1. doc.: IEEE 802.15-<doc#>
<month year>
doc.: IEEE <doc#>
Project: IEEE P Working Group for Wireless Personal Area Networks (WPANs)
Submission Title: Synchronous Channel Access for LECIM
Date Submitted: 16 January, 2012
Source: Seong-Soon Joo, Bong-Soo Kim, Jong-Arm Jun, Cheol-Sig Pyo
Company: ETRI
Address: 161 Gajeong-dong, Yuseong-gu, Daejeon, KOREA
Voice: , FAX: ,
Re:
Abstract: As an initial draft for the LECIM MAC, synchronous channel access for LECIM is considered.
Purpose: Initial draft for the LECIM MAC
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. Synchronous Channel Access for LECIM
<month year>
doc.: IEEE <doc#>
Synchronous Channel Access for LECIM
Seong-Soon Joo*,
Bong-Soo Kim, Jong-Arm Jun, Cheol-Sig Pyo
ETRI
<author>, <company>

3. LECIM MAC Design (I) Design considerations low bit rate PHY
25Kbps
transmission time should be less than 19ms to avoid interframe interference
long distance
asymmetric topology
1-n star topology over 1,000 devices
unbalanced power-source
need to extend the coverage
short data, less frequent
long life span without maintenance
20 years
various quality of service
delay sensitive, delay tolerant

4. LECIM MAC Design (II) Design goals
provide MAC link optimized to asymmetric topology
OAM messages
various required quality transport
global time information
low energy consumption enough to work over 20 years
to maximize effective data transmission rate against to overhead
minimize RF active duration such as tx & rx at device, especially cut down waiting period

5. LECIM MAC Design (III) Design concepts run on expected time
assigned up & down link per each device
prioritized up & down link
extension of link
soft defined link repeater : MAC relaying with light overhead
energy saving
simplified sequence, shorten frame length, avoid contention

6. LECIM MAC frame design (I)
sensing data
device/location ID : 2 ~ 4 bytes
time stamp : 2 ~ 4 bytes, (NTP : 8~ 16 bytes)
monitoring data :
vector data : 1 ~ 100 bytes
stream data : 4 Kbyte x n frame/s
data length
content ID (location+time stamp: 4~8 bytes) + contents (1~100 bytes)
5 bytes ~ 108 bytes
MAC header (IEEE TG4e)
min: frame crtl (2) + src/dst addr (2) + IE hdr (2) + IE content (var)
fragmented frame header (TG4k)

7. LECIM MAC frame design (II)
PHY header (TG4k)
preamble (0, 2, 4) + start frame delimiter (0, 1) + PHY header(0,1, 2)
avg: preamble(2)+SFD(1)+PHY hdr(1)
overhead assumption
PHY header : 5
fragement header : 5
MAC header : 6
overhead vs contents ratio
5 byte : 16 / 5 = 320%
100 byte: 16 / 100 = 16%
length of frame header affects to the life span of the network

8. multi-superframe duration = aBaseSuperframeDuration * 2MO symbols
DSME
DSME
unidirectional GTS
CAP is the only channel to device from coordinator
GTS allocation procedure
support for multi-hopped network, channel diversity
need all the neighbor device must be active
need to check & update GTS status
need association procedure for the all the devices
can assign time slots for over 1,000 devices
associate devices to network
delay sensitive transmission is supported ?
MAC layer relaying is possible ?
CAP
CAP 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
superframe
multi-superframe duration = aBaseSuperframeDuration * 2MO symbols
beacon interval (BI)

9. GTS of IEEE 802.15.4 restriction on GTS GTS operation
allocated before use on a first-come-first served basis
deallocated at the discretion of the PAN coordinator
data frame transmitted in an GTS shall use only short addressing
GTS direction is specified as either transmit or receive.
Only ACK is allowed to transmit bidirectionally.
GTS operation
tx GTS request command  rx Ack  track beacon for aGTSDescPersistencTime
allow multiple consecutive slots  need reallocation procedure

10. Slot-Link Access (I) modify the DSME CAP uni-directional GTS
separate configurable up-link and down-link
up-link for priority 0 data
down-link for management
configure number of slots for each link and appearance on slotted-superframe
uni-directional GTS
primary preemptive slot and multiple supplementary shared slots for one device
bi-directional slot
remove GTS allocation & deallocation procedure
prioritized transmission
MAC synchronous relaying

11. Slot-Link Access (II) modify the DSME slot-link structure beacon type
explicit link from coordinator & from device  separate CAP
bidirectional slot
remove GTS allocation & maintaining  probably preemptive slot
delay sensitive upward channel
slot-link structure
slotted-superframe
multi-superframe
cyclic-superframe
beacon type
cyclic-superframe beacon
multi-superframe beacon
slotted-superframe beacon
cyclic-superframe beacon
slotted-superframe beacon
slotted-superframe
multi-superframe beacon
multi-superframe
multi-superframe
multi-superframe
multi-superframe
cyclic-superframe

12. Slot-Link Access (III)
slot-link structure
slotted-superframe
beacon slot
prioritized device slot
coordinator slot
bidirectional device slot
multi-superframe
cyclic-superframe
Cyclic-superframe
Beacon
Slotted-superframe
Beacon
Multi-superframe
Beacon
Slotted-superframe
Beacon pr
device
slot
coord
slot
bidir.
device
slot pr
device
slot
coord
slot
bidir
device
slot 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
slotted-superframe
slotted-superframe
multi-superframe
cyclic-superframe

13. Slot-Link Access (IV) slot-link operation beacon slot
prioritized device slot
coordinator slot
bidirectional device slot
primary device slot
multiple supplementary device slot
operation
adjust transmission, flexible bandwidth control
retransmission on supplementary
coordinator slot
(cmd/OAM data, ALOHA)
supplementary-down-link
(cmd/OAM data, CSMA-CA)
primary-down-link
(cmd/OAM data, CSMA-CA)
supplementary-down-link
(cmd/OAM data, CSMA-CA)
prioritized device slot
(pr 0 data, ALOHA)
supplementary-up-link
(cmd/data, CSMA-CA)
primary-up-link
(cmd/data, ALOHA)
supplementary-up-link
(cmd/data, CSMA-CA) up dn
Slk up dn
Plk up dn
Slk up dn 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

14. Slot-Link Network Configuration
slott-link
cyclic-superframe BO
slotted-superframe SO
beacon slot
cyclic-superframe beacon
slotted-superframe beacon
inner repeater, peer repeater, outer repeater
arbitrated device slot
number of arbitrated device slot : macNumADeviceSlot
coordinator slot
number of coordinator slot : macNumCoordinatorSlot
preemptive device slot
primary device slot : macPrimaryDeviceSlot
list of supplementary device slot s: macSuplementaryDeviceSlotList
number of supplementary device slots: macNumSupplementaryDeviceSlot

15. Thanks for your Attention! ssjoo@etri.re.kr