E-MBS Zone Specific Pilot Patterns for MBSFN
Document Number: IEEE C80216m-09/0929
Date Submitted: 2009-05-01
Source:
Debdeep Chatterjee, Huaning Niu, Jong-kae (JK) Fwu, Hujun Yin Email: {[email protected], [email protected],
[email protected], [email protected]}
Intel Corporation
Venue:
IEEE Session #61, Cairo, Egypt.
Re: Category: SDD CR / Area: Chapter 11.5.3.2 (E-MBS zone specific pilot patterns for MBSFN)
“Comments on SDD section 11.5.3.2 E-MBS zone specific pilot patterns for MBSFN”
Purpose:
To discuss and adopt the proposed text in the revision of the 802.16m SDD.
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1
Overview
• E-MBS content is to be transmitted in the SFN mode, with multiple
BSs transmitting the same information for a particular MBS zone
• Delay spread is higher than typical unicast scenarios, and is
dependent on the ISD and the MBSFN channel model
• Unicast pilot patterns are not sufficient
• Need new pilot pattern designs for E-MBS
2
Simulation Parameters
OFDM parameters
10 MHz (1024 subcarriers)
Number of OFDM symbols per subframe
6
Data burst size
4 PRUs distributed uniformly over 48 PRUs
Permutation
Tone based LDRU
Number of total RU in one subframe
48
Number of Antennas
Transmission mode
Channel coding
Modulation/Coding
Channel model
2 transmitter antennas, 2 receiver antennas [2Tx,2Rx]
1 transmitter antenna, 2 receiver antennas [1Tx,2Rx]
Rate 1 transmission scheme: SFBC, SIMO
Rate 2 transmission scheme: Spatial Multiplexing (SM)
LTE FEC with 8 Turbo decoding iterations
QPSK ½, QPSK ¾, 16QAM ½, and 16QAM ¾ (for rate-1 transmission)
16QAM ½, and 16QAM ¾, 64QAM ½, and 64QAM ¾ (for rate-2 transmission)
MBSFN channel models for 1.5km ISD and 5km ISD with MS speeds of 3kmph
and 120kmph
Channel estimation
2-D MMSE channel estimator with 3 PRU level CE
Delay Spread perfectly known
Actual PDP unknown, assumed to be flat at receiver
MIMO detector
LMMSE for SFBC and SM
MRC for SIMO
Scenarios
Noise limited
3
Pilot Patterns Evaluated (1 of 3)
= pilot tone (ant. 1);
= pilot tone (ant. 2);
= data tone
4
Pilot Patterns Evaluated (2 of 3)
= pilot tone (ant. 1);
= pilot tone (ant. 2);
= data tone
5
Pilot Patterns Evaluated (3 of 3)
= pilot tone (ant. 1);
= pilot tone (ant. 2);
= data tone
6
Power Delay Profile: MBSFN, 1.5km ISD
7
Throughput: 1.5km ISD, Speed=120kmph, 2x2SFBC
INTC 5.5% pattern is the best choice, with very similar performances by MediaTek 5.56% and Samsung 5.56%
patterns
8
Throughput: 1.5km ISD, Speed=120kmph, 1x2SIMO
INTC 5.5% pattern is the best choice, with very similar performances by MediaTek 5.56% and Samsung 5.56%
patterns
9
Throughput: 1.5km ISD, Speed=120kmph, SFBC & SIMO Comparison
1x2 SIMO is a better option as compared to 2x2 SFBC as a rate-1 scheme (Also check C.E. MSE on slide # 20)
10
Throughput: 1.5km ISD, Speed=120kmph, 2x2 SM
• INTC 5.5% pattern is the best choice, and slightly outperforms MediaTek 5.56% and Samsung 5.56% patterns
• ITRI 8.33% pattern slightly outperforms INTC 8.33%
11
5km ISD
12
Throughput: 5km ISD, Speed = 120kmph, 1x2 SIMO
• INTC 11.11% pattern appears to be the optimal choice
• INTC 8.33% pattern also provides a decent tradeoff, and outperforms LGE 7.41%, ITRI 8.33%, and Samsung
A pattern (8.33%)
13
Summary
•
1x2 SIMO is a better option than 2x2 SFBC for rate-1 transmission
– Better overall channel estimation with less overhead
– Transmit diversity of SFBC not sufficient to overcome the increased overhead
penalty
•
We recommend two pilot patterns for different scenarios
– INTC 5.56% pattern for small cell sizes (e.g. 1.5km ISD)
– INTC 11.11% pattern for larger cell sizes (e.g. 5km ISD)
•
The following patterns may also be considered (with loss of optimality)
–
–
–
–
•
LGE 7.41%
INTC 8.33%
ITRI 8.33%
INTC 11.11% may be more suitable for larger cell sizes, like 5km ISD, especially, if
2x2 SM is considered for these scenarios
Samsung’s and MediaTek’s 5.56% pilot density patterns perform very close to
the INTC 5.56% pattern, with the latter slightly outperforming the former two.
More importantly, the 5.56% pilot density patterns fail to provide acceptable
performance for the 5km ISD scenario
14
Proposed SDD Text Change:
Replace the following text in red
on page 81, line 17 of Section
11.5.3.2:
“The definitions of the E-MBS
zone specific pilots are FFS”
with the following text in blue:
= pilot tone (ant. 1);
= pilot tone (ant. 1);
= pilot tone (ant. 2);
= pilot tone (ant. 2);
= data tone
= data tone
Fig. xxx: E-MBS zone
specific pilot Pattern 1
Fig. yyy: E-MBS zone
specific pilot Pattern 2
“The E-MBS zone specific pilot
patterns are specified within a
PRU. Pattern 1, shown in Fig.
xxx, is to be used for small cell
sizes (e.g. 1.5km ISD), whereas
Pattern 2, shown in Fig. yyy, is
to be used for larger cell sizes
(e.g. 5km ISD), with the
subcarrier indices increasing
from top to bottom, and OFDM
symbol indices increasing from
left to right.”
15
Appendix
• 3kmph Speed Throughput vs. SNR Results
– 1.5km ISD, 2x2 SFBC and 1x2 SIMO
– 1.5km ISD, 2x2 SM
– 5km ISD, 1x2 SIMO
• Channel Estimation MSE vs. SNR Results
– 1.5km ISD, 2x2 SFBC & SIMO
– 1.5km ISD, 2x2 SM
– 5km ISD, 1x2 SIMO
16
Throughput: 1.5km ISD, Speed = 3kmph, SFBC & SIMO
17
Throughput: 1.5km ISD, Speed = 3kmph, 2x2 SM
18
Throughput: 5km ISD, Speed = 3kmph, 1x2 SIMO
19
Channel Estimation MSE: 1.5km ISD, Speed=120kmph,
SFBC & SIMO Comparison
20
Channel Estimation MSE: 1.5km ISD, Speed=120kmph, 2x2 SM
21
Channel Estimation MSE: 5km ISD, Speed=120kmph, 1x2 SIMO
22