Gateway signaling method for frequency/timing offset, and device therefor
Disclosed herein are a gateway-signaling method for frequency/timing offsets and an apparatus for the same. An apparatus for transmitting a broadcast signal according to an embodiment of the present invention includes a frequency/timing decision unit for determining a center frequency to which a frequency offset is applied using a carrier offset, which is identified using a timing and a management packet transmitted through a Studio-to-Transmitter Link (STL); and an RF signal generation unit for generating an RF signal to be transmitted, which corresponds to the center frequency.
1. An apparatus for transmitting a radio frequency (RF) broadcast signal, the apparatus comprising:
a frequency/timing decision unit for determining a center frequency to which a frequency offset is applied using a carrier offset, the carrier offset identified by a carrier offset field of a received timing and management packet that was transmitted through a Studio-to-Transmitter Link (STL); and
an RF signal generation unit for generating the RF broadcast signal to be transmitted, which corresponds to the center frequency.
2. The apparatus of claim 1 , wherein the frequency/timing decision unit determines a timing offset to be applied to a bootstrap corresponding to the RF signal using the carrier offset.
3. The apparatus of claim 2 , further comprising:
a structure data extractor for extracting structure data, which is transmitted from a broadcast gateway device and includes data fields for all of transmitters in a transmitter group for transmitting a same waveform.
4. The apparatus of claim 3 , wherein the structure data extractor extracts the carrier offset field, which represents the carrier offset, from among the data fields.
5. The apparatus of claim 4 , wherein the carrier offset field is a two's complement signed integer binary number and is represented as a positive or negative integer corresponding to an OFDM carrier.
6. The apparatus of claim 5 , wherein the carrier offset is equal to a product of a carrier offset field value and carrier frequency spacing.
7. The apparatus of claim 6 , wherein the carrier frequency spacing is equal to a baseband sampling rate divided by a minimum FFT size.
8. The apparatus of claim 7 , wherein the timing offset is set so as to correspond to a delay when the carrier offset field value is a positive value, but is set so as to correspond to an advance when the carrier offset field value is a negative value.
9. A broadcast gateway device, comprising:
a packet generation unit for generating a timing and management packet for signaling a carrier offset to transmitters in a transmitter group for transmitting a same waveform; and
an STL transmission unit for transmitting the timing and management packet to the transmitters through a Studio-to-Transmitter Link (STL);
wherein the carrier offset is indicated by a carrier offset field, which is a two's complement signed integer binary number.
10. The broadcast gateway device of claim 9 , wherein the carrier offset is equal to a product of a carrier offset field value and carrier frequency spacing.
11. The broadcast gateway device of claim 10 , wherein the carrier frequency spacing is equal to a baseband sampling rate divided by a minimum FFT size.
12. The broadcast gateway device of claim 11 , wherein:
when the carrier offset field value is a positive value, a timing offset of a bootstrap corresponds to a delay, and
when the carrier offset field value is a negative value, the timing offset of the bootstrap corresponds to an advance.
13. The broadcast gateway device of claim 12 , wherein the carrier frequency spacing corresponds to a 6 MHz channel bandwidth and a baseband sampling rate of 6.192 Mega-samples/second.
14. The broadcast gateway device of claim 13 , wherein the same carrier frequency spacing is maintained even when different FFT sizes are used for multiple subframes.
15. A gateway-signaling method, comprising:
generating structure data for signaling a carrier offset to transmitters in a transmitter group for transmitting a same waveform;
generating a timing and management packet including the structure data; and
transmitting the timing and management packet to the transmitters through a Studio-to-Transmitter Link (STL);
wherein the carrier offset is indicated by a carrier offset field, which is a two's complement signed integer binary number.
16. The gateway-signaling method of claim 15 , wherein the carrier offset is equal to a product of a carrier offset field value and carrier frequency spacing.
17. The gateway-signaling method of claim 16 , wherein:
when the carrier offset field value is a positive value, a timing offset of a bootstrap corresponds to a delay, and
when the carrier offset field value is a negative value, the timing offset of the bootstrap corresponds to an advance.
18. The gateway-signaling method of claim 17 , wherein the same carrier frequency spacing is maintained even when different FFT sizes are used for multiple subframes.