CHANNELIZATION AND CHANNEL MONITORING IN FDMA COMMUNICATIONS

Abstract

In this paper the concept of spacecraft self-regulation of downlink power output is investigated for a hypothetical frequency division multiple access (FDMA) communication net. In this operation channels are filtered off (channelization) and monitored to determine those channels that are inactive; i.e., not transmitting. The results of the activity survey are then used to control channel gain in the spacecraft and regulate the drive power into the output amplifier. In this way, available repeater power normally not used during periods of low activity can be redistributed over the active channels to improve their performance. For maximum improvement, this requires not only adjustment of the individual channel gains, but removal of the inactive channels from the limiter. Equations are developed which are useful for system design and aid in the evaluation of resulting system performance and assessment of feasibility of implementation.