Performance Evaluation of Codebooks for CL SU MIMO and CL MU MIMO
IEEE 802.16 Presentation Submission Template (Rev. 9)
Document Number:
IEEE C80216m-09_1166
Date Submitted:
2009-05-03
Source:
David Mazzarese, Bruno Clerckx, Kwanhee Roh,
Wang Zhen, Heewon Kang, Hokyu Choi,
Samsung Electronics
d.mazzarese@samsung.com
Venue:
IEEE 802.16m Session#61, Cairo, Egypt
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Base Contribution:
IEEE C80216m-09_1166
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Discussion and approval
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Introduction
• This contribution presents the system-level
performance evaluation of base codebooks in DL
4x2 with CL SU MIMO and CL MU MIMO (ZFBF)
– AWD 6 bits base codebook
– Li’s 6 bits base codebook (09/0649r1, 09/0888)
• As a reply to AWD comment 292, we show that
there is no need to change the AWD 6 bits base
codebook. The AWD codebook is more robust.
DL 4x2 MU-MIMO (20 users)
Sector throughput relative to AWD codebook in ULA 0.5L
120.00
100.00 99.66
100.00
80.00
63.35
59.12
60.00
51.62 51.63
50.50 52.00
50.77 52.02
Dual-Pol
45-VH 10L
Dual-Pol
VH-VH 10L
61.61 63.01
61.71 63.12
Dual-Pol
45-VH 0.5L
Dual-Pol
VH-VH 0.5L
40.00
20.00
0.00
Single-Pol ULA 10L
Split linear array
Single-Pol ULA 0.5L
Li’s codebook shows a slight advantage in dual polarized channels with
MU-MIMO transmissions. Its throuhgput is similar to the AWD in ULA,
but worse by about 4% with split-linear arrays.
AWD
Li
DL 4x2 SU-MIMO (10 users)
Sector throughput relative to AWD codebook in VH-VH 0.5L
102.0
100.0
99.6
100.0
99.0
98.1
99.0
98.1
98.0
96.0
94.0
91.7
92.0
90.2
90.0
89.0
88.8
87.7
88.0
AWD
Li
AWD (rank 1 only)
Li (rank 1 only)
87.8
86.0
84.0
82.0
80.0
Single-Pol ULA 0.5L
Dual-Pol
45-VH 0.5L
Dual-Pol
VH-VH 0.5L
Conclusions cannot be based on the simulations of the rank 1
only. The AWD base codebook is significantly better once
rank adaption is taken into account.
DL 4x2 SU-MIMO (10 users)
Sector throughput relative to AWD codebook in VH-VH 0.5L
94.0
92.0
91.2
90.0
90.0
88.7
89.5
88.4
88.0
86.0
87.2 87.1
86.9
86.9
86.5 86.5
85.4
84.7
84.0
82.0
83.5
83.6
82.0
81.5
AWD
Li
AWD (rank 1 only)
Li (rank 1 only)
84.5
84.3
83.4
81.9
81.3
80.5
80.6
80.0
78.0
76.0
74.0
Single-Pol ULA 10L
Dual-Pol
45-VH 10L
Dual-Pol
VH-VH 10L
Dual-Pol
45-VH 4L
Dual-Pol
VH-VH 4L
Single-Pol ULA 4L
The AWD base codebook is more robust than Li’s codebook
Conclusions
• The AWD 6 bits codebook is more
robust than Li’s codebook
• There is no change to the DL 4Tx
base codebook
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