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Project: IEEE P802.15 Working Group for Wireless Personal Area Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs)Networks (WPANs)

Submission Title: Symbols or time for SUN PHYsDate Submitted: January 2011Source: James GilbContact: James GilbVoice: 858-229-4822, E-Mail: last name at ieee dot orgRe: d2P802-15-4g_Draft_Standard.pdf, LB62Abstract: 802.15.4 MAC timing is based on symbols. However, the SUN PHYs use

multiple symbol rates in a single band and have some timing specified in units of seconds.

Purpose: Resolve comments in LB62.Notice: This document has been prepared to assist the IEEE P802.15. 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 acknowledges and accepts that this contribution becomes the property of IEEE and may be made publicly available by P802.15.

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Introduction• The 802.15.4 MAC bases all timing on

symbols– e.g., superframe duration, slot duration,

minimum CAP size.

• The SUN PHYs allow multiple symbol rates (and hence symbol durations) in a single band.

• Some of the SUN PHY timing parameters are currently specified in seconds

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Comments addressed• 234, 372, 683, 918, 921, 1155

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Significance of timing• The LR-WPAN needs known timing

– Superframe duration, CAP duration, etc. all depend on it.

– Every device needs to use the same timing.

– Otherwise, synchronization issues

• For MAC, best is to use a common unit for describing time– In some standards, a time unit (TU)– In 802.15.4, it is the symbol

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MAC constants

No changes should be needed for the above constants.

This probably needs to have a different value for SUN PHYs

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MAC PIB attributes

Need to add the calculations for the SUN PHYs to 5.1.6.4.2

No change required at this location.

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MAC PIB attributes (cont.)

No change required at this location.

No change required at this location.

No change required at this location.

No change required at this location.

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MAC primitivesMLME-BEACON-NOTIFY.indication

UWB related, no change required.

No change required at this location.

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MAC primitives (2)

No change required for either of these at this location.

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MAC primitives (3)

No change required at this location.

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MAC primitives

No change required at this location.

UWB related, no change required.

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General PHY requirements

4g should verify that this detection period is correct and modify if necessary.

These will likely be different for SUN PHYs, perhaps different in some bands

Doesn’t apply to 4g, used for LBT PHYs

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PHY constants and PIB attributes

4g will probably need to alter this one, i.e. “for SUN PHYs …”

Should be fine

Does the next three need to be a list of values, each entry corresponding to a different data rate?

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PHY PIB attributes

phyCCADuration only applies to 905 MHz PHYs that need to do a special listen before talk.

phyUWBInsertedPreambleInterval only applies to UWB PHYs, no change required for 4g.

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Suggested resolution• Keep timing in symbols.

– Clarify that in the MAC clause, symbol means the symbol duration at the lowest mandatory rate, i.e., the longest mandatory symbol duration.

• Use symbols for SUN PHY timing– Translate all SUN PHY timing parameters

into symbols at the lowest mandatory rate

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Resolution text• Add to Clause 5

– “For the SUN PHYs, the symbol duration used for MAC and PHY timing parameters shall be the symbol duration of the lowest data rate mandatory mode each band. For the generic PHY, this corresponds to the lowest data rate defined for that generic PHY.”

• Add cross references at other locations (e.g., Clause 8, Clause 9), i.e.– “For the SUN PHYs, the meaning of a symbol

duration for timing parameters is described in 5.1.”