IEEE 802.15.4 Overview

1. Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs) Submission Title: [IEEE 802.15.4 Overview] Date Submitted: [12 November, 2001] Source: [Paul Gorday, Jose Gutierrez and PhilJamieson] Company: [Motorola/Eaton/Philips] Address: [8000 W. Sunrise Blvd., M/S 2141, Plantation, FL 33322] Voice:[(954) 723-4047], FAX: [(954) 723-3712], E-Mail:[paul.gorday@motorola.com] Re: [IEEE 802.15.4 Overview; Doc. IEEE 802.15-01/358r0] Abstract: [This presentation provides overviews for the 802.15.4 standard proposal.] Purpose: [] 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. Paul Gorday, Jose A. Gutierrez and Phil Jamieson

2. IEEE 802.15.4 Overview Paul Gorday, Jose A. Gutierrez and Phil Jamieson

3. 802.15.4 Applications Space • Home Networking • Automotive Networks • Industrial Networks • Interactive Toys • Remote Metering Paul Gorday, Jose A. Gutierrez and Phil Jamieson

4. 802.15.4 Applications Topology Cable replacement - Last meter connectivity Virtual Wire Wireless Hub Stick-On Sensor Mobility Ease of installation Paul Gorday, Jose A. Gutierrez and Phil Jamieson

5. Some needs in the sensor networks Thousands of sensors in a small space  Wireless but wireless implies Low Power! and low power implies Limited Range. Of course all of these is viable is a Low Cost transceiver is required Paul Gorday, Jose A. Gutierrez and Phil Jamieson

6. 802.15.4 General Characteristics Data rates of 250 kbps and 20 kbps. Star or Peer-to-Peer operation. Support for low latency devices. CSMA-CA channel access. Dynamic device addressing. Fully handshaked protocol for transfer reliability. Low power consumption. 16 channels in the 2.4GHz ISM band, 10 channels in the 915MHz ISM band and one channel in the European 868MHz band. Extremely low duty-cycle (<0.1%) Paul Gorday, Jose A. Gutierrez and Phil Jamieson

7. 802.15.4 Architecture Paul Gorday, Jose A. Gutierrez and Phil Jamieson

8. IEEE 802.15.4PHY Overview Paul Gorday Paul Gorday, Jose A. Gutierrez and Phil Jamieson

9. IEEE 802.15.4 PHY Overview Operating Frequency Bands 868MHz/ 915MHz PHY Channels 1-10 Channel 0 2 MHz 868.3 MHz 902 MHz 928 MHz 2.4 GHz PHY Channels 11-26 5 MHz 2.4 GHz 2.4835 GHz Paul Gorday, Jose A. Gutierrez and Phil Jamieson

10. IEEE 802.15.4 PHY Overview Packet Structure (Both PHY’s) • PHY Packet Fields • Preamble (32 bits) – synchronization • Start of Packet Delimiter (8 bits) – specifies one of 3 packet types • PHY Header (8 bits) – Sync Burst flag, PSDU length • PSDU (0 to 127 bytes) – Data field Start of Packet Delimiter PHY Header PHY Service Data Unit (PSDU) Preamble 6 Bytes 0-127 Bytes Paul Gorday, Jose A. Gutierrez and Phil Jamieson

11. IEEE 802.15.4 PHY Overview Modulation/Spreading • 2.4 GHz PHY • 250 kbps (4 bits/symbol, 62.5 kBaud) • Data modulation is 16-ary orthogonal modulation • 16 symbols are ~orthogonal set of 32-chip PN codes • Chip modulation is MSK at 2.0 Mchips/s • 868MHz/915MHz PHY • 20 kbps (1 bit/symbol, 20 kBaud) • Data modulation is BPSK with differential encoding • Spreading code is a 15-chip m-sequence • Chip modulation is BPSK at 0.3 Mchips/s Paul Gorday, Jose A. Gutierrez and Phil Jamieson

12. IEEE 802.15.4 PHY Overview Common Parameters • Transmit Power • Capable of at least 1 mW • Power reduction capability required if > 16 dBm • (reduce to < 4 dBm in single step) • Transmit Center Frequency Tolerance •  40 ppm • Receiver Sensitivity • -85 dBm (1% Packet Error Rate) • RSSI Measurements • Packet strength indication • Clear channel assessment • Dynamic channel selection Paul Gorday, Jose A. Gutierrez and Phil Jamieson

13. IEEE 802.15.4 PHY Overview PHY Primitives • PHY Data Service • PD-DATA – exchange data packets between MAC and PHY • PHY Management Service • PLME-CCA – clear channel assessment • PLME-GET – retrieve PHY parameters • PLME-RX-ENABLE – enable/disable receiver • PLME-SET – set PHY parameters Paul Gorday, Jose A. Gutierrez and Phil Jamieson

14. IEEE 802.15.4MAC/LLC Overview Phil Jamieson Paul Gorday, Jose A. Gutierrez and Phil Jamieson

15. Protocol Drivers • Extremely low cost • Ease of installation • Reliable data transfer • Short range operation • Reasonable battery life Simple but flexible protocol Paul Gorday, Jose A. Gutierrez and Phil Jamieson

16. Network coordinator Example Network Node 4 Node 1 Node 5 Node 2 Node 6 Node 3 Paul Gorday, Jose A. Gutierrez and Phil Jamieson

17. Device Classes • Full function device (FFD) • Any topology • Network coordinator capable • Talks to any other device • Reduced function device (RFD) • Limited to star topology • Cannot become a network coordinator • Talks only to a network coordinator • Very simple implementation Paul Gorday, Jose A. Gutierrez and Phil Jamieson

18. Example Network FFD RFD FFD RFD RFD RFD FFD Paul Gorday, Jose A. Gutierrez and Phil Jamieson

19. Star Topology Network coordinator Master/slave Full function device Communications flow Reduced function device Paul Gorday, Jose A. Gutierrez and Phil Jamieson

20. Peer-Peer Topology Point to point Cluster tree Full function device Communications flow Paul Gorday, Jose A. Gutierrez and Phil Jamieson

21. Combined Topology Clustered stars - for example, cluster nodes exist between rooms of a hotel and each room has a star network for control. Full function device Communications flow Reduced function device Paul Gorday, Jose A. Gutierrez and Phil Jamieson

22. Device Addressing • All devices have IEEE addresses • Short addresses can be allocated • Addressing modes: • Network + device identifier (star) • Source/destination identifier (peer-peer) • Source/destination cluster tree + device identifier (cluster tree) Paul Gorday, Jose A. Gutierrez and Phil Jamieson

23. General Data Packet Structure Preamble sequence Start of Packet Delimiter PRE SPD LEN PC ADDRESSING DSN Link Layer PDU CRC CRC-16 Data sequence number Addresses according to specified mode Flags specify addressing mode Length for decoding simplicity Paul Gorday, Jose A. Gutierrez and Phil Jamieson

24. GTS 3 GTS 2 GTS 1 Guaranteed Time Slot Reserved for nodes requiring guaranteed bandwidth [n = 0]. Optional Frame Structure 15ms * 2n where 0  n  14 Network beacon Transmitted by network coordinator. Contains network information, frame structure and notification of pending node messages. Beacon extension period Space reserved for beacon growth due to pending node messages Contention period Access by any node using CSMA-CA Paul Gorday, Jose A. Gutierrez and Phil Jamieson

25. Traffic Types • Periodic data • Application defined rate (e.g. sensors) • Intermittent data • Application/external stimulus defined rate (e.g. light switch) • Repetitive low latency data • Allocation of time slots (e.g. mouse) Paul Gorday, Jose A. Gutierrez and Phil Jamieson

26. Data Service Originator LLC Originator MAC Recipient MAC Recipient LLC MD-DATA.request Channel access DATA MD-DATA.confirm Packet validation HANDSHAKE MD-H/S.indication MD-DATA.indication Paul Gorday, Jose A. Gutierrez and Phil Jamieson

27. Management Service • Access to the PIB • GTS allocation • Message pending • Node notification • Network scanning/start • Network synchronization/search Paul Gorday, Jose A. Gutierrez and Phil Jamieson

28. Summary • Star and peer-to-peer topologies • Optional frame structure • CSMA-CA channel access mechanism • Packet validation and message rejection • Handshake generation (for speed) • Optional guaranteed time slots • Guaranteed packet delivery • Frame fragmentation/reconstitution Paul Gorday, Jose A. Gutierrez and Phil Jamieson