Software defined modem example

Table of Contents Compile Configuration file Enable SDM mode Run Configure SDM modem parameters Configure SDM reference signal SDM signal reception SDM signal transmission SDM communication example

Compile

Go to the directory with checked out evins and run:

make

Configuration file

In the example below is assumed, that you have two SDM EvoLogics modems with IP addresses 192.168.0.178 and 192.168.0.179.

Create configuration file /usr/local/etc/fsm.conf:

{module, m1, [{role, sdmcli, iface, {socket, "0.0.0.0", 7001, server}},
             {role, sdm, iface, {socket, "192.168.0.137", 4200, client}},
             {mfa, mod_sdm, run, []}]}.
{module, m2, [{role, sdmcli, iface, {socket, "0.0.0.0", 7002, server}},
             {role, sdm, iface, {socket, "192.168.0.138", 4200, client}},
             {mfa, mod_sdm, run, []}]}.

Enable SDM mode

Switch the modem to SDM mode by sending ATP command on both the modems:

> nc 192.168.0.137 9200
ATP
INITIATION PHY
AT?S
Local Address: 2
Remote Address: 0
Acoustic Link Status: PHY
Pool Status: 0 packages, 16384 bytes free
Promiscuous Mode: ON

Run

Go to the directory with checked out **evins** and run:

_rel/evins/bin/evins console 

in two another terminal windows run:

> nc localhost 7001

and

> nc localhost 7002

Configure SDM modem parameters

config_dsp,<threshold>,<gain>,<source_level>

Example:

> nc localhost 7001
config,300,0,3
report,config,1

Configure SDM reference signal

ref,<path>

where path is a path to the reference file, 1024 lines of short integer values in text file. Example

nc localhost 7001
ref,/tmp/ref
report,ref,1024

SDM signal reception

rx,<samples>,<path>

where samples is a number of samples to be stored at path file after reference signal triggering

> nc localhost 7001
rx,10000,/tmp/rx

On successful reception:

> nc localhost 7001
rx,10000,/tmp/rx
rx
stop

you will get the file with at least 10240 samples (reception is done 1024 samples per block):

wc /tmp/rx
10240 10240 48530 /tmp/rx

SDM signal transmission

Transmission signal must be generated as a sequence of short integer samples, one sample per line. Transmission signal must begin with the signal, that is used as a reference on the reception side. For transmission use the command:

tx,<path>

Example:

nc localhost 7001
tx,/tmp/tx
report,tx,10240

SDM communication example

> nc localhost 7001 ref,/tmp/ref report,ref,1024 config,300,0,3 report,config,1 tx,/tmp/tx report,tx,10240

> nc localhost 7002 ref,/tmp/ref report,ref,1024 config,300,0,3 report,config,1 rx,10000,/tmp/rx rx stop