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--- network_protocol_programming_lab:channel_sensing [2020/05/25 08:27] – rathke
+++ network_protocol_programming_lab:channel_sensing [2021/04/19 12:41] (current) – [Requirements] rathke
@@ Line 7: / Line 7: @@
 This task requires
-  * a ready BeagleBone Black equipped with the CC1200
+  * a ready BeagleBone Black equipped with the CC1200.
-  * one TI Development Kit for the CC1200
+  * 4C attached to a second BeagleBone Black equipped with the CC1200.
-  * Smart RF Studio.
 ===== Tasks  =====
-  * the programming is done by extending the source files from the previous lesson [[network_protocol_programming_lab:15.3_2_exercise|2. Exercise: Packet Reception]]. Make a copy of the files.
+  * the programming is done by extending the source files from the previous lesson [[network_protocol_programming_lab:change_frequency|Exercise: Changing the frequency]].
-  * Read chapter 9.12 ff. about programming the RF frequency in the [[http://www.ti.com/lit/ug/swru346b/swru346b.pdf?ts=1588225642109|CC1200 Users Guide]] and implement it.
+  * Extend your program by a function that measures the RSSI prior to packet reception. A packet should only be received, if a valid RSSI from the sende is detected. What means a valid RSSI ?
-  * you should implement a function for programming the frequency and printing the current programmed frequency.
+  * Don't forger to disable preamble recognition at the receiver.
-  * for testing compare your computed values of the FREQ registers with SmartRF Studio.
+  * For testing, start your program.
-  * now, set RF to an arbitrary value within the supported frequency band of CC1200
+  * Use SmartRF Studio to transmit packets at the RF frequency (do not forget to change the symbol rate and preamble count in SmartRF Studio).
-  * Bring SmartRF Studio in “Packet TX” mode using the default frequency.
+  * Your program should recognize a valid RSSI and start receiving packets.
-  * start the transmitter. At the receiver, the BeagleBone Black, you should now receive **NO** packet.
+  * Now, change RF to a frequency the receiver is not using. Stopping and restarting the transmitter ist not necessary.
-  * Now, stop the transmitter and change the frequency to your selected frequency.
+  * At the receiver, the BeagleBone Black, you should now measure no valid RSSI and therefore no packet will be received.
-  * Now, you should be able to receive the packets.
+  * Now, change the frequency of SmartRF Studio back to your selected frequency.
+  * Now, you should be able to receive the packets again.
+===== Hints  =====
+  * To determine a valid RSSI caused by the sender. Measure the RSSI of the noise level in a training phase at the beginning of your program. Make sure, that the sender is not transmit anything.