Performance Evaluation of Codebooks Proposed for IEEE 802.16m Amendment
IEEE 802.16 Presentation Submission Template (Rev. 9)
Document Number:
IEEE C80216m-09_0588
Date Submitted:
2009-03-07
Source:
David Mazzarese, Bruno Clerckx, Kwanhee Roh, Wang Zhen, Heewon Kang
Keun Chul Hwang, Soon-Young Yoon, Hokyu Choi, Jerry Pi, Jiann-An Tsai
Samsung Electronics
d.mazzarese@samsung.com
Alexei Davydov, Guangjie Li, Yang-seok, Gregory Morozov
Intel Corporation
alexei.davydov@intel.com
Yang Tang, Yang Tang, Zhigang Rong, Jianmin Lu
Huawei Technologies
YTang@huawei.com
Venue:
IEEE 802.16m Session#60, Vancouver, Canada
IEEE 80216m-09_0012, “Call for Contributions for P802.16m Amendment Text Proposals”.
Base Contribution:
IEEE C80216m-09_0577
Purpose:
Discussion and approval
Notice:
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Introduction
• This contribution presents the system-level
performance evaluation of base codebooks:
– DL: 2Tx, 4Tx, 8Tx
– UL: 2Tx, 4Tx
• Text proposal for the amendment with the detailed
codebook can be found in the latest revision of the
base contribution IEEE C80216m-09_0577
Codebook-based feedback
• Codebooks are used
– In uplink feedback for supporting downlink precoding
– In downling control (UL A-MAP) for uplink precoding
• SDD supports 3 codebook-based feedback modes
– Standard: base codebook
– Adaptive: correlation matrix transformation
– Differential: differential PMI feedback
Base Codebook Analysis
Base Codebook Candidates
Reference
Antenna configuration
Authors
Label used in figures
806.16e
DL/UL 2Tx (3 bits)
DL/UL 4Tx (3 bits, 6 bits)
802.16e
16e
C80216m-08/577
DL 2Tx (3 bits)
DL 4Tx (6 bits, 4 bits subset)
DL 8Tx (4 bits)
UL 2Tx (4 bits)
UL 4Tx (6bits)
Alexei Davydov
David Mazzarese
Yang Tang
09/577
C802.16m-08_983
C80216m-MIMO-08/69
DL 2Tx (same as 577)
DL 4Tx (4 bits)
Jaewan Kim
Kim_4bit
C80216m-08_1101
C80216m-MIMO-08/74
DL 2Tx (same as 577)
DL 4Tx (4 bits)
Bishwarup Mondal
Mondal_4bit
C80216m-MIMO-08_067
DL 4Tx (6 bits)
Shaohua li
Li_6bit
C80216m-08/916
C80216m-08/1264r1
DL 4Tx (4 bits)
Ron Porat
Porat_4bit
Measures of Codebook Goodness
Measure
Description
Throughput
First and foremost measure
Feedback overhead
Codebook size (number of bits)
DFT structure
Best for calibrated correlated linear arrays
Block-diagonal matrices
Adapted for dual polarized arrays at BS
Full nested property
Ranks 2, 3 and 4 matrices are composed of rank 1 precoders:
CQI computation complexity reduction
Constant modulus matrix
elements
Good for power amplifier transmit power balance, good for
PAPR in precoded systems
QPSK alphabet
CQI computation complexity reduction by avoiding
numerous complex multiplications
Comparison of 4Tx Codebooks
802.16e
09/577
09/577
Kim_4bit
Mondal_4bit
Li_6bit
Porat_4bit
Feedback
overhead
3/6 bits
4 bits
6 bits
4 bits
4 bits
6 bits
4 bits
Performance (SLS)
C: bad
U: good
C: good
U: good
C: good
U: good
C: good
U: bad
C: bad
U: bad
C: good
U: bad
C: bad
U: bad
DFT structure
No
Yes
Yes
Pure
Yes
No
No
Structure for dualpolarized arrays
No
Yes
Yes
No
No
No
No
Full nested
property
No
Yes
Yes
Yes
No
No
Yes
Constant modulus
No
Yes
No
Yes
Yes
No
Yes
QPSK alphabet
No
Partially
No
No
Yes
No
Yes
C: correlated channels
U: uncorrelated channels
Performance Evaluation
Simulation Environments
• CL SU MIMO SLS in DL 4x2
– ULA: uncorrelated, correlated channels @ BS
• CL MU MIMO (ZFBF) SLS in DL 4x2
– ULA: uncorrelated, correlated channels @ BS
• CL MU MIMO (ZFBF) SLS in DL 8x2
– ULA: correlated channel @ BS
• CL SU MIMO SLS in UL 2Tx and 4Tx
– ULA: uncorrelated
BS Antenna Array Configurations
DL 2x2 CL MU MIMO (ZFBF)
DL 2x2 CL MU MIMO (ZFBF)
124.38
Very correlated
channel
100.00
577_3bit
16e_3bit
101.15
Uncorrelated
channel
0.00
100.00
20.00
40.00
60.00
80.00
100.00
Sector throughput relative to 802.16e codebook
120.00
140.00
DL 4x2 CL SU MIMO
(uniform linear array)
SU-MIMO DL 4x2
100.51
Li_6bits
99.62
100.00
577_6bits
100.00
96.11
16e 6bit
100.54
96.22
Kim_4bits
95.91
Single-Pol ULA 0.5L
Single-Pol ULA 10L
94.89
Mondal_4bits
95.45
95.14
Porat_4bits
96.23
97.95
577_4bits
16e 3bit
90.00
97.07
91.43
93.18
92.00
94.00
96.00
98.00
100.00
Sector throughput relative to 6-bit codebook 09/0577
102.00
DL 4x2 CL SU MIMO
(dual-polarized arrays)
SU-MIMO DL 4x2
95.12
96.49
Li_6bits
101.15
98.57
100.00
100.00
100.00
100.00
577_6bits
97.64
98.51
16e 6bit
102.91
100.35
Dual-Pol
45-VH 0.5L
99.09
95.38
Kim_4bits
98.26
Dual-Pol
VH-VH 10L
94.81
Dual-Pol
45-VH 10L
97.65
96.66
96.30
95.85
Mondal_4bits
94.36
93.08
95.17
94.06
Porat_4bits
90.13
85.83
16e 3bit
95.61
91.22
75.00
80.00
85.00
90.00
95.00
Sector throughput relative to 6-bit codebook 09/0577
100.00
Dual-Pol
VH-VH 0.5L
105.00
DL 4x2 CL MU MIMO (ZFBF)
(uniform linear array)
With transformation
MU-MIMO DL 4x2
Tr Mondal_4bits
96.34
Tr Porat_4bits
96.13
Tr Kim_4bits
104.27
103.12
106.19
95.22
Tr Li_6bits
Tr 577_6bits
100.59
Tr 577_4bits
105.46
105.35
96.68
103.87
100.90
Tr 16e 6bits
Li_6bits
Single-Pol ULA 0.5L
Single-Pol ULA 10L
103.20
97.49
100.00
100.00
577_6bits
71.55
16e 6bits
100.31
69.71
Mondal_4bits
95.24
68.66
Porat_4bits
95.11
Kim_4bits
101.27
95.06
88.92
577_4bits
60.00
106.52
97.87
65.00
70.00
75.00
80.00
85.00
90.00
96.30
95.00
100.00
Sector throughput relative to 6-bit codebook 09/0577
105.00
110.00
DL 4x2 CL MU MIMO (ZFBF)
With transformation
(split linear array)
MU-MIMO DL 4x2 (split array)
Tr Mondal_4bits
109.55
Tr Porat_4bits
109.31
Tr Kim_4bits
107.65
Tr Li_6bits
112.12
Tr 577_6bits
113.35
Tr 577_4bits
108.77
Tr 16e 6bits
113.63
Li_6bits
92.33
577_6bits
100.00
16e 6bits
94.11
Mondal_4bits
92.20
Porat_4bits
91.94
Kim_4bits
91.27
577_4bits
80.00
94.55
85.00
90.00
95.00
100.00
105.00
110.00
Sector throughput relative to 6-bit codebook 09/0577
115.00
120.00
DL 4x2 CL MU MIMO
• 09/577 4Tx base codebook offers the most robust choice without
transformation
• Compared to other 6bit codebook candidates, the hierarchical structure
associated with the 09/577 4Tx base codebook can save the codeword
searching complexing by 70%
• 09/577 4bit subset codebook offers the most robust performance with
transformation and a good tradeoff between performance and feedback
overhead
DL 8x2 CL MU MIMO
• Cf C80216m-09_0442
Uplink Precoding
Simulation Assumptions
•
•
•
•
•
•
•
10MHz, 1024 FFT
2 and 4TX antenna at MS
2 Rx antennas at BS
MCS selection (QPSK, 16QAM, CTC R=1/2, 3/4)
Rank adaptation (rank-1, rank-2)
Extended ITU Ped.-B (3kmph) channel
2 frames feedback delay
Link Level Simulations
UL MIMO, 2TX/4TX MS, 10MHz, 1024FFT, CRU, eITU-Ped.B (3kmph), 2 frames delay
7
4TX MS, 6-bits CB
2TX MS, 3-bits CB
6
Open Loop
SE, b/s/Hz
5
4
3
2
1
0
0
2
4
6
8
10
12
SNR, dB
14
16
18
20
Proposed Amendment Text
• Cf latest revision of C80216m-09_0577
Appendix
Downlink System-Level
Simulation Assumptions
Number of Antennas
Antenna configuration
2 transmitter, 2 receiver [2Tx, 2Rx]
4 transmitter, 2 receiver [4Tx, 2Rx]
4 transmitter, 4 receiver [4Tx, 4Rx]
ULA: 0.5 lambda; 4 lambda, 10 lambda
Split Linear Array, Dual Polarized Array
MIMO Scheme
1.
Closed-loop single user with dynamic rank adaptation
2.
Zero-forcing multiple user MIMO
Schedule from 1 to 2 users dynamically based on the same rank-1 PMI feedback. No SU/MU
mode adaptation.
Channel Model
Modified Ped-B 3km/h
Channel correlation Scenario
PAPR
Antenna Calibration
1. Uncorrelated Channel : 4 lambda antenna spacing, angular spread of 15 degrees
2. High correlated channel: 0.5 lambda antenna spacing, angular spread of 3 degree
1. No constraint on per-antenna power imbalance
2. Limitation of per-antenna power imbalance by scaling in every subframe
1.
2.


Ideal antenna calibration (mandatory)
Uncalibrated antennas (optional)
Random phase on each transmit antenna + Random delay between each pair of adjacent
transmit antennas (uniformly distributed between 0 and N samples)
Fixed for one drop
OFDM parameters
10 MHz (1024 subcarriers)
OFDM symbols per subframe
6
Permutation
Localized
Number of total RU in one subframe
48
Scheduling Unit
Whole band (48 PRUs)
12 subbands
1 subband = 4 consecutive PRUs
1 PMI and 1 CQI feedback per subband
Number of RU
for PMI and CQI calculation
4 which is same as in IEEE 802.16e
CQI, PMI feedback period
Every 1 frame (5ms)
Feedback delay
1 frame (5ms)
Link Adaptation
(PHY abstraction)
QPSK 1/2 with repetition 1/2/4/6, QPSK 3/4, 16QAM 1/2, 16QAM 3/4, 64QAM 1/2,
64QAM 2/3, 64QAM 3/4, 64QAM 5/6
HARQ
Chase combining, non-adaptive, asynchronous. HARQ with maximum 4
retransmissions, 4 subframes ACK/NACK delay, no error on ACK/NACK.
HARQ retransmission occurs no earlier than the eighth subframe after the
previous transmission.
Scheduling
No control overhead, 12 subbands of 4 PRUs each, latency timescale 1.5s
MIMO receiver
Linear Minimum Mean Squared Error (LMMSE)
Data Channel Estimation
Perfect data channel estimation
Feedback Channel Measurement
Perfect feedback channel measurement
Cellular Layout
Hexagonal grid, 19 cell sites, wrap-around,
3 sectors per site
Distance-dependent path loss
L=130.19 + 37.6log10(.R), R in kilometers
Inter site distance
1.5km
Shadowing standard deviation
8 dB
Antenna pattern (horizontal)
(For 3-sector cell sites with fixed
antenna patterns)
3dB
   2

 , Am 
A    min 12

  3dB 

= 70 degrees, Am = 20 dB
Users per sector
10 (EMD)
Scheduling Criterion
Proportional Fair (PF for all the scheduled users)
Feedback channel error rate
No error