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Power Amp Effects for HRb OFDM

This paper discusses the non-ideal power amplifier effects for HRb OFDM, including spectral characteristics, pulse shaping requirements, PA output backoff, and PER with PA. The RAPP model is used to estimate subcarrier amplitude/phz over packet in a non-ideal scenario.

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Power Amp Effects for HRb OFDM

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  1. Power Amp Effects for HRb OFDM Paul Chiuchiolo and Mark Webster Intersil Corporation Paul Chiuchiolo and Mark Webster, Intersil

  2. Non-Ideal PA Effects for OFDM • Spectral characteristics of PA input/output • BPSK, QPSK, 16-QAM, 64-QAM • Over-sample rate of 4x • Pulse shaping requirements same as 802.11a • PER with PA • PA Output Backoff • Backoff from full saturation • RAPP model used with p=2 and 3 • Good approximation of existing amplifiers • 6.6, 13.2, 26.4 and 59.4 Mbps, 1000 bytes • Oversample rate of 4x • Estimate subcarrier amp/phz over packet (non-ideal) Paul Chiuchiolo and Mark Webster, Intersil

  3. RAPP Power Amplifier (PA) Model (Amplitude out/in) Paul Chiuchiolo and Mark Webster, Intersil

  4. RAPP Power Amplifier (PA) Model (dB out/in) Output from Full Saturation Paul Chiuchiolo and Mark Webster, Intersil

  5. "p" parameter 1 2 3 4 5 6 7 8 9 10 0 -1 -2 -3 -4 (dB) Output Power -5 -6 -7 -8 -9 -10 Output Power at 1 dB Compression Point Saturation Point 1 dB Compression Point vs. Full Saturation Where is 1 dB Compression Point? P=2: 2 dB from Full Saturation P=3: 1 dB from Full Saturation Paul Chiuchiolo and Mark Webster, Intersil

  6. PA Back-off for 802.11b 802.11 DSSS Barker Must Back-off PA 3.7 dB from full saturation to meet spectral mask. PA: Rapp Model p = 2 802.11b mask Paul Chiuchiolo and Mark Webster, Intersil

  7. PSD for PA Input with BPSK Subcarriers Equivalent 802.11a mask 11 MHz Paul Chiuchiolo and Mark Webster, Intersil

  8. backoff=3.7dB backoff=4.7dB backoff=8.2dB backoff=12.0dB backoff=16.0dB PSD for PA Output with BPSK Subcarriers Backoff from Full Saturation P = 2 Paul Chiuchiolo and Mark Webster, Intersil

  9. backoff=3.4dB backoff=4.6dB backoff=8.1dB backoff=12.0dB backoff=16.0dB PSD for PA Output with BPSK Subcarriers Backoff from Full Saturation P = 3 Paul Chiuchiolo and Mark Webster, Intersil

  10. PSD for PA Input with QPSK Subcarriers Equivalent 802.11a mask Paul Chiuchiolo and Mark Webster, Intersil

  11. backoff=3.7dB backoff=4.7dB backoff=8.2dB backoff=12.0dB backoff=16.0dB PSD for PA Output with QPSK Subcarriers Backoff from Full Saturation P = 2 Paul Chiuchiolo and Mark Webster, Intersil

  12. backoff=3.4dB backoff=4.6dB backoff=8.1dB backoff=12.0dB backoff=16.0dB PSD for PA Output with QPSK Subcarriers Backoff from Full Saturation P = 3 Paul Chiuchiolo and Mark Webster, Intersil

  13. PSD for PA Input with 16-QAM Subcarriers Equivalent 802.11a mask Paul Chiuchiolo and Mark Webster, Intersil

  14. backoff=3.7dB backoff=4.7dB backoff=8.2dB backoff=12.0dB backoff=16.0dB PSD for PA Output with 16-QAM Subcarriers Backoff from Full Saturation P = 2 Paul Chiuchiolo and Mark Webster, Intersil

  15. backoff=3.4dB backoff=4.6dB backoff=8.1dB backoff=12.0dB backoff=16.0dB PSD for PA Output with 16-QAM Subcarriers Backoff from Full Saturation P = 3 Paul Chiuchiolo and Mark Webster, Intersil

  16. PSD for PA Input with 64-QAM Subcarriers Equivalent 802.11a mask Paul Chiuchiolo and Mark Webster, Intersil

  17. backoff=3.7dB backoff=4.7dB backoff=8.2dB backoff=12.0dB backoff=16.0dB PSD for PA Output with 64-QAM Subcarriers Backoff from Full Saturation P = 2 Paul Chiuchiolo and Mark Webster, Intersil

  18. backoff=3.4dB backoff=4.6dB backoff=8.1dB backoff=12.0dB backoff=16.0dB PSD for PA Output with 64-QAM Subcarriers Backoff from Full Saturation P = 3 Paul Chiuchiolo and Mark Webster, Intersil

  19. PER for 6.6 Mbps with p=2 Backoff from Full Saturation 1000 byte Packets Backoff from full saturation. Paul Chiuchiolo and Mark Webster, Intersil

  20. PER for 6.6 Mbps with p=3 Backoff from Full Saturation 1000 byte Packets Backoff from full saturation. Paul Chiuchiolo and Mark Webster, Intersil

  21. PER for 13.2 Mbps with p=2 Backoff from Full Saturation 1000 byte Packets Paul Chiuchiolo and Mark Webster, Intersil

  22. PER for 13.2 Mbps with p=3 Backoff from Full Saturation 1000 byte Packets Paul Chiuchiolo and Mark Webster, Intersil

  23. PER for 26.4 Mbps with p=2 Backoff from Full Saturation 1000 byte Packets Paul Chiuchiolo and Mark Webster, Intersil

  24. PER for 26.4 Mbps with p=3 Backoff from Full Saturation 1000 byte Packets Paul Chiuchiolo and Mark Webster, Intersil

  25. PER for 59.4 Mbps with p=2 Backoff from Full Saturation 1000 byte Packets Paul Chiuchiolo and Mark Webster, Intersil

  26. PER for 59.4 Mbps with p=3 Backoff from Full Saturation 1000 byte Packets Paul Chiuchiolo and Mark Webster, Intersil

  27. SNR Degradation Table 1000 byte Packets Paul Chiuchiolo and Mark Webster, Intersil

  28. Conclusions • At the lower data rates up to 13.2 Mbps, PA back-off is the same as 802.11b. • Back-off PA more at higher data rates. • P=3 is slightly better than p=2. • OFDM is competitive Paul Chiuchiolo and Mark Webster, Intersil

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