OFDM and FBMC transmission techniques: a compatible high performance proposal for broadband power line communications

Abstract

A filter bank multicarrier (FBMC) system having a high level of compatibility with the IEEE P1901 OFDM scheme is proposed. In order to reach the level of robustness, selectivity and performance required by the broadband power line, the approach is based on near perfect reconstruction (NPR) filters combined with OQAM modulation. A key feature of the approach is the fractionally-spaced sub-channel equalizer, which is able to compensate the channel distortions and cope with residual timing offsets. The system initialization procedure and the results of OFDM are exploited by FBMC and an efficient and accurate technique is described for the derivation of the subchannel equalizer coefficients from the OFDM frequency domain equalizer coefficients. Then, the impact of the filter impulse response on the efficiency in packet transmission is minimized. Finally, the impact of the sub-channel spacing is investigated and, in a comparison on similar basis, it appears that the proposed FBMC system can reach 228 Mbit/s in maximum bit rate, versus 197 Mbit/s for OFDM, while providing a higher level of tone protection and robustness to jammers.

Low-complexity factor-graph-based MAP detector for filter bank multicarrier systems

“…If we want to use the PPN structure to reduce the complexity, the sub-channel filters have to be converted into a time domain [2] .…”

“…Usually, the ZF (Zero Forcing) or MMSE (Minimum Mean Square Error) criteria combined with per subcarrier channel equalizers are considered to deal with the interference because of their low computational complexity [2] . When the channel is perfectly equalized, the interference will be restored to the purely imaginary domain and will not disturb the detection.…”

“…After SMT modulation, the transmitted baseband signal can be expressed as There are two types of SMT receiver structures: PPN (Polyphase Network) [2] and FS (Frequency Despreading) [11,12] . PPN needs an M-point FFT (Fast Fourier Transform) operation, whereas FS needs an FFT operation whose size must equal the length of the prototype filter to cover the full spectrum.…”

Flat spectrum signal synthesis in filter bank multicarrier systems

“…Throughout this paper the choice of the prototype filter is identical to the one used in [5], known as the PHYDYAS filter, with = 4. In Figs.…”

On the effect of ISI in the error performance of precoded FBMC/OQAM systems

“…In this case, the orthogonality of (3) is no more verified, because the subchannels are also going to be frequency selective. These equalizers are fractionally spaced (because the system operates at twice the symbol rate) and can deal with residual misalignments and severe channel impairments [8].…”