Q7. You are to assign 4 DS-CDMA sender's chip sequences. Below, three potential sets of 4 chip sequences are given. Which of these sets of four would you choose, and why? (iii)-1+1+1-1+1+1+1-1-1-1-1-1-1 +1 +1 +1 +1-1 +1-1 +1-1+1-1+1-1+1-1+1-1 +1-1 Hint: you wouldn't chose the set in which any two codes are not orthogonal i.e. their dot product does not result in 0. Assume that receiver receives the following signal: (+111-3111313-1-1-11-31-1). Which station sent what data bit? Hint: compute the dot product of the received bits with the CDMA code of each sender. If the dot product is 1 then 1 was sent, if the dot product is -1 then 0 was sent and if the dot product is 0 then nothing was sent by that transmitter