User's Manual

Table Of Contents
162 Operation
Chapter 4 - Operation and Administration
4.9.5.3.1.1 ID Parameters
The Operator ID, Cell ID and Sector ID constitute together the Base Station ID,
which is the unique identifier of the AU. An SU can be authenticated by the AU
only if its defined parameters match the Base Station ID configured for the AU.
The Operator ID and Cell ID are defined for the Base Station (see Section 4.5.2.5)
and are used by all AUs in the Base Station. In the AU's MAC Parameters menu
they are available only in the Show option.
The Sector ID parameter consists of three digits in the range of 0 to 255.
The default Sector ID is 206.
Changes in Sector ID are applied only after reset.
4.9.5.3.1.2 Maximum Cell Radius
The Maximum Cell Radius is used to adapt various timing parameters of the MAC
to the time it takes a message to reach its destination. This time delay is
dependent upon the distance between the originating and receiving units. The
timing parameters should be adapted to the largest expected delay, which is
determined from the distance from the AU of the farthest SU served by it.
The basic time element (symbol) used by a system operating in TDD mode is 68
microseconds for a bandwidth of 3.5 MHz and 50 microseconds for a bandwidth of
5 MHz. This symbol size is translated to a round trip delay of approximately 20
km for 3.5 MHz bandwidth and 15 km for 5 MHz bandwidth, or a cell radius of 10
km or 7.5 km, respectively.
The values range for the Maximum Cell Radius is from 10 to 50 km for a
bandwidth of 3.5 MHz, and 7 to 45 km for a bandwidth of 5 MHz (representing a
maximum delay of 6 symbols).
NOTE
For Non-Line-Of-Sight (NLOS) links using refractions, the cell distance should be higher than the
line-of-sight distance. Typically a 10% margin is a good estimate for the increase in distance due to
the NLOS operation.
NOTE
An SU located at a distance larger than the Maximum Cell Radius will be rejected during the
network entry process.