RF-Link Technology NL6000 manual Over-the-Air Data Rates, Acknowledgements

Best Choice: Mobile Data Mode

Because you expect a corrupt channel, use the mode that has the greatest amount of error control. Mobile Data mode includes three types of error control, Reed-Solomon forward error correction, error detection, and a block interleaver. This mode provides for maximum transmission reliability on a corrupt channel. Since the packet size is large, any data added to the packet to fill the interleaver is insignificant.

Because you are more likely to recover from transmission errors with Mobile Data mode, you can use a large Maximum Packet Size. A larger packet size can compensate for the lower percentage of user data in each packet and provide good throughput on a corrupt channel.

Why not use Basic Telemetry Mode for this scenario? Basic Telemetry mode is not useful when you expect a corrupt channel because it uses error detection only. Basic Telemetry mode cannot recover data errors, so throughput would be poor.

Why not use Enhanced Telemetry Mode for this scenario? Enhanced Telemetry mode provides error correction, but if both the signal strength and path are poor, you might need to reduce the Maximum Packet Size to increase reliability. With Mobile Data mode you can increase the Maximum Packet Size and get better throughput on a very corrupt channel.

5.6.2.Maximum Packet Size

The NL6000 transmits a data packet on the radio channel when the amount of data in the input buffer is equal to the Maximum Packet Size or when there is a timeout on the serial port. The maximum packet size is the largest amount of user data in one RF packet.

5.6.3.Over-the-Air Data Rates

The NL6000 supports two over the air data rates: 12,000 bps or 22,050 bps. Select the data rate you want to use depending upon the bandwidth you occupy and your license.

5.6.4.Acknowledgements

The NL6000 can request an acknowledgement (ACK) from the destination modem with each transmission. If this option is enabled, the unit will retransmit a packet up to a specified number of times if it does not receive an ACK. If it does not receive an ACK after the final retry, the unit will transmit the next packet. You specify the desired maximum number of retries with the Max Retries option.

Note: When acting as a repeater, the unit never generates an ACK. ACKs are end-to-end and do not affect the repeater unit.

RF Neulink 24 NL6000 User Guide