Design of the CDMA Allocation A-MAP IE for Bandwidth Request Procedure

Document Number: IEEE C802.16m-09/1067

Date Submitted: 2009-04-30

Source: Heejeong Cho E-mail : hj77cho@lge.com

Youngsoo Yuk, Sunam Kim, Kiseon Ryu, Ronny Kim

LG Electronics

Kelvin Chou E-mail : Kelvin.Chou@mediatek.com Yih-Shen Chen, Paul Cheng MediaTek Inc.

Re: IEEE 802.16m-09/0020 -Call for Contributions on Project 802.16m Amendment Working Document (AWD) Content, on the topic of 802.16m AWD – Bandwidth Request Procedure

Purpose: For discussion and adoption in section 15.2.y.2 Grant of the IEEE C802.16m-09/0846 – Connection Management and QoS DG AWD text proposal

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• In the legacy system, CDMA Allocation A-MAP IE is used for allocation of bandwidth to a user that requested bandwidth using a ranging code.

• Ranging codes are classified into 4 subsets according to the purpose.– For initial ranging– For handover ranging– For periodic ranging– For bandwidth request

• However, code design for bandwidth request is different from that for ranging in the 802.16m system.

• Therefore, we propose the design of CDMA Allocation A-MAP IE for the 802.16m system.

Outline

MCRC of A-MAP IE (1/4)

< ABS’s operation generating MCRC for the identified user >

Input Data

Cyclic Generator PolynomialCRC generator

16-bit Parity

Masking 12-bit STID

16-bit Masked Parity (MCRC)

< ABS’s operation generating MCRC for the anonymous user >

• ABS’s operation– ABS appends a 16-bit CRC to the data burst using the cyclic

generator polynomial.– ABS masks 16-bit CRC by Station ID for the identified user or

Random Access ID for the anonymous user.• RAID is generated by random access attributes (e.g., time/frequency

index at which the code was transmitted, code index sent by the AMS)

12-bit RAID

Input Data

Cyclic Generator PolynomialCRC generator

16-bit Parity

Masking

16-bit Masked Parity (MCRC)

• AMS’s operation– AMS calculates the 16-bit CRC in the received A-MAP IE.– AMS masks 16-bit CRC by STID– Additionally, AMS masks 16-bit CRC by RAID only if it performed

random access procedure and waits for a response.– If the output is zero, AMS reads the rest of fields in the A-MAP IE.

Otherwise, AMS ignores the A-MAP IE.

MCRC of A-MAP IE (2/4)

< AMS’s operation only for STID >

Input Data + CRC

Cyclic Generator PolynomialCRC generator

16-bit Parity

Masking 12-bit STID

== 0 or != 0

< AMS’s operation for STID and RAID >

12-bit STID12-bit RAID

Input Data + CRC

Cyclic Generator PolynomialCRC generator

16-bit Parity

Masking

==0 or !=0

• However, some AMSs can recognize that the A-MAP IE is for own and then will perform a corresponding procedure in the following cases;– AMS’s STID is the same as other AMS’s RAID– RAID of a AMS which transmitted ranging code is the same as

RAID of another AMS which transmitted bandwidth request code

• To solve this ambiguous process,– ABS shall mask 16-bit CRC by 12-bit STID and Masking

Indicator or 12-bit RAID and Masking Indicator.– Masking indicator

• 0b0000 indicates that the CRC was masked by 12-bit STID.• 0b0001 indicates that the CRC was masked by 12-bit RAID for

Ranging.• 0b0010 indicates that the CRC was masked by 12-bit RAID for

Bandwidth request.

MCRC of A-MAP IE (3/4)

MCRC of A-MAP IE (4/4)

< A-MAP IE masked by STID > < A-MAP IE masked by RAID for bandwidth request >

Input Data

Cyclic Generator PolynomialCRC generator

16-bit Parity

Masking

12-bit STID ‘8’ + Masking indicator (0b0000)

16-bit Masked Parity (MCRC)

Input Data + CRC

Cyclic Generator PolynomialCRC generator

16-bit Parity

Masking12-bit STID ‘8’ + Masking indicator (0b0000)

== 0

Input Data

Cyclic Generator PolynomialCRC generator

16-bit Parity

Masking

12-bit RAID ‘8’ + Masking indicator (0b0010)

16-bit Masked Parity (MCRC)

Input Data + CRC

Cyclic Generator PolynomialCRC generator

16-bit Parity

Masking12-bit RAID ‘8’ + Masking indicator (0b0010)

== 0

Proposed text15.2.y.2 Grant

In the bandwidth request procedure, the grant for BW-REQ message is allocated by CDMA Allocation A-MAP IE, which is shown in Table yy. CDMA Allocation A-MAP IE is used for allocation of bandwidth to a user that requested bandwidth using a ranging code or BR code. AMS decodes the IE and checks the MCRC field by its specific 12-bit RA-ID and 4-bit Masking Indicator. The RA-ID is calculated by a hash function with the AMS’ random access attributes (i.e., frame number index, sub-frame number index, opportunity index and code index). Masking indicator indicates the identifier used for CRC masking, as shown in Table y2.

Table yy – CDMA Allocation A-MAP IE format

Table y2 – Description of the Masking Indicator

Syntax Size(bits) Notes

CDMA_Allocation_A-MAP IE() {

A-MAP IE type 4

Resource Assignment Information TBD

MCS 5 Modulation and coding scheme used for the burst

MCRC 16 CRC masked by RA-ID and Masking Indicator

}

Masking Indicator Descriptions

0b0000 MCRC is masked by 12-bit STID

0b0001 MCRC is masked by 12-bit RAID for Ranging

0b0010 MCRC is masked by 12-bit RAID for Bandwidth request