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10 Wireless Technology
10.1 Wireless Technology Overview
The LiNX control system uses Bluetooth wireless technology. Bluetooth is a wireless communications system that is designed to
operate in short-range wireless personal area networks (WPAN).
LiNX supports both the Smart (low energy) and Classic Bluetooth protocols. These operate in the spectrum range 2.400 GHz to
2.4835 GHz industrial, scientific and medical (ISM) band. Bluetooth Classic uses 79 x 1 MHz channels, and Bluetooth Smart uses 40 x
2 MHz channels.
Within a channel, data is transmitted using Gaussian frequency shift modulation. The bit rate is 1Mbit/s, and the maximum transmit
power is 5mW. Both Bluetooth protocols use frequency hopping to counteract narrowband interference problems.
Technical Specification
Classic Bluetooth
Smart (Low Energy) Bluetooth
Class
Class 2
Distance/Range
(theoretical maximum)
10 m (33 ft)
Over the Air Data Rate
1-3 Mbit/s
1 Mbit/s
Application Throughput
0.7-2.1 Mbit/s
0.27 Mbit/s
Security
56/128-bit and application layer
user defined
128-bit AES with Counter Mode CBCMAC and application layer
user defined
Robustness
Adaptive fast frequency
hopping, FEC, fast ACK
Adaptive frequency hopping, Lazy Acknowledgment, 24-bit CRC,
32-bit Message Integrity Check
Latency (from a non-
connected state)
Typically 100 ms
6 ms
Network Topology
Scatternet
Power Consumption
5 mW
Service Discovery
Yes
Profile Concept
Yes
Bluetooth Technology Specifications
10.2 Intended Wireless (Electromagnetic) Environment
The intended environments for the LiNX wheelchair are defined as the user's home, assisted living facilities, nursing homes,
vocational settings and healthcare facilities. Across these environments, numerous medical and non-medical equipment items also
operate wirelessly.
10.3 LiNX Wireless Functions
The LiNX control system functions that use Bluetooth include:
l
Remote diagnostics
—provides status information of the powered wheelchair (battery status, fault conditions etc.).
l
Configuration
—allows a trained provider, dealer, therapist or clinician using the programming and diagnostic tools to configure
the LiNX control system.
10.3.1 Remote Diagnostics
The system transmits wheelchair-specific diagnostic information to an Apple iOS device. This information helps with the technical
support of the wheelchair.
The information provides the status of the wheelchair electronics, including:
LiNX® Control System