Nortel Networks 411-2021-111 manual Cell Site Configurations, Overview, Omni configuration

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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.

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:

•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.

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.

DMS-MTX DualMode Metrocell Cell Site Description