doc.: IEEE 802.15-<doc#> <month year> doc.: IEEE 802.15-<doc#> Project: IEEE P802.15 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] E-Mail:[wjeong@etri.re.kr] 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 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. <author>, <company>

Low Energy Service Discovery MAC Protocol for PAC WPAN <month year> doc.: IEEE 802.15-<doc#> Low Energy Service Discovery MAC Protocol for PAC WPAN Wun-Cheol Jeong, Chang-Sub Shin, Tae-Joon Park, Hoyong Kang ETRI <author>, <company>

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

doc.: IEEE 802.15-<doc#> <month year> doc.: IEEE 802.15-<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>

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

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

Channel Sampling (CS) State <month year> doc.: IEEE 802.15-<doc#> Channel Sampling (CS) State Sleep Timer fire Sleep Rx macCSduration Tx completion Receive LESD request command Send Response Command <author>, <company>

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

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

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

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.

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.

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.

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.

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.

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.

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.

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.

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.

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

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

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

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

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

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

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 01010101.

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 0110 0011 1011 0001 1001 1100 1011 0001 Response 0110 0011 0100 1110 1001 1100 0100 1110 Notification 0110 0011 0110 0011 1001 1100 0110 0011 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.

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

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.

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.

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.

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.

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

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