In the domain of wireless digital communication, floating-point arithmetic is generally used to conduct performance evaluation studies of algorithms. This is typically limited to theoretical performance evaluation in terms of communication quality and error rates. For a practical implementation perspective, using fixed-point arithmetic instead of floating-point reduces significantly implementation costs in terms of area occupation and energy consumption. However, this implies a complex conversion process, particularly if the considered algorithm includes complex arithmetic operations with high accuracy requirements and if the target system presents many configuration parameters. In this context, the purpose of the paper is to present an efficient quantization and fixed-point representation for turbo-detection and turbo-demapping. The impact of floating-to-fixed-point conversion is illustrated upon the error-rate performance of the receiver for different system configurations. Only a slight degradation in the error-rate performance of the receiver is observed when implementing the detector and demapper modules which utilize the devised quantization and fixed-point arithmetic rather than floating-point arithmetic.