example of simulate code matlab for BPSK, QPSK, 8 QAM, square root raised cosine filter

In this project we are simulating code matlab program three modulation schemes; those are namely BPSK, QPSK and 8-QAM.Firstly, we applied Rectangular pulse shaping (RPS) to BPSK, QPSK and 8 QAM. Secondly,we considered BPSK modulation scheme and simulated the system using Square Root Raised Cosine (SQRC) filter as pulse shaping filter and matched filter and we found minimum number of co-efficientsuch that the loss did not exceed 0.5db .Applied same filter to QPSK and 8-QAM and compared the results.We evaluated the coded performance of BPSK, QPSK and 8QAM with SQRC pulse shaping.Finally, we analyzed the transmitted signal spectrum in each case.

1 INTRODUCTION

In digital communication different types of modulations scheme are used to transfer the data from one place to another. Among these modulation schemes the most common modulation schemes are Binary Phase Shift Keying (BPSK), Quadrature Phase Shift Keying and Quadrature Amplitude Shift Keying (QAM). A brief description of these schemes are as follows.

1.1 Binary phase shift keying (BPSK)

Binary phase shift keying (BPSK) is simplest form of phase shift keying (PSK).It uses two phases which are separated by 180⁰ .And it is also termed as 2-PSK,the Bit Error Rate (BER)of BPSK in AWGN can be calculated as

The constellation diagram of BPSK signal is as follows.

Fig 1.1: Constellation diagram of BPSK

In this bits are converted into antipodal noise symbols. It is unsuitable for high data rate applications because it is only modulate 1bit/symbol. BPSK is functionally equivalent to 2-QAM modulation.

1.2 Quadrature Phase Shift-Keying (QPSK)

In Quadrature Phase Shift Keying (QPSK), there is the phase difference of 90^o between transmitted signals. The transmitted signal can be expressed as

The constellation diagram of QPSK signal is as follows.

Fig 1.2: QPSK constellation diagram

1.3 Quadrature Amplitude Modulation (8 QAM)

In Quadrature Amplitude Modulation (QAM) each signal is transmitted as two components. The components are in-phase and quadrature and these components are 90^o phase from each other.

The bit error rate formula of QAM is.

The organization of this report is as follows:

In section 2, we discussed about the background and simulation model for simulation of BPSK, QPSK and 8 QAM with rectangular, SQRC pulse shaping and Hamming code. In section 3 we discussed the result obtained from the simulation. Finally the conclusion is presented in section 4