EL PLAN ESPECIAL DE TOLEDO

This section explains how Atoll calculates the received carrier power and interference when a transmitter has a connected repeater.

A mobile receiver receives signal from the donor transmitter as well as its repeater. Similarly, the signal from the mobile is received at the donor transmitter as well as its repeater. In practice, when a mobile receiver is in the vicinity of the donor transmitter, the signal to/from the repeater would be very weak due to high pathloss between the repeater and the mobile receiver. Similarly, when the mobile receiver is located in the vicinity of the repeater, the signal to/from the donor transmitter would be very weak due to the same reason.

Atoll does not differentiate between the mobile receiver being in the transmitter coverage area or being in its repeater coverage area. Atoll adds the signals received from the donor transmitter and its repeater to generate a combined pathloss matrix that is associated with the donor transmitter and includes the effect of its repeater.

Figure 1.9: Downlink Total Gain: Optical Fibre Link Repeaters or Remote Antennas

L_Fibre^D–R G_Amp^R L_Cov

TX Feeder– R

G_{Cov Ant}^R _–

P_DL^D  Gic + _Total^R P_Max^R G_{Cov Ant}^R _– L_Cov

TX Feeder–

– R

 +

P_DL^D  ic

G_Total^R P_Max^R L_Cov

TX Feeder– R

G_{Cov Ant}^R _–

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Calculation of Total Path Loss

The total pathloss, , is calculated by computing a downlink budget. If we take the case of a CDMA project, without considering any shadowing margin or indoor loss, the power received from the donor transmitter, Txd on a carrier ic, at the mobile receiver can be stated as (for a link over the air):

Where,

is the carrier power received at the receiver from the donor transmitter on a carrier ic (in W) is the pilot power of the donor transmitter on the carrier ic (in W)

is the donor transmitter antenna gain.

is the transmission feeder loss of the donor transmitter.

is the path loss between the donor transmitter and the mobile receiver.

Similarly, the power received at the mobile receiver from the repeater R is:

Where,

is the carrier power received at the mobile receiver from the repeater on a carrier ic (in W) is the pilot power of the donor transmitter on the carrier ic (in W)

is the total gain of repeater linked to a donor transmitter with an air link.

is the path loss between the repeater and the mobile receiver So, the total carrier power received at the mobile receiver is:

Since,

Therefore,

Hence,

This total path loss depends on the location of the mobile receiver in realistic network scenarios. As a mobile in the donor transmitter/repeater coverage area is likely to be far from the repeater/donor transmitter coverage area, the respective pathloss value will be very large. This implies that we can study the two cases separately without influencing the results much.

• Case 1: Receiver in Donor Transmitter Coverage Area L_Total

is likely to be very high, so the term can be ignored. This implies that:

Considering this total pathloss value, the total received power in the uplink and in the downlink can be stated as:

Where,

is the transmitted power from the mobile terminal on the carrier ic (in W)

is the reception feeder loss of the transmitter

• Case 2: Receiver in Repeater Coverage Area

is likely to be very high, so the term can be ignored. This implies that:

Where,

is the transmitted power from the mobile terminal (in W) is the reception feeder loss of the transmitter

Calculation of Eb/Nt Uplink

In the uplink, the quality level at the transmitter on a traffic channel is:

Where,

C is the carrier power received from the mobile terminal (in W) I is the total interference (in W)

W is the spreading bandwidth (Hz)

R is the effective service throughput in the uplink (bits/s) (W/R is the service processing gain in the uplink)

C and I are both evaluated at the same reference point, which is the entry of BTS using the following formulas.

L_Path^R–Mi G_Total^R

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Where,

is the sum of the signals received from mobile terminals inside the same cell and those outside (in W) is the transmitter equipment thermal noise (in W)

Therefore, for each mobile terminal Mi,

And,

Where,

is the noise figure of the transmitter equipment at the reference point, i.e. the entry of the BTS K is Boltzman constant

T is the ambient temperature (in K) Hence

1.5.2 GSM Documents

1.5.2.1 Signal Level Calculation

The received signal level (dBm) on a TRX type tt from a donor D at a pixel/mobile M_i via a repeater or remote antenna R (see Figure 1.10 on page 40) is calculated as follows:

Here:

• is the effective isotropic radiated power of the repeater or remote antenna R on the TRX type tt. It can be user-defined or calculated as explained in "EIRP Calculation" on page 40.

• the downlink transmission power of a donor D on carrier ic.

• is the power offset defined for the TRX type tt.

• is the path loss (dB) calculated as follows:

, with:

• is the path loss calculated using a propagation model.

• : Antenna attenuation (from antenna patterns) calculated for the antenna used by the repeater or remote antenna R.

• is the shadowing margin.

• is the indoor loss.

• is the terminal antenna gain for the pixel/mobile M_i.

• is the terminal loss for the pixel/mobile M_i.

• is the miscellaneous transmission losses defined for the repeater or remote antenna R.

I_Total N₀

I_Total P_Output^Mi G_Ant^D L_Total^D _–ULL_Total^Mi

--- 

 

 

Mi



=

N₀ = NF^D  K T W

NF^D

N₀ = NF^BTS  K T W

If a pixel/mobile M_i receives signals from the donor D and its repeater R, the total signal strength is the sum of the two signals:

C_DL^R  tt = EIRP_DL^R   P tttt –  –L_Path^R–Mi–M_Shadowing–L_Indoor+G^Mi–L^Mi–L_Misc^R _–DL

C_DL^D   Ctt + _DL^R  tt

EIRP_DL^R  tt

P tt  L_Path^R–Mi

L_Path^R–Mi = L_Model+L_Ant^R L_Model

L_Ant^R

M_Shadowing L_Indoor G^Mi L^Mi L_Misc^R _–DL