Doc.: IEEE 802.22-07/0099r0 Submission March 2007 Wu Yu-Chun, Huawei HisiSlide 1 FEC on Sync Burst and PSDU for the 802.22.1 IEEE P802.22 Wireless RANs

March 2007

Wu Yu-Chun, Huawei Hisi

Slide 1

doc.: IEEE 802.22-07/0099r0

Submission

FEC on Sync Burst and PSDU for the 802.22.1

IEEE P802.22 Wireless RANs Date: 2007-03-04

Name Company Address Phone email Wu Yu-chun Huawei Hisi Beijing, China 86-10-8282-9018 [email protected]

Soo-Young Chang

Huawei Technologies

Davis, CA, U.S. 1-916 278 6568 [email protected]

Jianwei Zhang Huawei

Technologies Shanghai, China 86-21-68644808 [email protected]

Authors:

Notice: This document has been prepared to assist IEEE 802.22. It is offered as a basis for discussion and is not binding on the contributing individual(s) or organization(s). The material in this document is subject to change in form and content after further study. The contributor(s) reserve(s) the right to add, amend or withdraw material contained herein.

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March 2007


Slide 2

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Submission

Abstract

• One of the most important and urgent problem that TG1 group must resolve to finish a complete draft that CAN WORK is: In order that WRAN can sense the beacon with high probability and at the same time, with small complexity and as short sensing window as possible, we must apply proper FEC technique on Sync Burst and PSDU.

• Here firstly we analyze the performance requirements for sensing the beacon; Then we introduce the design and simulation results of both the Sync Burst and PSDU.

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Slide 3

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Submission

Content

System Performance Requirements.

FEC Design on Sync Burst and Simulation Results.

FEC Design on PSDU and Simulation Results.

Questions

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Slide 4

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Submission

System Performance Requirements(1/2)

Based on following Constraints:The Maximum Beacon Power is 250mWReasonably assume that the Beacon Tx Antenna is always higher than

Wireless Mike’s Rx Antenna

Then from 【 3 】 , we can see that the worst SNR will be -2dB

Considering also that :WRAN can decode the Sync Burst 2~3 times within a 10ms FrameMost of the time, the BS can make its decision based on the sensing

results of several CPEs ；The Sensing requirements of TV signals ；

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Slide 5

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Submission

System Performance Requirements(2/2)

Then we establish the following performance requirements for beacon sensing :

Under the worst case -2dB, the WRAN should be able to sense the Sync Burst with probability of at least 90% in a 10ms Frame.

Under the worst case -2dB, the WRAN should be able to sense the PSDU with probability of at least 90% by one shot.

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Slide 6

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Submission

FEC Design on Sync Burst and Simulation Results (1/5)

Figure 1: The FEC Design on SyncBurst

Sync Frame With IndexX

Sync Frame With IndexX-1

Sync Frame With Index1

。。。

Sync Sequence(15 bits)

Index(7 bits)

Parity(8 bits)

Sync Frame Structure

Reserved(2 bits)

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Slide 7

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Submission


The FEC on Sync Burst is a (15,7) Linear Block Code, The reason that we choose this code is:

1) It has very simple Encoding and Decoding algorithms (Please refer to 【 1 】 for detail).

2) It doesn’t increase the Sync Frame Length too much (Only increase 1 byte).

3) It has error correcting capability and can improve the Sync Burst performance greatly(about 2~5dB).

4) It also provides error detection capability on Sync Burst, which is commonly believed to be a MUST for the Sync Burst.

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Slide 8

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Submission


Simulation Condition:

1) Assume Perfect Symbol Synchronization;

2) 6-bit Quantization of received signal;

3) DQPSK Modulation and 8-chip Spreading;

4) AWGN and WRAN Profile_A channel;

5) Statistic Length: 10,000 Frames

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Slide 9

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Submission


Figure 2: Sync Burst Performance with or without FEC under AWGN and Profile A channel

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Slide 10

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• From the simulation Results, we can see that under the typical WRAN environment: WRAN Profile A channel, at the SNR = -2 point:

1) Without FEC, the BLER is 67%. Even the WRAN can have 3 shots of Sync Burst sensing within a 10ms Frame, and under the assumption that any 1 of the 3 shots pass CRC check, we declare a success detection. the success detection probability is only 1-(0.67*0.67*0.67) = 70%;

2) With FEC, the BLER is 11.5%. Even the WRAN have only 1 shot of Sync Burst sensing within a 10ms Frame, it can almost meet the 90% performance requirements. Moreover, The WRAN can have 2 shots of Sync Burst sensing within a 10ms Frame, then the success detection probability will be 1-(0.115*0.115) = 98.68%;

• For AWGN Channel, at the SNR = -2 point, The result is same, i.e, with FEC, the performance requirement can be met, otherwise, it fails.

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Slide 11

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Submission

FEC Design on PSDU and Simulation Results (1/5)Here we take the Original PSDU Length as 26 bytes (208 bits) as proposed in 【 4 】

208-bit PSDU Frame

4-bit CRC

6-bit zero

½ Rate (Output 436-bit) Convolutional Code (CC), The CC is same as what used in WRAN with Constraint Length of 6

Repeat to 480-bit (50ms)

Modulation and Tx

Figure 3: The FEC Design on PSDU

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Slide 12

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Submission

FEC Design on PSDU and Simulation Results (2/5)

1) The Original 208-bit PSDU was added by 4-bit CRC and 6 Tail zero bit, now the number of total bits are 218 bits;

2) Then it was fed into ½ Convolutional Coder (the same as WRAN Convolutional Coder), the output are 436bits;

3) To ensure that the performance requirement can be met and at the same time, make PSDU not too long, it was repeated to 480bits(50ms);

4) Finally the repeated PSDU data was modulated and transmitted.

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Slide 13

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Submission


Simulation Condition:

1) Assume Perfect Symbol Synchronization;

2) 6-bit Quantization of received signal;

3) DQPSK Modulation and 8-chip Spreading;

4) AWGN and WRAN Profile_A channel;

5) Statistic Length: 10,000 Frames

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Slide 14

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Figure: PSDU Performance with or without FEC under AWGN and Profile A channel

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Slide 15

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Submission


• From the simulation Results, we can see that under the typical WRAN environment: WRAN Profile A channel, at the SNR = -2 point:

1) Without FEC, the BLER is 96.4%, it’s far away from the performance requirement.

2) With FEC, the BLER is 3.3%, it can meet the 90% performance requirement.

• For AWGN Channel, at the SNR = -2 point, The result is same, i.e, with FEC, the performance requirement can be met, otherwise, it fails.

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Submission

Questions? (1/1)

Any questions and suggestions on future work are highly appreciated

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Slide 17

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Submission

References

1. 《 22-07-0053-01-0001_Huawei_FEC_on_Sync_Frame 》

2. 《 22-06-0245-05-0000_WRAN_Sensing_Window 》

3. 《 22-07-0067-01-0001_Beacon_PER_vs_Distance 》

4. 《 22-07-0031-00-0001_TG1-SecurityOverview 》

Documents

Doc.: IEEE 802.22-07/0099r0 Submission March 2007 Wu Yu-Chun, Huawei HisiSlide 1 FEC on Sync Burst and PSDU for the 802.22.1 IEEE P802.22 Wireless RANs