Evaluation of 4RRC-filtered ODQPSK in mobile radio communications

The performance of 4´th-root-raised-cosine-filtered offset differential quadrature phase shift keying (4RRC-filtered ODQPSK) for mobile radio applications is studied. It has been shown that, using a simple binary DPSK receiver, such a scheme outperforms π/4-DQPSK in a linear AWGN channel. In the present work, its bit-error-rate performance using a multiple-symbol differential detection (MSDD) receiver is investigated by means of computer simulation. It is found that, with MSDD, ODQPSK has nearly the same error performance as π/4-DQPSK in a linear AWGN channel. In a hard-limited channel, it has a significant E_b/N_o gain over π/4-DQPSK. ODQPSK with MSDD is comparable to π/4-DQPSK in a fast Rayleigh fading environment