimation SIGNAL Data 1 Data 2 …Data N . . . Data Mod. Coding Bits per