Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs)

1. Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs) Submission Title: Enhancing the IEEE 802.15.4 MAC Date Submitted: 13 May, 2008 Source: Seong-Soon Joo, Chang-Sub Shin, Woon-Cheol Jung, Jong-Suk Chae Company: ETRI Address: 161 Gajeong-dong, Yuseong-gu, Daejeon, KOREA Voice: +82-42-860-6333, FAX: +82-42-860-4197, E-Mail: ssjoo@etri.re.kr Re: Abstract: To find the next step for developing the MAC enhancement idea, the related things are put in order from the integrated view of problem solving: specify the requirements, analyze the constraints, and discuss the criteria to be used in evaluating alternative solutions. Purpose: To raise an issue on the alternative solutions for enhancing the IEEE 802.15.4 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. ETRI

2. Enhancing the IEEE 802.15.4 MAC Seong-Soon Joo*, Chang-Sub Shin, Won-Cheol Jung, Jong-Suk Chae ETRI ETRI

3. The Next Step for Enhancing the MAC • To find the next step for developing the MAC enhancement idea, the related things are put in order from the integrated view of problem solving • Specify the requirements, analyze the constraints, discuss the criteria to be used in evaluating alternative solutions • Depending on the criteria, the possible solutions can be varied • Grouping of the problems is suggested ETRI

4. Requirements: IEEE 802.15.4 vs 15.4e • Scope of IEEE 802.15.4 • low-data-rate wireless connectivity with fixed, portable, and moving devices • with no battery or very limited battery consumption requirements • typically operating in the personal operating space (POS) of 10 m. • Scope of IEEE 802.15.4e • The intent of this amendment is to enhance and add functionality to the 802.15.4-2006 MAC to • a) better support the industrial markets and • b) permit compatibility with modifications being proposed within the Chinese WPAN ETRI

5. Requirements: IEEE 802.15.4 vs 15.4e IEEE 802.15.4e • Improve performance in accessing media and networking • latency, loss rate, fast recovery, power saving • Support multiple grades of services • latency jitter, loss rate, security level on data transmission • New features • direct RFD communication, … • Fine granularity of thethroughput • Deterministic latency • Bounded latency IEEE 802.15.4 • LR-WPAN is • a simple, • low-cost communication network • with limited power and • relaxed throughput requirements • The main objectives of an LR-WPAN are • ease of installation, • reliable data transfer, • short-range operation, • extremely low cost, and • a reasonable battery life, • while maintaining a simple and flexible protocol. ETRI

6. Constraints: IEEE 802.15.4 vs 15.4e IEEE 802.15.4 • low-cost • reasonable battery life • simple and flexible protocol IEEE 802.15.4e • low-cost • reasonable battery life • simple and flexible protocol • backward compatible • coexistence • interoperable ETRI

7. Solutions: IEEE 802.15.4 vs 15.4e IEEE 802.15.4e • TDMA: to provide a)determinism, b)enhanced utilization of bandwidth • Channel Hopping: to provide additional robustness in high interfering environments and enhance coexistence with other wireless networks • GTS: to increase its flexibility such as a) supporting peer to peer, b)the length of the slot, and c) number of slots • CSMA: to improve throughput and reduce energy consumption • Security: to add support for additional options such as asymmetrical keys • Low latency: to reduce end to end delivery time such as needed for control applications IEEE 802.15.4 • Over-the-air data rates of 250 kb/s, 100kb/s, 40 kb/s, and 20 kb/s • Star or peer-to-peer operation • Allocated 16-bit short or 64-bit extended addresses • Optional allocation of guaranteed time slots (GTSs) • Carrier sense multiple access with collision avoidance (CSMA-CA) channel access • Fully acknowledged protocol for transfer reliability • Low power consumption • Energy detection (ED) • Link quality indication (LQI) • 16 channels in the 2450 MHz band, 30 channels in the 915 MHz band, and 3 channels in the 868 MHz band ETRI

8. Solutions: IEEE 802.15.4 vs 15.4e IEEE 802.15.4e: Requirements & Constraints • Low-cost, Energy Efficiency • Simple operation (minimum overhead) • Minimization of idle listening period • Avoidance of the collision • Duty cycling • Various Grades of Quality • Fine granularity of the throughput • Deterministic latency • Bounded latency • Reliability • Secure transmission • Robust medium access • Backward compatible IEEE 802.15.4 • Channel access • Unslotted CSMA/CA • Slotted CSMA/CA • GTS • Control channel • reserving/occupying resources • in-band signaling • transmitting control and data on the same link • out-of-band signaling • separate link for control • Unslotted CSMA/CA • uncontrolled reservation • implicit control : backoff, CCA, ACK • Slotted CSMA/CA • uncontrolled reservation • implicit control : backoff, CCA, ACK, framing • GTS • in-band signaling : MAC command • explicit control : GTS request, ACK, beacon ETRI

9. Alternative Solutions (1) • Enhancing current functions • Channel access • Unslotted CSMA with beacon • Slotted CSMA with fixed slot size • GTS with fixed slot size, dynamic CFP • Control channel • Unslotted/Slotted CSMA/CA • controlled reservation with the probability • GTS • upstream control channel • Minimization of idle listening period • Avoidance of the collision • Fine granularity of throughput • Bounded latency • Introducing new concepts • Channel access • TDMA • Channel hopping • Integrated slot based access • Control channel • out-of-band signaling channel • link connection protocol • Avoidance of the collision • Fine granularity of throughput • Deterministic latency • Secure transmission • Robust medium access ETRI

10. Alternative Solutions (2) Backward compatible as a constraint • Coexistence • If a solution can be always possible not to interfere neighbor IEEE 802.15.4-2006 devices and can preserve the same SAPs of the IEEE 802.15.4-2006, • a solution will have the full degree of the design freedom • Interoperable • Be sure to provide full functions of the IEEE 802.15.4-2006 • a solution will have the partial degree of the design freedom • Coexistence or Interoperable ? • will determine the start point of the design ETRI

11. Conclusions • Requirements • Improve performance in accessing media and networking • Support multiple grades of services • New features • Fine granularity of throughput • Deterministic latency • Bounded latency • Constraints • low-cost • reasonable battery life • simple and flexible protocol • backward compatible • Design Approaches • Enhancing current functions • Introducing new concepts ETRI

12. Conclusions (continues) • Criteria • Certain level of compatibility • co-ex with non-coop, co-ex with coop • inclusive interoperating, exclusive interoperating • Performance goals • QoS (latency, throughput, reliability) • Simple, low-cost, energy efficient short range comm. • while maintaining a simple and flexible protocol • Suggestions • Before going further, let’s determine the criteria • Have a consensus on the level of compatibility for IEEE 802.15.4e at the initial stage ETRI