1. doc.: IEEE 802.15-<doc#>
<month year>
doc.: IEEE <doc#>
Project: IEEE P 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: ,
Re: IEEE P w 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 TG4w
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. This work was supported by IITP funded by MSIT (No. R , 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 P
<author>, <company>

2. Priority-Based CSMA/CA for LPWA
<month year>
doc.: IEEE <doc#>
Priority-Based CSMA/CA for LPWA
Tae-Joon Park, Seong-Soon Joo
ETRI
<author>, <company>

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 : MHz ~ 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
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
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 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 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)
<month year>
doc.: IEEE <doc#>
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 : IEEE k PHY
<author>, <company>

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)
<month year>
doc.: IEEE <doc#>
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 : 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
<author>, <company>

12. Proposals for Priority-Based CSMA/CA
Amend the LPWA CSMA-CA
Add a sub-section of IEEE
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?