1. IEEE P802.22 Wireless RANs Date: 2006-08-22
PAPR Comparison
IEEE P Wireless RANs Date:
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2. PAPR Comparison

3. The current draft includes the PN sequences for only 1 preamble of each kind (there are four kinds, SF, F each one with long and short PN sequence)
There is a mistake in the generator polynomial for the Q component described in the draft, which was then corrected.
The PAPR of each of the Preambles, proposed in the draft, was calculated, the results which vary from 8-11 are given in the following table

4. IEEE802.22 PAPR summary table:
PAPR Issues
The PRBS seed for the Q part was defined, in the draft, incorrectly. The old one was defined as and it didn`t match the result sequence. Philips sent us the new, correct one
IEEE PAPR summary table:
(dB)
7.8552
9.4196
8.6174

5. IEEE802.16 PAPR graph (114 PN sequences)
Average PAPR of all set of 114 Preambles is between dB

6. PAPR description (IEEE802.22 PAPR )
The figure shows the signal power. The red line is the maximum power of the signal. The cyan line is the average power of the signal. The PAPR is the ratio of the red and the cyan line

7. 2300 samples within the OFDM symbol
IEEE PAPR (Worst Case)
2300 samples within the OFDM symbol

8. Comparing the PAPR of the proposed preambles with the numerous number of preambles shows a significant advantage of the later preambles over the former.
In real life where a large number of deployed Base Stations, a big set of preambles is necessary. This important property is not supported in the current draft, allowing a generation of only 1 Preamble of each kind.
Use of a lower PAPR has a significant impact on RF chain, especially on the linear power amplifier. Reduction of 3dB in PAPR is translated into reduction by 50% in power dissipation of the RF chain
Our recommendation is definitely use of preambles