Abstract:
Provided are a beam combining and hybrid beam selection method that can improve digital broadcasting reception performance by combining more than two beam output signals (beam combination type) instead of simply selecting one of beam output signals (beam selection type), or even selecting an optimal method between the beam selection type and the beam combination type, and a digital broadcasting receiving apparatus using the same. The beam selecting method includes: a) calculating SMNRs (mainpath signal to multipath signal and noise ratios) with respect to a plurality of beam output signals, formed according to directions from a plurality of antenna output signals whose phases are shifted depending on arrangement positions of array antennas, by using corresponding channel impulse responses; b) selecting a first predetermined number of beam output signals according to magnitudes of the SMNRs by comparing the calculated SMNRs with respect to the respective beam output signals; c) calculating a delay time between mainpath signals of the selected beam output signals, and generating a combined beam output signal by combining the two beam output signals by adjusting the calculated delay time; d) when the SMNR of the combined beam output signal is less than the maximal SMNR of the selected beam output signals, calculating an SDMR (mainpath signal to dominant multipath signal ratio) with respect to the respective beam output signals, and selecting a beam output signal having the greatest SDMR; and e) calculating an SMNR of the combined beam output signal using channel impulse response of the combined beam output signal, and comparing the calculated SMNR with a maximal value among the SMNRs of the selected beam output signals; and f) when the SMNR of the combined beam output signal is greater than or equal to the maximal SMNR of the selected output signals, selecting the combined beam output signal generated in step c).
Abstract:
The present invention provides a digital multimedia broadcasting transmitting apparatus, including: a pilot signal generator that is used in estimating a transmission channel in a receiving apparatus and generates a pilot signal including at least one information a; a subcarrier mapping unit that maps the pilot signal to a subcarrier corresponding thereto; and a modulating unit that modulates an output of the subcarrier mapping unit, wherein the pilot signal has a value for specific information rather than a predetermined value in the receiving apparatus.
Abstract:
An apparatus for transmitting digital multimedia broadcasting includes: a base layer processor that outputs a base layer stream; an enhancement layer processor that outputs an enhancement layer stream; and a transmitter that modulates the enhancement layer stream based on one of a first and second hierarchical modulation modes using different modulation schemes and maps a symbol of the modulated enhancement layer stream based on a symbol position of the base layer stream to generate a transmission frame.
Abstract:
A hierarchical demodulation device channel estimates a reference symbol based on a given symbol to generate a channel estimate of the reference symbol, channel estimates a plurality of information symbols based on the channel estimate of the reference symbol to generate channel estimates of a plurality of information symbols, channel estimates a plurality of service symbols based on the channel estimates of a plurality of information symbols to generate channel estimates of a plurality of service symbols, channel equalizes a signal based on the channel estimate of the reference symbol, the channel estimates of a plurality of information symbols, and the channel estimates of a plurality of service symbols, and hierarchically separates the channel equalized signal to generate a first hierarchical modulation signal and a second hier¬ archical modulation signal. Therefore, receiving performance of the low priority signals can be improved without influencing the high priority signals while maintaining compatibility with the existing system.
Abstract:
In a method of transmitting broadcasting signals, a transmission frame has the same configuration as that of the existing terrestrial DMB signal. A transmission frame including a base layer service stream is modulated to a base layer, and a transmission frame including an enhancement layer service stream is modulated to an enhancement layer. The enhancement layer service stream is composed of additional data that is not included in the base layer service stream, in order to provide an enhancement layer service. In this way, the method can provide a high-quality service requiring high transmission efficiency while being compatible with the existing terrestrial DMB system. The high transmission efficiency means a higher data transfer rate than that of the existing terrestrial DMB system.
Abstract:
A hierarchical modulation device modulates a plurality of first hierarchical symbols according to a first modulation method to generate a plurality of first hierarchical modulation symbols, inserts a plurality of pilot symbols into a plurality of second hierarchical symbols to generate a plurality of pilot insertion symbols, modulates a plurality of pilot insertion symbols according to a second modulation method to generate a plurality of second hierarchical modulation symbols, and maps a plurality of first hierarchical modulation symbols and the plurality of second hier archical modulation symbols in the signal space to generate a plurality of hierarchical modulation symbols. Therefore, the hierarchical modulation device can improve receiving performance of the enhancement layer without influencing the base layer.
Abstract:
In a terrestrial DMB, a transmitting apparatus multiplexes a plurality of service streams generated for any service to a plurality of ensembles. In this case, the same sending time data is constructed in a time stamp field of each frame for each of a plurality of ensembles. With this configuration, a plurality of transmitting apparatuses can send a plurality of transmission frames including service streams for the same service at the same point of time, and thus receiving apparatuses can actually receive a plurality of transmission frames at the same point of time.
Abstract:
An apparatus for transmitting digital multimedia broadcasting includes: a base layer processor that outputs a base layer stream; an enhancement layer processor that outputs an enhancement layer stream; and a transmitter that modulates the enhancement layer stream based on one of a first and second hierarchical modulation modes using different modulation schemes and maps a symbol of the modulated enhancement layer stream based on a symbol position of the base layer stream to generate a transmission frame.
Abstract:
In a terrestrial DMB, a transmitting apparatus multiplexes a plurality of service streams generated for any service to a plurality of ensembles. In this case, the same sending time data is constructed in a time stamp field of each frame for each of a plurality of ensembles. With this configuration, a plurality of transmitting apparatuses can send a plurality of transmission frames including service streams for the same service at the same point of time, and thus receiving apparatuses can actually receive a plurality of transmission frames at the same point of time.
Abstract:
In a method of transmitting broadcasting signals, a transmission frame has the same configuration as that of the existing terrestrial DMB signal. A transmission frame including a base layer service stream is modulated to a base layer, and a transmission frame including an enhancement layer service stream is modulated to an enhancement layer. The enhancement layer service stream is composed of additional data that is not included in the base layer service stream, in order to provide an enhancement layer service. In this way, the method can provide a high-quality service requiring high transmission efficiency while being compatible with the existing terrestrial DMB system. The high transmission efficiency means a higher data transfer rate than that of the existing terrestrial DMB system.