Overview of Zigbee and Shortest Path Routing

Algorithm using MATLAB

Yash Agrawal#1, Dhirendra Pratap Singh#2, Rohit Dhiman#3, Rajeevan Chandel#4

# Department of Electronics & Communication Department

National Institute of Technology, Hamirpur 177 005 HP India 1mr.yashagrawal@gmail.com,

2dhirendrapratap.nith@gmail.com,

3rohitdhiman.nitham@gmail.com,

4rajeevanchandel@gmail.com

Abstract- Zigbee (IEEE 802.15.4) is a new wireless standard for

low data rate and low power consumption. Zigbee is meant for

small distance ranging from 10-100 metres. In the present paper

shortest routing algorithm is used for zigbee module. The routing

algorithm is defined in the network layer. It considers starting as

well as destination node distance for calculation of shortest

distance between the nodes. Also, BPSK encoding is used for

transmission of data. The analysis is carried out using MATLAB.

I. INTRODUCTION

Zigbee devices are required to conform IEEE 802.15.4-2003

i.e. Low Data Rate Wireless Personal Area Network

(WPAN) standard [1]. Depending on the power output

consumption, zigbee operation range is in between 10-

100m. Zigbee works on unlicensed RF band. The data rate

of zigbee is 250kbps at 2.4GHz (global), 40kbps at 915MHz

(America) and 20kbps at 868MHz (Europe).

It was developed by IEEE and Zigbee Alliance group.

Zigbee uses basic OSI model in which protocols of the

lower Physical and data link layer are defined by IEEE

802.15.4 and protocols of the upper stack (Network layer to

Application layer) are defined by Zigbee Alliance group. It

can be used in vast number of applications such as

luminance and temperature control, building automation and

industrial facilities [2, 3]. It can be integrated with sensors

which can send small packets of data wirelessly to

coordinator in the zigbee mesh network for smart and

intellectual applications [4-6].

In the present work shortest routing algorithm is used for

zigbee. For finding shortest distance, starting as well as

destination node distance is considered so as to have more

directional and shortest route between the starting and

destination node. The same is implemented and seen using

MATLAB.

The paper is arranged as: Section I is the introduction,

Section II gives a brief overview of the IEEE 802.15.4,

Section III discusses about zigbee protocol stack. Section IV

gives the routing algorithm.

Section V gives results and discussion. Conclusion is made

in Section VI and following it references are in Section VII.

II. ABOUT IEEE 802.15.4

802.15.4 defines the physical and MAC layers. The feature

of Physical layer is Energy Detection, channel selection,

link quality detection and transmitting and receiving of data

packets across the physical medium.

Physical layer operates in two layers depending on the

frequency range. Lower frequency layer works on 868MHz

in Europe and 915 MHz in US and Australia. The upper

frequency layer works on 2.4 GHz which is used worldwide.

Different modulation scheme and channel allocation is done

based on frequency band used. Medium Access Control

(MAC) layer provides reliable communication between

routers and end device.

The layers are as shown in figure 1.

Fig. 1 Zigbee Protocol Stack

III. ABOUT ZIGBEE PROTOCOL STACK

This defines the upper layers and consists of Network and

Application Layer. In network layer, routing algorithm is

defined. Research is being carried out on various routing

Application Layer

Network and Security

layer

MAC Layer

Physical Layer

Zigbee

Alliance IEEE

802.15.4

International Conference On Recent Advances in Electronics and Computer Engineering, 17th-18th Nov., 2011, Eternal University, H.P., INDIA 1

algorithms. The selection and efficiency of routing

algorithm depends on the network topology. The different

network topologies are star, tree and mesh network. It can

be seen in figure 2.

(a) Star Network

(b) Cluster tree Network

(c) Mesh Network

Monitoring Device

Router

End Device

Figure 2: Zigbee Network Topology

Zigbee network consists of coordinator, router and end

device. The zigbee coordinator forms the root of the

network tree and bridges other networks. The routers are

responsible of data transmission between coordinator and

end device. The zigbee network can be extended by

increasing number of routers. Zigbee end device can

transmit and receive signals but it cannot perform any

routing operations.

IV. ROUTING ALGORITHM

Routing is defined in the network layer. There are various

routing algorithms. Among all, shortest routing algorithm is

most widely used. In this information is transmitted between

the source and destination node through routers following

the shortest path.

Here for defining routing algorithm, mesh topology is used.

The nodes are distributed randomly in the mesh network. It

is shown in figure 3.

Fig. 3 Mesh Network Topology

Figure 4 shows the routing scheme. For better

understanding, it can be divided into three levels as N-1, N

and N+1. The information is to be send through A to B. It

can be seen in following steps as:

1. Initially starting node (A) calculates the number of router

around it. Here it is 3.

2. Then it calculate its distance with all the neighboring

routers around it viz. s1, s2, s3.

3. Then in the third step distance between all its neighbor

routers with the destination node is calculated viz. d1,

d2, d3.

4. Then addition of each router’s distance with its source

and destination node is done (s1+d1, s2+d2, s3+d3).

5. Finally, shortest distance is calculated from step 4 and

routing is made through the router giving minimum

distance between the source and destination node.

Fig. 4 Mesh Network

Nth Level (N-1)th Level (N+1)th Level

International Conference On Recent Advances in Electronics and Computer Engineering, 17 -18 Nov., 2011, Eternal University, H.P., INDIA 2

The same is analyzed in MATLAB. It is seen in figure 5.

Here routing path is defined between C to F.

Fig. 5 Routing Path in Mesh Network

The information and control signals are in the binary form.

For transmission of signals through channel this is to be

encoded. There are various encoding schemes. However

zigbee uses Binary Phase Shift Key (BPSK) as an encoding

scheme in the Physical layer.

In this binary data is converted to +1 or -1 depending on the

information bit.

Here BPSK encoding is analyzed and carried out in

MATLAB. It is seen in fig. 6.

Fig. 6 BPSK Encoding Scheme

V. RESULTS & DISCUSSION

The simulation is carried out using MATLAB. The mesh

network and shortest routing algorithm is defined. The same

is analyzed using MATLAB tool. Also, BPSK encoding is

done in the Physical layer.

VI. CONCLUSION

Zigbee is an emerging technology which can lead to

complete home and industrial automation. With its

monitoring features, it can be used in number of applications

such as temperature control, parking lot automation and

hence can make life simpler and comfortable. Zigbee uses

very low battery power and hence it can last for years.

VII. REFERENCES

[1] IEEE std. 802.15.4, “Wireless Medium Access Control (MAC) and

Physical Layer (PHY) Specification for Low-Rate Wireless Peronal Area

Network,” october 1, 2003.

[2] L. Shizhuang, L. Jingyu, F. Yanjun, “ ZigBee Based Wireless Sensor

Networks and Its Applications in Industry,” IEEE International Conference

on Automation and Logistics, pp.1979 -1983, 2007.

[3] L.F. Akyildiz, W. Su, Y. Sankarasubramaniam, E. Cayirci, “Wireless

Sensor Networks: A Survey,” Computer Network, vol. 38, pp. 393-422,

2002. [4] B. Yan-li, C. Qiao-lin, W. Fang, “Improved ZigBee Network Routing

Algorithm,” Engineering and applications of computer, 2009.

[5] S. Zheng, Z. Xiao-Guang, R. Dianxu Ruan, P. Hui Li, Xun, “A Routing

Protocol based on Flooding and AODV in the ZigBee Network,” Intelligent

Systems and Applications, pp.1-4, May 2009.

[6] A. Lubna, E. Ali and R. Aiyappa, “Scalability Analysis for wireless

sensor networks Routing Protocols,” AINAW, 22nd international

conference, pp. 139-144, March 2008.