1. Speaker: Qi-Hong Cai Advisor: Dr. Ho-Ting Wu 2017/4/13
A study on IEEE e compliant low-power multi-hop SUN with frame aggregation
Speaker: Qi-Hong Cai
Advisor: Dr. Ho-Ting Wu
2017/4/13

2. Outline
Introduction
Concept of Multi-Hop Transmission in Smart Utility Networks
Proposed Scheme and Necessary Modifications of IEEE MAC
Computer Simulation Results
Conclusions
Reference

3. Introduction
Smart utility networks (SUNs) for effective data collection from a large number of gas, water, and/or electric meters, to provide data to data-collection stations.
IEEE g task group standardized the PHY amendment for the IEEE standard to support SUNs.
IEEE e task group standardized the MAC modification required to realize an effective PHY amendment.

4. Introduction (Cont.)
Service area expansion and blind spot removal for meters via multi-hop transmission that enables frame relaying is considered an attractive solution.
In this paper, we propose employment of a periodical hearing-type MAC scheme in order to realize low-power performance and employment of effective multi-hop transmission exploiting the tree- shaped network topology construction.

5. Introduction (Cont.)
The concept of a turned-off beacon is introduced in the proposed system while assuming a beacon- enabled PAN structure in order to avoid power wastage from beacon transmission.
The active period allocated to each radio device is suitably defined while handling traffic situations during the beacon interval
The remaining period is considered sleeping time apart from the possible reception of a frame after the end of the superframe.

6. Introduction (Cont.)
Effective frame aggregation technology exploiting such low energy superframe structure is employed
In order to solve the bottle neck problems that seriously degrade the utility data collection performance in SUN

7. Concept of Multi-Hop Transmission in Smart Utility Networks

8. Concept of Multi-Hop Transmission in Smart Utility Networks (Cont.)
Tree-shaped topology
enables partly centralized control in such a hierarchical topology
but could suffer from bottlenecks for some meters that relay frames from a large number of lower meters
suited for low meter density
Mesh-shaped topology
bottlenecks are avoided due to the flexibility achieved by the availability of effective detour routes.
suited to high meter-density areas
This study focuses on the tree-shaped topology defined by the beacon-enabled PAN in 15.4MAC

9. Proposed Scheme and Necessary Modifications of IEEE 802.15.4 MAC
The star topology has definite master-slave relationships
the master can define the superframe that indicates communication timing for frame exchange, which means TDMA- based multiple access with synchronization.
peer-to-peer topology there is no master-slave relationship
CSMA-based multiple access without any synchronization.
Our study considers star topology since it provides hierarchical or centered control

10. Proposed Scheme and Necessary Modifications of IEEE 802. 15
Proposed Scheme and Necessary Modifications of IEEE MAC (Cont.)
Periodical broadcasting of the beacon can be omitted
There is no beacon broadcasting except when the beacon is clearly requested to transmit
Devices receiving a transmitted frame continue reception until complete, even if the active period has ended.

11. Proposed Scheme and Necessary Modifications of IEEE 802. 15
Proposed Scheme and Necessary Modifications of IEEE MAC (Cont.)
Because of this modification, devices not addressed by the frame or not interested in the frame can enter the sleeping state just after such a period
wherein not only the receiver but also all other devices should be standing by, and this helps reduce power consumption.

12. Proposed Scheme and Necessary Modifications of IEEE 802. 15
Proposed Scheme and Necessary Modifications of IEEE MAC (Cont.)

13. Proposed Scheme and Necessary Modifications of IEEE 802. 15
Proposed Scheme and Necessary Modifications of IEEE MAC (Cont.)

14. Proposed Scheme and Necessary Modifications of IEEE 802. 15
Proposed Scheme and Necessary Modifications of IEEE MAC (Cont.)

15. Computer Simulation Results

16. Computer Simulation Results (Cont.)
Frame success probability:
a) 15.4e-LE superframe, aggregation size=1
b) 15.4-superfarme, aggregation size=1
c) 15.4e-LE superframe,
aggregation size=8
d) 15.4-superfarme, aggregation size=8

17. Computer Simulation Results (Cont.)

18. Computer Simulation Results (Cont.)
Time ratio performances for device status:
a) transmitting status; b) Receiving or standing by status

19. Conclusions
In this paper, we propose a low-power, multi-hop transmission scheme using a long-life capability of IEEE e MAC modified from the existing IEEE MAC in order to realize long-lived performance and effective service area expansion capabilities in a SUN system.
Computer simulation results confirm that the proposed scheme realizes a frame success rate upward of 90% without error control while holding less than a 0.4% active period ratio under the situation of frame arrival intervals of 60 seconds.

20. Reference
F. Kojima and H. Harada, "A study on IEEE e compliant low-power multi-hop SUN with frame aggregation," 2013 IEEE International Conference on Communications (ICC), Budapest, , pp

21. Thanks for your attention.