Speaker: Qi-Hong Cai Advisor: Dr. Ho-Ting Wu 2017/4/13 A study on IEEE 802.15.4e compliant low-power multi-hop SUN with frame aggregation Speaker: Qi-Hong Cai Advisor: Dr. Ho-Ting Wu 2017/4/13

Outline Introduction Concept of Multi-Hop Transmission in Smart Utility Networks Proposed Scheme and Necessary Modifications of IEEE 802.15.4 MAC Computer Simulation Results Conclusions Reference

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 802.15.4g task group standardized the PHY amendment for the IEEE 802.15.4 standard to support SUNs. IEEE 802.15.4e task group standardized the MAC modification required to realize an effective PHY amendment.

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.

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.

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

Concept of Multi-Hop Transmission in Smart Utility Networks

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

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

Proposed Scheme and Necessary Modifications of IEEE 802. 15 Proposed Scheme and Necessary Modifications of IEEE 802.15.4 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.

Proposed Scheme and Necessary Modifications of IEEE 802. 15 Proposed Scheme and Necessary Modifications of IEEE 802.15.4 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.

Proposed Scheme and Necessary Modifications of IEEE 802. 15 Proposed Scheme and Necessary Modifications of IEEE 802.15.4 MAC (Cont.)

Proposed Scheme and Necessary Modifications of IEEE 802. 15 Proposed Scheme and Necessary Modifications of IEEE 802.15.4 MAC (Cont.)

Proposed Scheme and Necessary Modifications of IEEE 802. 15 Proposed Scheme and Necessary Modifications of IEEE 802.15.4 MAC (Cont.)

Computer Simulation Results

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

Computer Simulation Results (Cont.)

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

Conclusions In this paper, we propose a low-power, multi-hop transmission scheme using a long-life capability of IEEE 802.15.4e MAC modified from the existing IEEE 802.15.4 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.

Reference F. Kojima and H. Harada, "A study on IEEE 802.15.4e compliant low-power multi-hop SUN with frame aggregation," 2013 IEEE International Conference on Communications (ICC), Budapest, 2013, pp. 4041-4045.

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