具通訊傳輸品質認知性之IEEE 802.15.4e網路形成和快速加入演算法設計 The Design of Channel Quality Aware IEEE 802.15.4e Network Formation and Fast Re-Join Algorithms Speaker: Po-Hung Chen Advisor: Dr. Ho-Ting Wu 2017/05/04
Outline 相關背景及技術介紹 頻道品質估算方法 網路形成及快速加入演算法設計 模擬結果(只有部分) 目前進度 參考文獻
相關背景及技術介紹 WSN IEEE 802.15.4e RPL Network Formation
Wireless Sensor Network CC2420 CC2538
Wireless Sensor Network (Cont.)
IEEE 802.15.4e LR-WPAN IEEE 802.15.4 Layer 7 : Application 低傳輸速率 低成本 低耗能 Layer 7 : Application Layer 6 : Presentation Layer 5 : Session Layer 4 : Transport Layer 3 : Network Layer 2 : Data Link IEEE 802.15.4 MAC Layer 1 : Physical IEEE 802.15.4 PHY LR-WPAN
IEEE 802.15.4e (Cont.) Industrial WSN Layer 7 : Application 低延遲 高可靠度 可預測的延遲 保證頻寬 高能源使用效率 Layer 7 : Application Layer 6 : Presentation Layer 5 : Session Layer 4 : Transport Layer 3 : Network Layer 2 : Data Link IEEE 802.15.4e MAC Layer 1 : Physical IEEE 802.15.4 PHY
IEEE 802.15.4 IEEE 802.15.4e IEEE 802.15.4e (Cont.) 2003 Single Channel CSMA/CA IEEE 802.15.4e 2012 Multiple Channel TSCH
IEEE 802.15.4e (Cont.) Channel hopping TSCH Time slotted access Multiple channel Channel hopping Channel hopping P H channel = ASN+chOffset % N ch ∗ASN : absolute slot number
IEEE 802.15.4e (Cont.) TSCH A time slot is 10 ms. 4 ms Transmit Process 1 ms ACK Radio Turnaround 5 ms
IEEE 802.15.4e (Cont.) IEEE 802.15.4 PHY 定義了27個頻段 16 個 2.4 GHz 10 個 915 MHz 1 個 868 MHz
IEEE 802.15.4e (Cont.) Enhanced Beacon (EB) TSCH Synchronization IE ASN、Join Metric TSCH Timeslot IE Current slot in a slotframe Channel Hopping IE Channel hopping sequence TSCH Slotframe and Link IE Initial Schedule *Information Elements (IEs)
RPL IPv6 Routing Protocol for Low-Power and Lossy Networks Layer 7 : Application Layer 6 : Presentation Layer 5 : Session Layer 4 : Transport Layer 3 : Network RPL Layer 2 : Data Link IEEE 802.15.4e MAC Layer 1 : Physical IEEE 802.15.4 PHY *DAG (Directed acyclic graph)、DODAG (Destination Oriented DAG)
RPL (cont.) RPL 控制封包 DIO DODAG Information Object DAO Destination Advertisement Object DAO-ACK DAO Acknowledgement DIS DODAG Information Solicitation
RPL (Cont.) DIO DAO DAO-ACK DIS Trickle演算法
Network Formation
頻道品質估算方法 ACK Tx PDR Grouping Share Aggregation
Channel Quality Estimate 1. Grouping *Edge、Middle、None
Channel Quality Estimate (Cont.) 分群策略 分群數量 依照常用Wi-Fi頻道分群 A 4 {11~14}, {16~19}, {21~24}, {15, 20, 25, 26} 依照常用Wi-Fi頻道干擾特性分群 B 3 Edge {11, 14, 16, 19, 21, 24} Middle {12, 13, 17, 18, 22, 23} None {15, 20, 25, 26} C 7 Edge {11, 14}, {16, 19}, {21, 24} Middle {12, 13}, {17, 18}, {22, 23} 頻道個別評估 D 16 整體評估 E 1
Channel Quality Estimate (Cont.) 2. Share by TTL = 2 (with hop-count weight) 固定PDR Case Group C的情況下 200個樣本 平均PDR誤差 < ± 0.1 1 秒 1 個 packet Single Node Neighbor = 5 Node 200秒 40秒 hop-count weight 1 hop 0.7 2 hop 0.3
Channel Quality Estimate (Cont.) 3. 估計PDR封包的Aggregation 1 Byte 0 - 255 1 在短時間(200秒)內用來存Tx和Ack數值,各只需要1 Byte。 每個Group最多只需要2個Bytes 分群 數量 A 4 B 3 C 7 D 16 E 1 在廣播自己的估計PDR封包時,還可以將自己近期內(5秒)更新樣本的統計資訊包在同一個封包裡,一起廣播出去。
網路形成及快速加入演算法設計 Network Formation & Fast Re-Join Algorithms Which cells for send EB When to send EB Fast Re-Join Algorithm
Network Formation & Fast Re-Join Algorithms 協定沒明確訂定 耗電量 Trade-off IEEE 802.15.4e
Fast mNetwork Formation & Fast Re-Join Algorithms (Cont.) 1. 快速形成: 只傳送Control Message,提升單位時間內EB和RPL封包的數量,以快速建立TSCH網路。 2. 正常模式: 依照頻道品質估算的結果調整EB傳送的period,大部分cell用來傳送感測資料,少數用來維持網路的Control Message 。
Which cells for send EB Random (RD) Random Vertical (RV) Random Horizontal (RH) Uniform Distribution(UD)
Which cells for send EB (Cont.) Random (RD) 每一個cell都可以拿來傳送EB,全部隨機選擇 1 2 3 4 5 6 7 8 9 10 11 Channel Offset timeslot
Which cells for send EB (Cont.) Random Vertical (RV) 只會選擇第一個時槽的cell來傳送EB 1 2 3 4 5 6 7 8 9 10 11 Channel Offset timeslot
Which cells for send EB (Cont.) Random Horizontal (RH) 只會選擇第一個頻道的cell來傳送EB 1 2 3 4 5 6 7 8 9 10 11 Channel Offset timeslot
Which cells for send EB (Cont.) Uniform Distribution(UD) 將要規劃的cell均勻分布在第一個頻道上 1 2 3 4 5 6 7 8 9 10 11 Channel Offset timeslot
When to send EB Each frame random 1-hop avoid and randomize 每個Slotframe隨機選擇一個cell用來傳送一個EB 1-hop avoid and randomize 和1-hop的鄰居節點避開使用的cell,如果都被選用選擇最少被選擇的,並且傳送EB的機率為1-hop鄰居數量分之一 2-hop avoid 傳送EB時將自己以及鄰居節點選擇的cell和起始時間一起廣播出去,每3個slotframe送一次EB
Fast Re-Join Algorithm 耗電 時間 目標時間 PDR = 1 Channel Quality Estimate 事情就沒有那麼單純惹 PDR < 1 Collision Avoid EB Scheduling Neighbor Number
Fast Re-Join Algorithm (Cont.) Collision Avoid EB Scheduling by Coloring + RV. 2-hop Coloring Root 要知道整個拓樸的實際情況 1 : 14 15 2 3 4 5 … 97 89 99 100 101 Channel Offset timeslot
Fast Re-Join Algorithm (Cont.) Node 3 和 Node 4 因為相隔2-hop以上可以使用同 個Channel,但是對於未加入的Node 5會產生碰撞。 1 : 14 15 2 3 4 5 … 97 89 99 100 101 Channel Offset timeslot
模擬結果 Fast Network Formation Channel Quality Estimate Fast Re-Join (未完成) (Grouping) (未完成)
Channel Quality Estimate Grouping 採用固定PDR Case channel 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 Case 1 PDR 0.5 0.3 0.7 Case 2 PDR Case 3 PDR
Channel Quality Estimate Grouping (Cont.) 分群策略 PDR平均誤差收斂到小於0.1大約所需樣本數 Case 1 Case 2 Case 3 Group A 144 192 464 Group B 永遠到不了 (720 0.0172) (1088 0.0172) 80 Group C Group D 384 400 Group E (320 0.02) (320 0.028) (320 0.025)
Channel Quality Estimate Grouping (Cont.)
Channel Quality Estimate Grouping (Cont.)
Channel Quality Estimate Grouping (Cont.)
目前進度 已完成 未完成 演算法初步設計 Send EB 時機 Initial Scheduling Algorithm Channel Quality Estimate: Share Combine Initial and Data Scheduling Channel Quality Estimate: Aggregation Channel Quality Estimate: Grouping RPL Fast Re-Join Algorithm 模擬測試
Reference N. Salman; I. Rasool; A.H. Kemp, ” Overview of the IEEE 802.15.4 standards family for Low Rate Wireless Personal Area Networks” in 2010 7th International Symposium Wireless Communication Systems (ISWCS), pp.701-705 Domenico De Guglielmo; Simone Brienza; Giuseppe Anastasi, “A Model-based Beacon Scheduling algorithm for IEEE 802.15.4e TSCH networks” in 2016 IEEE 17th International Symposium on A World of Wireless, Mobile and Multimedia Networks (WoWMoM), June. 2016 , pp1-9 Domenico De Guglielmo; Alessio Seghetti; Giuseppe Anastasi; Marco Conti, “A performance analysis of the network formation process in IEEE 802.15.4e TSCH wireless sensor/actuator networks” in 2014 IEEE Symposium on Computers and Communication (ISCC), June 2014, pp1-6 T. Watteyne; A. Mehta and K. S. J. Pister, “Reliability Through Frequency Diversity: Why Channel Hopping Makes Sense”, Performance Evaluation of Wireless Ad Hoc, Sensor, and Ubiquitous Networks(PE-WASUN), Oct. 2009, pp116-123 IEEE Std 802.15.4™-2003 IEEE Std 802.15.4e™-2012 IETF RFC 6206 IETF RFC 6550 IETF RFC 7554 Minimal 6TiSCH Configuration draft-ietf-6tisch-minimal-21
Thank you for listening.