A LR-WPAN is a simple, low-cost communication network that allows wireless connectivity in applications
with limited power and relaxed throughput requirements. The main objectives of an LR-WPAN are ease of
installation, reliable data transfer, short-range operation, extremely low cost, and a reasonable battery life,
while maintaining a simple and flexible protocol.
Some of the characteristics of an LR-WPAN are
— Over-the-air data rates of 250 kb/s, 40 kb/s, and 20 kb/s
— Star or peer-to-peer operation
— Allocated 16 bit short or 64 bit extended addresses
— Allocation of guaranteed time slots (GTSs)
— Carrier sense multiple access with collision avoidance (CSMA-CA) channel access
— Fully acknowledged protocol for transfer reliability
— Low power consumption
— Energy detection (ED)
— Link quality indication (LQI)
— 16 channels in the 2450 MHz band, 10 channels in the 915 MHz band, and 1 channel in the 868 MHz
band
Two different device types can participate in an LR-WPAN network; a full-function device (FFD) and a
reduced-function device (RFD). The FFD can operate in three modes serving as a personal area network
(PAN) coordinator, a coordinator, or a device. An FFD can talk to RFDs or other FFDs, while an RFD can
talk only to an FFD. An RFD is intended for applications that are extremely simple, such as a light switch or
a passive infrared sensor; they do not have the need to send large amounts of data and may only associate
with a single FFD at a time. Consequently, the RFD can be implemented using minimal resources and mem-
ory capacity.
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