1.4.6 Receiver blocking

The level of interference determined by the interferer’s transmit power, the antenna gains and propagation loss, is further decreased due to the receiver blocking performance for a given interferer/victim frequency separation. Details on the iRSS_blocking calculation are given in ANNEX 5:.

Note that from SEAMCAT 5.0.1 onwards, the blocking attenuation is computed at the ILT frequency and that the ILT bandwidth is nowconsidered (see ANNEX 8:). There are 3 ways to calculate the blocking response which are described in more detail in ANNEX 8::

User Defined (dB):           Att_Blocking = Block_{UD (dB)}                                                                                                                                   (Eq. 13)

Protection Ratio (dB):       Att_Blocking = Block_{PR (dB)} + C/(N+I) _(dB) + (N+I)/N _(dB) - I/N _(dB)                                                     (Eq. 14)

Sensitivity Mode (dBm): Att_Blocking = Block_{Sens (dBm)} – Sensitivity_{VLR (dBm)} + C/(N+I) _(dB) – I/N _(dB)                                 (Eq. 15)

Figure 12: Illustration of the blocking of the victim link receiver (i.e. total emission power of ILT reduced by the blocking attenuation (selectivity) function of the VLR