ZigBeepds4.egloos.com/pds/200702/23/35/06-zigbee.pdf · ZigBee 802.15.4 and the ZigBee Alliance Motorola 802.15.4/ZigBee™ Platform Robot Sensor Networks Hanyang University Contents

Robot Sensor Networks

HanyangUniversity

ZigBee

802.15.4 and the ZigBee Alliance

Motorola 802.15.4/ZigBee™ Platform


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Contents

1. The ZigBee Alliance and 802.15.4

2. Features of Protocol Stack

3. ZigBee and Bluetooth

4. Reliability Throughout the Stacks

5. Robustness Throughout the Stacks

6. 802.15.4/ZigBee vs. Bluetooth

7. Motorola 802.15.4/ZigBee™ Platform

8. An Application Example


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The ZigBee Alliance and 802.15.4

1. The ZigBee Alliance is

A consortium of end users and solution providers, primarily responsible for

the development of the 802.15.4 standard

Developing applications and network capability utilizing the 802.15.4 packet

delivery mechanism

Addresses application and interoperability needs of a substantial part of the

market

2. IEEE 802.15.4

Composed of many of the individuals and companies that make up the

ZigBee Alliance

Developed the basic PHY and MAC standard with the requirement that 15.4

be simple and manageable and that high‐level functionality (networking,

security key management, applications) be considered


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ZigBee (1/2)

1. ZigBee is designed to be a low power, low cost, low data rate, wireless

solution.

2. ZigBee relies upon the robust IEEE 802.15.4 PHY/MAC to provide

reliable data transfer in noisy, interference‐rich environments

3. ZigBee layers on top of 15.4 with Mesh Networking, Security, and

Applications control


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ZigBee (2/2)

1. ZigBee Value Propositions

Addresses the unique needs of most remote monitoring and control network

applications

1) Infrequent, low rate and small packet data

Enables the broad‐based deployment of wireless networks with low cost &

low power solutions

1) Example: Lighting, security, HVAC,

2) Supports peer‐to‐peer, star and mesh networks

Monitor and sensor applications that need to have a battery life of years on

alkaline batteries

1) Example – security systems, smoke alarms


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What is the ZigBee Alliance?

1. Organization defining global standards for reliable, cost‐effective, low

power wireless applications

2. A rapidly growing, worldwide, non‐profit industry consortium of

Leading semiconductor manufacturers

Technology providers

OEMs

End‐users

3. Sensors are one of the reasons for ZigBee!


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What is ZigBee technology?

1. Cost‐effective, standards‐based wireless networking solution

2. Developed for and targets applications that need

Low to moderate data rates and low duty cycles

Low average power consumption / long battery life

Security and reliability

Flexible and dynamic network topologies

1) Star, cluster tree and mesh networks

Interoperable application frameworks controlled by an industry alliance to

ensure interoperability/compatibility


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The ZigBee Alliance Solution

1. Targeted at

Industrial and Commercial control/monitoring systems

Wireless sensor systems

Home and Building automation and controls

Medical monitoring

Consumer electronics

PC peripherals

2. Industry standard through application profiles running over IEEE802.15.4 radios

3. Primary drivers

Simplicity

Long battery life

Networking capabilities

Reliability

Low cost

4. Alliance member companies provide interoperability and certification testing


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Why do we need ZigBee technology?

1. ONLY standards‐based technology that

Addresses the unique needs of most remote monitoring and control and

sensory network applications

Enables the broad‐based deployment of wireless networks with low cost, low

power solutions

Provides the ability to run for years on inexpensive primary batteries for a

typical monitoring application


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1. Submission Title: [What You Should Know about the ZigBee Alliance]

2. Date Submitted: [24 September 2003

3. Source: [Jon Adams] Company [Motorola]

4. Address [2100 E Elliott Rd, Tempe AZ 85254]

5. Voice:[480‐413‐3439], FAX: [480‐413‐4433], E‐Mail:[[email protected]]

6. Re: [Sensors Expo Workshop]

7. Abstract: [Description of measures used to enhance reliability in IEEE

802.15.4/ZigBee]

8. Purpose: [Point of discussion for the Sensors Expo]

9. Notice: This document has been prepared to assist the ZigBee Alliance. 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.

10. Release: The contributor acknowledges and accepts that this contribution will be

posted in the member area of the ZigBee web site.

ZigBee Alliance


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Commercial Building Automation

Industrial Plant Monitoring

Home Automation

Commercial Building Automation

Industrial Plant Monitoring

Home Automation

Home Controls Lighting (since abandoned)

Application Profiles Supported

No frame compatibility with “ZigBee” or “ZigBee‐Pro”

8 bit clusters, KVP/MSG services

Joint routing

CSKIP addresses

Coordinator binding

Spec:

December 2004

Platform test: March 2005

Currently shipped by all platform suppliers!

“ZigBee V1.0”, “r06”

(sometimes referred

to as Home

Controls V0)

Frame compatibility with ZigBee expected without optional new features

No frame compatibility with “ZigBee V1.0”

No compatibility with “ZigBee” networks

Same as “ZigBee” stack, plus or minus:

Mutlicast (+)

Many to one (source) routing (+)

Fragmentation (+)

AODV‐jr routing only (‐)

New address assignment

Spec:

December 2006 (est)

Platform test:

January 2007 (est)

Please note: Past experience would say this is 6 months after the specification is complete, June 2007

“ZigBee‐Pro” stack

(formerly known as

Commercial,

Industrial,

Institutional)

Frame compatibility with ZigBee‐Pro expected

No frame compatibility with “ZigBee V1.0”

No compatibility with “ZigBee‐Pro” networks

16 bit clusters, KVP/MSG services removed

Joint routing with CSKIP addresses

Coordinator binding optional

ZigBee cluster library

Spec:

August 2006 (est)

Platform test:

August 2006 (est)

“ZigBee” stack

(formerly known as

Home Controls V1)

CompatibilityFeature summaryRelease date and statusStack Version

ZigBee Stack Release Matrix


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Architecture Objectives

1. Enables cost‐effective, low power, reliable devices for monitoring and

control

2. ZigBee’s architecture developed to target environments and applications

best suited to the technology

3. Provide a platform and implementation for wirelessly networked devices

4. Ensure interoperability through the definition of application profiles

5. Define the ZigBee network and stack models

6. Provide the framework to allow a separation of concerns for the

specification, design, and implementation of ZigBee devices

7. Allow future extension of ZigBee

ZigBee Architecture Objectives


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ZigBee Feature Set

1. ZigBee V1.0

Ad‐hoc self forming networks

1) Mesh, Cluster Tree and Star

Logical Device Types

1) Coordinator, Router and End Device

Applications

1) Device and Service Discovery

2) Messaging with optional responses

3) Home Controls Lighting Profile

4) General mechanism to define private Profiles

Security

1) Symmetric Key with AES‐128

2) Authentication and Encryption at MAC, NWK and Application levels

3) Master Keys, Network Keys and Link Keys

Qualification

1) Conformance Certification (Platform and Profile)

2) Interoperability Events


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How A ZigBee Network Forms

1. Devices are pre‐programmed for their network function

Coordinator scans to find an unused channel to start a network

Router (mesh device within a network) scans to find an active channel to join,

then permits other devices to join

End Device will always try to join an existing network

2. Devices discover other devices in the network providing complementary

services

Service Discovery can be initiated from any device within the network

3. Devices can be bound to other devices offering complementary services

Binding provides a command and control feature for specially identified sets

of devices


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ZigBee Address Architecture

1. Addressing

Every device has a unique 64 bit MAC address

Upon association, every device receives a unique 16 bit network address

Only the 16 bit network address is used to route packets within the network

Devices retain their 16 bit address if they disconnect from the network,

however, if the LEAVE the network, the 16 bit address is re‐assigned

NWK broadcast implemented above the MAC:

1) NWK address 0xFFFF is the broadcast address

2) Special algorithm in NWK to propagate the message

3) “Best Effort” or “Guaranteed Delivery” options

4) Radius Limited Broadcast feature


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Packet Structure

1. 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

Preamble

Start ofPacketDelimiter

PHYHeader

PHY ServiceData Unit (PSDU)

6 Bytes 0‐127 Bytes


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General Data Packet Structure

PRE SPD LEN PC CRCLink Layer PDUADDRESSING

Preamble sequence

Start of Packet Delimiter

Length for decoding simplicity

Flags specify addressing mode

Data sequence number

CRC‐16

DSN

Addresses according to specified mode


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ZigBee Network Model

ZigBee End Device (RFD or FFD)

ZigBee Router (FFD)

ZigBee Coordinator (FFD)

Mesh Link

1. Star networks support a single ZigBee coordinator with one or more

ZigBee End Devices (up to 65,536 in theory)

2. Mesh network routing permits path formation from any source device

to any destination device


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Wireless Networking Basics

1. Network Scan

Device scans the 16 channels to determine the best channel to occupy.

2. Creating/Joining a PAN

Device can create a network (coordinator) on a free channel or join an existing

network

3. Device Discovery

Device queries the network to discover the identity of devices on active

channels

4. Service Discovery

Device scans for supported services on devices within the network

5. Binding

Devices communicate via command/control messaging


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Network Pieces – PAN Coordinator

1. PAN Coordinator

“owns” the network

1) Starts it

2) Allows other devices to join it

3) Provides binding and address‐table

services

4) Saves messages until they can be

delivered

5) And more… could also have i/o

capability

A “full‐function device” – FFD

Mains powered

PAN Coordinator


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Network Pieces ‐ Router

1. Routers

Routes messages

Does not own or start network

1) Scans to find a network to join

Given a block of addresses to assign

A “full‐function device” – FFD

Mains powered depending on topology

Could also have i/o capability Routers


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Network Pieces – End Device

1. End Device

Communicates with a single device

Does not own or start network

1) Scans to find a network to join

Can be an FFD or RFD (reduced function device)

Usually battery powered

End Device


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Battery Life

1. ZigBee protocol was designed from the ground up to support

very long life battery applications

2. Users can expect

Near‐shelf life in a typical monitoring application

3. Battery life is ultimately a function of

battery capacity and application usage

4. Many industrial applications are in harsh thermal environments

Batteries may include alkalines or Li‐primaries

Other forms of power generation might include solar, mechanical,

piezoelectric


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ZigBee Membership Classes

1. Promoters

founding members of ZigBee, who form the Board of Directors. There are

currently 5 promoters + 1 chairperson

2. Participants

members who generally wish to make technical contributions and/or serve

on the Technical Group committees. These members have early access to

specifications, and they may also chair working group subcommittees. They

are in a position to help shape the ZigBee technology for industrial

applications and the connected home.


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Participants

And more each month…

Promoters

ZigBee Alliance Member


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IEEE 802.15.4

IEEE 802.15 Working Group


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Comparison between WPAN


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IEEE 802.15.4 Basics (1/2)

1. Simple packet data protocol for lightweight wireless networks

Released in May 2003

Channel Access is via Carrier Sense Multiple Access with collision avoidance

and optional time slotting

Message acknowledgement and an optional beacon structure

Multi‐level security

Works well for

1) Long battery life, selectable latency for controllers, sensors, remote monitoring and

portable electronics

Configured for maximum battery life, has the potential to last as long as the

shelf life of most batteries


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2.40 2.41 2.482.472.462.452.442.432.42

2.4622.4372.412 2.4835 (end of ISM Band)

Possible 802.11 Channel (North America)802.11 Spectrum Occupancy (Typical)802.11 DSSS

Normal Channel Occupancy

IEEE 802.15.4 Basics (2/2)

868.3 MHz

902‐928 MHz

2405‐2480 MHz

Frequency Band License Required? Geographic Region Data Rate Channel Number (s)

No

No

Europe

Americas

WorldwideNo

20 kbps

40 kbps

250 kbps

0

1‐10

11‐26


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IEEE 802.15.4 Standard (1/2)

1. IEEE 802.15.4 standard released May 2003

Semiconductor manufacturers

1) Sampling Transceiver ICs and platform hardware/software to Alpha Customers now

Users of the technology

1) Defining application profiles for the first products, an effort organized by the ZigBee

Alliance

2. Includes layers up to and including Link Layer Control

LLC is standardized in 802.1

3. Supports multiple network topologies including Star, Cluster Tree and

Mesh

Introduction to The IEEE 802.15.4 Standard


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IEEE 802.15.4 Standard (2/2)

IEEE 802.15.4 MAC

IEEE 802.15.4 LLC IEEE 802.2

LLC, Type I

IEEE 802.15.4

2400 MHz PHY

IEEE 802.15.4

868/915 MHz PHY

Data Link Controller (DLC)

Networking App Layer (NWK)

ZigBee Application Framework1. Features of the MAC:

Association/dissociation

ACK

frame delivery

channel access mechanism

frame validation

guaranteed time slot management

beacon management

channel scan

Low complexity:

1) 26 primitives versus 131 primitives for 802.15.1 (Bluetooth)


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1. PHY functionalities:

Activation and deactivation of the radio transceiver

Energy detection within the current channel

Link quality indication for received packets

Clear channel assessment for CSMA‐CA

Channel frequency selection

Data transmission and reception

IEEE 802.15.4 PHY overview


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PreambleStart ofPacketDelimiter

PHY Header

PHY ServiceData Unit (PSDU)

4 Octets0‐127 Bytes

Sync Header PHY Payload

1 Octets 1 Octets

Frame Length(7 bit)

Reserve(1 bit)

1. PHY packet fields

Preamble (32 bits) – synchronization

Start of packet delimiter (8 bits) – shall be formatted as “11100101”

PHY header (8 bits) –PSDU length

PSDU (0 to 127 bytes) – data field

PHY frame structure


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868MHz/915MHz PHY

2.4 GHz

868.3 MHz

Channel 0 Channels 1‐10

Channels 11‐26

2.4835 GHz

928 MHz902 MHz

5 MHz

2 MHz

2.4 GHz PHY

Operating frequency bands


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1. The standard specifies two PHYs :

868 MHz/915 MHz direct sequence spread spectrum (DSSS) PHY (11 channels)

1) 1 channel (20Kb/s) in European 868MHz band

2) 10 channels (40Kb/s) in 915 (902‐928)MHz ISM band

2450 MHz direct sequence spread spectrum (DSSS) PHY (16 channels)

1) 16 channels (250Kb/s) in 2.4GHz band

Frequency bands and data rates


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IEEE 802.15.4 MAC

1. Employs 64‐bit IEEE & 16‐bit short addresses

Ultimate network size can be >> nodes (more than we’ll probably need…)

Using local addressing, simple networks of more than 65,000 (2^16) nodes

can be configured, with reduced address overhead

2. Three devices specified

Network Coordinator

Full Function Device (FFD)

Reduced Function Device (RFD)

3. Simple frame structure


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IEEE 802.15.4 MAC

1. Reliable delivery of data

2. Association/disassociation

3. AES‐128 security

4. CSMA‐CA channel access

5. Optional super frame structure with beacons

6. Optional GTS mechanism


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MAC/PHY Frame Format

MAC protocol data unit

MAC HeaderMAC service data unit MAC footer

Framecontrol

Sequence number

Addressinfo

PayloadFrame checksequence

PHY service data unit

PHY protocol data unit

LengthPreamble

Bytes: 2 1 0‐20 variable 2

MACsub layer

MAC frame

Four frame types:

1. Beacon

2. Data

3. MAC command

4. Acknowledge

Max 127 Bytes

Bytes: 4 1 Max 127 Bytes

SFD

1

IEEE 802.15 .4 MAC/PHY Frame Format


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1. A superframe is divided into two parts

Inactive: all devices sleep

Active:

1) Active period will be divided into 16 slots

2) 16 slots can further divided into two parts

Contention access period

Contention free period

0 10987654321 14131211 15

GTS 0

GTS 1

Beacon Beacon

CAP CFP

Inactive

SD = aBaseSuperframeDuration*2SO symbols (Active)

BI = aBaseSuperframeDuration*2BO symbols

Superframe (1/3)


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1. Beacons are used for

starting superframes

synchronizing with associated devices

announcing the existence of a PAN

informing pending data in coordinators

2. In a beacon enabled network,

Devices use the slotted CAMA/CA mechanism to contend for the usage of

channels

FFDs which require fixed rates of transmissions can ask for guarantee time slots

(GTS) from the coordinator

3. The structure of superframes is controlled by two parameters: beacon

order (BO) and superframe order (SO)

BO decides the length of a superframe

SO decides the length of the active potion in a superframe

Superframe (2/3)


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Superframe (3/3)

1. For a beacon‐enabled network, the setting of BO and SO should satisfy

the relationship 0≦SO≦BO≦14

2. For channels 11 to 26, the length of a superframe can range from 15.36

msec to 215.7 sec.

which means very low duty cycle

3. Each device will be active for 2‐(BO‐SO) portion of the time, and sleep for 1‐

2‐(BO‐SO) portion of the time

4. In IEEE 802.15.4, devices’ duty cycle follow the specification

< 0.10.1950.390.781.563.1256.25122550100Duty cycle

(%)

≧109876543210BO-SO


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1. Data transferred from device to coordinator

In a beacon‐enable network, device finds the beacon to synchronize to the

superframe structure. Then using slotted CSMA/CA to transmit its data.

In a non beacon‐enable network, device simply transmits its data using

unslotted CSMA/CA

Communication to a coordinatorIn a beacon‐enabled network

Communication to a coordinatorIn a non beacon‐enabled network

Data Transfer Model (Device to Coordinator)

Device to Coordinator


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1. Data transferred from

coordinator to device

In a beacon‐enable network, the

coordinator indicates in the

beacon that the data is pending.

Device periodically listens to the

beacon and transmits a MAC

command request using slotted

CSMA/CA if necessary.

Communication from a coordinatorIn a beacon‐enabled network

Data Transfer Model (Coordinator to Device )

Coordinator to Device (1/2)


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Communication from a coordinator in a non beacon‐enabled network

1. Data transferred from coordinator to

device

In a non‐beacon‐enable network, a

device transmits a MAC command

request using unslotted CSMA/CA. If

the coordinator has its pending data,

the coordinator transmits data frame

using unslotted CSMA/CA. Otherwise,

coordinator transmits a data frame

with zero length payload.

Data Transfer Model (Coordinator to Device )

Coordinator to Device (2/2)


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1. Two type channel access mechanism:

In non‐beacon‐enabled networks unslotted CSMA/CA channel access

mechanism

In beacon‐enabled networks slotted CSMA/CA channel access mechanism

Channel Access Mechanism


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1. In slotted CSMA/CA

The backoff period boundaries of every device in the PAN shall be aligned

with the superframe slot boundaries of the PAN coordinator

1) i.e. the start of first backoff period of each device is aligned with the start of the

beacon transmission

The MAC sublayer shall ensure that the PHY layer commences all of its

transmissions on the boundary of a backoff period

2. Each device shall maintain three variables for each transmission attempt

NB: number of time the CSMA/CA algorithm was required to backoff while

attempting the current transmission

CW: contention window length, the number of backoff periods that needs to

be clear of channel activity before transmission can commence (initial to 2 and

reset to 2 if sensed channel to be busy)

BE: the backoff exponent which is related to how many backoff periods a

device shall wait before attempting to assess a channel

CSMA/CA Algorithm


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IEEE 802.15.4 MAC Options

1. Two channel access mechanisms

Non‐beacon network

1) Standard ALOHA CSMA‐CA communications

2) Positive acknowledgement for successfully received packets

Beacon‐enabled network

1) Super frame structure

For dedicated bandwidth and low latency

Set up by network coordinator to transmit beacons at predetermined intervals

15ms to 252sec (15.38ms*2n where 0 ≤ n ≤ 14)

16 equal‐width time slots between beacons

Channel access in each time slot is contention free

Three security levels specified

1) None

2) Access control lists

3) Symmetric key employing AES‐128


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IEEE 802.15.4 Device Types

1. Three device types

Network Coordinator

1) Maintains overall network knowledge; most sophisticated of the three types; most

memory and computing power

Full Function Device

1) Carries full 802.15.4 functionality and all features specified by the standard

2) Additional memory, computing power make it ideal for a network router function

3) Could also be used in network edge devices (where the network touches the real

world)

Reduced Function Device

1) Carriers limited (as specified by the standard) functionality to control cost and

complexity

2) General usage will be in network edge devices

2. All of these devices can be no more complicated than the transceiver, a

simple 8‐bit MCU and a pair of AAA batteries!


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Data Frame Format

1. One of two most basic and important structures in 15.4

2. Provides up to 104 byte data payload capacity

3. Data sequence numbering to ensure that all packets are tracked

4. Robust frame structure improves reception in difficult conditions

5. Frame Check Sequence (FCS) ensures that packets received are without

error


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Acknowledgement Frame Format

1. The other most important structure for 15.4

2. Provides active feedback from receiver to sender that packet was received

without error

3. Short packet that takes advantage of standards‐specified “quiet time”

immediately after data packet transmission


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MAC Command Frame Format

1. Mechanism for remote control/configuration of client nodes

2. Allows a centralized network manager to configure individual clients

no matter how large the network


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1. Beacons add a new level of functionality to a network

2. Client devices can wake up only when a beacon is to be broadcast, listen

for their address, and if not heard, return to sleep

3. Beacons are important for mesh and cluster tree networks to keep all of the

nodes synchronized without requiring nodes to consume precious battery

energy listening for long periods of time

Beacon Frame Format


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Frequencies and Data Rates

1. The two PHY bands (UHF/Microwave) have different physical,

protocol‐based and geopolitical characteristics

Worldwide coverage available at 2.4GHz at 250kbps

900MHz for Americas and some of the Pacific

868MHz for European‐specific markets


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ISM Band Interference and Coexistence

1. Potential for interference exists in every ISM band, not just 2.4GHz

2. IEEE 802.11 and 802.15.2 committees are addressing coexistence issues

3. ZigBee/802.15.4 Protocol is very robust

Clear channel checking before transmission

Backoff and retry if no acknowledgement received

Duty cycle of a ZigBee‐compliant device is usually extremely low

It’s the “cockroach that survives the nuclear war”

1) Waits for an opening in otherwise busy RF spectrum

2) Waits for acknowledgements to verify packet reception at other end


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IEEE 1451.5 Sensor Group

1. A survey was conducted mid‐2002 on the characteristics of a wireless

sensor network most important to its users

2. In order of importance, these characteristics are

Data Reliability

Battery Life

Cost

Transmission Range

Data Rate

Data Latency

Physical Size

Data Security

3. How would you modify these requirements, if at all?

IEEE 1451.5 Sensor Group Wireless Criteria


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Freescale 802.15.14 Radio Example

1. Key Features

IEEE® 802.15.4 Compliant

1) 2.4GHz

2) 16 selectable channels

3) 250Kbps Data Rate

4) 250Kbps 0‐QPSK DSSS

Multiple Power Saving Modes

1) Hibernate 2.3uA

2) Doze 35uA

3) Idle 500uA

RF Data Modem

Up to 7 GPIO

SPI Interface to Micro

PowerManagement

MC13191/2/3

Analog Receiver

Internal Clock

Generator

8-ch 10-BitADC

BDMHCS08 CPU

2xSCI

4-ch 16-bitTimer

FlashMemory

RAM

COP

IIC

Up to36 GPIO

SPI

LVI

MC9S08GT Family

Sensors

MMA Series Accelerometers

MPX Series Pressure Sensors

MC Series Ion and

Smoke PhotoSensors

Voltage Regulators

FrequencyGenerator

AnalogTransmitter

Dig

ital

Tra

ns

ce

ive

r GPIO

SPI

Timers

IRQ Arbiter

RAM Arbiter

Buffer RAM

ControlLogic


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Freescale 802.15.14 Radio Example

cont’d

Internal Timer comparators (reduce MCU resources)

‐16.6dBm to +3.6dBm output power

1) Software selectable

2) On‐chip regulator

Up to ‐92 Rx sensitivity at 1% PER

2V to 3.4 operating voltage

‐40˚C to +85˚C operating temperature

Low external component count

1) Requires single 16Mhz Xtal (Auto Trim)

5mmx5mm QFN‐32

1) Lead‐Free


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IEEE 802.15.4

ZigBee StackIEEE 802.15.4 MACSimple MAC (SMAC)Software

Integrated on‐chipTx/Rx Switch

$3.28$2.75$2.3510K SRP

5x5x1 mm 32‐pin QFN (Meets RoHS requirements)Package

Packet and StreamingPacketTransfer Mode

Peer‐to‐Peer, Star and MeshPoint‐to‐Point and StarNetwork Topology

250 Kbps, O‐QPSK Modulation, DSSS Energy Spreading SchemeThroughput

‐40º to +85ºC Operating TemperatureOperating Temp

Programmable clock output available to MCU

Buffered transmit and receive data packets for use with low cost MCUs

Low component count reduces complexity and cost

‐27 dBm to +4 dBm (software selectable)Power Output

SPI Interface to MCUMCU Interface

Optimized for 8‐bit HCS08 Family8‐bit MCU, ColdFire, S12, DSCMCU Support

2.0 to 3.4 VPower Supply

‐94 dBm‐91 dBmSensitivity

Off, Hibernate, Doze and IdleLow Power Modes

ZigBee‐Ready 2.4 GHz transceiverIEEE 802.15.4 Compliant 2.4 GHz

transceiver

Low cost 2.4 GHz transceiver for

proprietary applicationsOverview

MC13203MC13202MC13201


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The 802.15.4 / Zigbee Sandbox

Range

Pea

k D

ata

Rat

e

Closer Farther

Slo

wer

Fas

ter

UWB

HomeRF

Wireless Data Applications

Wireless Video Applications

IrDA

802.11g

802.11b

802.11a

2.5G/3G

ZigBee

802.15.4

Bluetooth

ISM Link

WiFi


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The Application Space

BUILDING AUTOMATION

Security, HVAC,AMR,

Lighting Control, Access Control

CONSUMER ELECTRONICS

Remote Control

PERSONAL HEALTH CARE

Patient monitoring

INDUSTRIALCONTROL

Asset Mgt, Process Control,

Energy Mgt

RESIDENTIAL/LIGHT COMMERCIAL

CONTROL

Security, HVAC,Lighting Control,Access Control

PC & PERIPHERALS

Mouse, Keyboard,Joystick

The Application Space for 802.15.4/ZigBee


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The Wireless Market

PAN

< RANGE

> LAN

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Bluetooth1

Bluetooth 2

ZigBee

802.11b

802.11a/HL2 & 802.11g


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Market Size

1. Strong growth in areas such as wireless sensors will help fuel the

growth of 802.15.4 and ZigBee

Harbor Research reports that by 2008, 100 million wireless sensors will be in

use

On World reports that by 2010, more then 500 million nodes will ship for wireless

sensor applications

2. ABI Research forecasts shipments of ZigBee devices in 2005 at about 1

million, growing to 80 million units by the end of 2006

3. In‐Stat 2004 report has an aggressive forecast of over 150 million annual

units of 802.15.4 and ZigBee chipsets by 2008

802.15.4/ZigBee Market Size


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Features of Protocol Stack

1. ZigBee Alliance

50+ companies: semiconductor mfrs, IP providers, OEMs, etc.

Defining upper layers of protocol stack: from network to application, including

application profiles

First profiles published mid 2003

2. IEEE 802.15.4 Working Group

Defining lower layers of protocol stack: MAC and PHY scheduled for release in April

SILICON

ZIGBEE STACK

APPLICATION Customer

IEEE802.15.4

ZigBee Alliance

Development of the Standard


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Frequencies and Data Rates

868 MHz

915 MHz

BAND COVERAGE DATA RATE # OF CHANNEL(S)

Europe 20 kbps 1

2.4 GHz ISM Worldwide 250 kbps 16

ISM Americas 40 kbps 10


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Stack Reference Model (1/2)

IEEE 802.15.4 PHY

IEEE 802.15.4 MAC (CPS)

ZigBee NWK

MAC (SSCS)802.2 LLC

IP

API UDP

ZA1 ZA2 … ZAn IA1 IAn

Transmission & reception on the physical radio channel

Channel access, PAN maintenance, reliable data transport

Topology management, MAC management, routing, discovery protocol,

security management

Application interface designed Using general profile

End developer applications, designed using application profiles


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Stack Reference Model (2/2)

1. Microcontroller utilized

2. Full protocol stack <32 k

3. Simple node-only stack ~4k

4. Coordinators require extra RAM

Node device database

Transaction table

Pairing table

PHY LAYER2.4 GHz 915MHz 868 MHz

MAC LAYERMAC LAYER

NETWORK LAYERStar/Cluster/Mesh

APPLICATION INTERFACE

APPLICATIONS

SiliconApplication ZigBee Stack

Customer

IEEE802.15.4

ZigBee Alliance

SECURITY


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ZigBee and Bluetooth

ZigBee

Smaller packets over large

network

Mostly Static networks with

many, infrequently used devices

Home automation, toys, remote

controls, etc.

Bluetooth

Larger packets over small network

Ad‐hoc networks

File transfer

Screen graphics, pictures, hands‐

free audio, Mobile phones,

headsets, PDAs, etc.

Optimized for different applications


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Address Different Needs

1. Bluetooth is a cable replacement for items

like Phones, Laptop Computers, Headsets

2. Bluetooth expects regular charging

Target is to use <10% of host power

3. ZigBee is better for devices Where the

battery is ‘rarely’ replaced

Targets are :

1) Tiny fraction of host power

2) New opportunities where wireless not yet

used


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ZigBee

1. DSSS‐ 11 chips/ symbol

2. 62.5 K symbols/s

3. 4 Bits/ symbol

4. Peak Information Rate

~128 Kbit/second

Bluetooth

1. FHSS

2. 1 M Symbol / second

3. Peak Information Rate

~720 Kbit / second

Air Interface


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Silicon

PHY Layer

MAC LayerMAC Layer

Data Link Layer

Network Layer

ZigBeeStack

Application

Application Interface

Application

Zigbee

Silicon

RF

Baseband

Link Controller

Vo

ice

Link Manager

Host Control Interface

L2CAP

TelephonyControlProtocol

Inte

rco

m

Hea

dse

t

Co

rdle

ss

Gro

up

Cal

l

RFCOMM(Serial Port)

OBEX

BluetoothStack

Applications

vCar

d

vCal

vNo

te

vMes

sag

e

Dia

l-u

pN

etw

ork

ing

Fax ServiceDiscoveryProtocol

User Interface

Bluetooth

Protocol Stack Comparison


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Bluetooth:Network join time = >3s

Sleeping slave changing to active = 3s typically

Active slave channel access time = 2ms typically

ZigBee:Network join time = 30ms typically

Sleeping slave changing to active = 15ms typically

Active slave channel access time = 15ms typically

ZigBee protocol is optimized for timing critical applications

Timing Considerations


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Comparison Overview

Bluetooth ZigBee

AIR INTERFACE FHSS DSSS

PROTOCOL STACK 250 kb 28 kb

BATTERY rechargeable non‐rechargeable

DEVICES/NETWORK 8 255

LINK RATE 1 Mbps 250 kbps

RANGE ~10 meters (w/o pa) ~30 meters


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Reliability Throughout the Stacks (1/8)

1. Consistently perform a given task to the desired result despite all

changes of environmental behavior

2. Without fail

3. A necessary ingredient of trust

4. “When the sensor measures its environment; the controller always

knows that same value”

5. The wireless medium is not a protected environment like the wired

medium, but rather, it is fraught with degradations, disruptions, and

pitfalls such as dispersion, multipath, interference, frequency dependent

fading, sleeping nodes, hidden nodes, and security issues.


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1. Each of these degradations and disruptions can be mitigated by various

mechanisms within the ISO layers; but not all mechanisms are compatible

with all other mechanisms or may negatively impact critical performance

attributes

2. The system must be optimized for the best performance in a realistic

environment

3. In addition to the previous disruptions there is the case of sending

messages to devices that are not receiving, e.g. they’re in the “sleep” mode.

When this happens the message needs to be buffered by another device

that is able to send the message when the sleeping device wakes up.



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Router

X X

Hidden Node

Interferer

Multipath

Sleeping Node NetworkCoordinator


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1. IEEE 802.15.4 has built upon the successes of previous IEEE 802

standards by selecting those mechanisms proven to ensure good

reliability without seriously degrading system and device performance.

ISO Layers:

1. PHY: Direct Sequence with Frequency Agility (DS/FA)

2. MAC: ARQ, Coordinator buffering

3. Network: Mesh Network (redundant routing)

4. Application Support Layer: Security


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PHY Layers:

1. Direct sequence: allows the radio to reject multipath and interference by

use of a special “chip” sequence. The more chips per symbol, the higher

its ability to reject multipath and interference.

2. Frequency Agility: ability to change frequencies to avoid interference

from a known interferer or other signal source.


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MAC:

1. ARQ (acknowledgement request) is where a successful transmission is

verified by replying with an acknowledge (ACK). If the ACK is not

received the transmission is sent again

2. Coordinator buffering is where the network coordinator buffers

messages for sleeping nodes until they wake again

Network:

1. Mesh Networking: allows various paths of routing data to the

destination device. In this way if a device in the primary route is not able

to pass the data, a different valid route is formed, transparent to the user.


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Application Support Sub‐layer(APS):

1. Security: supports reliability by keeping other devices from corrupting

communications.

2. The APS configures the security emplaced in the MAC layer and also

adds some of its own.


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ZigBee End Device (RFD or FFD)

ZigBee Router (FFD)

ZigBee Coordinator (FFD)

Mesh Link

Star Link

Reliability: Mesh Networking


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IEEE 802 Direct Sequence

1. As can be seen from above, IEEE802.15.4/ZigBee has more processing

gain (chips/symbol) than its predecessors

32151111Chips/Symbol

15.4(2.4)

15.4(900)

11b11IEEE 802.


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Direct Sequence and Frequency Agility

2.4 GHz

Channels 11‐26

2.4835 GHz

5 MHz2.4 GHz PHY

Over the Air After DS correlation

Interferer Desired Signal


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Robustness Throughout the Stacks (1/4)

1. Let’s define robustness as the ability to tolerate significant degrading

phenomena in the physical medium

2. Multipath and interference are probably the most significant

degradations to the channel model.

Robustness of IEEE 802.15.4 and ZigBee


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1. Frequency hopping is a method that allows the radio to periodically

change channels to over time minimize the effect of a “bad” channel.

While this technique is very effective in some circumstances it creates

other problems such as latency, network uncertainty for sleeping nodes,

loss of the product bandwidth x time, etc.

2. Direct Sequence with Frequency Agility (DS/FA) combines the best

features of DS and FH without most of the problems caused by frequency

hopping because frequency changes aren’t necessary most of the time,

rather they’re appropriate only on an exception basis.


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1. The 802.11 Working Group couldn’t agree upon which of the following

PHYs was the best: FH, IR, or DS. So all three were standardized and left

to the market to decide.

2. Of the three PHYs; DS was the clear market winner. DS provided

sufficient robustness with higher overall performance.

3. Excess robustness does not achieve higher performance, rather it

typically costs performance


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1. IEEE 802.15.4/ZigBee have addressed reliability throughout the ISO stack

with proven mechanisms to minimize the uncertainty of the wireless

medium

Reliability and Robustness throughout the stacks of IEEE

802.15.4 and ZigBee


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802.15.4/ZigBee vs Bluetooth

1. Bluetooth and 802.15.4 transceiver physical characteristics are very

similar

2. Protocols are substantially different and designed for different purposes

3. 802.15.4 designed for low to very low duty cycle static and dynamic

environments with many active nodes

4. Bluetooth designed for high QoS, variety of duty cycles, moderate data

rates in fairly static simple networks with limited active nodes

5. Bluetooth costs and system performance are in line with 3rd and 4th

generation products hitting market while 1st generation 15.4 products

will be appearing only late this year


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Transceiver Comparisons

1. Instantaneous Power Consumption

15.4 Transceivers are “similar” to Bluetooth Transceivers1) 802.15.4

OQPSK with shaping

Max data rate 250kbps over the air

2Mchips/s over the air Direct Sequence Spread Spectrum (62.5ksps*32 spread)

‐90 dBm sensitivity

40ppm xtal

2) Bluetooth

FSK

Max data rate 720kbps over the air

1Msps over the air Frequency Hop Spread Spectrum (79 channels @ 1600 hps)

‐85dBm sensitivity

20ppm xtal

2. Instantaneous power consumption will be similar for the raw

transceivers without protocol

3. Bluetooth’s frequency hop makes it extremely difficult to create

extended networks without large synchronization cost


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General Schematic

802.15.4XCVR

MCU

32.768kHz

IRQ

SPI SPI

16.000MHz

VccVcc

INTIRQ/

4

OSC1 OSC2

3Vdc

RESET

HeartbeatSensor

Plus about 10‐12 small value capacitors, resistors

excluding any special components for heartbeat sensor)


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802.15.4/ZigBee Operation Mode

1. 802.15.4/ZigBee ModeNetwork environment using Guaranteed Time Slot (GTS)

Network beacons occurring either every1) 960ms or 61.44s (closest values to 1 and 60 s)

2) Guaranteed time slot occurs at some predetermined point in the beacon interval

2. Sensor has two ongoing processesHeartbeat time logging

Transmit heartrate and other information (8 bytes total)1) Instantaneous heartrate (1/timeinterval between last two pulses,1ms precision)

2) Running average heartrate (1/time interval between last twenty pulses, 1ms precision)

3) Sensor average temperature (0.1C precision)

4) Sensor average battery state (0.1V precision)

time

heartbeat

GTS

Beacon


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Protocol Makes the Difference

1. 15.4 Protocol was developed for very different reasons than Bluetooth

802.15.4

1) Very low duty cycle, very long primary battery life applications

2) Static and dynamic star and mesh network structures with potentially a very large number (>>65534) of client units, low latency available but not necessary

3) Ability to remain quiescent for long periods of time without communicating to the network

Bluetooth

1) Moderate duty cycle, secondary battery operation where battery lasts about the same as master unit

2) Wire replacement for consumer devices that need moderate data rates with very high QoS and very low, guaranteed latency

3) Quasi‐static star network structure with up to 7 clients (and ability to participate in more than one network simultaneously)

4) Generally used in applications where either power is cycled (headsets, cellphones) or mains‐powered (printers, car kits)

2. Protocol differences can lead to tremendous optimizations in power consumption


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Applications

1. Industrial Control/Monitoring Space

Asset Management

1) Basic identification

Device ID, Device PN/SN, Device source/destination, etc.

2) Asset “health”Temperature, humidity, shock, fuel levels, etc.

Nearly any parameter can be monitored given an appropriate sensor

Asset Tracking

1) Location tracking through two‐way communication

Simplest form is communication/identification when passes a checkpoint

Same as other RFID tagging systems

More sophisticated “what other devices can it hear/communicate with?”

Other options include ranging (time of flight) and SNR measurement

Has the potential for very precise location measurement

The wireless network uses protocol gateways to move command/monitor

data between the end devices and the network data management center


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HVAC

Field Service or mobile worker

ServiceProvider

Retailer

Corp Office

Mfg Flow

Temp. Sensor

Security Sensor

DatabaseGateway

Telephone Cable line

Back EndServer

Materials handling

Warehouses, Fleet management, Factory, Supermarkets,

Office complexes

Gas/Water/Electric meter, HVAC

Smoke, CO, H2O detector

Refrigeration case or appliance

Equipment management services & PM

Security services

Lighting control

Assembly line and work flow, Inventory

Materials processing systems (heat, gas flow, cooling,

chemical)

Energy, diagnostics, e‐Business services

Gateway or Field Service links to sensors &

equipment

Monitored to suggest PM, product updates, status

changes

Nodes link to PC for database storage

PC Modem calls retailer, Service Provider, or Corp

headquarters

Corp headquarters remotely monitors assets, billing,

energy management

Product Examples


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Data CommunicationTwo way

Dealer

Server

Field Service

Retailer SOHO

Telephone Cable line

ServiceProvider

AC or heat Pump

Gateway(s)

Temp. Sensor

Body monitor

Security Sensor

PC & peripherals Entertainment

Back EndServer

Customers

White goods

1. Mobile clients link to PC for database storage

PC links to peripherals, interactive toys

PC Modem calls retailer, SOHO, Service Provider

2. Gateway links to security system, temperature sensor, AC system, entertainment, health.

3. Gateway links to field sales/service

Home & Diagnostics Examples


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Motorola 802.15.4/ZigBee™ Platform

Motorola RF Packet Radio Motorola 8‐Bit MCU

System Simplicity and Flexibility


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Motorola 802.15.4 / ZigBee™ Solution

1. Features

2.4 GHz Band, ‐90 dBm RX sensitivity at 1% PER

1) IEEE spec is –85 dBm

Power supply 2.0‐3.6 V w/ on‐chip regulator, logic interface 1.7 to 3.3

1) Runs off a single Li or 2 alkaline cells

Complete RF transceiver data modem – antenna in, fully packetized data out

Data and control interface via standard SPI at 4 to 8 MHz

802.15.4 MAC

A large number of Motorola’s substantial line of HC08 MCUs will

interoperate with the data modem chip

1) Often 802.15.4 functionality can be added to existing systems simply by including

the modem chip and reprogramming an existing MCU that may already be in the

application

HC08 RAM/FLASH configurations from 384B/4kB to 2kB/60kB depending

upon application SW needs


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1. Designed for the IEEE 802.15.4 and ZigBee™ standards

Operates in the 2.4 GHz ISM band available worldwide

Cost effective CMOS design

Low external components, no T/R switch required

On‐chip low noise amplifier

0dBm (1.0 mW) PA, step adjustable to –30dBm

Integrated VCO, no external components

Full spread‐spectrum encoding and decoding compatible with 802.15.4

RX sensitivity of –90 dBm at 1% PER, better than specification

Engineered to support 250 kBit/s O‐QPSK data in 5.0 MHz channels, per the

IEEE 802.15.4 specification

No line‐of‐sight limitations as with infrared (IR)

RF Data Modem Transceiver (1/2)


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1. Designed to run DIRECTLY off two alkaline AA or AAA cells, or one

Lithium cell

2.0 to 3.6 V with on‐chip voltage regulator

Can use the full capacity of the battery (to end of life ~1.0V per cell)

2. Buffered transmit and receive data packets for simplified use with low‐

end microcontrollers

3. SPI data and control interface, operates up to 8MHz

4. Designed to support peer to peer and star topologies

5. On‐board timers to support optional Superframe/Guaranteed Time Slots

for low latency transfer

6. Will support optional Zigbee™ Network layer software

7. Application‐configurable power‐saving modes that take best advantage

of battery operation

RX/TX > Idle > Doze > Hibernate > Off

RF Data Modem Transceiver (2/2)


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12kB FLASH 8‐BitMicrocontroller

Application

RF Transmitter

RF Receiver DigitalProcessing

RF Transceiver ICSPI

32kB FLASH 8‐BitMicrocontroller

Application

Application‐specific interfaces

RF Transmitter



3kB FLASH (min) 8‐BitMicrocontroller

Application

RF Transmitter



Direct SPI Calls

802.15.4 PHY Compliant Transceiver

System Complexity and Cost

15.4 RFD MAC

15.4 RFD MAC

>32kB FLASH 8‐BitMicrocontroller

Application

RF Transmitter



15.4 FFD MAC

Zigbee NWK

Zigbee NWK

802.15.4 is a guest in existing microcontrollers

Scalability to Address Specific Needs


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1. Total System Solution

Single source for platform solution

1) Integrated Circuits, Reference Designs, Modules, Stack Software, Development Systems

2. Key technology enhancements provide for a superior solution

Adjacent channel rejection

1) Improvements in noisy environment

High Sensitivity Radio Solution

1) 5 dBm beyond spec – longer range

Extended Temperature Operating Range

1) ‐40°C to +85°C for industrial and automotive applications

Operating voltage range optimized for alkaline or lithium primary cells

1) 2.0 Vdc to 3.6 Vdc, disposable

Adjustable TX Output power

1) Improved coexistence for short range applications, improved battery life

3. IEEE and ZigBee™ Alliance membership

Technology and standards driver

Early access to new technology

Advantages


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An Application Example (1/7)

1. Scenario Parameters

Battery‐operated keyboard

1) Part of a device group including a mouse or trackball, sketchpad, other human

input devices

2) Each device has a unique ID

3) Device set includes a USB to wireless interface dongle

Dongle powered continuously from computer

4) Keyboard does not have ON/OFF switch

5) Power modes

Keyboard normally in lowest power mode

Upon first keystroke, wakes up and stays in a “more aware” state until 5 seconds of inactivity have passes, then transitions back to lowest power mode

Wireless Keyboard


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1. Typing Rates

10, 25, 50, 75 and 100 words per minute

2. Typing Pattern

Theoretical: Type continuously until battery is depleted

1) Measures total number of hours based upon available battery energy

Keyboard Usage



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1. 802.15.4 Operation Parameters

Star network

Non‐beacon mode (CSMA‐CA)

USB Dongle is a PAN Coordinator Full Functional Device (FFD)

Keyboard is a Reduced Function Device (RFD)

Power Modes

1) Quiescent Mode used for lowest power state

First keystroke latency is approx 25ms

2) Idle mode used for “more aware” stateKeystroke latency 8‐12 ms latency

Wireless Keyboard Using 802.15.4



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1. 802.15.4 Chipset Parameters

1) Motorola 802.15.4 Transceiver and HCS08 MCU

2) Battery operating voltage 2.0 – 3.6 V

All required regulation internal to ICs

Nearly all available energy usable with end of life voltage at 2.0 volts

Wireless Keyboard Using 802.15.4



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1. Bluetooth Operation Parameters

Piconet network

USB Dongle is piconet Master

Keyboard is a piconet Slave

Power Modes

1) Park mode used for lowest power state

1.28 second park interval

First keystroke latency is 1.28s

2) Sniff mode used for “more aware” state

15ms sniff interval

15ms latency

Wireless Keyboard Using Bluetooth



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1. Bluetooth Chipset Parameters

CSR BlueCore 2 –External + Flash + Regulator

Battery Operating Voltage 2.7 – 3.6 Vdc

1) Requires external regulator for best performance

2) Only 19 to 30 percent of available battery life usable with 2.7V cutoff voltage

Power Consumption (estimated)

1) Park Mode @ 1.28 s interval: 0.05mA avg

2) Sniff Mode @ 15ms interval: 8mA avg

3) NOTE: I do not assume a deep sleep mode since wake up time of 4 to 30 seconds

seems unacceptable

Wireless Keyboard Using Bluetooth



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BT: Approximately 5 operating days

802.15.4: Approx 38 days

Bad Hunt n’Peck

By the way, WirelessUSB looks

much like BT

Bluetooth vs. 15.4 Keyboard Comparison



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Q & A

1. 경청해주셔서감사합니다.

2. Q & A

Documents

ZigBeepds4.egloos.com/pds/200702/23/35/06-zigbee.pdf · ZigBee 802.15.4 and the ZigBee Alliance Motorola 802.15.4/ZigBee™ Platform Robot Sensor Networks Hanyang University Contents