This annex provides guidance on the derivation for calculating the minimum E-field strength levels to coordinate between RRBS.

### B1. Guidance on RRBS customer premises equipment (CPE) receiver protection

The RRBS CPE receiver protection is defined using a minimum co-channel C/I ratio of +4 dB,^{Footnote a} which is equivalent to the minimum required signal-to-noise ratio (SNR) for robust RRBS operation.

The first adjacent channel CPE receiver rejection is 41.0 dB, whereas the equivalent first adjacent channel rejection resulting from the transmit emission mask described in RSS-196 is 31.7 dB, resulting in a compound rejection of 31.2 dB. The second adjacent channel CPE receiver rejection is 63.2 dB, whereas the equivalent second adjacent channel rejection resulting from the transmit emission mask described in RSS-196 is 54.3 dB, resulting in a compound rejection of 53.7 dB. The compound effect is assumed to be a power addition of the interference resulting from the two interference mechanisms: leakage of the RRBS main interfering signal into the victim receiver due to limited receiver filtering performance, and out-of-band power emitted by the interfering RRBS transmitter into the channel selected at the victim RRBS receiver.

Typical CPE parameters and calculated values for the maximum non-interfering field strengths for co-channel, first adjacent, and second adjacent channels may be found in table B1. These values are based on Equations (B1), (B2), and (B3).

At the edge of coverage, the maximum non-interfering field strength for the co-channel is calculated using Equation (B1):

FS_{CPEMIN} − SNR − IA_{Rx} − I/N_{ACC} = FS_{CPEMAXco}

(B1)

Where:

- FS
_{CPEMIN} is the required minimum field strength in dBµV/m;
- SNR is the minimum required SNR in dB;
- IA
_{Rx} is the interference allowance (RX desensitization) in dB;
- I/N
_{ACC} is the acceptable I/N ratio in dB; and
- FS
_{CPEMAXco} is the maximum non-interfering field strength for co-channel in dBµV/m.

The maximum non-interfering field strength for the first adjacent channel is calculated using Equation (B2):

FS_{CPEMIN} − SNR − IA_{Rx} − I/N_{ACC} + REJ_{CPE1} = FS_{CPEMAX1}

(B2)

Where:

- REJ
_{CPE1} is the compounded CPE receiver rejection; and
- FS
_{CPEMAX1} is the maximum non-interfering field strength for the first adjacent channel in dBµV/m.

The maximum non-interfering field strength for the second adjacent channel is calculated using Equation (B3):

FS_{CPEMIN} − SNR − IA_{Rx} − I/N_{ACC} + REJ_{CPE2} = FS_{CPEMAX2}

(B3)

Where:

- REJ
_{CPE2} is the compounded CPE receiver rejection; and
- FS
_{CPEMAX2} is the maximum non-interfering field strength for the second adjacent channel in dBµV/m.

Table B1 — Calculation of RRBS CPE protection
Parameter |
Value |
Units |

Frequency |
617 |
MHz |

Boltzman's constant |
−168.6 |
dBW/MHz |

Reference temperature |
290 |
deg. Kelvin |

Bandwidth |
6 |
MHz |

Receiver noise figure |
6 |
dB |

Receiver noise floor |
−100.2 |
dBm/6 MHz |

Interference allowance (RX desensitization)( IA_{Rx}) |
3.0 |
dB |

Acceptable I/N ratio (I/N_{ACC}) |
0.0 |
dB |

Miscellaneous radio frequency losses |
2 |
dB |

Required minimum Eb/No |
6 |
dB |

Downstream capacity |
3.8 |
Mbit/s |

Required minimum SNR (SNR) |
4.0 |
dB |

Receiver sensitivity |
-91.2 |
dBm/6 MHz |

Effective antenna aperture |
−17.3 |
dB(m^{2}) |

Antenna Gmax |
11 |
dBi |

Antenna height |
30 |
m |

Required minimum power flux density |
-114.9 |
dB (W/m^{2}) |

Required minimum field strength F(50,90) (FS_{CPEMIN}) |
30.8 |
dBµV/m |

Co-channel C/I ratio |
4.0 |
dB |

Interference allowance (RX desensitization)( IA_{Rx}) |
3.0 |
dB |

Acceptable I/N ratio (I/N_{ACC}) |
0.0 |
dB |

Maximum interfering field strength: Co-channel (FS_{CPEMAXco}) |
23.8 |
dBµV/m |

First adjacent channel CPE receiver rejection |
41.0 |
dB |

First adjacent channel equivalent RF mask rejection |
31.7 |
dBr |

Compounded CPE receiver rejection (REJ_{CPE1}) |
31.2 |
dB |

Maximum non-interfering field strength: first adjacent channel (FS_{CPEMAX1}) |
55 |
dBµV/m |

Second adjacent channel CPE receiver rejection |
63.2 |
dB |

Second adjacent channel equivalent RF mask rejection |
54.3 |
dBr |

Compounded CPE receiver rejection (REJ_{CPE2}) |
53.7 |
dB |

Maximum non-interfering field strength: second adjacent channel (FS_{CPEMAX2}) |
77.6 |
dBµV/m |

### B2. Guidance on RRBS base station receiver protection

The RRBS base station receiver protection can be defined using a minimum co-channel C/I ratio of +4 dB^{Footnote b}, which is equivalent to the minimum required SNR for robust RRBS operation.

The first adjacent channel base station receiver rejection is 41.0 dB, whereas the equivalent first adjacent channel rejection resulting from the transmit emission mask described in RSS-196 is 31.2 dB, resulting in a compound rejection of 31.2 dB. The second adjacent channel base station receiver rejection is 63.2 dB, whereas the equivalent second adjacent channel rejection resulting from the transmit emission mask described in RSS-196 is 54.3 dB, resulting in a compound rejection of 53.7 dB. The compound effect is assumed to be a power addition of the interference resulting from the two interference mechanisms: leakage of the RRBS main interfering signal into the victim receiver due to limited receiver filtering performance and out-of-band power emitted by the interfering RRBS transmitter into the channel selected at the victim RRBS receiver.

Typical base station parameters and calculated values for the maximum non-interfering field strengths for co-channel, first adjacent, and second adjacent channels may be found in table B2. These values are based on Equations (B4), (B5), and (B6).

At the edge of coverage, the maximum interfering field strength for the co-channel is calculated using Equation (B4):

FS_{BSMIN} − SNR − IA_{Rx} - I/N_{ACC} = FS_{BSMAXco}

(B4)

Where:

- FS
_{BSMIN} is the required minimum field strength in dBµV/m;
- SNR is the minimum required SNR in dB;
- IA
_{Rx} is the interference allowance (RX desensitization) in dB;
- I/N
_{ACC} is the acceptable I/N ratio in dB; and
- FS
_{BSMAXco} is the maximum non-interfering field strength for co-channel in dBµV/m.

The maximum non-interfering field strength for the first adjacent channel is calculated using Equation (B5):

FS_{BSMIN} − SNR − IA_{Rx} − I/N_{ACC} + REJ_{BS1} = FS_{BSMAX1}

(B5)

Where:

- REJ
_{BS1} is the compounded BS receiver rejection; and
- FS
_{BSMAX1} is the maximum non-interfering field strength for the first adjacent channel in dBµV/m.

The maximum non-interfering field strength for the second adjacent channel is calculated using Equation (B6):

FS_{BSMIN} − SNR − IA_{Rx} − I/N_{ACC} + REJ_{BS2} = FS_{BSMAX2}

(B6)

Where:

- REJ
_{BS2} is the compounded BS receiver rejection; and
- FS
_{BSMAX2} is the maximum non-interfering field strength for the first adjacent channel in dBµV/m.

Table B2 — Calculation of RRBS base station (BS) protection
Parameter |
Value |
Units |

Frequency |
617 |
MHz |

Boltzman's constant |
−168.6 |
dBW/MHz |

Reference temperature |
290 |
deg. Kelvin |

Bandwidth |
6 |
MHz |

Receiver noise figure |
4 |
dB |

Receiver noise floor |
−102.2 |
dBm/6 MHz |

Interference allowance (RX desensitization)( IA_{Rx}) |
3.0 |
dB |

Acceptable I/N ratio (I/N_{ACC}) |
0 |
dB |

Miscellaneous radio frequency losses |
2 |
dB |

Required minimum Eb/No |
6 |
dB |

Upstream capacity |
0.384 |
Mbit/s |

Required minimum SNR (SNR) |
−5.9 |
dB |

Receiver sensitivity for given upstream capacity |
−103.1 |
dBm/6 MHz |

Receiver equivalent sensitivity for full capacity |
−93.2 |
dBm/6 MHz |

Effective antenna aperture |
−17.3 |
dB(m^{2}) |

Antenna Gmax |
8 |
dBi |

Antenna height |
30 |
m |

Required minimum power flux density |
−123.9 |
dB (W/m^{2}) |

Required minimum field strength F(50,90) (FS_{BSMIN}) |
21.9 |
dBµV/m |

Co-channel C/I ratio |
4.0 |
dB |

Interference allowance (RX desensitization)( IA_{Rx}) |
3.0 |
dB |

Acceptable I/N ratio (I/N_{ACC}) |
0 |
dB |

Maximum interfering field strength: Co-channel |
14.8 |
dBµV/m |

First adjacent base station receiver rejection |
41.0 |
dB |

Second adjacent channel equivalent radio frquency mask rejection |
31.7 |
dBr |

Compounded base station receiver rejection (REJ_{BS1}) |
31.2 |
dB |

Maximum non-interfering field strength: first adjacent channel (FS_{BSMAX1}) |
46.0 |
dBµV/m |

Second adjacent channel base station receiver rejection |
63.2 |
dB |

Second adjacent channel equivalent radio frequency mask rejection |
54.3 |
dBr |

Compounded base station receiver rejection (REJ_{BS2}) |
53.7 |
dB |

Maximum non-interfering field strength: second adjacent channel (FS_{BSMAX2}) |
68.6 |
dBµV/m |

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