A Review paper on History, Current trends and Future of Zigbee (IEEE ) Standard

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1 International Journal of Advances in Engineering Science and Technology and ISSN: A Review paper on History, Current trends and Future of Zigbee (IEEE ) Standard Parneet Dhillon, Pooja Malhotra Department of computer science and engineering RIMT-IET, Mandi-Gobindgarh Punjab technical university Parneet.dhillon7@gmail.com Abstract- Zigbee is specification formalized by IEEE standard for low power low cost low data rate wireless PAN..Zigbee communication is a communication technology to connect local wireless nodes and high stability and transfer rate due to data communication with low power. The wireless communication technologies are rapidly spreading to many new areas, including the automation and the importance of the use of wireless technologies in data-acquisition, building control, monitoring systems and automation of manufacturing processes will grow. From the existing wireless standard seems very promising the new international standard ZigBee. This paper aims at providing the concept of ZigBee and various research work that has been done on it by various researchers and various challenges that people are facing while deploying this technology. Keywords-Sensor Networks;Zigbee;Mobile coordinator 1. Introduction A Wireless sensor network(wsn) comprises of spatially distributed devices also known as wireless sensor nodes at the bottommost layer.these sensor nodes are battery powered devices consuming very low power.data is routed from these devices to the gateway by the subsystem on the top of these devices.these sensor nodes can act both as a full functional device and reduced functional device.but one of the major issue in wireless sensor networks is the hot-spot i.e all the FFD s connected to the coordinator are responsible for sending the data to the coordinator on the behalf of nodes connected to them.so these nodes consume more power and die out munch earlier as compared to other nodes which breaks the connection with the entire network.in order to overcome the hot-spot problem,using the mobile coordinator is the best solution. 2. Zigbee and IEEE ZigBee is developed by ZigBee alliance, which has hundreds of member companies (Ember, Freescale, Chipcon, Invensys, Mitsubishi, CompXs, AMI Semiconductors, ENQ Semi conductors), from semiconductor and software developers to original equipment manufacturers. ZigBee and are not the same. ZigBee is a standard based network protocol supported solely by the ZigBee alliance that uses the transport services of the IEEE network specification. ZigBee alliance is responsible for ZigBee standard and IEEE is for IEEE It is like TCP/IP using IEEE b network specification. ZigBee alliance (software) defines the network, security and application layers. IEEE (hardware) defines the physical and media access control

2 IJAEST, Volume 2, Number 3 Parneet Dhillon and Pooja Malhotra layers for LR-WPAN. Power needed for ZigBee is very small. In most cases it uses 1mW (or less power). But still it provides range up to 150 meters in outdoor which is achieved by the technique called Direct Sequence Spread Spectrum (DSSS). Also DSSS consumes less power compared to Frequency Hopping Spread Spectrum (FHSS). It works in the 868 MHz (Europe), 915 MHz (North America and Australia) and 2.4 GHz (available worldwide) ISM band with up to 20kbps, 40kbps and 250kbps data rate respectively. Because these wave bands are different from the bands of current common wireless networks, Wireless Fidelity (Wi-Fi), Bluetooth, Wireless USB etc. Mutual interferences between them will not occur, therefore, this guarantees our system will not interfere other wireless networks and will not be affected as well.the IEEE standard employs 64-bit and 16-bit short addresses to support theoretically more than 65,000 nodes per network. ZigBee network can have up to devices, the distance between ZigBee devices can be up to 50 meters, and each node can relay data to other nodes. This leads capability of making a very big network which covering significant distances. Based on data processing capabilities, two types of physical devices are provided in IEEE : Full Function Devices (FFD) and Reduced Function Devices (RFD). Full Function Devices can perform all available

3 A Review paper on History, Current trends and Future of Zigbee (IEEE ) Standard 295 operations within the standard, including routing mechanism, coordination tasks and sensing task. The FFD plays role of coordinator or router or end devices (It can be either FFD or RFD depends on its intended application). A typical FFD in a ZigBee network will be powered from an AC-fed main supply, as it must always be active and listening to the network. Reduced Function Devices, on the other hand, implements a limited version of the IEEE protocol. The RFDs do not route packets and must be associated with an FFD. These are end devices such as sensors actuators which only doing limited tasks like recording temperature data, monitoring lighting condition or controlling external devices. The current ZigBee standard requires FFDs to be always on, which in practice means that FFDs must be constantly powered. Battery-powered FFDs have a lifetime on the order of a few days. There are three categories of nodes in a ZigBee system. Coordinators, Routers and End devices.coordinator sets up all the network parameter for eg topology,packet size etc.it is the gateway for the outside world to interact with the network.zigbee route is an intermediate device in a network which routes the data from the source to the destination.these devices route the data as well as sense the data from their surrounding environments.end device can be low-power /battery-powered devices.they have the least computing capability.they can collect various information from sensors and switches. They have sufficient functionality to talk to their parents (either the coordinator or a router) and cannot relay data from other devices. This reduced functionality allows for the potential to reduce their cost. They support better low power models. These devices do not have to stay awake the whole time, while the devices belonging to the other two categories have to. Each end device can have up to 240 end nodes which are separate applications sharing the same radio. Access Modes: Two ways of multi-access in ZigBee protocol, are Beacon and Non-beacon. In non beacon enabled network, every node in the network can send the data when the channel is free. In beacon enabled network, nodes can only transmit in predetermined time slots. Here PAN coordinator allocates guaranteed time slots (GTS) for each device; therefore devices will transmit their data during their own slot. All devices should be synchronized for this process. This will be achieved by sending beacon signal. The coordinator is responsible to transmit beacon signals to synchronize the devices attached to it. Network in which the coordinator does not transmit beacon signal is known as non-beacon network. It cannot have GTS and contention free periods, because the devices are not synchronized. Battery life is better than beacon enabled network, because the devices are wake up less often. 2.1 Zigbee Applications Throughput of ZigBee is low rate of data transfer is about 250kbps. So this ZigBee system is useful for applications needs low data rate. Some of its applications are Home Automation and Control, Automatic Meter Reading, Residential & commercial utility systems, Building Automation, Personal health care, Body area networks, Fitness monitoring: home, gym, on-the-move, ZigBee Smart Energy, Hospital & institutional, Patient monitoring, Cable replacements, Automotive, In vehicle control: vehicular & entertainment, Status monitoring, Telecom Services. 2.2 Impact of Node Mobility and Node Heterogeneity

4 IJAEST, Volume 2, Number 3 Parneet Dhillon and Pooja Malhotra Routing in ZigBee network is exactly different from the routing in traditional MANET networks because the routing protocols or algorithms in MANET are mainly concerned about the node mobility while in ZigBee network Full Function Devices (FFD) can serve as network coordinators or network routers, Reduced Function Devices (RFD) can only associate and communicate with FFDs. Therefore, the node heterogeneity plays an important role in ZigBee network routing. Nia-Chang et al.(1) performed an extensive evaluation to study the impact of node heterogeneity on zigbee mesh network routing.the research was particularly focused to find out how different mixture of mobile ZigBee routers and mobile ZigBee end devices influences the performance of ZigBee mesh routing. The results indicate that the ZigBee mesh routing algorithm exhibits significant performance difference when the network is highly heterogenous. Routing performance in ZigBee network does degrade when the network comprises of an increasing number of ZigBee end devices. Moreover, the delivery ratio worsens when there are more instances of mobility in the network (in highly mobile scenarios. Moreover, comparing to AODV routing results, significant differences in routing performance have seen, when network nodes are not assumed to be equally capable. It has also revealed that the ZigBee end devices tend to perform worse than ZigBee routers in both sending and receiving packets, since the end devices incur much overhead in associating with new parents when there is network mobility. On the other hand, ZigBee routers typically suffer less packet loss when there are intensive amounts of mobility in the ZigBee network, yet the additional service overhead of ZigBee (such as association with children devices) still degrades the performance of ZigBee routers in almost all scenarios. With a major application of ZigBee standard in mobile nodes, the effect of the mobility of the nodes on the performance of ZigBee protocol is also a considerable research area. Jiasong Mu and Kaihua Liu [2] analyzed the effect of the node mobility and the change of the network dimension in Zigbee networks. The whole research was carried out by using a network evaluation tool called OPNET. The analysis was done by using various route finding strategies specified in the network layer standard in ZigBee, such that Suppress Route Discovery (SRD), Enable Route Discovery (ERD) and Force Route Discovery (FRD) with the change of node mobility and network dimensions. After the extensive simulations, it has found that although the forced routing made the network always find the shortest path, the FRD always had the worst performance in all the scenes. In the dynamic networks, ERD had the most efficiency because ERD and AODV has the same working principle and both are more suitable for the dynamic environments. As to the stable network, ERD and SRD had similar efficiency in the small ones. However, the SRD based on tree routing, required no memory cache. SRD also had the lowest network load when the scale of the network expanded. Whereas the ERD might do reduplicate routing due to the restricted memory space. The SRD was the best routing option for the stable networks and the ERD performed most efficient in the unstable networks. The effective positioning of the nodes in a ZigBee network is particularly important in improving the performance (e.g., throughput) of ZigBee networks. In the wireless sensor networks (WSN) the use of a mobile sink is often recommended as an effective defense against the so-called hot-spot phenomenon and the effects of mobile coordinator on the performance of the network need to be considered. Harsh Dhaka et al. [3] perform extensive evaluation, using OPNET Modeler, to study the impact of coordinator mobility on ZigBee mesh network. After the

5 A Review paper on History, Current trends and Future of Zigbee (IEEE ) Standard 297 intensive simulation, it has been indicated that by keeping the sink static gives the best performance. If a trajectory has to be chosen for other reasons, then the trajectory should give a considerable amount of time to each route that is the link route for a segment of the network. Otherwise(as in the case of Diagonal trajectory), the throughput is very low. The type of the trajectory along with the node density and the traffic are also major factors that decide the system performance. Choosing a random topology is among the means possible to prevent exceptionally low throughput. Having the routers placed within range for effective meshing gives sharper curves which are closer but even in this case, it is better to keep the sink static at a location from where each route has an access to the sink possible with minimum hops. In circumstances sink movement is necessary, clever selection of the trajectory is essential for best throughput. 2.3 Energy Consumption in Zigbee ZigBee was specifically designed for home applications and have some features like high latency due to the low power consumption. As mainly focused on the cheaper design and energy efficiency, the proper configuration of the zigbee nodes, proper selection routing method and placement topology plays an important role. A mixed routing strategy of AODV and Tree Routing is designed in the ZigBee specification. But there is no method designed to balance these two Routing modes in order to achieve better performance. Ran Peng et al. [4] realized the ZigBee protocol module to analyze the ZigBee network performance. According to the analysis, a strategy of ZigBee routing selection based on data services has been proposed. The simulation results show that such routing selection strategy has excellent network performance and low energy consumption. Additionally, the power control is not much considered in ZigBee Routing specification. But for the ad hoc wireless network application, power control is the most significant issue in ZigBee. So a power control strategy is also proposed to improve the ZigBee routing, the simulation results show that the proposed power control strategy will greatly balance the node energy, avoid that nodes use up all the battery power and die too early. Various Challenges to Deploy Zigbee Standard are- 1) An effective positioning of nodes is particularly important for improving the performance of zigbee networks as the mobility has large impact on the throughput of a zigbee network. 2) In a zigbee network a tree topology is often used to construct a wireless sensor network for data delivery applications.however delivery failures constantly occur in zigbee wireless applications due to node movements and network topology changes. 3) Very few of the teams that currently oversee the networks in industrial settings have extensive experience working with RF devices.this presents a significant obstacle to zigbee whichmeans that most of the wireless devices will have a level of automated intelligence embedded in them to enable easy commissioning and flexible use.addressing this challenge will require advanced planning to automate issues faced by the people who will actually have responsibility for installing the Zigbee application.

6 IJAEST, Volume 2, Number 3 Parneet Dhillon and Pooja Malhotra 4) The signal strength which is sent by coordinators cab be weekened as distance from it increases, causing communication with target nodes to become difficult and abuse of thewireless resources.therefore,it is difficult to perform stable and reliable wireless communuication with wide range nodes. 5) These challenges also include different development stages,early adopter imcomptibilities and the right direction to move forward between the zigbee alliance members. 6) Due to limited physical size,zigbee devices have limited battery energy supply,internal memory and processing capability.the use of Zigbee in industrial environments is not well document and hence this technology may be limited for residential automation system. Conclusion It is likely that Zigbee will increasingly play an important role in the future of computer and communication technology.the low cost allows the technology to be widely deployed in wireless control and monitoring applications,the low power-usage allows longer life with small batteries and the mesh networking provides high reliability and larger range.zigbee technology is very useful from the perspective of the security as the devices maintain a list of trusted devices within the network and frame integrity to protect data from being modified by parties without cryptographic keys.zigbee technology is designed to best suit these applications,for the reason that it enables reduced costs of development and very fast market adoption. References [1] Nia-Chiang Liang, Ping-Chieh Chen, Tony Sun, Guang Yang, Ling-Jyh Chen, and Mario Gerla, "Impact of Node Heterogeneity in ZigBee Mesh Networks." IEEE International Conference on Systems, Man and Cybernetics, p.p , October 2006, Taipei,Taiwan [2] ]Jiasong Mu and Kaihua Liu, "Effect of node mobility and network dimension to the Zigbee routing method." 6th International Conference Wireless Communications Networking and Mobile Computing (WiCOM), p.p. 1-5, September 2010, Tianjin, China. [3] Harsh Dhaka, Atishay Jain and Karun Verma, " Impact of Coordinator Mobility on the throughput in a Zigbee Mesh Networks." IEEE 2nd International Advance Computing Conference, p.p , June 2010, Patiala, India. [4] Chiung-Hsing Chen, Hung-Wei Lin, Yen-Sou Huang, Jwu Jenq Chen, "Power Management System Based on ZigBee." International Conference on Anti-Conterfeiting, Security and Identification (ASID), p.p. 1-5, August 2012, Kaohsiung, Taiwan. [5] Ran Peng, Sun Mao-heng, Zou You-min, "Zigbee Routing Selection Strategy Based on Data Services and Energy-balanced ZigBee Routing." IEEE Asia-Pacific Conference on Services Computing (APSCC'06), p.p , December 2006, Tongji, China. [6] Jianpo Li, Xuning Zhu, Ning Tang and Jisheng Sui, "Study on ZigBee Network Architecture and Routing Algorithm." 2nd International Conference on Signal Processing Systems (ICSPS), p.p , Vol. 2, May 2010, Jilin, China. [7] Jo Woon Chong, Ho Young Hwang, Chang Yong Jung, and Dan Keun Sung, "Analysis of Throughput and Energy Consumption in a ZigBee Network under the Presence of Bluetooth Interference." IEEE Global Telecommunications Conference (GLOBECOM), p.p , November 2007, Daejeon, Korea. [8] Muthu Ramya. C, Shanmugaraj. M, Prabhakaran. R, "STUDY ON ZIGBEE TECHNOLOGY." International Conference on Electronics Computer Technology (ICECT), p.p , Vol. 6, April 2011, Tiruchirappalli, India.