Question 4 [12] Instead of GSM system, the CDMA system is employed for cellular technology. The system is necessary to transmit data bit sequences of User 1 for '1001' and User 2 for '0110' from transmitter to receiver for accessing the information. (Suppose chip 1 is represented by a square waveform with amplitude of +1 and chip 0 is represented by a square waveform with amplitude of -1.) Given a set of PN codes A, B, C and D (PN codes in binary (chip rate= 4)). PNA = 1010 PNB = 0111 PNC -0101 PND = 1110 a) Suppose a CDMA base station encodes two 4-bit signals for User 1 1001 and User 2 0110", select a pair of suitable PN codes for encoding the 4-bit signals for User 1 and User 2. Show the steps for encoding and give the encoded values and waveform. [6] b) What is the output (waveform and encoded values) after combining the encoded signals 1 and 2 from Part a)? [4] c) State one advantage of using CDMA instead of TDMA for cellular technology. [2] Question 4 [12] Instead of GSM system, the CDMA system is employed for cellular technology. The system is necessary to transmit data bit sequences of User 1 for '1001' and User 2 for '0110' from transmitter to receiver for accessing the information. (Suppose chip 1 is represented by a square waveform with amplitude of +1 and chip 0 is represented by a square waveform with amplitude of -1.) Given a set of PN codes A, B, C and D (PN codes in binary (chip rate= 4)). PNA = 1010 PNB = 0111 PNC -0101 PND = 1110 a) Suppose a CDMA base station encodes two 4-bit signals for User 1 1001 and User 2 0110", select a pair of suitable PN codes for encoding the 4-bit signals for User 1 and User 2. Show the steps for encoding and give the encoded values and waveform. [6] b) What is the output (waveform and encoded values) after combining the encoded signals 1 and 2 from Part a)? [4] c) State one advantage of using CDMA instead of TDMA for cellular technology. [2]