Setting Power; Overview; The Reference Carrier - iDirect evolution x1 Installation Manual

17 Setting Power

This chapter describes how to set initial acquisition power and maximum transmit power for
the remote site in iBuilder. These procedures are performed by the Network Operator.
This chapter includes the following sections:
• "Overview" on page 99
• "Setting Power" on page 101

17.1 Overview

Remote site transmit power is controlled by the hub Protocol Processor Uplink Control Process
(UCP). UCP operates in a manner similar to other uplink power control systems, in that
received signal strength is compared to a nominal value, and adjustments are made based
upon the comparison. The UCP constantly measures performance and adjusts power as
needed. See the iDirect Technical Reference Guide for details.
The power of acquisition bursts transmitted by the Satellite Router must be set as a constant
since during acquisition the Satellite Router is not yet participating in the UCP loop. An
acquisition or "initial" power must be configured that guarantees acquisition without
overpowering the transponder or the receiver. iDirect defines initial power as the acquisition
burst power. Initial power varies from site to site.
A separate quantity, referred to as maximum power, is the "never exceed" IF output power
for the site. Maximum transmit power also varies from site to site. UCP enforces this limit,
and uses the configured value to determine the available power headroom at each site.
After the 1 dB compression point has been determined, the Network Operator enters the
initial and maximum power settings for the remote site in iBuilder. Immediately afterward,
the Network Operator generates a new options file containing the updated information and
sends it to the Satellite Router over the air.

17.1.1 The Reference Carrier

In an Adaptive TDMA network, the upstream transmission can change frequency, MODCOD,
symbol rate and/or spreading factor at any time depending upon network demand, rain fade,
or other rules. To provide a constant baseline for comparison, a reference carrier is defined
for each remote site by the Network Operator. Reference carrier properties are set by the
Network Operator on the Remote Information tab in iBuilder. For TDMA remotes, the initial
transmit power is configured in relation to the Reference Carrier.
iDirect Satellite Router Installation and Commissioning Guide
iDX Release 3.3
99