3. (5 points) Suppose we have two CDMA users A and B. User A uses this spreading sequence (1,1,1,-1,-1,1,-1) and user B uses this sequence (1,-1,-1,-1,1,1,-1). Also, suppose the base station receives the following signal which is spread using DSSS from all active users in the cell (1,1,3,1,-1,-1,-1; 1,-3,-1,1,3,-1,-1). a) How many data bits are represented by the received DSSS signal? b) Decode the data bits that were transmitted by user A. c) Decode the data bits that were transmitted by user B.