Codificação para o Canal Gaussiano de Múltiplo Acesso

Marco Cazarotto, Renato da Rocha Lopes

DOI: 10.14209/sbrt.2013.133

Evento: XXXI Simpósio Brasileiro de Telecomunicações (SBrT2013)

Keywords: Gaussian Multiple Access Channel Low Density Parity Check Shaping Fourier Transform.

Abstract

In this paper we propose a coding strategy for the two-user Gaussian Multiple Access Channel. We are interested in the problem from the point of view of the detection of the first user, which will treat the signals from the other user as noise. This strategy is known as Successive Interference Cancellation (SIC). Our coding scheme is based on the Low Density Parity Check (LDPC) codes. On detection, LDPC assumes that the noise is Gaussian. This is not true for the first user, if, e.g., the other user uses 2-PSK modulation. Therefore, we propose two new strategies to modify the second user’s distribution, aiming at making it more Gaussian. The first strategy will utilize Shaping and the second one is based on the discrete Fourier transform. We will show that both strategies outperform the strategy of using a 2-PSK modulation for the second user.

Download