| 主权项 |
1. A received signal processing device that regards, as one process, phase compensation for one separated symbol group acquired by separating every certain number of symbols of a modulated received signal and making the symbols form a block, and sequentially performs the process multiple times according to the number of the separated symbol group, the device comprising: a carrier recovery unit that includes:
a separation and output section that temporally separates the symbols input into the block in a constant time interval, for every constant number of symbols to obtain the separated symbol group, and outputs the group in a sequence of the separated symbols constituting the separated symbol group; an a priori state estimation section that obtains an intra-block a priori estimation frequency and an intra-block a priori estimation central phase, as a priori estimates that are estimates of values processed this time, from values processed last time of one intra-block frequency determined based on phase variation of each of the separated symbols with respect to time, and one intra-block central phase determined as a temporal center of each phase of each of the separated symbols; a provisional compensation section that calculates an a priori estimation phase of each of the separated symbols from the a priori estimate, and provisionally compensates the phase of each of the separated symbols based on the a priori estimation phase; a decision section that regards, as a symbol before decision, each of the separated symbols whose phase has been provisionally compensated, performs decision for the symbol before decision based on the reference signal set according to a modulation scheme of the received signal, and obtains a symbol after decision that coincides with a reference point of the reference signal; an error estimation section that calculates a frequency error between an observed value of the intra-block frequency and the intra-block a priori estimation frequency which are determined based on the symbol before decision and the symbol after decision, and calculates a phase error between an observed value of the intra-block central phase and the intra-block a priori estimation central phase which are determined based on the symbol before decision and the symbol after decision; an a posteriori state estimation section that corrects the a priori estimates based on the frequency error and the phase error, and obtains an intra-block a posteriori estimation frequency and an intra-block a posteriori estimation central phase as a posteriori estimates obtained by estimating most likely values processed this time that are of the intra-block frequency and the intra-block central phase; an actual compensation section that calculates an a posteriori estimation phase of each of the separated symbols from the a posteriori estimate, and actually compensates the phase of each of the separated symbols based on the a posteriori estimation phase; and a feedback processing section that performs a feedback process so that the a priori state estimation section can adopt the a posteriori estimates as the values processed last time of the intra-block frequency and the intra-block central phase, and obtains the a priori estimates for the separated symbol group in the next phase compensation. |
