Technical Specs

Physical Layer
RMEs use the communication module in a manner that is compliant with the IEEE 802.15.4g PHY standard. The following PHY
parameters are determined by the capabilities of the hardware:
• 902-to-928 MHz ISM band, with 64 non-overlapping channels, 400 kHz spacing and 150kbps data rate for 2-FSK;
CGM-WPAN-OFDM supports 2-FSK with 200 kHz channel spacing and 50kbps data rates with 129 channels.
• OFDM Option 2 802.15.4g. Frequency hopping between up to quantity 31 800 kHz channels, PHY data rates of 50 kbps, 200
kbps, 400kpbs,800 kbps and 1200kbps
• BFSK modulation
• Forward Error Correction (FEC) with Interleaving
• 150 kbaud data rate, 75 bit rate due to FEC
See Physical-Layer Specifications, on page 10 for interface default values and default frequencies for each channel.
Media Access Control (MAC) Layer
RMEs implement a proprietary Media Access Control (MAC) layer that utilizes the enhanced frame formats specified by IEEE
802.15.4e-2012 and IEEE 802-15.4g-2012.
Network Discovery
Enhanced Beacon (EB) messages allow communication modules to discover PANs that they can join. RMEs also use EB messages
that disseminate useful PAN information to devices that are in the process of joining the PAN. Joining nodes are nodes that have not
yet been granted access to the PAN. As such, joining nodes cannot communicate IPv6 datagrams with neighboring devices. The EB
message is the only message sent in the clear that can provide useful information to joining nodes. CGRs drive the dissemination
process for all PAN-wide information.
Joining devices also use the RSSI value of the received EB message to determine if a neighbor is likely to provide a good link. The
transceiver hardware provides the RSSI value. Neighbors that have an RSSI value below the minimum threshold during the course
of receiving EB messages, are not considered for PAN access requests.
Frame Formats
RMEs support the enhanced frame formats, specified by IEEE 802.15.4e-2012 and IEEE 802-15.4g-2012, that allow link frames to
carry the following information:
• Frequency hopping synchronization
• Security capabilities in EB frames
• Received Signal Strength Indication (RSSI) information in acknowledgments for bi-directional link quality estimation
In addition, RMEs use secure, enhanced acknowledgment frames which are the same security mechanisms used to secure data frames.
Link-layer Access Control
RMEs implement link-layer access control mechanisms that follow the functionality defined by the IEEE 802.1X standard for node
authentication.
• Admitting nodes—The access control mechanism follows the concepts established by 802.1X for mutual authentication and
802.11i for group key management. RMEs use certificate-based EAP-TLS to perform mutual authentication with an AAA server.
RMEs implement the supplicant, and the CGR implements the authenticator. RMEs use a stateless EAP proxy that forwards
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