ZigBee Today

In comparison to 802.11 devices which seek to provide Ethernet speeds (11-104Mbps) and long range (100-300ft), ZigBee devices are concerned with long battery life and the area directly around the user or the central unit (20ft). ZigBee devices also provide automatic network routing with intelligent mesh networks, and modern security capabilities.

The ZigBee Alliance released version 1.0 of the standard in late 2004 and as of 2005 the cost of a mass produced radio was down to $1.10 per unit. Many manufacturers provide a wide variety of OEM radios for different applications with devices generally being very small like the unit below, Figure 1.

Being a relatively new player in the wireless field, ZigBee must compete with more accepted protocols such as Bluetooth, GPRS/GSM, and Wi-Fi (802.11). ZigBee does provide some unique capabilities which open up applications unavailable to the more mainstream protocols mentioned. Table 1, below provides a simple comparison of these protocols.

Market Name	ZigBee 802.15.4	GPRS/GSM 1xRTT/CDMA	WiFi ™ 802.11b	Bluetooth ™ 802.15.1
Application Focus:	Monitoring & Control	Wide Area Voice & Data	Web, Email, Video	Temporary Data Exchange
System Resources:	4KB - 32KB	16MB+	1MB+	250KB+
Battery Life (days):	100 - 1,000+	1-7	less than 5	1 - 7
Network Size:	2⁶⁴	1	32	7
Data Rate:	20 kbits/s 40 kbits/s 250kbits/s	64 – 128kbits/s	11 Mbits/s 54 Mbits/s	1 Mbits/s
Transmission Range (meters):	1-20 (typical – further through automatic repeating)	1,000+	100	10
Success Metrics:	Reliability, Power, Cost	Reach, Quality	Speed, Flexibility	Cost, Convenience

Table 1 - Comparison of ZigBee an competing wireless procotols

The ZigBee Alliance has exceeded 150 members and includes companies that produce the chips, produce oem radios, and produce final products. Because of the competing protocols, ZigBee must find its own market. According to the ZigBee Alliance three areas have been identified as primary target "Initial markets":

Home Automation and Building Automation are relatively similar with the major difference being the scale of the automation. Home Automation is aimed at the domestic market (i.e. Homes) while Building Automation would be targeted at commercial structures. An example of home automation follows, Figure 2:

Because of it's central location and direct power connection, we might assign light fixture B to be the network coordinator. We can also notice that all of the network routers (any node that is not an end point) are devices traditionally connected to constant power: A, F, G, H, J, D, E are all light fixtures; C is a smoke detector with battery backup; and K is an HVAC unit. Units b and d might represent battery powered light switches, portable or not. Although this image only represents communications links, it graphically illustrates the variety of devices that could interact through ZigBee. Even though light fixture B has no control over HVAC, ZigBee compliance allows it to route commands to and feedback from the unit. It even allows the router to build an alternate route for backup usage. A link somewhere in the network to a PC (or network appliance) could allow remote monitoring and control of all home systems, scheduled tasks, security alerts, notification of emergency services, etc.
Building Automation would simply be Home Automation scaled up. Security systems, sprinklers, as well as environmental controls could all be centrally (or remotely) monitored and controlled. The ZigBee Alliance proposes that all lights in a building be ZigBee controlled. This would allow workspace lighting to be quickly reassigned as modular offices are reshaped within the building. Similarly, distributed sensors would allow more intelligent control of smarter HVAC systems, conserving energy.

Industrial Automation proposes ZigBee connected sensors and controllers throughout the manufacturing process - monitoring and streamlining the lines. Similarly, asset tracking would be much more intelligent. With the added positioning capabilities of IEEE 802.15.4-2006, assets would no longer have just a serial number, but know when they are in motion and where to.

Besides these three "Initial Markets," manufacturers are producing many other ZigBee powered solutions. CrossBow Technologies, for one, produces tiny motes which combine ZigBee communications with onboard sensors and a programmable microcontroller. Similar devices can be used to monitor rainfall, triangulate the position of a hostile shooter, etc. Other companies are developing wearable computers with ZigBee enabled accessories. One such possibility would be manual asset tracking in a large warehouse. Instead of using a laptop with corded barcode scanner an employee might use a wearable computer with ZigBee enable barcode scanner.

Team C2J

Team C²J