The cellular satellites have much different bandwidths. For example, Globalstar has 16.5 MHz transponder channels to accommodate 13 of the CDMA 1.23 MHz channels. The wideband Internet relay satellites proposed at Ka-band may have transponders with 1 GHz bandwidths, to accommodate multiple 155 Mbps channels for trunking Internet data between computers. The satellite communication world is becoming much more complex.

133 Link Design

The overall process of link design and, subsequently, payload sizing, is summarized in Table 13-9 and described in detail in this and the next section. The process for developing the communications architecture and determining the link requirements was detailed in Table 13-1.

To understand link design, we need to define the relationship between data rate, antenna size, propagation path length, and transmitter power. This relationship is

TABLE 13-9- Link Design and Payload Sizing Process.


Process (= Detailed Step)


1. Define Requirements (or Each Link

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