Transmitting/receiving system and method of processing broadcast signal in transmitting/receiving system
A receiving system and a method of processing broadcast signal are disclosed herein. The receiving system includes a signal receiving unit, a detector, and a channel equalizer. The signal receiving unit receives a broadcast signal including mobile service data and a data group including N number of training sequences. The detector detects N number of training sequences from the broadcast signal (wherein N≧5), wherein the detected N number of training sequences are received during N number of training sections. And, the equalizer estimates a channel impulse response (CIR) of N number of training sections, based upon the detected N number of training sequences, applies the channel impulse response estimated in M number of training sections (wherein N≧M) to a cubic spline interpolation function, so as to generate a channel impulse response of (N−1) number of mobile service data sections located between the N number of training sections, thereby performing channel-equalization on the mobile service data of the corresponding mobile service data section.
1. A receiving system, comprising:
a signal receiving unit receiving a broadcast signal, the broadcast signal comprising mobile service data and a data group including N number of training sequences;
a detector detecting N number of training sequences from the broadcast signal (wherein N≧5), the detected N number of training sequences being received during N number of training sections;
an equalizer estimating a channel impulse response (CIR) of N number of training sections, based upon the detected N number of training sequences, applying the channel impulse response estimated in M number of training sections (wherein N≧M) to a cubic spline interpolation function, generating a channel impulse response of (N−1) number of mobile service data sections located between the N number of training sections, thereby performing channel-equalization on the mobile service data of the corresponding mobile service data section;
a block decoder performing turbo-decoding in block units on the channel-equalized mobile service data; and
an error correction unit performing error correction decoding on the turbo-decoded mobile service data, thereby correcting errors occurring in the mobile service data.
2. The receiving system of claim 1 , each of the N number of training sequences is located at constant intervals within the data group.
3. The receiving system of claim 2 , wherein the data group being received corresponds to one of a data group including field synchronization data and a data group not including any field synchronization data, wherein, in the data group including field synchronization data, N is equal to 6, and 6 training sequences correspond to 1 field synchronization data sequence and 5 known data sequences, and wherein, in data group not including any field synchronization data, N is equal to 5, and 5 training sequences correspond to 5 known data sequences.
4. The receiving system of claim 3 , wherein the equalizer applies channel impulse responses (CIRs) estimated in 5 training sections to each cubic spline interpolation function of (N−1) number of mobile service data sections, thereby generating a CIR for each mobile service data section.
5. The receiving system of claim 4 , wherein each cubic spline interpolation function of the (N−1) number of mobile service data sections consists of a cubic equation, and wherein coefficients of the cubic equation of the (N−1) number of mobile service data sections are calculated by multiplying a [16×5] constant matrix by a [5×1] CIR matrix.
6. The receiving system of claim 5 , wherein, when the data group includes field synchronization data, 5 CIRs of the [5×1] CIR matrix used in the cubic equation of first and second mobile service data sections, among the (N−1) number of mobile service data sections, correspond to 5 CIRs obtained earlier among the N number of CIRs obtained in N number of training section.
7. The receiving system of claim 5 , wherein, when the data group includes field synchronization data, 5 CIRs of the [5×1] CIR matrix used in the cubic equation of third to fifth mobile service data sections, among the (N−1) number of mobile service data sections, correspond to 5 CIRs obtained later among the N number of CIRs obtained in N number of training section.
8. The receiving system of claim 1 , wherein, when the mobile service data are not located between training sections, the equalizer generates a CIR of an extrapolation section including the mobile service data by applying channel impulse responses (CIRs) estimated in at least 2 training sections to an extrapolation function, and performs channel-equalization on the mobile service data of the extrapolation section.
9. The receiving system of claim 8 , wherein the equalizer compensates a power of a CIR of the extrapolation section, so that a proportional relation between a power of a signal and the compensated power of the CIR both measured in the extrapolation section can become identical to a proportional relation between a power of a signal and a power of a CIR both measured in at least one training section.
10. A broadcast signal processing method in a receiving system, comprising:
receiving a broadcast signal, the broadcast signal comprising mobile service data and a data group including N number of training sequences;
detecting N number of training sequences from the broadcast signal (wherein N≧5), the detected N number of training sequences being received during N number of training sections;
estimating a channel impulse response (CIR) of N number of training sections, based upon the detected N number of training sequences, applying the channel impulse response estimated in M number of training sections (wherein N≧M) to a cubic spline interpolation function, generating a channel impulse response of (N−1) number of mobile service data sections located between the N number of training sections, thereby performing channel-equalization on the mobile service data of the corresponding mobile service data section;
performing turbo-decoding in block units on the channel-equalized mobile service data; and
performing error correction decoding on the turbo-decoded mobile service data, thereby correcting errors occurring in the mobile service data.
11. The method of claim 10 , wherein the data group being received corresponds to one of a data group including field synchronization data and a data group not including any field synchronization data, wherein, in the data group including field synchronization data, N is equal to 6, and 6 training sequences correspond to 1 field synchronization data sequence and 5 known data sequences, and wherein, in data group not including any field synchronization data, N is equal to 5, and 5 training sequences correspond to 5 known data sequences.
12. The method of claim 11 , wherein performing channel-equalization applies channel impulse responses (CIRs) estimated in 5 training sections to each cubic spline interpolation function of (N−1) number of mobile service data sections, thereby generating a CIR for each mobile service data section.
13. The method of claim 12 , wherein each cubic spline interpolation function of the (N−1) number of mobile service data sections consists of a cubic equation, and wherein coefficients of the cubic equation of the (N−1) number of mobile service data sections are calculated by multiplying a [16×5] constant matrix by a [5×1] CIR matrix.
14. The method of claim 13 , wherein, when the data group includes field synchronization data, 5 CIRs of the [5×1] CIR matrix used in the cubic equation of first and second mobile service data sections, among the (N−1) number of mobile service data sections, correspond to 5 CIRs obtained earlier among the N number of CIRs obtained in N number of training section.
15. The method of claim 13 , wherein, when the data group includes field synchronization data, 5 CIRs of the [5×1] CIR matrix used in the cubic equation of third to fifth mobile service data sections, among the (N−1) number of mobile service data sections, correspond to 5 CIRs obtained later among the N number of CIRs obtained in N number of training section.
16. The method of claim 10 , wherein performing channel-equalization comprises:
when the mobile service data are not located between training sections, generating a CIR of an extrapolation section including the mobile service data by applying channel impulse responses (CIRs) estimated in at least 2 training sections to an extrapolation function; and
performing channel-equalization on the mobile service data of the extrapolation section.
17. The method of claim 16 , comprising:
compensating a power of a CIR of the extrapolation section, so that a proportional relation between a power of a signal and the compensated power of the CIR both measured in the extrapolation section can become identical to a proportional relation between a power of a signal and a power of a CIR both measured in at least one training section.