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Proposed Randomization for 16m
Document Number: S80216m-09/1415
Date Submitted: 2009-07-07
Source:
Changlong Xu, Tom Harel, Huaning Niu, Jong-Kae Fwu, Yang-Seok Choi, Hujun Yin
Intel Corporation
Venue:
IEEE Session #62, San Francisco, US.
Re:
Base Contribution:
N/A
Purpose:
To be discussed and adopted by TGm for the 802.16m amendment.
Notice:
This document does not represent the agreed views of the IEEE 802.16 Working Group or any of its subgroups. It represents only the views of the participants listed inthe “Source(s)” field above. It is offered as a basis for discussion. It is not binding on the contributor(s), who reserve(s) the right to add, amend or withdraw materialcontained herein.
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Outline
•Data randomization and subcarrier randomization in 16e
•Data randomization in current AWD text
•Proposed randomization
•Summary
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1.Data randomizer and subcarrierrandomizer in 16e
Figure 1 Channel coding process for regular and repetition coding transmission
Subcarrierrandomizer
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1.1 Data randomizer
• Generator polynomial 1 + x14+x15
• Initial Vector [LSB] 0 1 1 0 1 1 1 0 0 0 1 0 1 0 1 [MSB] –Each FEC block
• Function Avoiding long runs of bit that are bad for modulator
Example, long runs of 1’s, coming from the data source or padding,generate the peak amplitude of 64 QAM modulator consumes 3.7dBhigher power than the average.
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1.2 Subcarrier Randomizer
•Generator polynomial 1 + x14+ x15
•Initial Vector - Each sub-frame
–b0 .. b4 5 LSB of IDcell
–b5,b6 the segment number + 1
–b7..b10 0b1111 for downlink; four least significant bits of the Framenumber in the uplink.
•Function
–Randomize the interference between different cells
–Avoid exact repetition of QAM symbol. Repetition within an OFDMsymbol causes high PAPR and repetitive interference.
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2. Data randomization in current AWD text
Figure 2 Channel coding procedure in current AWD text
Subcarrierrandomizer
Necessary
Problem:
Data Randomize is same as that in 16e. Thus, subcarrier randomizer is necessary.
Solution:
1.Adding subcarrier randomizer
2.Proposed algorithm
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3. Proposed randomization
Move randomizer to the position before the modulation
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•Generator polynomial 1 + x18+x23
•Initial Vector
b13 … b22 IDcell
b12 1
b0 … b11 STID
Reset the seed for each burst
Parameters for proposed randomization
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Summary
•Proposed a new randomizer instead of the original one in currentAWD
•Merit of the proposed randomizer
–Low complexity (one randomizer instead of the two randomizer in 16e)
–Good performance
•Randomize the interference between adjacent cell
•Avoid exact repetition of QAM symbol
•Avoiding long runs of bit
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