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InterReach Fusion SingleStar Installation, Operation, and Reference Manual 5-1
D-620605-0-20 Rev A
CONFIDENTIAL
SECTION 5
Designing a Fusion SingleStar
Solution
Designing a Fusion SingleStar solution is a matter of determining coverage and
capacity needs. This requires the following steps:
1.
Determine the wireless service provider’s requirements: Refer to Section 5.1,
“Downlink RSSI Design Goal,” on page 5-3.
The following information is typically provided by the service provider:
• Frequency (for example, 1900 MHz)
• Band (for example, “A-F” band in the PCS spectrum)
• Protocol (for example, COMA, GSM, 1xRTT, GPRS, and so on)
• Number of sectors and peak capacity per sector (translates to the umber of RF
carriers that the system will have to transmit)
• Downlink RSSI design goal (RSSI, received signal strength at the wireless
handset, for example, –85 dBm)
The design goal is always a stronger signal than the mobile phone needs. It
includes inherent factors which affect performance.
• RF source (base station or BDA), type of equipment if possible.
2.
Determine the downlink power per carrier from the RF source through the
DAS: Refer to Section 5.2, “Maximum Output Power per Carrier,” on page
5-4.
The maximum power per carrier is a function of modulation type, the number of
RF carriers, signal quality issues, regulatory emissions requirements, and Fusion
SS’s RF performance. Power per carrier decreases as the number of carriers
increases.
3.
Develop an RF link budget: Refer to Section 5.4, “Estimating RF Coverage,”
on page 5-13.
Knowing both the power per carrier and RSSI design goal, you can develop an RF
downlink link budget which estimates the allowable path loss from an RAU’s
antenna to the wireless handset.
allowable path loss = power per c antenna gain – design goal
Satisfactory performance can be expected as long as path loss is below this level.