simulation results for 8 tx antenna pilots document number: ieee c802.16m-09/0786 date submitted:...

Simulation Results for 8 Tx Antenna Pilots

Document Number: IEEE C802.16m-09/0786Date Submitted: 2009-04-24

Source: Jie Zhang ([email protected]), Hua Zhou ([email protected]), Yanling Lu([email protected])

Fujitsu R & D Center. 13/F Ocean International Center, No. 56 Dongsihuan Zhong Rd, Chaoyang District, Beijing, P. R. China

Re: TGm SDD: Other; in response to the TGm Call for Contributions and Comments for Session 61.Purpose: Propose to be discussed and adopted by TGm for the use in Project 802.16m SDDNotice:

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IntroductionIntroduction▪ In current SDD and AWD draft, 8-stream

pilot is not specified yet.

▪ This contribution propose 8-stream pilot pattern in the amendment for IEEE 802.16m downlink.

▪ Moreover, some concerns on the performance, implementation issue are listed and simulation comparisons in MSE performance are given as well

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8Tx Pilot Pattern 1—P18Tx Pilot Pattern 1—P1▪ This pilot structure is what we

propose in this contribution.▪ Overhead:

– 2/108 = 1.85% per Tx antenna– 16/108 = 14.8% for all antennas

▪ The time-frequency structure to that for 4-Tx antenna case: same

– The same subcarrier permutation in resource allocation as that in 4 Tx antenna case

– The same rate matching as in 4 Tx case

▪ Extension to 5 or 7-symbol RU: easy – For 5-symbol sub-frame remove 3rd

OFDM symbol– For 7-symbol sub-frame, append the 3rd

OFDM symbol to the end of the 6-symbol sub-frame

▪ Suitable for SFBC usage: yes– Adjacent data subcarriers can be paired

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8Tx Pilot Pattern 2—P28Tx Pilot Pattern 2—P2▪ This pilot structure is what we proposed

in #59 session.▪ Overhead:


▪ The time-frequency structure to that for 4-Tx antenna case: different

– Different subcarrier permutation in resource allocation from 4-Tx case

– Different rate matching from that in 4-Tx case

▪ Extension to 5 or 7-symbol RU: easy but make the number of pilot on each antenna imbalanced

– For 5-symbol sub-frame remove 3rd OFDM symbol

– For 7-symbol sub-frame, append the 3rd OFDM symbol to the end of the 6-symbol sub-frame

▪ Suitable for SFBC usage: no– Not all adjacent data subcarriers can be

paired 44

8Tx Pilot Pattern 3—P38Tx Pilot Pattern 3—P3▪ This pilot structure is proposed in last

session, “C80216m-09_0515.doc”.▪ Overhead:



– Different subcarrier permutation in resource allocation from 4-Tx case

– Different rate matching from that in 4-Tx case

▪ Extension to 5 or 7-symbol RU: easy – For 5-symbol sub-frame remove 3rd OFDM symbol– For 7-symbol sub-frame, append the 3rd OFDM

symbol to the end of the 6-symbol sub-frame

▪ Suitable for SFBC usage: yes– Adjacent data subcarriers can be paired

5

2 5 6 17 4 3 8

6 1 2 58 3 4 7

5 2 1 64 7 8 3

5

8Tx Pilot Pattern 4—P48Tx Pilot Pattern 4—P4▪ This pilot structure is proposed in

“C80216m-09_0570.ppt” in last session.

▪ Overhead: – 2/108 = 1.85% per Tx antenna– 16/108 = 14.8% for all antennas


– Different subcarrier permutation in resource allocation from 4Tx case

– The same rate matching as in 4-Tx case

▪ Extension to 5 or 7-symbol RU: easy – For 5-symbol sub-frame remove 3rd

OFDM symbol– For 7-symbol sub-frame, append the 3rd



paired6

P2P7

P5P4

P6P3

P1P8

P6 P1 P2 P5P3 P8 P7 P4

P2P7

P5P4

P6P3

P1P8

P6 P1 P2 P5P3 P8 P7 P4P6 P1 P2 P5P3 P8 P7 P4

6

8Tx Pilot Pattern 4’—P4’8Tx Pilot Pattern 4’—P4’▪ This pilot structure is proposed in

C80216m-09_0499.ppt in last session.▪ Overhead:



– Different subcarrier permutation in resource allocation from 4Tx case

– The same rate matching as in 4-Tx case

▪ Extension to 5 or 7-symbol RU: easy – For 5-symbol sub-frame remove 3rd OFDM

symbol– For 7-symbol sub-frame, append the 3rd



paired

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Simulation AssumptionsSimulation Assumptions▪ MSE of channel estimation is the metric▪ Pilot Patterns: P1, P2, P3, P4, P4’

– Due to very similar structure of P4 and P4’, their performance in channel estimation MSE and BLER is rather similar each other

– We just show the simulation results of P4 in following figures.

▪ ITU Channel Models– Ped-B in 3km/h velocity with 2G Hz carrier.– Veh-A in 30km/h velocity with 2G Hz carrier– Veh-A in 120km/h velocity with 2G Hz carrier

▪ 2D-MMSE channel estimation per 1, 2, 3, and 4RUs– In some scenarios, the number of RU allocated to one user maybe

larger than 1– User can estimate the channel cross several RUs allocated to

itself.– The correlation statistics in time and frequency domain are

assumed known in advance.

88

Simulation resultsSimulation results

9

MSE performance under ITU PB 3km/h channel using 1 and 2 RUs for channel estimation

9

10

MSE performance under ITU PB 3km/h channel using 3 and 4 RUs for channel estimation

10

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MSE performance under ITU VA 30km/h channel using 1 and 2 RUs for channel estimation

11

12


12

13


13

14


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Single-link Throughput AnalysisSingle-link Throughput Analysis▪ MSE analysis

– For 2 pilot structures, P1 and P4 have almost the same MSE performance

– For 3 pilot structures, P2 and P3 have almost the same MSE performance, especially in low speed channel scenarios.

▪ Single-link throughput– Due to the fact that, the larger number of pilot in one RU is, the

better channel estimation performance– It’s necessary to compare single-link throughput spectral

efficiency performance between 2 pilots/RU and 3 pilots/RU cases.

– As shown in in last session, the throughput of 2 pilots/RU pattern is better than that of 3 pilots/RU under indoor hotspot channel with velocity 3 km/h.

15

C80216m-09_0570.ppt

15

ConclusionConclusion

▪ From observations above, we suggest to adopt pilot structure 1 (P1) as the pilot pattern for 8-stream case in IEEE 802.16m.

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Metric

Pilot

Total Overhead

MSE Throughput Different resource allocation

Different rate

matching

Extension to 5 or 7-symbol

SFC support

P1 14.8% Medium Good No No Easy Yes

P4 14.8% Medium Good Yes Yes Easy No

P4’ 14.8% Medium Good Yes Yes Easy No

P2 22.2% Good Medium Yes Yes Easy/imbalanced

pilot #

No

P3 22.2% Good Medium Yes Yes Easy Yes

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simulation results for 8 tx antenna pilots document number: ieee c802.16m-09/0786 date submitted:...

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