User's Manual

Overview
6-2 InterReach Fusion Installation, Operation, and Reference Manual
CONFIDENTIAL D-620610-0-20 Rev F
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 bidirectional amplifier or repeater), type of equip-
ment if possible.
2. Determine the downlink power per carrier from the RF source through the
DAS: Refer to Section 6.3, “Maximum Output Power per Carrier,” on page
6-4.
The maximum power per carrier is a function of modulation type, the number of
RF carriers, signal quality issues, regulatory emissions requirements, and Fusion’s
RF performance. Power per carrier decreases as the number of carriers increases.
3. Develop an RF link budget: Refer to Section 6.5, “Estimating RF Coverage,”
on page 6-15.
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 carrier + antenna gain – design goal
Satisfactory performance can be expected as long as path loss is below this level.
4. Determine the in-building environment: Refer to Section 6.5, “Estimating RF
Coverage,” on page 6-15.
• Determine which areas of the building require coverage (entire building, public
areas, parking levels, and so on.)
• Obtain floor plans to determine floor space of building and the wall layout of
the proposed areas to be covered. Floor plans are also useful when you are
selecting antenna locations.
• If possible, determine the building’s construction materials (sheetrock, metal,
concrete, and so on.)
• Determine the type of environment:
– Open layout (for example, a convention center)
– Dense, close walls (for example, a hospital)
– Mixed use (for example, an office building with hard wall offices and cubi-
cles)
5. Determine the appropriate estimated path loss slope that corresponds to the
type of building and its layout, and estimate the coverage distance for each
RAU: Refer to Section 6.5, “Estimating RF Coverage,” on page 6-15.
Use the path loss slope (PLS), which gives a value to the RF propagation charac-
teristics within the building, to convert the RF link budget into an estimate of the
coverage distance per antenna. This helps establish the quantities of Fusion equip-
ment you need. The actual path loss slope that corresponds to the specific RF
environment inside the building can also be determined empirically by perform-
ing an RF site-survey of the building. This involves transmitting a calibrated tone
for a fixed antenna and making measurements with a mobile antenna throughout
the area surrounding the transmitter.