Adaptive use of two decode-and-forward algorithms in relay-enhanced wireless transmissions

The use of cooperative channel coding is shown to increase the performance of relay-assisted wireless transmissions. This paper analyzes the spectral efficiencies provided by two cooperative channel coding algorithms and by the non-cooperative transmission, while ensuring a coded-block error rate (BLER) smaller than a target value BLERt. The results obtained in the study are used to propose an adaptive employment of these transmission configurations, in order to provide the greatest spectral efficiency, while observing the BLERt constraint, in terms of the SNR values of the involved channels. The cooperation algorithm can be seen as a new dimension of link adaptation, besides the modulations and channel coding type and rate. The paper also analyzes the effects of the configuration´s parameters, i.e. different modulations and coding rates used on the component links, upon the spectral efficiencies provided by the studied algorithms.