Self-Organizing MAC Issues for BAN

1. Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs) Submission Title:[Self-Organizing MAC Issues for BAN] Date Submitted: [14thJuly, 2008] Source: [Seung-Hoon Park / Ranjeet Kumar Patro / Noh-Gyoung Kang / Chihong Cho / Eun-Tae Won] Company [Samsung Electronics Co. Ltd.] Address [416, Maetan-3dong, Yeongtong-gu, Suwon-si, Gyeonggi-do, 443-742, Korea] Voice: [+82-31-279-4579], FAX: [+82-31-279-5130], E-Mail: [shannon.park@samsung.com] Re: [] Abstract: [This document describes the necessity of self-organizing concept for BAN system] Purpose: [To promote discussion within the BAN group of the necessity of self-organizing MAC] Notice: This document has been prepared to assist the IEEE P802.15. 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 P802.15. Seung-Hoon Park et al., Samsung

2. Self-Organizing MAC Issues for BAN “Global order can arise from local interactions” <Alan Turing> Seung-Hoon Park et al., Samsung

3. What is Self-Organization? • Each individual entity is organized without any external or central dedicated control entity • Through local interactions & simple rule, emergent behavior (structure or pattern) is emerged Seung-Hoon Park et al., Samsung

4. Properties of Self-Organized System Seung-Hoon Park et al., Samsung

5. Self-Organization Example: Time Synchronization of Fire-flies • Modeling one fire-fly • Integrate-and-fire oscillator • Modeling two fire-flies • Coupled integrate-and-fire oscillator • Firing of one oscillator causes other oscillator to increment phase Seung-Hoon Park et al., Samsung

6. Protocols of BAN • BAN requirements • Energy efficiency from minimizing collisions, overhearing, Idle listening, or protocol overhead • Low complexity for limited sensor capability • Considerable protocols to meet BAN requirements • Channel access • Topology • Routing • Time synchronization • Dense condition of nodes on and around the body • Topology does not change frequently • 1-hop transmission in most cases • Time synchronization is easier than sparse condition • Channel access is most considerable challenge for BAN performance Seung-Hoon Park et al., Samsung

7. Contention-based Channel Access • Random access • Pros • resource reservation is not preceded • high scalability, high adaptability • Cons • channel monitoring in idle mode  high energy consumption • contention for the channel  long delay • scheduling to reduce collision  control overhead • QoS is not guaranteed Seung-Hoon Park et al., Samsung

8. Contention-free Channel Access • Scheduled access • Pros • Low energy consumption • Low delay & guaranteed QoS • Cons • Pre-defined resource slot  low assignment flexibility • Low scalability  hierarchical structure is required • Time synchronization is required • Centralized scheduling • channel state information & channel assignment overhead • peer-to-peer direct communication is impossible • lack of flexibility when the amount or the period of traffic generated by a node vary with time Seung-Hoon Park et al., Samsung

9. Hybrid Channel Access • Tradeoff & mix-up between contention based and contention-free channel access • Pros • Adaptability to the changing & heterogeneous traffic load • Cons • Too much control overhead & high system complexity to provide hybrid benefits • Support for real-time VBR traffic is not easy • Centralized control is not sufficient to dynamic change of system condition • Can distributed control solve this problem? Seung-Hoon Park et al., Samsung

10. Centralized System permanent control (fixed hierarchies) C S1 S2 S3 S4 Seung-Hoon Park et al., Samsung

11. Distributed System temporary control (dynamic organization) C S2 System A System B System C Application S1 S4 Distributed control, i.e. middleware architecture Local system control (HW, OS) Local system control (HW, OS) Local system control (HW, OS) S3 Communication network Seung-Hoon Park et al., Samsung

12. C C C C C C S1 S3 S5 S6 S4 S2 Self-Organized System Local interactions (environment, neighborhood) Local system control Simple local behavior Seung-Hoon Park et al., Samsung

13. System Comparison by Control Type Seung-Hoon Park et al., Samsung

14. Basic Methods in Self-Organized System • Positive and negative feedback • Positive feedback: amplification, accelerated system response • Negative feedback: suppression, stabilization • Interactions among individuals and with the environment • Direct communication among neighboring systems • Indirect communication via the environment • Interaction with the environment • Probabilistic techniques • leaving local optima • adaptability to dynamics Seung-Hoon Park et al., Samsung

15. Self-Organizing Channel Access • Positive and negative feedback • Control the medium access (timing, number of slots, power, etc) • Control protocol or control parameters • Interactions among individuals and with the environment • Direct: intensive protocol inherent interactions between neigh-boring nodes to detect, avoid or prevent collisions • Indirect: information exchange using signal strength measurements • Emergent functionality (time synchronization or channel assignment, etc) based on exchanged information or interacting protocol messages • Probabilistic techniques • Reduced collision probability through randomized medium access • Fairness and mutual exclusion Seung-Hoon Park et al., Samsung

16. Self-Organizing Channel Access • Potential goals • Low power consumption • Low control overhead • Improve fairness, delay, bandwidth • High resource efficiency • Reduce collision, idle listening, overhearing • at high traffic load or high node density condition • Adaptability to heterogeneous traffic • Technical challenges • Minimize unpredictable behavior • Preserve simplicity supporting complex management Seung-Hoon Park et al., Samsung

17. Self-Organizing Channel Access • Referential MAC algorithms • Sensor MAC • supports multiple schedules and long sleep cycles with adaptive listening • Power Control MAC • well-controlled transmission power, can be combined with any RTS/CTS based MAC protocol • WiMedia MAC • distributed MAC using DRP (Distributed Reservation Protocol) and PCA (Prioritized Channel Access) Seung-Hoon Park et al., Samsung

18. Conclusion • BAN MAC has unique requirement • Energy efficiency • Scalability • QoS • Reliability • Robustness • Lightweight system • Self-Organization techniques are needed to meet these requirement in the resource-limited sensor condition Seung-Hoon Park et al., Samsung

19. References • [1] “Self-Organization in Sensor and Actor Networks”, Falko Dressler, WILEY; ISBN: 978-0-470-02820-9; Hardcover; 386 pages; January 2008 • [2] “Self-organization in communication networks: principles and design paradigms”, Prehofer, C.; Bettstetter, C.; Communications Magazine, IEEE, Volume 43, Issue 7 , July 2005 Page(s):78 – 85, Digital Object Identifier 10.1109/MCOM.2005.1470824 • [3] “Self-organisation in future mobile communications”, Spilling, A.G.; Nix, A.R.; Beach, M.A.; Harrold, T.J.; Electronics & Communication Engineering Journal, Volume 12, Issue 3 , June 2000 Page(s):133 - 147 • [4] IEEE 802.15-08-0053-01-0006, “The MAC Protocol Requirements for BAN”, Maulin Patel, Philips • [5] IEEE 802.15-08-0305-00-0006, “MAC considerations of Non-medical Application for the BAN”, SungHyup Lee, KORPA • [6] IEEE 802.15-08-0331-01-0006, “Literature Review of Energy Efficient MAC in WSN/BAN”, Hind Chebbo, Fujitsu • [7] IEEE 802.15-08-0334-02-0006, “A Perspective of the BAN MAC”, Okundu Omeni, Toumaz Technology Ltd Seung-Hoon Park et al., Samsung