Downlink BER is terrible when the UE is put in multichannel mode

[asedlmayr]

Hardware Configuration (-DUSE_ARGOS=true)

When ue_channels = "AB" the second user reports a ~50% BER.

While using the same number of users in 1 channel mode the BER for both users is acceptable.
This is repeatable with dl-powder.json while modifing the ue_channels variable in the json and adding / subtracting a user from the topology (and keeping everything else the same).

All the test showed the same results (Channel B Ber ~45%)
Basestation (Channel B)
Basestation (Channel A)
User (Channel A & B)

• Sync on Channel A,
• Sync on Channel B
  Resync on every 5 Beacons. (sample offset 0 95% of the time) (edited)

UE 0: Downlink bit errors (BER) 1253/352000(0.00355966), block errors (BLER) 8/1000 (0.008)
UE 1: Downlink bit errors (BER) 181735/352000(0.516293), block errors (BLER) 1000/1000 (1)