1. <month year>
doc.: IEEE
May 2014
Project: IEEE P Working Group for Wireless Personal Area Networks (WPANs)
Submission Title: [L2 Preliminary Proposal]
Date Submitted: [ 12 May, 2014]
Source1: [Noriyuki Sato, Kiyoshi Fukui] Company [OKI]
Address [2-5-7 Hommachi chuo-ku, Osaka, Japan]
Voice:[ ], FAX: [ ],
Re: [This is the original document.]
Abstract: [This documents describes OKI’s L2R proposal to CfPP.]
Purpose: [To make a proposal]
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
N. Sato and K. Fukui (OKI)
<author>, <company>

2. L2R Preliminary Proposal
<month year>
doc.: IEEE
May 2014
L2R Preliminary Proposal
TG10 presentation
11th May 2014 Waikoloa HA
Noriyuki Sato / Kiyoshi Fukui
OKI Electric Industry Co., Ltd.
N. Sato and K. Fukui (OKI)
<author>, <company>

3. <month year>
doc.: IEEE
May 2014
Outline of L2R protocol
Routing establishment consists of upward / downward route establishments
Upward routing is established by exchanging information between neighbors. (many-to-one)
Downward routing is established by sending information of parent-child relationship to the concentrator. (source routing)
Both information are updated periodically.
HOP-by-HOP retry
L2R layer provides hop-by-hop retransmission
Change route to an alternate parent
BS switch consideration
N. Sato and K. Fukui (OKI)
<author>, <company>

4. Upward routing establishment
<month year>
doc.: IEEE
May 2014
Upward routing establishment
All nodes broadcast “HELLO” frame to the neighbor nodes periodically.
“HELLO” frame carries link costs between its neighbor nodes and itself. In the other words, outgoing link cost is told from the other side. (a)
Each node decides incoming link cost. (b)
A node decide the mutual link costs from the outgoing (a) and the incoming (b).
HELLO frame also carries path cost. The Originator (concentrator, PAN coordinator or L2R former)’s cost is zero.
A node receives path costs from its neighbors and its own path cost is calculated by using the derived mutual link cost.
A node chooses the lowest one from them and broadcast to the neighbor nodes.
N. Sato and K. Fukui (OKI)
<author>, <company>

5. How to set a incoming link cost.
May 2014
Node B has no neighbor information.
Just after receiving a first hello from node A and C, node B sets a highest value as incoming link costs from these nodes.
After receiving enough hellos, incoming link costs are updated to appropriate values.
Node A
Node B
Node C
NOA ①
NOA AD LC 2 A 15 C ②
NOA AD LC 2 A 1 C ③
NOA: Number of Address
AD: Address
LC: Link Cost
N. Sato and K. Fukui (OKI)

6. Calculation of path cost & parent selection
May 2014
Calculation of path cost & parent selection
A node calculates path costs between each neighbor node.
It selects the node which has the lowest path cost as the parent node. a
LC = 2 1
Node h’s candidate parents 5 b f
Neighbor
ADDR PC LC
My PC d 6 2 8 g 5 1 j 4 1 1 2 3 e 4 i c 2 4 2 2 g 3
PC: Path Cost
LC: Link Cost 2 j d 1 2 1 h
N. Sato and K. Fukui (OKI)

7. Downward routing establishment
<month year>
doc.: IEEE
May 2014
Downward routing establishment
A node start to send RREC (route record) frame to its parent node periodically after upward routing is established.
RREC carries the parent-child relationship information.
Merged RREC is sent if RREC from a child is received.
PAN coordinator gathers all parent-child relationship from the network.
For the downward transmission, PAN coordinator send a frame by source routing.
N. Sato and K. Fukui (OKI)
<author>, <company>

8. Establishment of downward route
May 2014
Establishment of downward route
PAN coordinator (node A) achieve path to h by following steps.
Node h send RREC to the PAN coordinator (node a).
Each node on the path adds its address to address list of RREC.
PAN coordinator gets path information to node h.
Address list of RREC a
NOA
AD1
AD2
AD3
AD4 4 h j i f
LC = 2 1
f ⇒ a 5 b f 1
NOA
AD1
AD2
AD3 3 h j i 1 2 3
i ⇒ f e 4 i c 2
NOA
AD1
AD2 2 h j 4
j ⇒ i 2 2 3 g 2 j d
NOA
AD1 1 h 1
h ⇒ j
NOA: Number of Address
AD: Address 2 1 h
N. Sato and K. Fukui (OKI)

9. Hop-by-hop retry Hop-by-hop retransmission Change routing
<month year>
doc.: IEEE
May 2014
Hop-by-hop retry
Hop-by-hop retransmission
Retransmission timing is determined by macMinBE and macMaxBE is up to 2^(macMaxBE) * aUnitBackoffPeriod, which is intend to avoid neighbor collision
L2R provides retransmission so that it retries after longer period than MAC provides.
Change routing
If transmission is failed to the parent, a node may change next hop to transmit. Next hop is chosen from candidates of parent which were obtained during upward route establishment / update
N. Sato and K. Fukui (OKI)
<author>, <company>

10. BS switch consideration
<month year>
doc.: IEEE
May 2014
BS switch consideration
GW works as PAN coordinator
Each BSs are connected to GW on the wires.
A BS is downward next hop of GW.
Even if one of BS is down, a node automatically updates routing information so that it connect to another BS.
Hello GW
BS1
BS2
BS3
BS4
Example of self healing functionality
N. Sato and K. Fukui (OKI)
<author>, <company>

11. Simulation result of 11x11 Number of nodes Distance from concentrator
May 2014
Simulation result of 11x11
Number of nodes
11x11 = 121
Distance from concentrator
28 nodes on 1 hop distance.
72 on 2hops distance
20 on 3 hops distance
Average 1.93hops
N. Sato and K. Fukui (OKI)

12. Simulation result of 33x33 Number of nodes Distance 33×33=1089
May 2014
Simulation result of 33x33
Number of nodes
33×33=1089
Distance
28 nodes on 1 hop
76 nodes on 2 hops distance
124 nodes on 3hops distance
172 nodes on 4 hops dist.
220 nodes on 5 hops dist.
244 nodes on 6 hops dist.
160 nodes on 7 hops dist.
64 nodes on 8 hops dist.
Average distance 4.99hops
N. Sato and K. Fukui (OKI)

13. Condition of simulation
May 2014
Condition of simulation
Nodes within 3 units on the grid are neighbor where one unit is minimum distance between nodes on the grid.
HELLO period: 64 (s)
RREC: None
L2R retransmission: Yes
Delay of forwarding: 10 (ms)
Data
Size: 127 (Bytes)
Sending period is set so that concentrator receive it 1 times per second.
11×11 each node sends once in 120 (sec) , 33×33once in 1088 (sec)
NW establishment time
All nodes detect route to the concentrator (s) – concentrator issued first hello (s)
It may not always be optimum route.
Data are sent after 15 minutes of begin of simulation .
Number of trials
1 set consits (NW formation + data transmission 5 times)
100 sets of trials
N. Sato and K. Fukui (OKI)

14. Result of simulation 11×11 33×33 Establishment time (s) 62.35 104.51
May 2014
Result of simulation
11×11
33×33
Establishment time (s)
62.35
104.51
Data arrival ration
Average delay of data (s)
0.0446
0.1121
N. Sato and K. Fukui (OKI)