I'm not sure that we can quantify ARQ vs. broadcast. One thing which has been over looked is that we think of ARQ as sending a "packet(s)" and the receiving station sends an ACK. If however each packet is numbered and contains a CRC number, then if the receiving station misses a packet (missing number) or does not resolve the CRC number, only then does it transmit and that is a NAK.
In this condition, you could broadcast and only provide fills to those stations for specific packets. If two stations missed the packet, then if the re-transmission to one stations is copied by the second stations...so only one retransmission per packet would be needed even is several stations missed the same packet. ACK is out...NAK is in. Combine varying levels of FEC with ARQ NAKs will increase error free information without utilizing a lot of time with retransmissions. Walt/K5YFW -----Original Message----- From: digitalradio@yahoogroups.com [mailto:[EMAIL PROTECTED] Sent: Wednesday, August 23, 2006 8:17 PM To: digitalradio@yahoogroups.com Subject: RE: [digitalradio] The digital throughput challenge on HF At 04:29 PM 8/23/2006, you wrote: >It in deed would. That is the reason Pactor and Amtor >work so well. It's the AQR - even with the hi S/N needed. There is some value to ARQ, I wonder how we would quantify the advantage? In a point to point link I think it would be easy, but in a point to multipoint network, I think the value is significantly diminished. From an efficiency standpoint, broadcast modes like soundcard modes are very efficient. Point to point modes can be very reliable and very accurate, but very inefficient. I am not sure how one quantifies these differences. When it comes to speed and or throughput, we have the bandwidth, power, and coding barrier with which we much deal. 73, Mark N5RFX Need a Digital mode QSO? Connect to Telnet://cluster.dynalias.org Other areas of interest: The MixW Reflector : http://groups.yahoo.com/group/themixwgroup/ DigiPol: http://groups.yahoo.com/group/Digipol (band plan policy discussion) Yahoo! Groups Links Need a Digital mode QSO? Connect to Telnet://cluster.dynalias.org Other areas of interest: The MixW Reflector : http://groups.yahoo.com/group/themixwgroup/ DigiPol: http://groups.yahoo.com/group/Digipol (band plan policy discussion) Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/digitalradio/ <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
