HK1139265B - A digital multimedia receiver and a digital multimedia receiving method thereof - Google Patents

Description

Digital multimedia receiver and digital multimedia receiving method thereof

This application is a divisional application of patent applications entitled "digital multimedia receiver and digital multimedia receiving method thereof", filed on 17.12.2004 and having an application number of 200410098816.9.

Technical Field

The present invention relates to a digital multimedia receiver and a digital multimedia receiving method, and more particularly, to a digital multimedia receiver and a digital multimedia receiving method for processing a multi-carrier modulated digital multimedia signal and a single-carrier modulated digital multimedia signal.

Background

In the era of multimedia communication and broadcasting, digitalization of analog broadcasting is performed in countries around the world. Especially in developed countries like the united states, europe and japan, digital broadcasting systems have been developed and put into practical use. According to such rapid development, different standards have been proposed for digital broadcasting in various countries.

The Federal Communications Commission (FCC) in the united states proposed the Advanced Television Systems Committee (ATSC) digital television standard as the next generation television broadcast standard 24/12 in 1996. All terrestrial broadcast operators must comply with the ATSC standard with respect to the specifications of video/audio compression, packet data transmission structure, and modulation and transmission systems. The specification regarding only video formats is not specified and is left to the industry.

The ATSC digital TV standard transmits high quality video, audio, and additional data over a bandwidth of 6MHz using a single carrier VSB scheme, and simultaneously supports a terrestrial broadcast mode and a high data rate cable broadcast mode. The main aspect of this approach is the 8-VSB modulation method for digital modulation, which is a modified form of the existing BSB approach.

In europe, COFDM (coded orthogonal frequency division multiplexing) systems have been applied to DVB-T (digital video broadcasting-terrestrial) for its high frequency utilization and interference rejection capability.

Other digital multimedia broadcasting schemes using a plurality of modulation methods have been proposed, and all schemes can be classified into a multi-carrier scheme and a single-carrier scheme. Accordingly, the conventional digital multimedia receiver is classified into a multi-carrier digital multimedia receiver and a single-carrier digital multimedia receiver.

Fig. 1 is a schematic block diagram illustrating a multi-carrier digital multimedia receiver according to the prior art.

The conventional multi-carrier digital multimedia receiver includes: a tuner 110 for receiving a multi-carrier modulated digital multimedia signal; an analog-to-digital converter (ADC)120 for converting the signal output from the tuner 110 into a digital signal; a demodulator 130 for demodulating the multicarrier-modulated signal output from the ADC 120; a Fast Fourier Transform (FFT) unit 140 for performing fast fourier transform on the signal output from the demodulator 130; a Synchronization (SYNC) unit 150 for synchronizing the demodulator 130 by using a signal output from the demodulator 130 or a signal output from the FFT unit 140; an equalization unit 160 for equalizing the signal output from the FFT unit 140; a Forward Error Correction (FEC) unit 170 for performing forward error correction on the signal output from the equalization unit 160; and a descrambler 180 for descrambling the signal output from the FEC unit 170 to obtain an MPEG stream.

Fig. 2 is a schematic block diagram illustrating a single carrier digital multimedia receiver according to the prior art.

A conventional single carrier digital multimedia receiver includes: a tuner 210 for receiving a single-carrier modulated digital multimedia signal; an analog-to-digital converter (ADC)220 for converting the signal output from the tuner 210 into a digital signal; a demodulator 230 for demodulating the single-carrier modulated signal output from the ADC 220; a Synchronization (SYNC) unit 240 for synchronizing the demodulator 230 by using a signal output from the demodulator 230; an equalization unit 250 for equalizing the signal output from the demodulator 230; a Forward Error Correction (FEC) unit 260 for performing forward error correction on the signal output from the equalization unit 250; and a descrambler 270 for descrambling the signal output from the FEC unit 260 to obtain an MPEG stream.

It is known in the prior art that there is no digital multimedia receiver that handles both multi-carrier modulated digital multimedia signals and single carrier modulated digital multimedia signals, i.e., a conventional digital multimedia receiver cannot operate in multiple digital multimedia broadcasting systems.

Disclosure of Invention

The present invention has been developed in order to solve the above-mentioned disadvantages and other problems of the conventional solutions.

According to an aspect of the present invention, a digital multimedia receiver for processing a multi-carrier modulated digital multimedia signal and a single-carrier modulated digital multimedia signal includes: a tuner for receiving the modulated digital multimedia signal; an analog-to-digital converter (ADC) for converting the signal output from the tuner into a digital signal; a pattern detector for detecting whether the signal output from the ADC is a digital multi-carrier modulated signal or a digital single-carrier modulated signal, based on the identification information read from the signal output from the ADC; and a demodulation unit for demodulating the digital multi-carrier modulated signal and the digital single-carrier modulated signal output from the ADC according to the detection result output from the pattern detector.

According to an aspect of the present invention, a demodulation unit of a digital multimedia receiver includes: a switch for switching a signal output from the ADC according to a result output from the mode detector; a multi-carrier demodulator for demodulating the digital multi-carrier modulated signal output from the ADC via the switch; and a single carrier demodulator for demodulating the digital single carrier modulated signal output from the ADC via the switch.

According to an aspect of the present invention, a demodulation unit of a digital multimedia receiver includes: a demodulator in which multi-carrier and single-carrier demodulation parameters are preset, for demodulating one of the digital multi-carrier modulated signal and the digital single-carrier modulated signal output from the ADC, based on a result output from the pattern detector; and a switch for switching the signal output from the demodulator according to the signal output from the mode detector.

According to the digital multimedia receiver of the present invention, the identification information detected by the pattern detector is a PN (pseudo random noise) sequence inserted into the header of the data frame of the digital multimedia signal.

According to the digital multimedia receiver of the present invention, the identification information detected by the pattern detector is at least one pilot inserted into the modulated digital multimedia signal.

According to the digital multimedia receiver of the present invention, the identification information detected by the pattern detector is a PN sequence inserted into a header of a data frame of the digital multimedia signal and at least one pilot inserted into the modulated digital multimedia signal.

According to another aspect of the present invention, a digital multimedia receiving method for processing a multi-carrier modulated digital multimedia signal and a single-carrier modulated digital multimedia signal includes the steps of: a) receiving a modulated digital multimedia signal; b) converting the signal output from step a) into a digital signal; c) detecting whether the signal output from step b) is a digital multi-carrier modulated signal or a digital single-carrier modulated signal based on the identification information read from the signal output from step b); and d) demodulating the digital multi-carrier modulated signal and the digital single-carrier modulated signal output from step b) according to the detection result output from step c).

According to the digital multimedia receiving method of the present invention, in step c), the identification information is a PN (pseudo random noise) sequence inserted into a header of a data frame of the digital multimedia signal.

According to the digital multimedia receiving method of the present invention, in step c), the identification information is at least one pilot inserted into the modulated digital multimedia signal.

According to the digital multimedia receiving method of the present invention, in step c), the identification information is a PN sequence inserted into a header of a data frame of the digital multimedia signal and at least one pilot inserted into the modulated digital multimedia signal.

Accordingly, identification information such as a PN sequence inserted into a header of a data frame of the digital multimedia signal and at least one pilot inserted into the modulated digital multimedia signal is detected, so that the receiver can determine whether the currently processed signal is a multi-carrier modulated signal or a single-carrier modulated signal.

Drawings

The foregoing aspects and other features and advantages of the invention will become more apparent from the following detailed description, taken in conjunction with the accompanying drawings, in which:

fig. 1 is a schematic block diagram illustrating a multi-carrier digital multimedia receiver according to the prior art;

fig. 2 is a schematic block diagram illustrating a single carrier digital multimedia receiver according to the prior art;

FIG. 3 is an exemplary block diagram illustrating a digital multimedia transmitter for transmitting a digital multimedia signal with identification information inserted therein;

FIG. 4 is an exemplary block diagram illustrating a digital multimedia receiver for processing a multi-carrier modulated digital multimedia signal and a single carrier modulated digital multimedia signal in accordance with a first embodiment of the present invention;

FIG. 5 is an exemplary block diagram illustrating a digital multimedia receiver for processing a multi-carrier modulated digital multimedia signal and a single carrier modulated digital multimedia signal in accordance with a second embodiment of the present invention;

fig. 6a is a schematic diagram showing a structure of a demodulation unit of a digital multimedia receiver according to a second embodiment of the present invention;

fig. 6b is a diagram showing demodulation parameters for a multi-carrier modulated signal and a single-carrier modulated signal stored in a register array in a demodulator of a demodulation unit according to the second embodiment of the present invention;

fig. 7 is a schematic diagram showing the PN sequence-based pattern detection principle and the structures of a data frame of a multicarrier-modulated signal and a data frame of a single-carrier-modulated signal into which a PN sequence is inserted;

fig. 8 is a diagram illustrating a pilot-based pattern detection principle and a pilot inserted into a modulated signal; and

fig. 9 is a flowchart of a digital multimedia receiving method for processing a multi-carrier modulated signal and a single-carrier modulated signal according to the present invention.

Detailed Description

The present invention is described in detail with reference to the accompanying drawings. Like reference numerals in the drawings refer to like elements.

Fig. 3 is an exemplary block diagram illustrating a digital multimedia transmitter for transmitting a digital multimedia signal into which identification information is inserted.

Wherein the transmitter having the identification information inserted therein in the digital multimedia signal to be transmitted comprises: a scrambler 310 for scrambling the MPEG stream; a FEC (forward error correction) unit 320 for performing forward error correction on the signal output from the scrambler 310; a modulation/IDFT (inverse discrete fourier transform) unit 330 for modulating or inverse discrete fourier transforming the signal output from the FEC unit 320; a PN sequence inserting unit 340 for inserting a PN sequence into the head of the data frame of the signal output from the modulation/IDFT unit 330; a pilot inserting unit 350 for inserting at least one pilot into the signal output from the PN sequence inserting unit 340; and an RF unit 360 for converting a signal output from the pilot inserting unit 350 into an RF signal.

In conventional multi-carrier and single-carrier digital multimedia systems, the PN sequence and at least one pilot inserted into the signal at the transmitter are used in the receiver for synchronization and channel estimation. However, in the present invention, the PN sequence and the pilot may be used as identification information for distinguishing a multi-carrier modulated signal from a single-carrier modulated signal.

Whether only one kind of identification information such as a PN sequence or at least one pilot or both kinds of identification information are inserted into a signal depends on a transmitter. If the modulation mode or the structure of the data frame is changed, other identification information corresponding to the transmission mode in the transmitter may be inserted into the signal.

Fig. 4 is an exemplary block diagram illustrating a digital multimedia receiver for processing a multi-carrier modulated digital multimedia signal and a single-carrier modulated digital multimedia signal according to a first embodiment of the present invention.

A digital multimedia receiver for processing a multi-carrier modulated signal and a single-carrier modulated signal comprising: a tuner 410; an ADC (analog-to-digital converter) 420; a pattern detector 430 for detecting whether the signal output from the ADC420 is a digital multi-carrier modulated signal or a digital single-carrier modulated signal, based on the identification information read from the signal output from the ADC 420; a demodulation unit 440 for demodulating the digital multi-carrier modulated signal and the digital single-carrier modulated signal output from the ADC420 according to the detection result output from the pattern detector 430; and a multi-carrier and single-carrier processing unit after the demodulation unit 440. All elements of the digital multimedia receiver according to the present invention except for the pattern detector 430 and the demodulation element 440 operate in the same manner as those of the conventional receiver. Therefore, the operation of those units will not be described in detail.

Demodulation unit 440 includes switch 441, multi-carrier demodulator 442, and single-carrier demodulator 443.

As shown in fig. 4, the pattern detector 430 detects identification information such as a specific PN sequence and at least one specific pilot inserted into a signal from the signal output from the ADC420, so that it can determine whether the signal output from the ADC420 is a multi-carrier modulated signal or a single-carrier modulated signal. Thereafter, the mode detector 430 outputs the detection result to the switch 441. In response to the detection result output from the mode detector 430, the switch 441 switches to allow the multi-carrier demodulator 442 or the single-carrier demodulator 443 to process the multi-carrier modulated signal or the single-carrier modulated signal output from the ADC420 accordingly. Thereafter, the multi-carrier demodulator 442 or the single-carrier demodulator 443, respectively, transmits the demodulated signals to a respective subsequent multi-carrier or single-carrier processing unit.

Next, a process of detecting the identification information in the pattern detector 430 will be described with reference to fig. 7 and 8.

Fig. 7 is a schematic diagram showing the PN sequence-based pattern detection principle and the structures of a data frame of a multicarrier-modulated signal and a data frame of a single-carrier-modulated signal into which a PN sequence is inserted.

As described above with reference to fig. 3, identification information such as a PN sequence and at least one pilot is inserted into a signal at a digital multimedia transmitter. After receiving the digital multimedia transmission signal from the transmitter, the digital multimedia receiver processes the received signal.

When detecting a multi-carrier mode or a single-carrier mode from the PN sequence, the mode detector 430 reads the PN sequence from the head of the data frame of the signal output from the ADC 420. Thereafter, the pattern detector 430 compares the PN sequence read from the head of the data frame of the signal output from the ADC420 with the PN sequences corresponding to the multi-carrier modulated signal and the single-carrier modulated signal stored in the pattern detector 430, thereby determining which preset PN sequence stored in the pattern detector 430 corresponds to the read PN sequence. From the comparison, the mode detector 430 determines whether the transmission mode of the digital multimedia signal (i.e., the signal from which the PN sequence is read) is a multi-carrier mode or a single-carrier mode. Thereafter, the mode detector 430 outputs the detection result to the switch 441.

Fig. 8 is a diagram illustrating a pilot-based pattern detection principle and a pilot inserted into a modulated signal.

When detecting a multi-carrier mode or a single-carrier mode from at least one pilot, the mode detector 430 detects the at least one pilot from the signal output from the ADC 420. Thereafter, the pattern detector 430 calculates a power difference between a peak value of the power of the pilot and an average power value of the signal output from the ADC 420. If the detected power difference is within the range of the value for the multicarrier signal preset in the pattern detector 430, it is determined that the pilot corresponding to Pm is the pilot for the multicarrier modulated signal, the Pm being the power difference between the peak value of the power of the pilot for the multicarrier modulated signal and the average power value of the multicarrier modulated signal. In other words, the modulated signal into which the pilot corresponding to Pm is inserted is a multicarrier modulated signal. Similarly, the modulation signal into which the pilot is inserted is determined to be a single-carrier modulated signal if the detected pilot corresponds to Ps, which is a power difference between a peak value of the power of the pilot for the single-carrier modulated signal and an average power value of the single-carrier modulated signal.

Those skilled in the art will readily appreciate that these two types of identification information may be used separately or in combination.

Fig. 5 is an exemplary block diagram illustrating a digital multimedia receiver for processing a multi-carrier modulated digital multimedia signal and a single carrier modulated digital multimedia signal according to a second embodiment of the present invention.

All processing units of the digital multimedia receiver shown in fig. 5 are the same as those shown in fig. 4, except for a demodulation unit 540 including a demodulator 541, a switch 542. Therefore, the operation process for detecting identification information such as a PN sequence and at least one pilot in this embodiment is the same as the detection operation process of the embodiment shown in fig. 4. However, the demodulation process according to the detection result output from the pattern detector 430 is different from the demodulation process in the embodiment shown in fig. 4.

As shown in fig. 5, a plurality of multi-carrier and single-carrier demodulation parameters are stored in the register array of demodulator 541, so that demodulator 541 can demodulate a multi-carrier modulated signal and a single-carrier modulated signal, respectively, according to these parameters.

This operation process will be described later in conjunction with fig. 6a and 6 b.

Fig. 6a is a schematic diagram showing the structure of a demodulation unit of a digital multimedia receiver according to a second embodiment of the present invention.

Fig. 6b is a diagram showing demodulation parameters for a multi-carrier modulated signal and a single-carrier modulated signal stored in a register array in a demodulator of a demodulation unit according to the second embodiment of the present invention.

As shown in fig. 6a, demodulator 541 includes a plurality of multiplication units M1-M4 for performing demodulation calculations and a register array storing multi-carrier and single-carrier demodulation parameters. These multiplication units M1 to M4 perform multi-carrier demodulation calculation or single-carrier demodulation calculation accordingly by using the demodulation parameters for the multi-carrier mode or the demodulation parameters for the single-carrier mode as shown in fig. 6 b. According to the detection result output from the pattern detector 430, the multiplication units M1 to M4 read the demodulation parameters C11 to C14 for the multi-carrier mode, respectively, to perform multi-carrier demodulation calculation, or read the demodulation parameters C21 to C24 for the single-carrier mode, respectively, to perform single-carrier demodulation calculation. In this way, a multi-carrier demodulated signal or a single-carrier demodulated signal is obtained.

If the pattern detector 430 detects that the signal output from the ADC420 is a multicarrier-modulated signal, the switch 542 switches according to the detection result to allow a subsequent multicarrier processing unit to process the demodulated signal output from the demodulator 541. Similarly, if the pattern detector 430 detects that the signal output from the ADC420 is a single-carrier modulated signal, the switch 542 switches according to the detection result to allow a subsequent single-carrier processing unit to process the demodulated signal output from the demodulator 541.

Fig. 9 is a flowchart of a digital multimedia receiving method for processing a multi-carrier modulated signal and a single-carrier modulated signal according to the present invention.

In step S910, the receiver receives a multi-carrier modulated digital multimedia signal or a single-carrier modulated digital multimedia signal. In step S920, the ADC converts the signal output from step S910 into a digital signal. In step S930, the pattern detector 430 detects whether the signal is a multicarrier modulated signal based on the identification information inserted into the signal in the transmitter. If the detected signal is a multicarrier-modulated signal, the demodulation unit demodulates the signal in a multicarrier demodulation mode in step S940, and thereafter performs processing after multicarrier demodulation in the receiver in step S950. If the detected signal is not a multicarrier modulated signal, the demodulation unit demodulates the signal in a single carrier demodulation mode in step S960, and thereafter performs processing after single carrier demodulation in the receiver in step S970.

The detailed processing in step S930 is similar to that described above with reference to fig. 4 with respect to the pattern detector 430 and thus will be omitted.

The identification information inserted into the digital multimedia signal as described above includes a PN sequence, at least one pilot, or both thereof. Those skilled in the art will readily appreciate that any other identifying information corresponding to the transmission mode may be used to identify a multi-carrier modulated signal or a single carrier modulated signal.

As described above, according to the digital multimedia receiver and the digital multimedia receiving method of the present invention, not only the multi-carrier modulated digital multimedia signal but also the single-carrier modulated digital multimedia signal can be processed by detecting the identification information inserted into the signal in the transmitter. That is, the digital multimedia receiver according to the present invention can operate in various digital multimedia broadcasting systems.

Although embodiments of the present invention have been shown and described, it would be appreciated by those skilled in the art that changes and modifications may be made without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.

Claims (5)

1. A digital broadcast receiver, comprising:

a tuner for receiving a signal, wherein data frames of the signal are modulated by a single carrier or multi-carrier, and a plurality of pilots are inserted into each data frame;

an analog-to-digital converter ADC for converting a signal output from the tuner into a digital signal;

a pattern detector for detecting whether the signal output from the ADC is a digital multi-carrier modulated signal or a digital single-carrier modulated signal, based on the identification information read from the signal output from the ADC;

a demodulation unit for demodulating a signal output from the ADC; and

a multi-carrier and single-carrier processing unit for performing processing after multi-carrier demodulation and single-carrier demodulation,

wherein, demodulation unit includes: a switch for switching a signal output from the ADC according to a result output from the mode detector; a multi-carrier demodulator for demodulating the digital multi-carrier modulated signal output from the ADC via the switch; and a single carrier demodulator for demodulating the digital single carrier modulated signal output from the ADC via the switch.

2. The digital broadcast receiver of claim 1, wherein the multi-carrier demodulator and the single-carrier demodulator are preset with multi-carrier and single-carrier demodulation parameters for demodulating one of the digital multi-carrier modulated signal and the digital single-carrier modulated signal output from the ADC according to the result output from the pattern detector.

3. The digital broadcast receiver of claim 1 or 2, wherein the identification information detected by the pattern detector is a PN sequence inserted into a header of a data frame of the digital broadcast signal.

4. The digital broadcast receiver of claim 1 or 2, wherein the identification information detected by the pattern detector is at least one pilot inserted into the modulated digital broadcast signal.

5. The digital broadcast receiver of claim 1 or 2, wherein the identification information detected by the pattern detector is a PN sequence inserted into a header of a data frame of the digital broadcast signal and at least one pilot inserted into the modulated digital broadcast signal.