1. S802.16m-08/319r1
New Preamble Sequence Design Using Quasi Complete Complementary Codes for IEEE m
Document Number: S802.16m-08/319r1
Date Submitted:
May 05, 2008
Source:
Pei-Kai Liao and Paul Cheng
MediaTek Inc. No. 1 Dusing Rd. 1 Hsinchu Science Park Hsinchu City 300 Taiwan;
Chao-Yu Chen Kuei-Ying Lu and Chi-Chao Chao
Institute of Communications Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan;
Yih-Guang Jan and Yang-Han Lee
Tamkang University;
Shiann-Tsong Sheu
National Central Univeristy
Venue:
Macao, China
Base Contribution:
IEEE C802.16m-08/319r1
Purpose:
Propose to be discussed and adopted by TGm for the use in Project m SDD.
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2. Introduction Motivation Purpose and Summary
Non-structural code sequence for e preamble
Memory for the storage of code sequence
Longer searching time of code matching
Structural code sequence with low PAPR, low crorss-correlation and similar performance is desired
Purpose and Summary
A new code sequence using QCCC is proposed for m preamble
Propose to be discussed and included in m SDD

3. Design Considerations
Mathematical structure
Structural code sequences reduce hardware complexity of transceiver design
Low PAPR
To maximize transmission power efficiency, code sequences with low PAPR is desirable
Large peak to cross-correlation ratio
Large peak to cross-correlation ratio reduces the possibility of misjudgment of code matching
More code sequences
More Cell_ID is desired

4. Auto-Complementary Code
Definition: A set of M sequences c1,c2,…,cM of length n is called an ACC of order M or Golay complementary set of order M, if the auto-correlation functions satisfy
Aperiodic Auto-correlation Function
Auto-correlation is all zero except the peak at zero time shift

5. Complete Complementary Code
Definition: The M sets of M length-n sequences {c11,c21,…,cM1},…,{c1M,c2M,…,cMM} are called a complete complementary code of order M if every set is an ACC and every two distinct sets satisfy
Cross-correlation is all zero;
Auto-correlation is all zero except the peak at zero time shift
Problem: the number of set, M, is limited by the length!!
(More code sets require longer code length, not feasible)

6. Quasi Auto-Complementary Code
Definition: We call a pair of length-n sequences {c1, c2} a quasi auto-complementary code of order 2 if
If the left equality holds, this set is in fact an auto-complementary code (ACC) of order 2 or called a Golay pair
Auto-correlation is of a small positive value
except the peak at zero time shift

7. Quasi Complete Complementary Code
Definition: The sets of length-n pair {c11,c21}, {c12,c22}, …, {c1M,c2M} are called a quasi complete complementary code of order M if every pair is a QACC and every two distinct pairs satisfy
for any u; j, k=1,2,…,M; j≠k.
Cross-correlation is of a small positive value;
Auto-correlation is all of a small positive value
except the peak at zero time shift
More code sets with reasonable code length, feasible!!

8. Construction of QCCC

9. Properties of QCCC
Comparisons of PAPR and cross-correlation between QCCC-based and PN-based e preambles for 10 MHz (1024 sub-carriers)
Code length 256
Code length 284

10. Preamble Structure – Cascade over Frequency Domain
Constructed QCCC code sequence is modulated by BPSK at sub-carriers and interleaved by 3

11. Simulation Results
Performance comparison between PN-based and QCCC-based preambles on modified ITU Pedestrian B channel with velocity 3km/hr

12. Simulation Results
Performance comparison between PN-based and QCCC-based preambles on modified ITU Vehicular A channel with velocity 30km/hr

13. Simulation Results
Performance comparison between PN-based and QCCC-based preambles on modified ITU Vehicular A channel with velocity 120km/hr

14. Conclusion
A code sequence with mathematical structure for 16m preamble is proposed
It waives the memory storage of all code sequences
It enables the possibility of more efficient code matching algorithm instead of full search
More code sequences for Cell_IDs
Performance of the proposed code sequence, QCCC, is close to that of 16e PRBS