Priority-Based CSMA/CA for LPWA

1. Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs) Submission Title: Priority-Based CSMA/CA for LPWA Date Submitted: 06 July, 2018 Source: Tae-Joon Park, Seong-Soon Joo Company: ETRI Address: 218 Gajeong-ro, Yuseong-gu, Daejeon, 34129, KOREA Voice: +82-42-860-6902, E-Mail: tjpark@etri.re.kr Re: IEEE P802.15.4w Low Power Wide Area Call for Proposals Abstract: This is a preliminary proposal for Priority-Based CSMA/CA for Large-scale Populated LPWA services. Purpose: Preliminary proposal for IEEE 802.15 TG4w 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. This work was supported by IITP funded by MSIT (No. R-20160227-002863, LPWA IoT network core technology development). Release: The contributor acknowledges and accepts that this contribution becomes the property of IEEE and may be made publicly available by P802.15.

2. Priority-Based CSMA/CA for LPWA Tae-Joon Park, Seong-Soon Joo ETRI

3. Contents • CCA for Korean Frequency Regulations • IFS and BE for Priority-Based CSMA/CA

4. Korean Frequency Regulations for LPWA (I) • Frequency band : 262 MHz ~ 264 MHz • Max. ERP : 100mW • Max. channel bandwidth : 200kHz • Duty cycle limit. : 1 % • Frequency band : 940.1 MHz ~ 946.3 MHz • Max. ERP : 200mW • Duty cycle limit. : 0.1% / hour [1] Tae-Joon Park et al., “Korean Frequency Regulations for LPWA,” 15-17/153r0, 2017.

5. Korean Frequency Regulations for LPWA (II)917 MHz ~ 923.5 MHz • 4 classes of maximum effective radiated power • Output control • Case 1) Frequency hopping • Use at least 16 or more non-duplicated channels • Maximum hopping time : 0.4 sec • Case 2) LBT AFA • Carrier sense 5ms or more • at -65dBm or less • Sending duration : 4sec or less • Pause duration : 50ms or more • Case 3) Duty cycle limitation • ~ 10mW : Below 2% in 20sec duration • 10mW ~ 25mW : Below 1% in 40sec duration • 25mW ~ : Below 0.5% in 80sec duration [1] Tae-Joon Park et al., “Korean Frequency Regulations for LPWA,” 15-17/153r0, 2017.

6. Domestic Constraints on 917 MHz • Frequency Hopping • Different Max. ERP on four groups channels • 3, 10, 25, 100 mW • Not possible to use consecutive channels for FHSS • Listen Before Talk • Carrier sense 5ms or more • at -65dBm or less • Sending duration : 4sec or less • Pause duration : 50ms or more • The current LoRaWAN specification in KOREA exclusively uses LBT channel access rule • to maximize MACPayload size length and comply with the South Korea regulations.

7. CCA Proposals for Korean Frequency Regulations • Amend the CCA for LPWA • Add a sub-section of IEEE 802.15.4-2015 • 10.2.5 Receiver ED • The minimum ED value (zero) other than 917MHz band shall indicate received power less than 10 dB above the lowest specified receiver sensitivity, in dBm, for the PHY. The ED value of 917MHz band shall be -65 dBm or less. • Add phrases of IEEE 802.15.4-2015 • 10.2.7 Clear channel assessment (CCA) • a) Except for the SUN O-QPSK PHY and 917MHz band, the ED threshold shall correspond to a received signal power of at most 10 dB greater than the specified receiver sensitivity for that PHY, or in accordance with local regulations. For the SUN O-QPSK PHY, the ED threshold shall comply with the specification in 22.5.13. For the 917MHz band, the ED threshold shall be -65 dBm or less. • b) Except for the 917 MHz and 920 MHz band PHYs and the RCC PHYs, the CCA detection time shall be equal to aCcaTime, as defined in Table 11-1. For the 920 MHz band, and the RCC PHYs, phyCCADuration symbol periods shall be used. For the 917 MHz band, the CCA detection time shall be equal to 5ms or more.

8. Contents • CCA for Korean Frequency Regulations • IFS and BE for Priority-Based CSMA/CA

9. Large-scale Populated Services(I) • Large-scale populated services with reliable and secure services • Public Services: Critical facility monitoring, Public Infrastructure monitoring, Children Guardians • Industrial Services: Process monitoring, Smart Building • Urban Information System • PHY for Korea LPWA • FSK of LECIM … • Manhole monitoring System : IEEE802.15.4k PHY

10. Large-scale Populated Services(II) • Priority based random access for CAP • Priority based channel access for heterogeneous traffic • Optimal access control for various requirements • Dynamic resource allocation for mission oriented services • Extended Access Barring • Dynamic channel access control • LPWA needs a new priority based CSMA/CA [2] Tae-Joon Park et al., “Proposal for Suitability Analysis of IG LPWA Report,” 15-17/0155r01, 2017

11. Large-scale Populated Services(III) • Active Interfering Users per Timeframe • The number of active users in a given network cell • Interfering users may also originate from different uses-cases (e.g. for application area smart city) Source : 15-16-0771-00-lpwa-use-cases-and-technical-requirements-for-lpwa-networks [2] Tae-Joon Park et al., “Proposal for Suitability Analysis of IG LPWA Report,” 15-17/0155r01, 2017

12. Proposals for Priority-Based CSMA/CA • Amend the LPWA CSMA-CA • Add a sub-section of IEEE 802.15.4-2015 • 6.2.4 IFS • AIFS ≤ SIFS < HpIFS < MpIFS < LpIFS • Table 8-81—MAC PIB attributes • macMinBeHp : The minimum value of the backoff exponent (BE) of High Priority connection in the CSMA-CA algorithm • macMinBeMp : The minimum value of the backoff exponent (BE) of Medium Priority connection in the CSMA-CA algorithm • macMinBeLp : The minimum value of the backoff exponent (BE) of Low Priority connection in the CSMA-CA algorithm • macHpifsPeriod : The minimum time forming a HpIFS(High priority interframe spacing) period • macMpifsPeriod : The minimum time forming a MpIFS(Medium priority interframe spacing) period • macLpifsPeriod : The minimum time forming a LpIFS(Low priority interframe spacing) period

13. Thank you very much for your attention Any Questions?