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

September, 2001

H. Gan, V. Sapozhnykov, et. al.Slide 1

doc.: IEEE 802.15-01/435r2

Submission

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

Submission Title: [Adaptive Frequency Hopping - An instant channel replacement approach for both ACL and SCO]Date Submitted: [September, 2001]Source: [H. Gan, V. Sapozhnykov, B. Treister, E. Skafidas, et. al.] Company [Bandspeed Inc.]Address [Level 9, 500 Collins Street, Melbourne, Victoria, Australia]Voice:[61 3 9614 6299 , FAX: [61 3 9614 6699]E-Mail:[h.gan, b.treister, v.sapozhnykov@bandspeed.com.au]

Re: [A new simple approach for adaptive frequency hopping]

Abstract: [This document describes a new simple approach for adaptive frequency hopping, an instant channel replacement to intelligently use bad channels in the hopping sequence]

Purpose: [Introducing a new approach for adaptive frequency hoping to include in 802.15.2]

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.

September, 2001

doc.: IEEE 802.15-01/435r2

Submission

Adaptive Frequency Hopping (AFH) - A Simple Instant Channel Replacement

Approach for both ACL and SCO

Hongbing Gan, Vitaliy Sapozhnykov, Bijan Treister, Stan Skafidas, et. al.

Bandspeed Inc.

September, 2001

doc.: IEEE 802.15-01/435r2

Submission

Definition of Channel Pair A channel pair is comprised of two channels:

• First channel, Master Tx/Slave Rx channel, at even-numbered timeslot

• Second channel, Slave Tx/Master Rx, ie, Slave return channel, at odd-numbered timeslot

Master Tx Rx Tx Rx

Slave Rx Tx Rx Tx

Channel Pair Channel Pair

Even-numbered Timeslot

Odd-numbered Timeslot

September, 2001

doc.: IEEE 802.15-01/435r2

Submission

Definitions • N: Total number of hopping channels• Nmin: Minimum number of channels to be used, set by regulations such as FCC • G: Good channel• B: Bad channel• BN: Bad channel to be removed legally from the hopping

sequence • BK: Bad channel to keep in the hopping sequence

• NG, NB, NBN, NBK: Number of good channel, Number of bad

channel, Number of bad channel to remove, Number of bad channel to keep, respectively

• N = NG + NB

• NB = BK + BN

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doc.: IEEE 802.15-01/435r2

Submission

AFH Covers All Possible Channel Classification Scenarios

• Scenario 1:

• BN = 0, Bk > 0, all Bad channels are kept, the AFH intelligently use BK in the new hopping sequence

• Scenario 2:

• BN > 0, BK > 0, the AFH replaces BN with good channels G or BK, and intelligently use BK in the new hoping sequence

• Scenario 3: (Ideal scenario)

• BN > 0, BK = 0, all Bad channels are replaced with Good channels in the new hopping sequence

September, 2001

doc.: IEEE 802.15-01/435r2

Submission

AFH Covers All the Traffic TypesType Traffic Type Priority if Mixed

AFH Instant Channel Replacement (ICR) Approach

1 1 ACL Standard, as described in 01/435r0 2 1 HV1 Standard, as described in 01/435r0 3 1 HV2 Fit Best ICR, described in this document4 2 HV2 Standard, as described in 01/435r0 5 1 HV3 Fit Best ICR, described in this document6 2 HV3 Fit Best ICR, described in this document7 3 HV3 Standard, as described in 01/435r0 8 Non Standard, as described in 01/435r0 9 ACL higher Fit Best ICR, described in this document10 SCO higher Fit Best ICR, described in this document11 Non Standard, as described in 01/435r0 12 ACL higher Fit Best ICR, described in this document13 SCO higher Fit Best ICR, described in this document14 Non Standard, as described in 01/435r0 15 ACL higher Fit Best ICR, described in this document16 SCO higher Fit Best ICR, described in this document

1 HV2 + ACL

1 HV3 + ACL

2 HV3 + ACL

September, 2001

doc.: IEEE 802.15-01/435r2

Submission

AFH Approach 1

- Standard Instant Channel Replacement (Standard ICR)

(Details in IEEE 802.15 Document 01/435r0, 01/438r0)

September, 2001

doc.: IEEE 802.15-01/435r2

Submission

Principle of Standard ICR

G G G B B G B BOriginal

Pass BlockedBlockedRe-transmission

G G G G B B B BNew

Pass BlockedBlockedPass

• Original ‘Good Good’ and ‘Bad Bad’ channel pairs are kept in their original positions in the hopping sequence

• ‘Good Bad’ channel pairs are instantly replaced to ‘Good Good’ channel pairs

• ‘Bad Good’ channel pairs are instantly replaced to ‘Bad Bad’ channel pair

• Throughput improved due to newly created ‘Good Good’ channel pairs

September, 2001

doc.: IEEE 802.15-01/435r2

Submission

Principle of Standard ICR For each channel pair, starting from Master Tx channel: Removing BN by replacing it with a randomly selected G

or BK, to maintain equal usage of G and BK

Whenever Master Tx channel is OR replaced to G, replace the Slave return channel to G if it is BN or BK originally, to form a ‘G G’ channel pair and secure a transaction

Whenever Master Tx channel is OR replaced to BK, replace the Slave return channel to BK if it is BN or G originally, to form a ‘BK BK’ channel pair, to remove BN and save a usage of G

Channel replacement on a per channel pair basis

September, 2001

doc.: IEEE 802.15-01/435r2

Submission

Standard ICR Processing Table

• When NO BK, Case 1, 3 ,4, 6 are processed

• When NO BN, Case 1, 2, 10, 11 are processed

Replacing Case

Master Tx channel

Slave Return Channel

1 G G2 G BK

3 G BN

4 BN G5 BN BK

6 BN BN

7 BN G8 BN BK

9 BN BN

10 BK G11 BK BK

12 BK BN

Channel pair in original hopping sequence

Master Tx channel

G GG GG GG GG GG GBK BK

Channel pair after replacement of BN and intelligent use of BK

In case Master TX BN replaced with a BK

In case Master TX BN replaced with a G

September, 2001

doc.: IEEE 802.15-01/435r2

Submission

Example Portion of Original and AFH Hopping Sequence

G G G BK G BN G GBN BNBN BKBN G

BK G BK BN BK BK BN GG GBN GG BK

G G G G G G G GG GG GG G

BK BK BK BK BK BK G GG GBK BKG G

In this example, 7 more ‘Good Good’ channel pairs are created

September, 2001

doc.: IEEE 802.15-01/435r2

Submission

Flowchart A:Used for Master Tx/Slave Rx timeslots, i.e., Even-numbered timeslot

W hat k ind of channel ? G , B K or B N

Standard H opping channelse lection kernel

B kB N

S electing a good channe lG or B K random ly

M aster TxS lave R x

M aster Tx*S lave R x

* A s the m aster knows it's abad channe l, it can e ither:- N ot to transm it in th istim eslo t- T ransm it a short packetw ithout tra ffic , such as P O LL- D ecrease Tx power

O utputs a channe l

Using thereplaced goodchannel

Using the channeld irectly

M aster Tx*S lave R x

September, 2001

doc.: IEEE 802.15-01/435r2

Submission

Flowchart B:

Used for Slave Tx/Master Rx timeslots, i.e., Odd-numbered timeslot W hat k ind o f channe l

? G , B K o r B N

Standard H opping channelselection kernel

B kB N

G ood C hannel BankKept Bad C hannel Bank

(A ll B K)

S lave T xM aster R X

B k (p revious)W hat k ind o f channel inprevious tim eslot?

G , or B K

W hat k ind o f channel inprevious tim eslot?

G , or B K

W hat k ind o f channel inprevious tim eslot?

G , or B K

G (p revious)

Selecting a goodchannel random ly from

G ood C hannel Bank

Selecting a bad channelrandom ly from Kept Bad

C hannel Bank

G B k G G B k

Output a Channel

S lave T x*M aster R X

B k(previous)

G(p revious)

Selecting a bad channelrandom ly from Kept Bad

C hannel Bank

U sing the se lectedgood channe l

U sing the se lectedbad channe l

U sing the ou tpu tchanne l d irectly

U sing the se lectedbad channe l

B k (p revious)G

(p revious)

Selecting a goodchannel random ly from

G ood C hannel Bank

U sing the se lectedgood channe l

U sing the ou tpu tchanne l d irectly

*A s the p revious M aster T x channe l isB k as w e ll, S lave rece ived incorrectly,o r no th ing is transm itted from M aster,S o a t th is s lave re tu rn tim eslo t, no th ingw ill be re tu rned to M aster

September, 2001

doc.: IEEE 802.15-01/435r2

Submission

AFH Approach 2

- ‘Fit Best’ Instant Channel Replacement (Fit Best ICR)

September, 2001

doc.: IEEE 802.15-01/435r2

Submission

General Principle of Fit Best ICR• For HV2 and HV3:

– Fit the best channels to channel pairs of the reserved SCO Timeslots

• For mixed SCO + ACL:– Fit the best channels to channel pairs of the

reserved SCO Timeslots, if SCO has higher priority

– Fit the best channels to channel pairs of the ACL Timeslots, if ACL has higher priority

– Use Standard ICR if neither ACL nor SCO has higher priority

September, 2001

doc.: IEEE 802.15-01/435r2

Submission

Mixed SCO (HV2, HV3) and ACL Links

T R T RT RT R T R T R

HV2HV2ACL ACLACL

ACL ACLACL ACLHV3

HV2 reserves half Timeslots, transmits every four Timeslots

HV3 reserves one third Timeslots, transmits every six Timeslots

September, 2001

doc.: IEEE 802.15-01/435r2

Submission

How Fit Best ICR works• For channel pairs at higher priority timeslots:

• Case 1: ‘Good Good’ ‘Good Good’

• Case 2: ‘Good Bad’ ‘Good Good’

• Case 3: ‘Bad Good’ ‘Good Good’

• Case 4: ‘Bad Bad’ ’Good Good’

• For every Case 3 replacement, a Good Channel Usage Debt (GUD) Counter is incremented by 1; For every Case 4 replacement, the GUD Counter is incremented by 2.

• In lower priority timeslots, if there is GUD debt, a ‘Good Bad’ channel pair will be replaced to ‘Bad Bad’ channel pair to repay the GUD by 1; A ‘Good Good’ channel pair will be replaced to ‘Bad Bad’ channel pair to repay the GUD by 2.

• GUD balance is always towards ZERO, to maintain equal channel usage.

September, 2001

doc.: IEEE 802.15-01/435r2

Submission

How Fit Best ICR works• Example: HV2 + ACL, HV2 Voice Link has higher priority (shown

in next slide) • In HV2 slots, do the following replacement:

– ‘Good Good’ channel pairs are kept as usual – ‘Good Bad’ replaced to ‘Good Good’ as usual – ‘Bad Good’ replaced to ‘Good Good’, increment GUD debt

counter by 1 – ‘Bad Bad’ replaced to ‘Good Good’, increment GUD debt

counter by 2 • In ACL slots, do the following replacements

– If any GUD Debt, ‘Good Good’ channel pairs are replace to ‘Bad Bad’, decrease GUD debt counter by 2

– If any GUD Debt, ‘Good Bad’ replaced to ‘Bad Bad’, decrease GUD debt counter by 1

– ‘Bad Good’ replaced to ‘Bad Bad’ as usual – ‘Bad Bad’ are kept as usual

• If ACL has higher priority, just do the reverse.

September, 2001

doc.: IEEE 802.15-01/435r2

Submission

How Fit Best ICR works(Assuming HV2 has higher priority)

G G G BK G BK BK BKG BKBK GBK G

G G BK BK BK GG GG GG BK

HV2 HV2ACL

ACLACL ACL

ACLACL

HV2 HV2

HV2HV2HV2

G G G G G G G GBK BKG GBK BK

BK BK BK BK BK BKG GG GG G

HV2 HV2ACL

ACLACL ACL

ACLACL

HV2 HV2

HV2HV2HV2

1 2 3 4 5 6 7

8 9 10 11 12 13 14

September, 2001

doc.: IEEE 802.15-01/435r2

Submission

Fit Best ICR Processing TableReplacing

Case Master Tx channel

Master Tx channel

GUD Counter Comments

1 G G G G2 G BK G G3 BK G G G Plus 1

4 BK BK G G Plus 2

Replacing Case

Master Tx channel

GUD Counter Comments

1 G G G G2 G BK G G3 BK G BK BK

4 BK BK BK BK

5 G G BK BKMinus 2

Repay the Good channel Usgae Debt (GUD) if any

6G BK BK BK

Minus 1

Repay the Good channel Usgae Debt (GUD) if any

At timeslots for higher priority traffic, such as voice HV2

At timeslots for lower priority traffic

September, 2001

doc.: IEEE 802.15-01/435r2

Submission

Traffic Type VS. AFH MethodType Traffic Type

Priority if Mixed

AFH Method Comments

1 1 ACL Standard2 1 HV1 Standard3 1 HV2 Fit Best Fit best channels to SCO slots

4 2 HV2 Standard5 1 HV3 Fit Best Fit best channels to SCO slots

6 2 HV3 Fit Best Fit best channels to SCO slots

7 3 HV3 Standard8 Non Standard9 ACL higher Fit Best Fit best channels to ACL slots

10 SCO higher Fit Best Fit best channels to SCO slots

11 Non Standard12 ACL higher Fit Best Fit best channels to ACL slots

14 Non Standard15 ACL higher Fit Best Fit best channels to ACL slots

1 HV2 + ACL

1 HV3 + ACL

2 HV3 + ACL

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

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

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

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