Changeset 384

Timestamp:

07/27/09 18:57:37 (15 years ago)

Author:

sriram

Message:

Adding the get_freq function which gets the new frequency from the cognitive engine

Files:

• vtcross/branches/sriram/dsa.py (modified) (8 diffs)

vtcross/branches/sriram/dsa.py

@@ -8 +8 @@
 from numpy import random
 import random, time, struct, sys, math
+from datetime import datetime
 
 # from current dir
@@ -31 +32 @@
 def main():
         print "inside main"
-        global n_rcvd, n_right,sync_status,mode,ch,traffic_flag,n_attempts
+        global n_rcvd, n_right,sync_status,mode,ch,traffic_flag,n_attempts,return_flag
         n_rcvd = 0
         n_right = 0
         n_attempts = 5
+        return_flag = 0
         def send_pkt(self, payload='', eof=False):
                 return self.txpath.send_pkt(payload, eof)
-
+        
+        def get_freq(hop_freq,probe_level,absent_time):
+
+                channel = int(random.choice([1,7,8,14]))
+                if channel < 8:
+                        hop_freq = float(1e6 * (462.5625+(channel-1)*0.025))#setting the centre freq frequency for sending packets
+                else:
+                        hop_freq = float(1e6 * (467.5625+(channel-8)*0.025))#setting the centre freq frequency for sending packets      
+
+                return channel,hop_freq #returning the channel number and hop frequency
+        
 
         def rx_callback(ok, payload):
@@ -129 +141 @@
         
         ############# Setting some default values for tx side of the block
-        options_tx.tx_freq = 470e6#462.5625e6
+        options_tx.tx_freq = 462.5625e6
         options_tx.samples_per_symbol =  2
         options_tx.modulation = 'dbpsk'
@@ -169 +181 @@
                 sys.exit(1)
         ############# Setting some default values for rx side of the block
-        options_rx.rx_freq = 470e6#462.5625e6 #setting default rx_freq value
+        options_rx.rx_freq = 462.5625e6 #setting default rx_freq value
         options_rx.samples_per_symbol =  2
         options_rx.modulation = 'dbpsk'
@@ -200 +212 @@
         global ch
         running = True
-    
+        ch_energy = tb.rxpath.probe.level() #setting initial value
+        hop_freq = options_tx.tx_freq #  = options_rx.rx_freq...same for tx and rx side
         while running:
-
 
                 ################################################sync mode####################################
                 if mode == "sync":
                         if sync_status != True:
-                                ch = int(random.choice([1,7,8,14]))
-                                if ch < 8:
-                                        hop_freq = float(1e6 * (462.5625+(ch-1)*0.025))#setting the centre freq frequency for sending packets
-                                else:
-                                        hop_freq = float(1e6 * (467.5625+(ch-8)*0.025))#setting the centre freq frequency for sending packets
-                        
-            
-                                tb.txpath.set_freq(hop_freq)
+                                
+                                if return_flag == 0:
+                                        ch,hop_freq = get_freq(hop_freq,ch_energy,0)
+                                else:
+                                        ch,hop_freq = get_freq(hop_freq,ch_energy,elapsed_time)
+                                        return_flag = 0
+
+                                tb.txpath.set_freq(hop_freq)
                                 tb.rxpath.set_freq(hop_freq)
-                        
-                                k = 0
-                                total_energy = 0 
-                                while k <  1:
-                                        ch_energy = tb.rxpath.probe.level() #check if primary user is present
-                                        total_energy = total_energy + ch_energy
-                                        k+=1
-                        
-                                avg_energy = total_energy/1
-                                print "printing hop frequency ",hop_freq,"and energy is ",avg_energy,"\n"
-                                if int(avg_energy) > 2e7: #if primary user is there then dont transmit on this channel
+                
+                                ch_energy = tb.rxpath.probe.level() #check if primary user is present
+                                
+                                print "printing hop frequency ",hop_freq,"and energy is ",ch_energy,"\n"
+                                if int(ch_energy) > 1.5e8: #if primary user is there then dont transmit on this channel
                                         #while 
                                         continue
                                         #print "present"
-                        
-                                nbytes = 5 #int(1e6 * .0003)
+                                
+                                nbytes = 5 #int(1e6 * .0003)
                                 pkt_size = 5
                                 n = 0
@@ -262 +268 @@
                                 traffic_flag = False
                                 sync_status="False"
+                                start_time = datetime.now() #measuring the time for which the primary user is away
         
                 ################################################end of sync mode####################################
@@ -297 +304 @@
                                 data_pktno += 1
                                 #print "before sleeping for 10 seconds and value of resend count is",resend_count
-                                time.sleep(0.1 + 0.05*int(random.choice([0,1,2,3])))
+                                time.sleep(0.2 + 0.05*int(random.choice([0,1,2,3])))
 
                                 if traffic_flag != True:
@@ -307 +314 @@
                                 ch_energy = tb.rxpath.probe.level() #check if primary user is present
                                 print "channel energy is ",ch_energy,"\n"
-                                if int(ch_energy) > 2e7: #if primary user is there then dont transmit on this channel
+                                if int(ch_energy) > 1.5e8: #if primary user is there then dont transmit on this channel
+                                        stop_time = datetime.now()      
+                                        _elapsed_time  = start_time - stop_time
+                                        elapsed_time = _elapsed_time.seconds
                                         mode = "sync"
+                                        return_flag = 1