doc.: ieee 802.22-06/0227r0 submission nov 2006 wu yu-chun, huawei hisislide 1 beacon sync frame...

Nov 2006

Wu Yu-Chun, Huawei Hisi

Slide 1

doc.: IEEE 802.22-06/0227r0

Submission

Beacon Sync Frame Proposal for the 802.22.1IEEE P802.22 Wireless RANs Date: 2006-11-02

Name Company Address Phone email Wu Yu-chun Huawei Hisi Xinxi Rd., Shangdi St, Haidian

Dist, Beijing 100085 China 86-10-8288-2630 [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]

Feng Shu-Lan Huawei Hisi Beijing, China 86-10-82882562 [email protected]

Linjun Lu Huawei

Technologies Shenzhen, China 86-755-28973119 [email protected]

Yang Yu-Li Huawei Hisi Beijing, China 86-10-82882930 [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.

Release: The contributor grants a free, irrevocable license to the IEEE to incorporate material contained in this contribution, and any modifications thereof, in the creation of an IEEE Standards publication; to copyright in the IEEE’s name any IEEE Standards publication even though it may include portions of this contribution; and at the IEEE’s sole discretion to permit others to reproduce in whole or in part the resulting IEEE Standards publication. The contributor also acknowledges and accepts that this contribution may be made public by IEEE 802.22.

Patent Policy and Procedures: The contributor is familiar with the IEEE 802 Patent Policy and Procedures http://standards.ieee.org/guides/bylaws/sb-bylaws.pdf including the statement "IEEE standards may include the known use of patent(s), including patent applications, provided the IEEE receives assurance from the patent holder or applicant with respect to patents essential for compliance with both mandatory and optional portions of the standard." Early disclosure to the Working Group of patent information that might be relevant to the standard is essential to reduce the possibility for delays in the development process and increase the likelihood that the draft publication will be approved for publication. Please notify the Chair Carl R. Stevenson as early as possible, in written or electronic form, if patented technology (or technology under patent application) might be incorporated into a draft standard being developed within the IEEE 802.22 Working Group. If you have questions, contact the IEEE Patent Committee Administrator at [email protected].>

Nov 2006


Slide 2

doc.: IEEE 802.22-06/0227r0

Submission

Abstract

• A New Sync Frame Scheme for the IEEE 802.22.1 standard is proposed. The FEC adopted in this new scheme provides error correction and error detection capability for the Sync Frame. Thus, the robustness can be improved and the probability of successful synchronization can be increased.

• One of attractive features of this new scheme is that we can gain about 6dB with the new scheme on the AWGN channel with very simple encoding and decoding algorithms. In fact, its encoding is just like adding a CRC, and for decoding, only three XOR operations, one addition operation and one comparison operation are needed for each bit to be decoded.

Nov 2006


Slide 3

doc.: IEEE 802.22-06/0227r0

Submission

Content

Introduction of the New Sync Frame

Scheme

Encoding

Decoding

Simulation Results

Conclusions

Nov 2006


Slide 4

doc.: IEEE 802.22-06/0227r0

Submission

Introduction of the New Sync Frame Scheme

Ri ght

Sync(15)

I ndex=x(4)

Lef t

Pari ty (26)

。。。 Beacon PSDUSync(15)

I ndex=x-1(4)

Pari ty (26)

Sync(15)

I ndex=0(4)

Pari ty (26)

Sync Frame Data FrameSync Frame

Comparing to the Original Sync Frame Scheme, we add a 26-bit Parity part into the Sync Frame, and replace the 9-bit Index with a 4-bit Index.

Our goal is to apply an FEC code to provide both Error Correction and Error Detection ability in the Sync Frame, so that the robustness can be improved and the probability of successful synchronization can be increased.

Nov 2006


Slide 5

doc.: IEEE 802.22-06/0227r0

Submission

The FEC code we select here is a shortened

code, which is a (n,k) = (63-18=45, 37-18=19) linear block code. )2,2()2,( 3EGmEG s

In the transmitter side, the encoding is just like adding a CRC. The generator polynomial we are using here is

The 15-bit Sync sequence and 4-bit Index are combined together as a message to be encoded and denoted in a polynomial form as

1)( 261012131415162426 xxxxxxxxxxxg

181716

217

118

0)( uxuxuxuxuxu

Encoding (1/3)

Nov 2006


Slide 6

doc.: IEEE 802.22-06/0227r0

Submission

Then

The data will be transmitted in the order of

where is transmitted first.

)(]%)([)( 262524

241

250 xgxxupxpxpxpxp

2521018210 ,,,,, ppppuuuu

0u

Encoding (2/3)

Nov 2006


Slide 7

doc.: IEEE 802.22-06/0227r0

Submission

The Encoding procedure can be implemented as following circuit:

Encoding (3/3)

Dn-k-1D0 D1+

g0

+ +

g1 gn-k-1

uk-1. . . u2, u1, u0. . . . . .

. . . . . .

K0

K1A10 A11 0

A00

A01

Output

Nov 2006


Slide 8

doc.: IEEE 802.22-06/0227r0

Submission

For decoding, after finding the start point of the Sync Frame by correlating with 15-bit Sync Sequence, we extract 45-bit data of a Sync Frame and extend it to 63 bit by filling with 0 in the first 18 positions

},{},,,00,0{ 6210'

44'

2'

1'

0 rrrrrrrr

Then, is fed into the decoder. r

Decoding (1/3)

Nov 2006


Slide 9

doc.: IEEE 802.22-06/0227r0

Submission

…r0=0r1=0

r18

r17=0

r19

r63

s0+

r6=0

r30

r40

r41

r44

r56

r61

s1

s63+

e0=0e1=0

e18

e17=0

e19

e63+

+ >4 ?

>4 ?

z0=0

z17=0

181818 erz 191919 erz

636363 erz

s0+s1

s63+

Step1(Cal cul ateSyndrome Vector) :

8- i nput XOR

Step2(Cal cul ate ErrorVector) :

8- i nput Add and Comp

Step3(Error Correct) :2- i nput XOR

Step4(Error Detect) :8- i nput XOR

s6

s18

s21

s22

s32

s56

s62

z1=0

The decoder can be implemented as following circuit diagram:

Nov 2006


Slide 10

doc.: IEEE 802.22-06/0227r0

Submission

From above figure, we can see that only three XOR operations, one addition operation, and one comparison operation are needed for each bit to be decoded. So its complexity is increased very slightly and this is highly preferred for the implementation.

Decoding (3/3)

Nov 2006


Slide 11

doc.: IEEE 802.22-06/0227r0

Submission

Simulation Results (1/3)

For simplicity and to emphasize the key point of FEC, we do not include a Differential Encoder, the Direct Sequence Spread Spectrum (DSSS), and pulse shaping in our simulations. The block diagram of the New Sync Frame Scheme (with FEC) simulator is:

15-bi t Fi xedSync Sequence

4-bi t I ndex

Mul t i pl exChannelEncoder

BPSK

AWGN

ChannelDecoder

Hard J udge

FERstati st i cs

Nov 2006


Slide 12

doc.: IEEE 802.22-06/0227r0

Submission

Simulation Results (2/3)

To compare with Original Sync Frame Scheme (with No FEC): The block diagram of the Original Sync Frame Scheme (with No FEC) simulator is:

15-bi t Fi xedSync Sequence

9-bi t I ndex

Mul t i pl ex BPSK

AWGN

Hard J udge

FERstati st i cs

Nov 2006


Slide 13

doc.: IEEE 802.22-06/0227r0

Submission

Simulation Results (3/3)The simulation results on the AWGN channel are plotted in the following figure. We can see that 6dB was gained with New Sync Frame Scheme over the original Sync Frame Scheme.

Nov 2006


Slide 14

doc.: IEEE 802.22-06/0227r0

Submission

Conclusions (1/2)

From the previous slides, we can see that the new Sync Frame Scheme has following advantages:

The new scheme maintains the merits of the Fixed Sync Sequence. In other words, in the new scheme, we can still find the start point of Sync Frame quickly by searching the Fixed Sync Sequence.

The new scheme provides error correction capability, which greatly improves the Sync performance (about 6dB gain over the Original Sync Frame scheme when FER≤10-3 ) and robustness.

Nov 2006


Slide 15

doc.: IEEE 802.22-06/0227r0

Submission

Conclusions (2/2)

The new scheme provides the error detection capability. Once we decode one Sync Frame successfully, we can obtain the start point of Beacon PSDU with high-level confidence.

The FEC used here has a very simple encoding algorithm as well as a very simple decoding algorithm. The encoding procedure is just like adding a CRC. Regarding decoding complexity, only three XOR operations, one addition operation, and one comparison operation are needed for each bit.

The new scheme needs very small buffer to save the information of g(x) and H, because it is needed only to save one row of H rather than whole H.

Nov 2006


Slide 16

doc.: IEEE 802.22-06/0227r0

Submission

Thank you!

Any comments and questions

will be highly appreciated!

doc.: ieee 802.22-06/0227r0 submission nov 2006 wu yu-chun, huawei hisislide 1 beacon sync frame...

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