A Code Division Multiple Access $($CDMA$)$ wireless system assigned the following

unique codes to users A$,$ B and C for shared medium access simultaneously:

UA $=[-1,1,-1,1,-1,1,-1,1]$

UB $=[-1,1,1,-1,-1,1,1,-1]$

UC $=[-1,-1,1,1,-1,-1,1,1]$

$($a$)$ Determine the decoder output of the receiver if user A transmits a data bit $1$ and user

B transmits a data bit $1$ when user C transmitting data bit $0$;

$($b$)$ Determine the composite signal transmitted on a common transmission channel.

$($c$)$ Draw the waveform of the data available in the channel for $($b$)$ the above

transmission.