MAC PDU Multiplexing Scheme for IEEE 802.16m

Document Number: IEEE C802.16m-08/1015r1

Date Submitted: 2008-09-05

Source:Fang-Ching (Frank) Ren, Richard Li E-mail: frank_ren@itri.org.tw, richard929@itri.org.twITRI

Yih-Shen Chen yihshen.chen@mediatek.comMediaTek Inc.

Venue:IEEE 802.16m-08/033, Call for Contributions and Comments on Project 802.16m System Description Document (SDD)”.- Target topic: “Upper MAC (Data Plane Functions)”

Base Contribution: None

Purpose:To be discussed and adopted by TGm for the 802.16m SDD

Notice:This document does not represent the agreed views of the IEEE 802.16 Working Group or any of its subgroups. It represents only the views of the participants listed in the “Source(s)” field above. It is offered as a basis for discussion. It is not binding on the contributor(s), who reserve(s) the right to add, amend or withdraw material contained herein.

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Motivation (1)

• MPDU multiplexing in 802.16e – Multiple MAC PDUs may be concatenated into a single

transmission in either the UL or DL directions.• Example of “MAC PDU concatenation” shown in Figure 42 of

P802.16Rev2/D6.

• Drawbacks– Possible error propagation due to MPDU header error– Less efficient for resource allocation

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Motivation (2)

• Error Propagation– When MAC header error occurs in MPDU A,

• There is no valid “length” indication for MPDU A.• It is unavailable to detect MAC header of MPDU B.• MPDU B will be regarded as “error”.

• Each MPDU needs a “length” fields– Flexible but not necessary, e.g., VoIP. Therefore, the length field

could be condensed.

MAC header

Payload (optional)CRC

(optional)

MAC header

Payload (optional)CRC

(optional)

PHY BurstError

MPDU A MPDU B

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Proposed MPDU Multiplexing Scheme

• A MS may activate multiple transport service flows and management connections.– To avoid error propagation impact, it is better to split

control header and data part. Therefore, the aggregated control headers can be protected with higher level coding.

– Dependent on the traffic volume and transmission requirement, each service flow or management connection can be configured for transmission with smaller set of MPDU sizes.

• A MPDU concatenation index (MCI) can be adopted to indicate the combination of concatenated MPDUs.

• MCI should be part of resource allocation, e.g., MAP_IE in 16e.

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Example of MCI

– Service Flow 1: Format A, Format B, Format C,– Service Flow 2: Format X, Format Y,

Service Flow 1 Service Flow 2 MCI

A X 0

A Y 1

B X 2

B Y 3

C X 4

C Y 5

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Text Proposal for 802.16m SDD

10.x Construction and transmission of MAC PDUs10.x.1 Concatenation

• Multiple MAC PDUs may be concatenated into a single transmission in either the UL or DL directions.

• The control header and data part of MPDUs can be split and protected with different level coding.

• A MS should negotiate or update the allowable combination of concatenated MPDUs, which are indicated by MPDU concatenation index (MCI), with BS when a new connection is initiated, terminated, or re-configured.

• MCI should be protected under lower error probability than MPDU data parts to achieve better performance MPDU de-concatenation.