Abstract: Phase noise estimation and cancellation as disclosed herein may allow cost-efficient increase of capacity in communications by enabling very high QAM levels. The proposed solution is potentially applicable to any single carrier applications where phase noise is a limiting factor and a required order of modulation is very high. For example, disclosed embodiments may enable high QAM levels for microwave backhauls despite severe phase noise sensitivity. One embodiment involves a pilot-aided and BCJR-based sequential search algorithm that accurately estimates and subtracts fast-varying phase noise symbol-by-symbol. Residual BER performance is evaluated under the most challenging phase noise scenarios. FPGA emulation results show detection and removal of a significant amount of phase noise and zero BER performance even for complex 1K-QAM and above.

Abstract: Cross-phase interference occurs in dual polarized or orthogonal polarized microwave links when independent local oscillators (LOs) are utilized in each outdoor unit (ODU) transceiver operating on the same frequency channel. If the cross-phase noise is not compensated the performance of the microwave link will be degraded. In order to reduce cross-phase noise two or more pilot symbols are utilized to enable cross-phase noise estimates to be determined at the receiver of the microwave link. The pilot symbols enable a cross-phase noise compensation factor to be determined for the signal from the one or more cross-phase noise estimates. The received signal can then be compensated using the estimated cross-phase noise compensation factor.

Abstract: Phase noise estimation and cancellation as disclosed herein may allow cost-efficient increase of capacity in communications by enabling very high QAM levels. The proposed solution is potentially applicable to any single carrier applications where phase noise is a limiting factor and a required order of modulation is very high. For example, disclosed embodiments may enable high QAM levels for microwave backhauls despite severe phase noise sensitivity. One embodiment involves a pilot-aided and BCJR-based sequential search algorithm that accurately estimates and subtracts fast-varying phase noise symbol-by-symbol. Residual BER performance is evaluated under the most challenging phase noise scenarios. FPGA emulation results show detection and removal of a significant amount of phase noise and zero BER performance even for complex 1K-QAM and above.

Abstract: Cross-phase interference occurs in dual polarized or orthogonal polarized microwave links when independent local oscillators (LOs) are utilized in each outdoor unit (ODU) transceiver operating on the same frequency channel. If the cross-phase noise is not compensated the performance of the microwave link will be degraded. In order to reduce cross-phase noise two or more pilot symbols are utilized to enable cross-phase noise estimates to be determined at the receiver of the microwave link. The pilot symbols enable a cross-phase noise compensation factor to be determined for the signal from the one or more cross-phase noise estimates. The received signal can then be compensated using the estimated cross-phase noise compensation factor.