1. doc.: IEEE 802.15-<doc#>
<month year>
doc.: IEEE <doc#>
Project: IEEE P Working Group for Wireless Personal Area Networks (WPANs)
Submission Title: Low Energy Service Discovery MAC protocol for PAC WPAN
Date Submitted: [July 2013]
Source: [Wun-Cheol Jeong, Chang-Sub Shin, Tae-Joon Park, Hoyong Kang]
Company: [ETRI]
Re: []
Abstract: This proposal document describes how common discovery is supported from the MAC’s perspective.
Notice: This document has been prepared to assist the IEEE P 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 P
<author>, <company>

2. Low Energy Service Discovery MAC Protocol for PAC WPAN
<month year>
doc.: IEEE <doc#>
Low Energy Service Discovery MAC Protocol for PAC WPAN
Wun-Cheol Jeong, Chang-Sub Shin,
Tae-Joon Park, Hoyong Kang
ETRI
<author>, <company>

3. Low Energy Service Discovery Protocol
Abbreviations and acronyms
CS Channel Sampling
LESD Low Energy Service Discovery
MAC Medium Access Control
MHR MAC Header
MLME MAC sublayer Management Entity
MLSDE MAC sublayer Service Discovery Entity
PAN Personal Area Network
PD PAC Device
PLME PHY layer Management Entity
WPAN Wireless Personal Area Network

4. doc.: IEEE 802.15-<doc#>
<month year>
doc.: IEEE <doc#>
State Diagram of LESD
Passive LESD scan
Search
Success
Join PAN
Search
Fail
Channel Sampling
(CS)
Active LESD scan
Search
Success
Start PAN
Search
Fail
<author>, <company>

5. Passive LESD Scan Procedure
NHL
MLSDE
MLSDE-LESD-SCAN.request
Passive LESD Scan
LESD response
LESD notification
MLSDE-LESD.confirm
LESD notification
MLSDE-LESD-NOTIFY.indication
MLSDE-LESD-SCAN.confirm

6. Active LESD Scan Procedure
NHL
MLSDE
MLSDE
NHL
MLSDE-LESD.request
LESD request
MLSDE-LESD.indication
macLESDResponseWaitTime
MLSDE-LESD.response
LESD response
LESD notification
MLSDE-LESD-NOTIFY.indication
MLSDE-LESD.confirm
macNumLESDRequestRetries
> macMaxLESDRequestRetries
MLSDE-LESD-SCAN.confirm

7. Channel Sampling (CS) State
<month year>
doc.: IEEE <doc#>
Channel Sampling (CS) State
Sleep Timer fire
Sleep Rx
macCSduration
Tx completion
Receive
LESD request
command
Send
Response Command
<author>, <company>

8. Illustration of CS procedure
LESD request command
CS Interval
Sender
TBRB
LIFS
CS Interval
Receiver
CSDuration

9. CS Procedure NHL MLSDE MLSDE-LESD-CS.request MLSDE-LESD-CS.confirm
LESD request
Rx on for
macCSDuration
MLME-LESD.indication
MLME-LESD.response
LESD response
macCSInterval
Rx off

10. MAC Primitives for LESD
request
indication
response
confirm
MLSDE-LESD-SCAN O
MLSDE-LESD
MLSDE-LESD-NOTIFY
MLSDE-LESD-CS

11. MLSDE-LESD-SCAN: request MLSDE‑LESD-SCAN.request parameters
NumBRB,
ServiceID,
LESDChannelID,
AvailableChannelID )
MLSDE‑LESD-SCAN.request parameters
Name
Type
Valid Range
Description
NumBRB
Integer
0x00-0xff
Number of BRB to be repeated
ServiceID
0x0-0xf
PAC service ID to search.
LESDChannelID
0x0000-0xffff
Channel number for service discovery
AvailableChannelID
Set of octets
0x0000-0xffff for each element
List of channel numbers that PD is capable of use.

12. MLSDE-LESD-SCAN: confirm MLSDE‑LESD-SCAN.confirm parameters
Status )
MLSDE‑LESD-SCAN.confirm parameters
Name
Type
Valid Range
Description
Status
Enumeration
SUCCESS,
SCAN_IN_PROGRESS,
INVALID_PARAMETER
The result of the passive LESD scan request.

13. MLSDE‑LESD.request parameters
NumBRB,
ServiceID,
LESDChannelID,
AvailableChannelID )
MLSDE‑LESD.request parameters
Name
Type
Valid Range
Description
NumBRB
Integer
0x00-0xff
Number of BRB to be repeated
ServiceID
0x0-0xf
PAC service ID to search.
LESDChannelID
0x0000-0xffff
Channel number to be used for LESD.
AvailableChannelID
Set of octets
0x0000-0xffff for each element
List of channel numbers that PD is capable of use.

14. MLSDE-LESD: indication MLSDE‑LESD.indication parameters
ServiceID,
AvailableChannelID )
MLSDE‑LESD.indication parameters
Name
Type
Valid Range
Description
ServiceID
Integer
0x0-0xf
PAC service ID to search.
AvailableChannelID
Set of octets
0x0000-0xffff for each element
List of channel numbers that PD is capable of use.

15. MLSDE‑LESD.response parameters
PANID,
ServiceID,
CommunicationChannelID )
MLSDE‑LESD.response parameters
Name
Type
Valid Range
Description
PANId
Integer
0x0000–0xffff
The PAN identifier used by the PD.
ServiceID
0x0-0xf
The Service ID of the PAC WPAN that the PD is associated with.
CommunicationChannelID
Set of octets
0x0000-0xffff for each element
List of channel numbers in use at the PAC WPAN that the PD is associated with.

16. MLSDE‑LESD.confirm parameters
PANID,
ServiceID,
CommunicationChannelID,
Status )
MLSDE‑LESD.confirm parameters
Name
Type
Valid Range
Description
PANId
Integer
0x0000–0xffff
The PAN identifier used in the PAC WPAN
ServiceID
0x0-0xf
PAC service ID used in the PAC WPAN
CommunicationChannelID
Set of octets
0x0000-0xffff for each element
List of channel numbers used in the PAC WPAN.
Status
Enumeration
SUCCESS, TRANSACTION_EXPIRED, INVALID_PARAMETER
The result of the LESD request.

17. MLSDE-LESD-NOTIFY: indication MLSDE‑LESD-NOTIFY.indication parameters
PANID,
ServiceID,
CommunicationChannelID )
MLSDE‑LESD-NOTIFY.indication parameters
Name
Type
Valid Range
Description
PANId
Integer
0x0000–0xffff
The PAN identifier used in the PAC WPAN
ServiceID
0x0-0xf
PAC service ID used in the PAC WPAN
CommunicationChannelID
Set of octets
0x0000-0xffff for each element
List of channel numbers used in the PAC WPAN.

18. MLSDE-LESD-NOTIFY: indication MLSDE‑LESD-CS.request parameters
PANID,
NumBRB,
ServiceID,
CSDuration,
CommunicationChannelID )
MLSDE‑LESD-CS.request parameters
Name
Type
Valid Range
Description
PANId
Integer
0x0000–0xffff
The PAN identifier used in the PAC WPAN
NumBRB
0x00-0xff
Number of BRB to be repeated
ServiceID
0x0-0xf
PAC service ID used in the PAC WPAN
CSDuration
0x0000-0xffff
Time duration that a PD listens to the channel.
CommunicationChannelID
Set of octets
0x0000-0xffff for each element
List of channel numbers used in the PAC WPAN.

19. MLSDE-LESD-NOTIFY: indication MLSDE‑LESD-CS.confirm parameters
Status )
MLSDE‑LESD-CS.confirm parameters
Name
Type
Valid Range
Description
Status
Enumeration
SUCCESS, FAILURE, INVALID_PARAMETER
The result of the LESD CS request.

20. MAC Commands for LESD
LESD request command
LESD response command
LESD notification command

21. LESD Command Frames Octets: 1 MHR Service ID Available Channel ID
LESD request command format
Octets: 1
MHR
Service ID
Communication Channel ID
LESD response command format
Octets: 1
MHR
Service ID
Communication Channel ID
LESD notification command format

22. CSMA-CA Algorithm START BE=macBE BC=random(2BE-1)
Start Backoff Counter
Perform CCA
Channel idle? No
BRB check
Rx off
Wait for (TBRB-TCCA)
Yes No
Rx BRB?
FALSE
EndOfBackoff?
Yes
TRUE
Process BRB No
BRB check
Perform CCA
Rx BRB?
Channel idle?
Yes
Yes No
Process BRB Tx

23. Backoff counter for CSMA-CA Algorithm
Start Backoff counter
BC=BC-1
Delay for UnitBackoff
EndOfBackoff = FALSE No
BC=0
Yes
EndOfBackoff=TRUE

24. Clear Channel Assessment (CCA)
PHY Frame structure
Preamble
PHY Header
PHY Payload
SFD
SHR
PHR
PSDU
Octets 1
Variable 6 2
Basic Repetition Block (BRB)
- Samples the channel for 6 bit symbol periods
- Find the average value of channel samples
Compare the average value (ravg) with CCAThreshold
Declare
Busy if ravg > CCAThreshold
Idle otherwise

25. CSMA-CA Algorithm for LESD: BRB Check
PHY Frame structure
Preamble
PHY Header
PHY Payload
SFD
SHR
PHR
PSDU
Octets 1
Variable 6 2
Basic Repetition Block (BRB)
IFS
LESD request command
TBRB
LESD response command
LESD notification command

26. CSMA-CA Algorithm for LESD: BRB Check
PHY Frame structure
Preamble
PHY Header
PHY Payload
SFD
SHR
PHR
PSDU
Octets 1
Variable 6 2
BRB
Preamble consists of multiple of 8-bit sequence

27. CSMA-CA Algorithm for LESD: BRB Check
PHY Frame structure
Preamble
PHY Header
PHY Payload
SFD
SHR
PHR
PSDU
Octets 1
Variable 6 2
BRB
Message type
SFD value for uncoded (PHR+PSDU)
SFD value for coded (PHR+PSDU)
Request
Response
Notification
SFD Format
If PHY detects command frame of interest, decodes the rest of BRB + PSDU,
and passes it to MAC. PHY discards the rx frames otherwise.

28. CSMA-CA Algorithm for LESD: BRB Check
PHY Frame structure
Preamble
PHY Header
PHY Payload
SFD
SHR
PHR
PSDU
Octets 1
Variable 6 2
BRB
Bit string index
1–7
Bit mapping T0
L6–L0
Field name
PSDU Flag
Frame Length / BRB count T0
Description
Frame Length follows 1
BRB count follows

29. CSMA-CA Algorithm for LESD: BRB Processing
Switch Rx Command Frame Type
Case LESD request command:
If T0 is 1, turn off the radio for (BRB Count -1) x (TBRB+TLIFS).
Then, switch to Rx to receive the last BRB. Then, resume BC timer.
If T0 is 0, MAC check the pending frame type.
- If it is LESD request command with the same serviceID,
discard the pending frame, and set timer for macLESDResponseWaitTime to wait for response (or notificaiton) command.
- Otherwise, MAC discards the received frame and resume BC to send the pending frame.

30. CSMA-CA Algorithm for LESD: BRB Processing
Switch Rx Command Frame Type
Case LESD response command
- If the pending command type is either request or response command, perform valid frame check.
If it is valid, then discard the pending command and report the reception to NHL via MLSDE-LESD.confirm.
- Otherwise, PD discards the received frame and resume BC to transmit the pending frame.

31. CSMA-CA Algorithm for LESD: BRB Processing
Switch Rx Command Frame Type
Case LESD notification command
MAC performs valid frame check.
If it is valid and the pending frame is either request or response command frame, then discard the pending command and report the reception to NHL via MLSDE-LESD-NOTIFY.indication.
If it is valid and the pending frame is notification command frame, and discard the received frame and remove the pending frame.
- Otherwise, PD discards the received frame and resume BC to transmit the pending frame.

32. MAC PIB attributes Attribute Type Range Description Default
macLESDcapable
Boolean
TRUE or FALSE
If TRUE, the device is capable of functionality specific to LESD.
Implementation
specific
macLESDenabled
If TRUE, the device is using functionality specific to LESD.
macPANID
Integer
0x0000-0xffff
The identifier of the PAN on which the PD is operating. If this value is 0xffff, the device is not associated.
0xffff
macServiceID
0x0-0xf
PAC service ID used in the PAC WPAN.
0xf
macAvailableChannelID
0x0000-0xfffff for each
elemets
List of channel numbers that PD is capable of use. -
macLESDResponseWaitTime
The maximum time that a device shall wait for a LESD response command to be available following a LESD request command frame.

33. MAC PIB attributes (cont’d)
Type
Range
Description
Default
macCSInterval
Integer
0x0000-0xffff
Time duration that PD alternates sampling the channel and sleeping as illustrated in Figure 4. -
macCSDuration
Time duration that PD listens to on the channel specified by macLESDChannelID.
macCommunicationChannelID
List of channel numbers in use at the PAC WPAN
macLESDChannelID
The channel number to use for LESD procedure.
macLESDdone
Boolean
TRUE or FALSE
Indicates if PAC service specified by macServiceID is found. TRUE if the service is found; FALSE otherwise.
macMaxLESDRequestRetries
0x00-0xff
The maximum number of retries to send LESD request command 10
macNumLESDRequestRetries
The number of retries to send LESD request command

34. Thank you.
Q & A