Theoretical Analysis and CRLB Evaluation for Pilot-Aided Channel Estimation in GFDM

New waveform candidates are being investigated for the fifth generation wireless systems. Among the promising candidates, generalized frequency division multiplexing (GFDM) offers the flexibility to address a wide range of requirements (e.g. low latency, coarse synchronization, etc.). Due to the non- orthogonality of GFDM, the transmit signal subjects to inter-symbol and inter-carrier interference. In this paper, the problem of GFDM channel estimation with the aid of reference signals (pilots) is investigated. In GFDM, the receive signal is a combination of pilots, data and the noise part. Hence, when utilizing the conventional estimation techniques, degradation of channel estimation performance due to interference from data symbols further challenges the receiver design for GFDM. We show that if we employ multiple pilots per subcarrier within a single GFDM block, different pilot patterns have significant impact on the resulting interference term and thus, the quality of the channel estimation in GFDM. Such results are then compared with the performance of channel estimation in orthogonal frequency division multiplexing (OFDM) which takes advantage of clear pilot observation.