This standard was developed for low-rate WPAN. It was designed to address the following needs in residential and industrial environment.
- Low data rate,
- Low power consumption,
- Low cost wireless networking among inexpensive, fixed, portable and moving devices.
It supports one-hop star and multi-hop peer-to-peer topologies. Among applications that benefit from this standard are automation and control in homes, factories and warehouses, monitoring for public safety, health and environment, and entertainment.
802.15.4 Physical Layer (PHY)
There are 14 PHY primitives with 2 PHY options based on direct sequence spread spectrum (DSSS) methods:- 2.4 GHz PHY operates in the ISM band with data rate of 250 kbps,
- 868/915 MHz PHY operates in 868 MHz band in Europe; 915 MHz ISM band in the USA with data rates of 20 kbps and 40 kbps, respectively.
It supports one-hop star and multi-hop peer-to-peer topologies. There are 2 types of devices: full function device (FFD) and reduced function device (RFD). FFD is required to support all 45 MAC primitives and can function in any topology. It can talk to RFDs and FFDs.
RFD is required to support 38 MAC primitives under minimal configuration. It is limited to star topology and can only talk to FFD. It is meant for very simple apps. It cannot act as network coordinator.
A network requires at least one FFD as a network coordinator. FFD operates in one of 3 modes: PAN coordinator, router or device. The transmission range between 10 – 20 m.
