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A TIME INTERLEAVED BLOCK WINDOWED BURST ORTHOGONAL FREQUENCY DIVISION MULTIPLEXING COMMUNICATION SYSTEM
EP3991374
To improve the spectral efficiency of TIBWB-OFDM, it is proposed a communication system that implements an alternative packing of the windowed OFDM component blocks that form a TIBWB-OFDM symbol. Adjacent windowed OFDM blocks are partially overlapped, instead of being juxtapose as in original proposed TIBWB-OFDM technique. Although the proposed packing method enables a highly efficient spectral transmission, this is achieved at the expense of intentionally introduced interference, by the transmitter, between consecutive sub-blocks that shape the TIBWB-OFDM symbol, which deteriorates the bit error rate performance. To cope with this additional interference, the receiver must entail both channel equalization and inter-block interference cancellation between OFDM component blocks of the TIBWB-OFDM symbol.
TIBWB-OFDM, as presented in, claims several advantages to conventional CP-OFDM. The use of a zero-padding (ZP) improves power efficiency since no power is wasted on its transmission. A spectral efficiency gain is also claimed by the use of time domain square root raised cosine (SRRC) windowing, that improves the spectral confinement and reduces out of band (OOB) emissions of the OFDM-based blocks. Furthermore, in order to achieve higher robustness against channel's deep fades, a time interleave operation is performed between the samples of the OFDM-based blocks. Although spectral confinement increases for higher window's roll-off, the length of the TIBWB-OFDM block increases proportionally, due to the juxtaposition of the component symbols. This implies a reduction of symbol rate, which limits spectral efficiency gains. Also, the overall average power of the TIBWB-OFDM block is reduced thus implying an increase of the PAPR transmitted signal, which limits achievable power efficiency gains.