Low Rate Wireless Personal Area Network Computer Science Essay

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In the past few years there is too much growth in wireless network .But up to now the main focused wireless network is on high speed communications and relatively long range application such as the IEE 802.11 wireless local Area network (WLAN) standards. The rest well focusing on Low-rate wireless personal area Network (LP-WPAN) was Bluetooth.

But it has limited capacity for networking for many nodes. There are many other wireless monitoring and controlling application in industrial and home environments which require long battery life, less complexity and lower data rates than those from existing standards.

The New wireless standard called IEE 802.15.4 has been developed for such wireless application the new standard is called Zigbee.

1.2: Goal:-

The goal of the project is to develop a full function Zigbee and IEEE 802.15.4 modules .This includes designing using Freescale MC9S12NE64 and implementation of Zigbee chip on the Freescale MC9S12NE64 board. A literature study must be performed to evaluate the new standard and and to test a zigbee modules and test application will be developed as well.

1.3 Method:-

The work is divided into different stages.

The first is a literature study.

The Second Purchased Zigbee Kit.

The Third Start the Zigbee device and IEEE 802.15.4

The Fourth Use Freescale MC9S12NE64 to design a Zigbee module.

The Modules are manufacture outside the university, assembled at home and tested at the university, after the hardware developed, and the implementation of software will be performed as well.

The information of this project is obtained mainly from books, Internet and the university tutors.

Chapter 2

Type of Wireless Technology:

2.1: Different type of wireless technology :

The wireless communication is use to transfer an information over a distance without using of wire .the distance can be long like thousands or millions of kilometres using radio communication or short like a few meter like a television remote control.

The wireless technology is generally considered to be a branch of telecommunication including mobile, portable two-way radio, PDA (personal digital assistants), Wireless network, GPS, Wireless mice and keyboards, Satellite Television and cordless Telephone. These are the type of wireless technology .The main type of technology which is use in the industry are





2.2: Radio:-

A radio is a standard mated for a radio broadcast its especially depend on radio frequencies and transmitters a continuous flow of wave in Am and FM.

2.3: WiFi:-

A wireless network which use radio wave just like a TV ,Mobile phone and radio it s self .

A communication on the wireless network is like two way radio communication for example;

A computer wireless adopter converted data in a radio signal and transmitted through an antenna. Radio signal will decodes and then router send the information to the internet using physical wired Ethernet connection. The radio waves used by the Wifi are same to the radio wave which used in cell phone and other devices. They also send and received the radio waves and can convert 1s and 0s in radio waver and convent Radio waves into 1s and 0s.

But WiFi radio wave are little different from other radio waves.

The WiFi used 2.4GHz or 5GHz.The WiFi radio frequency is higher than the frequency used in cell phone, TV and walkie-Talkies. The more high frequency it can carry more amount of data.

The wifi network standard is IEEE802.11 but it has different type of flavours they are;6a00d8341ccc5153ef00e54f38d8638834-800wi.jpg

IEEE 802.11a

IEEE 802.11b

IEEE 802.11g


2.4: Bluetooth:-

Bluetooth is a shot range radio hook-up that resides on microchip it was developed by Swedish mobile phone mark Ericsson in 1994.bluetooth-30.jpg

The Bluetooth was published by Bluetooth SIG.

The Bluetooth connection is to provide short-range wireless capability .It use 2.4GHZ band which is unlicensed low-power uses .The two Bluetooth device can connect up to 10mitter and can share up to 720Kbps of capacity. Bluetooth is usually used in sending a audio, Graphics and even a video our a short range.

2.5: Zigbee:-

Zigbee is made by Zigbee Alliance and the Alliance is an combination of different companies work to gather to ensure the success of the open global standard.

Zigbee is built onIEEE802.15.4 standard .Zigbee provides routing and multihop function to the packet based radio protocol.DSCF5324.JPG

Chapter 3


3.1 Zigbee Alliance:-

The zigbee alliance is an association of the companies which work together on an open task to define standard and marking a low power wireless network. The zigbee alliance work to create a specification and defining how to build different network topologies with security. The chip manufacture companies and system integration companies are member of zigbee alliance. The number of zagbee alliance are rapidly growing day by day currently there are 125 companies like Philips, Motorola, Samsung and LG are some of the biggest name of zigbee alliance.

The zigbee first specification was ratified in 2004 and zigbee first generation product is reach to the market in 2005.

The man and big challenge for zigbee alliance to make a product compatible that it can work with different type of product. To solve that problem zigbee in introduce the the zigbee profile depending on what type of category the product belong to for example in zigbee the profile call home lighting that defines how different brands of home lighting product should communicate with each other .

"Help create the future of wireless data networking. As a ZigBee Alliance member, you can actively shape and take advantage of the evolution in wireless monitoring and control markets worldwide. By participating in member meetings, committees, and working groups, your company can help shape the ZigBee standard for reliable, secure, and low-power wireless communications. Companies from virtually every industry and every country are joining the ZigBee Alliance."

3.2 The Name Zigbee:-

the name zigbee come from the domestic honeybee which use zig-zag type of dance to communicate with other domestic honeybee. The communication dance makes engineers to think that this simple organisms that joint to gather to tackle complex task.

As Zigbee its work seemlier like a domestic honeybee works.

There is story as well that how the zigbee get a name .

"The Aztecs were a Pre-Columbian Mesoamerican people of what is now known as Central


Chapultepec, "at the grasshopper hill" in the Nahuatl language, is a large hill on the

outskirts of central Mexico City. In the days when Tenochtitlán was the island capital of the Aztecs, built on a series of islets in Lake Texcocoth, the city was linked to Chapultepec by a causeway. Aztec chiefs turned the hill and the surrounding forest into a royal retreat. The poet-king Nezahualcóyotl built a palace there in the 1400s, along with an aqueduct to carry spring water to the Aztec capital, and a sculpture of Moctezuma can still be seen carved into the rock of Chapultepec, not far from Huemac's cave. One of the pleasures the royalty enjoyed during this time was one we take for granted today: ice.

Ice, as you can imagine, was very difficult to come by in the hot climate of Central

America. The Aztecs would cut ice from glaciers in the nearby mountains and runners would carry the ice packed in skins, down to Chapultepec.

No single runner could make it all the way with a packet of unmelted ice, so a series of runners were stationed along the route, each to take the ice and pass it along to the next runner, eventually to end up at the final destination-Chapultepec. They called this service Zigibi. Zigibi was similar to how ZigBee functions today: multi-hopping packets along a route from one node, through a series of other nodes to the final destination, ensuring that the packet arrives in a timely manner.

The hill of Chapultepec and the surrounding land are now Chapultepec Park, a popular spot both for locals and tourists. The park covers 1,600 acres of land, with centuries-old forest, several small lakes, landscaped areas and outdoor cafes. Chapultepec Zoo is located there, as well as an amusement park, La Feria, and it is the official residence of the President of Mexico, Los Pinos."

3.3 IEEE 802.15.4:-

When IEEE802.15.4 standard was introduced its goal was to provide a standard to a ultra-low, ultra-low power, consumption and low data rate wireless connectivity among other wireless device. The data rate in IEEE 805.15.4 is high enough (250 kb/s mix) for the application like sensors, toys and alarms etc.

3.4 IEEE 802.15.4:-

IEEE 802.15.4 is using three different types of devices.


The full function FFD supports all IEEE 802.15.4 function. It can work as a coordinator more memory and a computing power make it ideal for the network routing function

The network maintain the overall network knowledge it is highly complicated or most developed one of the three types, and it required most of the memory and computing power.

3. RFD.

The RFD (Reduced Functionality device) its carries limited function to low cost and complexity it's found in network-edge devices. The RFD can be use in very two power place.

3.4 Network Topologies:-

IEEE 802.15.4 has two type of topology.

Peer -To-Peer topology.

Star topology.

In zigbee these two topology can combine and build a network called mash network. As show in a Figure.

A description...

Peer-to-Peer topology:

The peer to peer topology also called pan coordinator. It allow the devices to communicated with another device as long they are connect in range format to each other.

The peer to peer topology can grow bigger and bigger and become a mach network.

Star Topology.

When FFD establish its own network it's become (PAN)Personal aria network. The both devices FFD and RFD can connect with PAN. All the nods which connect with the PAN must talk with the PAN coordinator.

Chapter 4

Zigbee Architecture

4.1: OSI Overview:-

In zigbee OSI layer each layer doesn't know about the layer above it. The above layer is a master who command other layer what work they need to do.

But zigbee does not exactly fit i n OSI 7 layer network model but it do some of work like PHY (physical layer), MAC(link Layer), NWK (network layer). The transport layer, session layer, and application layers are put in the APS and ZDO layers in zigbee module.

The SAP (Service Access Points) can provide an API that can work in layer above and below.

The IEEE180.15.4 specification Zigbee use two SAP per Layer one form a data layer and one form a management layer.

The lower two layer MAC and PHY are defending in IEEE180.15. The physical layer translates packets into the air and back.

The MAC layer provides a PAN ID and fined a network. Its joint a network by using some commands and provide per-hop acknowledgment. The MAC does not multi-Hop or mesh.

For the mesh network NWK layer is responsible and its has a responsibility to broadcasting packets across the network and make sure packet are send from one node to another and other node received that packet.

The NWK also work for security as well it's include secure joining and rejoining the zigbee network and encrypted entire payload by NWK.

The responsible for application meaning is APS layer. Its filter the application running above on end points and simplifies logic in those applications. If the NWK Layer sends a duplicate message the APS layer filters those messages.

The ZDO layer is a Zigbee Device profile. It is responsible for local over the air management of the network. Screenshot-2.png

(Zigbee OSI Layers) Figure 4.1

It work to find other nodes and services in the network and it's also responsible current state of the node in and on the network.

4.2: Modulation /Spreading:-

The modulation /Spreading job is to convert binary to a modulated signal in the 2450MHz frequency as its show in the figure.


(Convert binary to a modulated signal) Figure 4.2

In this figure number show how the binary data "0000b" converted to a baseband chip sequence with pulse shaping.

4.3: Bit to Symbol:-

The step to make symbols from the bit is to encode all the PPDU (PHY Protocol Data unit to binary data and them in symbol. Every bite is divide into two symbols and the least signification symbol is transmitted first. The last significant byte are send first in multi-byte field but the most significant byte transmitted first in security related fields.

4.4: Hardware:-

The IEEE180.15.4 transceiver chips are currently increasing in the market. The 2.4GHZ transceiver chips are currently in the market as show in figure blow.


2.4GHz transceivers Figure 4.4

The table don't show more feature of Chips which built in zigbee stack, ADC or DAC.

4.5: Security:-

There are three type of security in zigbee device


Access Control list.

Secures mode.


Unsecured as by name it is not secured at all.

Access Control List.

The access control list is not encrypted but it reject unknown devices which try to connect with the zigbee network.

Secured Mode.

The secure mode can use Access control list and Data encryption by using (AES 128 bit encryption). It use MIC (Message integrity code) as well to save the data from modified by other parties without the key. It also in shored the data which come from other party must have cryptographic key.

4.6 Zigbee Network:-

Now a days the WSN (Wireless sensor network) is so advance they not only is so advance they not only send a data one to another but can receive data from one and send to another until the data reaches to destination

Zigbee network can extend and connect over thousand of nodes. The FFD can

Become a router to send and received the messages from other FFD.

The zigbee network make for low duty cycle network (<1%). If the new nodes want to connect with the network it takes 30ms and 15ms to wake up sleeping nodes.

The zigbee can connect to the network very quick and its go to deep sleep when nothing to send that how it saves power and extended the battery life.

4.7 AODV :-

AODV (Ad hoc on-Demand distance vector) is a routing protocol for wireless ad-hoc network and mobile ad-hoc network can find in the most common routing protocol of the internet. In AODV they find its routing path independently.

The AODV stay Silent until other nods need a connection. The node which need a connection broadcast a request to the connection. The other ADOV node create a temporary routes between the sender and receiver nodes and record the node where the message coming from and forward the message. When the node receive the message from the sender then at that time the receiver will have a temporary route do it will send a message back through that route then the send node start communicate though the shortest path.

In this process if the link fails the error message send back to the sender then the sender node start the hole processes again.

The complex function in this protocol is these.

All the nodes has sequence number so in that case all the nodes save each other sequence numbers one the routing done so they don't need to do the routhu=ing request again and again which they all ready done it .

Second function is that every rout has a "time to live" that mean how many time they can be re connect .

Third function is that if the request fail then another request time waiting period will be increase.

The advantage if AODV is

It doesn't make overflow communication traffic on existing link.

The communication with the distance routing is easy and simple those routing don't required to much memory and calculation.

The AODV is on-demand routing protocol it only activate when the node want to send the data packet form the sender to receiver.

It also required a sequence number to find out a shortest path to the destination.

The different between AODV and DSR is the DSR (Dynamic Source Routing)

Chapter 5:

Hardware Design

5.1: Device Overview

The MC9s12ne64 is a 112/80-pin board which is cost-effective, low-end connectivity application MCU family. The 6-bit central processing unit (HCS12 CPU), 64K bytes of FLASH EEPROM, 8K bytes of RAM, Ethernet media access controller (EMAC) with integrated 10/100 Mbps Ethernet physical transceiver (EPHY), two synchronous serial communications interface modules (SCI), a serial peripheral interface (SPI), one inter-IC bus (IIC), a 4-channel/16-bit timer module (TIM), an 8-channel/10-bit analogy-to-digital converter (ATD), up to 21 pins available as keypad wakeup inputs (KWU), and two additional external asynchronous interrupts are built on MC9S12NE64 Board.