10.3. Direct Sequence Spread Spectrum
In this section, features of the DSSS wireless Ethernet are highlighted by examining the packet structure, the 11-bit Barker code modulation process, and the spectrum mask.
10.3.1. Summary of DSSS Standards
The packet format for the DSSS implementation of wireless Ethernet is shown in Figure 10.17. A DSSS packet consists of a preamble, a header, and a MAC frame. The DSSS preamble has a Sync field of 128 bits and a Start Frame Delimiter of 16 bits. The DSSS header has a Signal field of 8 bits, a Service field of 8 bits, a Length field of 16 bits, and a CRC field of 16 bits.
Figure 10.17. DSSS Packet Format
The DSSS preamble Sync field contains 128 bits of scrambled 1s to be used by the receiver to detect ...
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