Specifications

Interface Protocols

Operating Characteristics

August 08, 2000 68P81095E55-E 3-11

Cell Sites

In normal operating conditions, output power of a Base Radio (BR) at a cell site will

be limited to the cell’s coverage area. The signalling and timing of the system

restricts the maximum cell size to approximately 70 miles. The size of a cell

coverage area is typically between one and 10 miles. By limiting the range of a radio

with its output power, the base radio’s frequency may be used in other parts of the

network at the distance defined by the re-use pattern. The iDEN system supports

both Omi-directional and Sectored cell site configurations in the same system.

Note

System design, frequency coordination and planning is primarily a service

provider responsibility. Network Element and system capacity may vary based

on system design and implementation.

Omni-directional

Site

An Omni site uses an antenna system that radiates RF power equally in all directions.

In ideal conditions the coverage area would form a circular pattern (Figure 3-8). The

Omni cell pattern reduces the number of radio channels (BRs) required but limits the

number of calls that the site can handle.

Figure 3-8 Omni-Directional Site

Sectored Site A sectored site uses an antenna system the divides the logical coverage area into

areas (usually 3 but maybe 6 or 12). Under ideal conditions a 3-sectored site will

produce a circular pattern would be divided into 3 “pie” segments of 120° each

(Figure 3-9). This increase the number of channels required to cover a given area but

it also increases the traffic capacity and frequency re-use.

Figure 3-9 3-Sector Site

T. N. French