Multiple Rx and one Tx in Sionna RT Stream Management

[pablosreyero]

Hi,

I was wondering if Sionna OFDM Stream Management function, supports multiple receivers in a scene with just one Tx. I am asking this, due to the fact that with the following code I do not obtain the indexes of all Rxs, and therefore, most of stream_management properties are incorrect.

Here the code:
OFDM_MIMO_RT_code.zip

Here the stream_management properties I obtain:

rx_tx_association = np.zeros([num_Rx, num_Tx])

# rx_tx_association[0, 0] = 1
# rx_tx_association[1, 0] = 1
# rx_tx_association[2, 0] = 1
# rx_tx_association[3, 0] = 1
# rx_tx_association[4, 0] = 1

rx_tx_association[:,0] =  1 # lo tenemos que hacer asi

#----------------RESULTS----------------#

'''
Here the number of streams per tx:  1 # this one is correct
Here the number of streams per rx:  0 # this one should one
Here the IDs:
 [[0]] # this array should be populated
[]
This is the number of rx communicating with a tx:  5 # correct
This is the number of interfering streams per tx:  1 # i'm not sure about this one
'''

[jhoydis]

Hi,

We'll have a look and come back to you quickly.

[jhoydis]

Hi,

I had a quick look at your code and there are multiple issues:

1. You want to have one TX and 5 RX. In this case, you must set num_streams_per_tx=5 because the TX is sending 5 streams, one for each RX.

2. You cannot send 5 streams with a single TX antenna. The number of streams must be smaller than or equal to the number of TX antennas.

3. The TX would probably need to apply a form of precoding.

Here is a code snippet, that shows the correct setting:

num_tx = 1
num_rx = 5
num_streams_per_tx = num_rx
rx_tx_association = np.zeros([num_rx, num_tx])
rx_tx_association[:,0] =  1 
sm = StreamManagement(rx_tx_association, num_streams_per_tx)
print('Number of streams per tx: ', sm.num_streams_per_tx)
print('Number of streams per rx: ', sm.num_streams_per_rx)
print('Stream IDs:\n', sm.tx_stream_ids)
print('Number of rx communicating with a tx: ', sm.num_rx_per_tx)
print('Number of interfering streams per rx: ', sm.num_interfering_streams_per_rx)

Number of streams per tx:  5
Number of streams per rx:  1
Stream IDs:
 [[0 1 2 3 4]]
Number of rx communicating with a tx:  5
Number of interfering streams per rx:  4

[pablosreyero]

Hi Jakob,

Thanks for your clear response, I'm a bit new to this world, so I misunderstood some concepts and while implementing my code, it did not make that much sense. Everything is clear now.

Cheers,

Pablo.-