Transcript IEEE C802.16m-09/1877

E-MBS Feedback Channel Design (E-MBS)
Document Number: IEEE C802.16m-09/1877
Date Submitted: 2009-08-28
Source:
Chih-Yuan Lin ([email protected]), Pei-Kai Liao ([email protected]), Yih-Shen Chen ([email protected]),
Yu-Hao Chang ([email protected]), and Paul Cheng ([email protected])
MediaTek Inc.
Venue:
IEEE Session #63, Jeju, Korea
Re:
P802.16m/D1 E-MBS
Base Contribution: N/A
Purpose: Propose to be discussed and adopted by TGm for the use in Project 802.16m AWD
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Objectives
▪ Details of E-MBS feedback channel are missing
– Aim to propose detailed PHY structure and corresponding sequences
▪ Design criteria
– Common feedback channel
• All AMs can announce their NACKs in this feedback channel
– FDM and CDM hybrid PHY structure
• Example
C0
C1
C0
C1
C0
C1
C0
C1
C0
C0
C1
C0
C0
C0
C1
C0
C0
C1
C1
C1
C0
C1
C1
C1
C0
C0
C1
C0
C0
C0
C1
C0
C0
C1
C1
C1
C0
C1
C1
C1
C0
C0
C0
C0
C1
C1
C1
C1
C0
C2
C0
C2
C0
C2
C1
C3
C1
C3
C1
C3
C0
C0
C2
C2
C0
C4
C2
C6
C0
C8
C2
C10
C1
C1
C3
C3
C1
C5
C3
C7
C1
C9
C3
C11
C0
C0
C2
C2
C0
C4
C2
C6
C0
C8
C2
C10
C1
C1
C3
C3
C1
C5
C3
C7
C1
C9
C3
C11
C0
C2
C4
C6
C8
C10
C1
C3
C5
C7
C9
C11
2x2
2x2
2x6
2x2
2x6
2x6
AMS randomly chooses a frequency partition,
and also randomly chooses a code to announce
its NACK
E-MBS Feedback PHY (1/2)
▪ Possible candidates for E-MBS mini-tile (EMT)
– 1x2 / 2x1 / 2x2 / 2x6 / 6x2 / 6x6 / 18x6
▪ Frequency-first manner to allocate CDM code
1x2
C0
C0
C0
C0
C0
C0
C0
C0
C0
C0
C0
C0
2x1
C0
C1
C0
C1
C0
C1
C0
C1
C0
C1
C0
C1
C0
C0
C0
C0
C0
C0
C1
C1
C1
C1
C1
C1
C0
C2
C0
C2
C0
C2
C1
C3
C1
C3
C1
C3
C0
C2
C4
C6
C8
C10
C1
C3
C5
C7
C9
C11
2x2
2x6
18x6
18x6
6x3
6x3
6x6
C9C9
6x2
6x2
6x6
6x6
C0C0
C6C6 C12
C12
C0C0
C6C6
C0C0
C6C6
C12
C12 C18
C18 C24
C24 C30C30
C1C1
C7C7 C13
C13
C1C1
C7C7
C1C1
C7C7
C13
C13 C19
C19 C25
C25 C31C31
C2C2
C8C8 C14
C14
C2C2
C8C8
C2C2
C8C8
C14
C14 C20
C20 C26
C26 C32C32
C3C3
C9C9 C15
C15
C3C3
C9C9
C3C3
C9C9
C15
C15 C21
C21 C27
C27 C33C33
C4C4 C10
C10 C16
C16
C4C4 C10
C10
C4C4
C10
C10 C16
C16 C22
C22 C28
C28 C34C34
C5C5 C11
C11 C17
C17
C5C5 C11
C11
C5C5
C11
C11 C17
C17 C23
C23 C29
C29 C35C35
C12
C12 C15
C15
C10
C10 C13
C13 C16
C16
C11
C11 C14
C14 C17
C17
C0C0
C18C18 C36C36 C54C54 C72C72 C90C90
C1C1
C19C19 C37C37 C55C55 C73C73 C91C91
C2C2
C20C20 C38C38 C56C56 C74C74 C92C92
C105
C15C15 C33C33 C51C51 C69C69 C87C87 C105
C106
C16C16 C34C34 C52C52 C70C70 C88C88 C106
C107
C17C17 C35C35 C53C53 C71C71 C89C89 C107
E-MBS Feedback PHY (2/2)
▪ Comparison between different tile sizes
– Time-domain span should not be too large
• Easy to maintain code orthogonality under high-mobility case
– Feedback resource unit is easy to be put into existing feedback mini-tile or
DRU tile
• No need to create new tile size and permutation rule for E-MBS feedback
channel
• As a result, 2x1, 2x2 and 6x2 mini-tile sizes are preferred
– 2x2 case is the same as the HARQ mini-tile and so is a good choice
since corresponding length-4 orthogonal codes are already determined
Simulation Parameters (1/1)
▪ 1x2 SIMO
– MSs have one TX antenna and BS has two RX antennas
▪ Code type: orthogonal code
– For 2x2, 6x2, and 2x6 unit sizes, hadamard code is used
– For 6x6 and 18x6 unit sizes, DFT code is used since there are no length-36
and length-108 hadamard codes
▪ Receiver type: non-coherent detection
▪ Each MS has equal TX power
▪ Feedback resource : one LRU (18x6)
– 108 feedback opportunities in total
▪ Channel model: VA 120
▪ Performance metric: estimation error of number of users
Simulation Results (1/2)
▪ VA 120 and number of users = 80 (collision free)
2x2 tile size
2x6 tile size
6x2 tile size
6x6 tile size
18x6 tile size
SNR (dB)
-4
-2
0
2
4
6
8
10
Error (HDM)
2.0416
1.6833
1.3750
1.3500
1.4666
1.0250
1.0083
1.1750
SNR (dB)
-4
-2
0
2
4
6
8
10
Error (HDM)
8.0700
8.3800
7.8500
7.3200
7.1900
6.8300
7.0000
6.7300
SNR (dB)
-4
-2
0
2
4
6
8
10
Error (HDM)
1.5916
1.2750
1.1416
1.0750
0.9583
1.1666
0.8250
0.8916
SNR (dB)
-4
-2
0
2
4
6
8
10
Error (DFT)
4.9250
4.6916
4.4750
4.4166
4.3500
3.8250
4.2666
4.2083
SNR (dB)
-4
-2
0
2
4
6
8
10
Error (DFT)
6.8083
6.3166
6.3250
5.9250
6.4583
6.2250
6.1500
5.9000
Simulation Results (2/2)
▪ VA 120 and number of users = 80 (10% of them collide with others)
– 8 AMSs randomly choose 8 feedback channels among that of other 72 MSs
2x2 tile size
2x6 tile size
6x2 tile size
6x6 tile size
18x6 tile size
SNR (dB)
-4
-2
0
2
4
6
8
10
Error (HDM)
6.3000
6.5500
6.6666
6.2500
5.5000
4.6833
4.1333
3.4666
SNR (dB)
-4
-2
0
2
4
6
8
10
Error (HDM)
20.0333
19.7666
20.1166
19.4166
18.2500
17.9666
16.2666
15.0333
SNR (dB)
-4
-2
0
2
4
6
8
10
Error (HDM)
4.0166
3.9666
3.4333
3.9166
3.2000
3.1333
3.0166
2.7333
SNR (dB)
-4
-2
0
2
4
6
8
10
Error (DFT)
15.9250
14. 550
14.4750
14. 2666
14. 4166
13.8250
14. 0333
14.2083
SNR (dB)
-4
-2
0
2
4
6
8
10
Error (DFT)
16.2000
16.0666
16.6833
15.9333
15.3166
15.6000
15.5833
15.5166
Conclusion (1/1)
▪ The cases with 2x2 and 6x2 tile sizes perform relatively good
– Experience less channel time variation effect
▪ EMT of size 2x2 is preferred
– Same PHY structure as HARQ feedback channel and thus no additional
complexity
• One E-MBS feedback is composed of 3 FMTs to
provide 36 feedback opportunities
Freq.
– Better to be used in legacy zone, whose tile size is 4x6
time
C0
C2
C0
C2
C0
C2
C1
C3
C1
C3
C1
C3
C0
C2
C0
C2
C0
C2
C1
C3
C1
C3
C1
C3
C0
C2
C0
C2
C0
C2
C1
C3
C1
C3
C1
C3
Text Proposal
Appendix (1/2)
▪ Determination of threshold of non-coherent detection
– Received signal model in a mini resource block
r
N 1
c
i 0
hi  n
i
• N : number of users
N
1
• ci  subcarrier : ith user’s code with Nsubcarreir denoted as number of tones in a
CDM resource unit
N
1
• hi  subcarrier : ith user’s channel frequency response in a CDM resource unit
• n
N subcarrier 1
: noise vector
– Non-coherent detection
• Detect kth user
zk  c r  c
H
k
H
k
 ci
hi  
N 1

i 0,i k
ckH  ci
hi   ckH n
Appendix (2/2)
– Detection criteria : output power of non-coherent detector is larger than
interference-plus-noise power, i.e.,
zk
2
 N 1
 E   ckH  ci
 i 0,i k

hi   c n 

2
H
k
• Expectation can be expanded as
 N 1
E   ckH  ci
 i 0,i k


 N subcarrier 1 N 1
hi   c n     ck*, j ci , j E hi , j hi*, j ci*, j ck , j   n2ckH ck
j 0
i  0,i k

2
H
k
– E hi , j hi*, j can be obtained by predefining MS mobility and channel delay spread
▪ In simulations, mobility is set to be 120 km/hr and channel delay spread is set to be 5 us
for all scenario
▪ N is set to be (maximal allowable number of users)/2