|
D-Star Data and Throughput |
|
|
|
|
Written by K7VE
|
|
Monday, 11 June 2007 |
D-Star Data and ThroughputSome have commented that D-STAR cannot support EMCOMM data throughput requirments. I believe this is a just an artifact of viewing D-STAR narrowly through the Icom implementation.
There is more to the story:
I have been pondering the discussion about the D-STAR/P25/Packet data moving capability and throughput. I was looking over the format of the DV (Digital Voice - Format) and DD (Digital Data - Format) under the D-STAR protocol. It appears to me that there is nothing in the protocol to prevent someone from implementing a DD system that uses the 6.25 kHz. channel and dedicate the entire data stream to data rather than DV. If Icom has designed their UHF/VHF repeaters or the associated controller so that it will not pass a 6.25 kHz./4800 baud DD data stream then it is merely a design flaw that could be fixed with a firmware upgrade. The issue then is to build a radio that formats DD packets using using GMSK on VHF/UHF -- this would be a much simpler design than the current D-STAR radios that are being built with the AMBE2020 chips to handle the DV. Furthermore, I believe (and I'm no expert on GMSK) that to get higher speeds and throughput would only require higher data rate GMSK modulation with its accompanying increased bandwidth up or down to any required data rate. D-STAR does not equal Icom's implementation and Icom's implementation does not equal D-STAR. As was demonstrated at Dayton, a D-STAR radio can be built using readily available components and some associated software/firmware. Let's think about the protocol in terms of how it can be applied and work with those who have the skills to design the hardware / software / firmware to implement the types of networks we need. I can't wait for the open source designs to start appearing on http://opendstar.org/... |
|
Last Updated ( Monday, 11 June 2007 )
|
