ALOHA/TDM Systems with Multiple Downlink Capacity

The concept of a processing satellite with multiple slotted ALOHA uplinks to efficiently fill a TDM downlink is extended to include multiple downlinks. Throughput is derived for a general configuration with
n
ALOHA uplinks and
m
TDM downlinks. An optimization procedure is described to select the
n
and
m
which maximize throughput for a given bandwidth constraint. The ALOHA/TDM system with multiple downlink capacity is found to be up to 32% more spectrum-efficient than the conventional slotted ALOHA system. The ALOHA/TDM system also has the potential for payload power and weight savings and decreased passive intermodulation problems.