User's Manual

ADCP-75-132 • Issue 2C • August 2006

Page 25

of the problem by observing the LED indicators on each unit and then performing various tests to

isolate the problem. Once the source of the fault is isolated, the appropriate action can be taken to

correct the problem. The only unit components that can be replaced are the cooling fans which are

mounted in the DHU and the DEU and the modular optical transceivers. The failure of any other

component within a unit will require replacement of the unit. Basic trouble-shooting procedures are

provided in Section 6 of this manual.

3.10 System Design Recommendations

Follow a systematic process when designing an in-building coverage solution. The following

sub sections outline the four phases of the in-building coverage solution design process.

System design and planning services are available from ADC if required. Refer to Section 7 of this

manual for additional information.

3.10.1 Phase One – Initial Evaluation

Qualify the Installation: Confirm that there are no extenuating circumstances that would

prevent a successful installation such as: extreme cellular system issues (blocking, severe

interference, site problems, etc.), building issues, power issues, or safety issues (site should

not present any hazards or conditions that would make operation of the equipment unsafe).

Analyze the RF Situation: Determine how the system RF link to the outside world will be

provided. Will it be a direct feed from a BTS (microcell) or an over-the-air connection via a

donor antenna? If it is a donor antenna, is the customer within the coverage footprint of a

serving cell or better? The coverage can be determined during the preliminary walkthrough by

checking the downlink Received Signal Strength Indication (RSSI) outside the building with a

unity gain sampling antenna. Sometimes a rooftop reading is needed to obtain a sufficient

signal level. Note that it is an FCC violation to expand the normal coverage footprint of a

cellular site with an in-building product without prior approval of the service provider. In

addition, consider the impact the system will have on traffic, especially the busy hour.

Confirm with the service provider that the expected increase in the volume of calls will be

addressed (if needed), possibly with additional equipment such as additional channels or a

microcell.

Determine the Amount of Building Attenuation: If a donor antenna will provide the RF link

to the BTS, determine if there is enough signal isolation between the donor antenna and the in-

building system to avoid a feedback loop and signal degradation. This step can often be

accomplished during the preliminary walkthrough.

Discuss Installation with Building Management and Engineering: Discuss all initially

anticipated Digivance ICS coverage areas (including any obviously desirable cable routings,

equipment installations, power and mechanical requirements) with the authorized client and

building personnel for an initial approval/confirmation. This gives a good estimate of the

extent of the system work needed. Occasionally, some of the system design work can be

accomplished at this point.