MiWi Wireless Networking Protocol Stack

AN1066 MiWi™ Wireless Networking Protocol Stack CONSIDERATIONS Author: David Flowers and Yifeng Yang Microchip Technology Inc. A network using the MiWi protocol is capable of having a maximum of 1024 nodes on a network. Each coordi- nator is only capable of having 127 children, with a INTRODUCTION maximum of 8 coordinators in a network. Packets can travel a maximum of 4 hops in the network and 2 hopsImplementing applications with wireless networking is maximum from the PAN coordinator. becoming commonplace. From consumer devices to industrial applications, there is a growing expectation If, after reading this application note, you determine that our devices will have built-in the ability to talk to that you require a standardized wireless platform, each other without a hard-wired connection. The chal- larger network sizes or common marketing logos, lenge is to select the right wireless networking protocol AN965, "Theplease refer to Microchip application note and implement it in a cost-effective manner. (DS00965).Microchip Stack for the ZigBee™ Protocol" Alternatively, users may wish to consider using theThe MiWi™ Wireless Networking Protocol is a simple basic MiWi protocol and modifying it to suit their ownprotocol designed for low data rate, short distance, applications.low-cost networks. Fundamentally based on IEEE 802.15.4™ for wireless personal area networks For the most up-to-date list of limitations of the Stack, (WPANs), the MiWi protocol provides an easy-to-use please refer to the Readme file located with the Stack alternative for wireless communication. In particular, it download. targets smaller applications that have relatively small network sizes, with few hops between nodes, using TERMINOLOGY Microchip's MRF24J40 2.4 GHz transceiver for IEEE 802.15.4 compliant networks. In describing the MiWi protocol, two specific terms are This application note covers the definition of the MiWi used throughout that are borrowed from the IEEE Wireless Networking Protocol Stack and how it works. standard. The example Stack implementation data structures, The first term is cluster, which refers to a grouping of usage and APIs are covered in this document, as well nodes that form a network. A MiWi protocol cluster can as resource requirements for this implementation. For be up to 3 nodes deep and is controlled by a cluster- completeness, the document also introduces several head. In the current implementation of the MiWi protocol, aspects of wireless networking, as well as key features the cluster-head is always the PAN coordinator. (For of IEEE 802.15.4. However, it is assumed that the user further information, see Table 3 on page 2.) is already familiar with the C programming language The second term is socket, which refers to a virtual and IEEE 802.15.4. You are strongly advised to read connection between two devices. Rather than have an the specification in detail prior to using the Microchip exclusive hard-wired connection between devices, MiWi Wireless Networking Protocol Stack. many devices with many types of sockets share a common communications medium and use some FEATURES common method to associate applications and devices. When a new device or application is added to The current implementation of the MiWi protocol