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IDEAS.TXT
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1995-06-08
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IDEAS.txt 7.0 OTHER SUGGESTED IDEAS FOR SOFTWARE WRITERS!
Don't let me have all the fun. There are lots of additional utilities and
other neat applications for APRS waiting to be written! Please consider
taking one of these on...
WIDE-N UNIVERSAL DIGIPEAT MODE!
This may be the simplest mechanism for making an order of magnitude
improvement in APRS status and position reporting networks. In a WIDE-N
network, each WIDE digi simply repeats ANY packet with the VIA address of
WIDE-N; but ONLY ONCE. It subtracts 1 from the SSID and then keeps a
copy of the last 30 seconds of packets (or just a checksum of each one),
and compares each new packet that it hears with the LAST ones that it
digipeated. This way it avoids TRANSMITting it again! This simple
algorithm could develop into the ULTIMATE GENERIC MOBILE GPS NETWORK!
Mobiles traveling within a 100 mile radius of home could simply set a
path of UNPROTO APRS VIA WIDE-3 without fear of clogging the network!
This WIDE-N ROM would not have to do anything else! For more details
see DIGIS.TXT.
LEVEL FOUR UI FRAME ROUTING! (this idea IS OBE if the WIDE-N idea works)
For people with the ability to write code for TAPR-2 clones, there is
a real nead for LEVEL-4 distribution of APRS UI frames through a network.
Rather than using dumb digipeaters with the generic RELAY and WIDE callsigns,
the level-4 network should only need the single NODE-NAME of the HOME
or DESTINATION node for APRS UI frames. The network should know the routing
and paths to use to deliver the UI frame to that destination node. There,
the UI frame is transmitted ONCE (or maybe twice some time later) as if it
had been originated locally.
Since APRS UI position reports are redundant, and rapidly become obsolete
as they are refreshed by a moving station, the level-4 NETWORK only has to
make a feeble attempt to route the packets to the desired destination HOME
node. They need not clutter the Nodes buffers, and can be time-ed out
rather quickly. For more thoughts on this subject, read the DIGIPTR.txt file.
PRE-EMPTIVE DIGIPEATING (this idea may be OBE if the "ALL"net idea works)
Until we get level-four routing of UI frames, it shuld be possible to
modify TNC code for pre-emptive digipeating. This means that a digipeater
will look for its callsign ANYWHERE in the digi-calls list in a packet header
and if it finds itself, it will go ahead and digipeat the packet and cancel
all of the earlier digipeat bits. This way a mobile only has to provide
a list of DIGI calls in the fartherest sequence that he may travel, and his
packets will all arrive at the last one in the list, no matter where along
the string he is located! See more in the DIGIPTR.txt file.
AUTODF NETWORK
Now, if you make an "ALL"net ROM for TNC digipeaters, then there should
be plenty of room for adding the A/D routine to take the LIMITER current from
a DF receiver at the same site, and converting that to a signal strength
value. Then transmitting that report in an APRS OMNI-SIGNAL-STRENGTH DF
report. This way, each APRS ALL digipeater site, could also be used as
an OMNI-DF site for reporting DF signal strengths. See the README\DF.txt
file for details!
CALLSIGN and POSITION DATABASE NETWORK SERVER
Since APRS includes the single station QUERY format for requesting a
station to respond with his position report, there is no reason why any PC
interfaced with the HAMCALL CD ROM could not listen for such QUERYS, and
respond with a properly formatted APRS POSITION report for that station!
The APRS station sending the single UI frame QUERY gets rewarded by seeing
the location of the requested station SHOW UP ON HIS MAP! The database PC
would of-course wait about 30 seconds to be sure the requested call is not
LOCAL and then respond with an APRS OBJECT position report, which would
include the station's name and address!
ALL FUTURE TNC BEACON CODE:
For future designs, the LOCATION TEXT and BEACON TEXT timing periods
should be 1 minute for manual entries, but the LText UI frame should be sent
out ONCE everytime a new manual entry is made. The ultimate objective for
all UI beacons should be to have the optional APRS DECAYING time period
algorithm built into all TNC's. With the DECAY option, each new manual
entry of BText or LText will force a UI frame immediately, 15 sec later,
30 after that, 60 after that, 2 mins, then 4 mins, then 8 mins and so on
to N minutes, and stay at N minutes forever. This way, new UI information
is transmitted immediately to all stations on the net, but old beacons soon
fade away. The minimum value of N for the DECAY option would be about 10
minutes with a default of 60. One other addition to complete the APRS
philosophy, is to have the TNC respond with both its LText and BText
randomly within one minute of seeing an APRS query; a UI frame to the
address of APRS with the text field set equal to ?APRS?. This way,
stations could drop back to a decayed beacon rate of once every 4 hours or
so, but still would pop up on an APRS map if requested.