Evaluation of IR-HARQ schemes in FBMC/OQAM systems with imperfect CSIR

This paper characterizes the sources of distortion of offset-QAM based filter bank multicarrier systems when perfect channel state information at the receiver (CSIR) is not available. The statistical information of the distortion reveals that the mapping scheme, which determines how symbols are inserted in the frequency-time grid, can be optimized to reduce the impact of the estimation error. Moreover, the distortion analysis has been exploited to design variable incremental redundancy hybrid automatic repeat request (IR-HARQ) schemes. Numerical results show that the algorithm devised in this work guarantees the target block error rate (BLER) in low mobility scenarios. In addition, the proposed variable IR-HARQ scheme allows to relinquish up to 75 % of the resources to other users when the initial transmission fails.