I understand how the Barker code is used to create a sequence of chips. Where I am confused is how the chips are actually transmitted on the network. Does DSSS divide each 22MHz channel into smaller subcarriers (perhaps 1MHz each) so the chips can be transmitted in parallel? That would make sense. However I can find no place where the process is explained in such detail. Also the only diagrams I have found suggest the info is transmitted serially. Would that not be a narrowband transmission? Any help would be greatly appreciated.
DSSS combines a data signal at the sending station with a higher data rate bit sequence, which is referred to as a chipping code or processing gain. A high processing gain increases the signal's resistance to interference. The minimum linear processing gain that the FCC allows is 10. The IEEE working group has set their minimum processing gain reqyuirements at 11. The process of direct sequence begins with a carrier being modulated with a code sequence. The number of chips in the code will determine how much spreading occurs, and the number of chips per bit and the speed of the code will determine the data rate.
That's the part that I understand. It's the next part, where the chips are actually transmitted that I don't understand. Are they transmitted serially on a single frequency or in parallel across several sub-frequencies?