User's Manual

Designing an LGCell Solution

7-18 LGCell 4.0 Installation, Operation, and Reference Manual PN 8100-40

620004-0 Rev. B

7.2 Estimating RF Coverage

The maximum power per carrier (based on the number and type of RF carriers that

are being transmitted) and the minimum acceptable received power at the wireless

device (i.e., RSSI, the design goal) establish the RF link budget, and consequently the

path loss between the antenna and the wireless device.

Figure 7-1 Determining Path Loss between the Antenna and the Wireless Device

(P + G) – RSSI = PL (1)

The path loss (PL) is the loss in decibels (dB) between the antenna and the wireless

device. The distance, d, from the antenna corresponding to this path loss can be calcu-

lated using the path loss equation in Section 7.2.1 or in Section 7.2.3.

The losses due to the coaxial cable that connects the RAU to the antenna are not

included in this equation because, typically, the cable is short and the losses are mod-

est. However, if further precision is desired, you can use the coaxial cable losses

listed in the following table.

Table 7-14 Coaxial Cable Losses

Length of

Cable

Loss at

800 MHz

(dB)

Loss at

1900 MHz

(dB)

0.9 m (3 ft) 0.4 0.6

1.8 m (6 ft) 0.9 1.4

3.0 m (10 ft) 1.5 2.4

RAU

P = power per

Antenna and Gain (G)

RSSI = power at the

wireless device

carrier from the RAU