Assuming 4 stations with chip sequences defined as:

A = (-1 -1 -1 +1 +1 -1 +1 +1)

B = (-1 -1 +1 -1 +1 +1 +1 -1)

C = (-1 +1 -1 +1 +1 +1 -1 -1)

D = (+1 +1 +1 -1 -1 +1 -1 -1)

1) A CDMA receiver gets the following chip sequence: (1 +1 3 +1 1 3 +1 +1).

Which stations transmitted, and which bits did each one send? Show your calculations.

2) Suppose that A, B, and D are simultaneously transmitting 0 bits, using a CDMA system. What is the resulting chip sequence?

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