Implementing An IEEE 802.15.4/ZigBee-Compliant RF Solution
Considerations of technology and integration level
By Svein Anders Tunheim, CTO
Chipcon AS
Abstract
The reduction of unit costs and power consumption are the driving forces behind new RFIC developments for short-range wireless communication systems. Cost-effective CMOS technology used in combination with highly integrated receiver and transmitter architectures is the key to satisfying these demands. CMOS technology also enables development of true system-on-chips (SoCs) for wireless communication. For those markets addressed by IEEE 802.15.4/ZigBee (i.e. wireless monitoring and control), SoCs are expected to become increasingly important. A clear trend in the market is also the need for chip vendors to provide complete solutions -- proven platforms of hardware and software on which the system developer directly can build the applications. With ZigBee, this is now possible.
Introduction
The market for IEEE 802.15.4/ZigBee-based low-power, short-range wireless sensor and control technology is expected to experience explosive growth during the coming years. The typical applications are home and building automation, industrial control and monitoring, automatic meter reading (AMR), and alarm/security. Products within these types of wireless applications are generally extremely price sensitive, and since many systems are battery operated, there is a stringent demand on low power dissipation to extend battery lifetime. Small physical size is also important. Together, these requirements increase the focus on highly integrated RFIC implementations and the use of cost efficient technology.
CMOS is a very attractive technology for RFIC development, due to its low production costs and the possibility for designing highly integrated solutions. Of utmost importance for IEEE 802.15.4/ZigBee-based systems is the possibility to implement true SoCs -- singl- chip solutions containing the RF transceiver, microcontroller, memory (RAM/Flash), and peripheral modules.
This article focuses on trends and challenges in the development of RFICs for low data rate, low power, and short range communication systems with emphasis on IEEE 802.15.4/ZigBee-based systems. Chapter 2 in this article provides a brief overview of ZigBee and IEEE 802.15.4. In Chapter 3 the advantages of CMOS technology are briefly described, and Chapter 4 gives an overview of highly integrated radio receiver/transmitter architectures suitable for low power and low cost RFICs. Chapter 5 includes considerations about hardware/software system partitioning and SoCs. Following this, Chapter 6 gives an example of the implementation of an IEEE 802.15.4 and ZigBee-ready 2.4 GHz RF transceiver, and finally, in Chapter 7, the article provides some thoughts on future developments/trends.
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