Nortel Networks 411-2021-111 User Manual
2-1
DMS-MTX DualMode Metrocell Cell Site Description
2
Cell Site Configurations
Overview
The DualMode Metrocell can be configured in the following ways:
•
Omni-directional transmit/receive
•
120
°
Sectored Transmit Sectored Receive (STSR)
•
60
°
Sectored Transmit Sectored Receive (STSR)
The majority of systems may begin as Omni-directional to minimize startup
costs. As the subscriber traffic increases, the Omni configuration may reach
its maximum traffic capacity. At that time it will be necessary to provide
additional capacity through expanded spectrum, 120 degree sectorization, 60
degree sectorization, or frequency borrowing.
costs. As the subscriber traffic increases, the Omni configuration may reach
its maximum traffic capacity. At that time it will be necessary to provide
additional capacity through expanded spectrum, 120 degree sectorization, 60
degree sectorization, or frequency borrowing.
It is important that the operator selects a frequency plan before the Omni
configuration is installed. If not, future expansions will be very difficult. The
most common frequency plans are:
configuration is installed. If not, future expansions will be very difficult. The
most common frequency plans are:
•
7 Cell Cluster (N=7)—This frequency plan allows proper expansion from
Omni to 120 degree sectorization (see Figure 2-1 and Figure 2-2).
•
4 or 12 Cell Cluster (N=4 or N=12)—This frequency plan allows proper
expansion from Omni to 60 degree sectorization (see Figure 2-3).
Both non-expanded and expanded spectrums are shown in Appendix B for the
N=7 and N=4 frequency groups.
N=7 and N=4 frequency groups.
Omni configuration
In an Omni (N=7) configuration, the 416 RF channels are divided among a
group of seven cells (often known as a cluster). Each cell consists of a
maximum of 59 or 60 RF channels (four cells with 59 channels and three cells
with 60 channels, where three of the 59 or 60 channels are Control channels).
The RF channels are reused by other cell clusters. Frequency reuse refers to
the use of RF channels on the same carrier frequency in different areas which
are separated from one another by the greatest possible distance so that co-
channel interference is minimized.
group of seven cells (often known as a cluster). Each cell consists of a
maximum of 59 or 60 RF channels (four cells with 59 channels and three cells
with 60 channels, where three of the 59 or 60 channels are Control channels).
The RF channels are reused by other cell clusters. Frequency reuse refers to
the use of RF channels on the same carrier frequency in different areas which
are separated from one another by the greatest possible distance so that co-
channel interference is minimized.