Add something about lte_softmodem on version 0.6

v0.6/lte_softmodem.md

@@ -1,3 +1,81 @@
 
 For the OAI eNodeB application, the file where main function is placed is {{lte-softmodem.c=/targets/RT/USER/lte-softmodem.c:1363}}.
-This function just initalize the process, parsing the command line options, creating the data-structures, filling the configurations and starting the threads.
+It is possible to make a list of the things it does:
+
+1. Parse the command line options
+2. Create the data-structures
+1. Initialize the logging system(s)
+3. Fill the configurations
+  1. Configure the eNodeB parameters
+  2. Configure eNodeB interfaces with RF (or fronthaul) and MAC
+4. Start the thread(s).
+
+## Interfaces (MAC and RF/Fronthaul)
+
+In the startup configuration it is possible to find two points where the interface
+functions are configured:
+
+- l2_init(): configures the interface between eNodeB and MAC as shown {{l2_init=/openair2/LAYER2/MAC/main.c:435}}
+- init_eNB(): 
+
+
+Two really important functions are init_eNB() and l2_init().
+
+Functions configured on init_eNB()
+
+
+| Function                 | Description                   | Who Calls   |
+==========================================================================
+| eNB->do_prach            | do_prach;                     |             |
+| eNB->fep                 | eNB_fep_full;                 |             |
+| eNB->td                  | ulsch_decoding_data;          |             |
+| eNB->te                  | dlsch_encoding;               |             |
+| eNB->proc_uespec_rx      | phy_procedures_eNB_uespec_RX; |             |
+| eNB->proc_tx             | proc_tx_full;                 | rxtx (eNB_thread_rxtx, eNB_thread_single) |
+| eNB->tx_fh               | NULL;                         | tx_proc_full, tx_proc_high |
+| eNB->rx_fh               | rx_rf;                        | eNB_thread_fh, eNB_thread_single |
+| eNB->start_rf            | start_rf;                     |             |
+| eNB->start_if            | NULL;                         |             |
+| eNB->fh_asynch           | NULL;                         | eNB_thread_asynch_rxtx |
+| eNB->rfdevice.host_type  | BBU_HOST;                     |             |
+| eNB->ifdevice.host_type  | BBU_HOST;                     |             |
+
+
+# eNodeB Start 
+
+The init_eNB_proc starts some threads, wich can be listed:
+
+* eNB_thread_prach
+  * Always created
+  * Functions called:
+    * prach_procedures:
+* eNB_thread_synch
+  * Always created
+  * Functions called:
+    * Runs initial synchronization like UE
+* eNB_thread_single
+  * Called when the setup process uses single thread (default):
+  * Functions called:
+     * start_rf, start_if at the before the loop
+     * Check if the eNodeB is slave (???)
+     * On the main loop:
+        * rx_fh()
+        * wakeup_slaves()
+        * rxtx()
+* eNB_thread_rxtx
+  * There are two threads of this type per Component Carrier (CC), one process the even subframes the other process the odd.
+  * This thread receives the subframe **N** and sends the subframe **N+4**
+  * Internaly this thread calls:
+    * eNB->do_prach
+    * phy_procedures_eNB_common_RX
+    * proc_uespec_rx
+    * proc_tx
+* eNB_thread_FH
+  * Actually get the samples from fronthaul, it calls:
+    - rx_fh
+      - trx_write_func
+      - trx_read_func
+    - wakeup_slaves
+    - wakeup_rxtx
+* eNB_thread_asynch_rxtx
+  * Started when the functino split is IF5 or IF4p5 and node timing is synch_to_other

v0.6/lte_softmodem.txt

@@ -10,30 +10,32 @@ main():
 		Initialize frame parameters
 
 	### Now the function will initilize several logging systems
-		logInit() =>
-			Initilize logging
-		get_options() => 
-			Get comand line opetions
-		T_init() =>
-		set_glog =>
-		set_taus_seed() => 
-		itti_init() => 
 
-	### Now the function will initilize several parameters
-		init_ul_hoping =>
-			Initilize system for ul hoping
-		init_frame_parameters =>
-			Initialize more frame parameters
-		phy_init_lte_top =>
-			Initiliaze tables and signals for PHY: viterby, trelis, scranble, reference signals ...
-		For each component carrier:
-			init_lte_eNB =>
-				Allocate and initilize resources for eNB
-			compute_prach_seq =>
-				Conpute the zadoff-chu sequence based on previous parameters
-				the sequence is hold in Xu vector
-		fill_modeled_runtime_table =>
-			Pre calculate a model of the amount of time used on tx and rx
+	logInit() =>
+		Initilize logging
+	get_options() => 
+		Get comand line opetions
+	T_init() =>
+	set_glog =>
+	set_taus_seed() => 
+	itti_init() => 
+
+	### Now the system
+
+	init_ul_hoping =>
+		Initilize system for ul hoping
+	init_frame_parameters =>
+		Initialize more frame parameters
+	phy_init_lte_top =>
+		Initiliaze tables and signals for PHY: viterby, trelis, scranble, reference signals ...
+	For each component carrier:
+		init_lte_eNB =>
+			Allocate and initilize resources for eNB
+		compute_prach_seq =>
+			Conpute the zadoff-chu sequence based onprevious parameters
+			the sequence is hold in Xu vector
+	fill_modeled_runtime_table =>
+		Pre calculate a model of the amount of time used on tx and rx
 
 	dump_frame_parms =>
 		Show the configured parameters on the stdout
@@ -47,8 +49,10 @@ main():
 		Initilize functions to interface between l1 and l2
 		the list of functions is big, see it in: openair2/LAYER2/MAC/main.c:435=l2_init
 
+	### Initialize the eNodeB
+
 	init_eNB => 
-		Hear the eNodeB is configured and started
+		Here the eNodeB is configured and started
 		this function calls init_eNB_proc that will create the threads and mutexes
 		The threads created are:
 		eNB_thread_rxtx