Apparatus and method for receiving digital multimedia broadcasting in a wireless terminal

Provided are an apparatus and method for receiving digital multimedia broadcasting (DMB) signals in a wireless terminal. The apparatus includes a first antenna for receiving a satellite DMB signal and a first terrestrial DMB signal, a second antenna for receiving a second terrestrial DMB signal, a satellite DMB receiver for processing the satellite DMB signal, a terrestrial DMB receiver for processing the first and second terrestrial DMB signals, and a switch for switching the satellite DMB signal and the first terrestrial DMB signal received by the first antenna to one of the satellite DMB receiver and the terrestrial DMB receiver.

PRIORITY

This application claims priority to an application entitled “APPARATUS AND METHOD FOR RECEIVING DIGITAL MULTIMEDIA BROADCASTING IN A WIRELESS TERMINAL”, filed in the Korean Intellectual Property Office on May 12, 2004 and assigned Ser. No. 2004-33424, the entire contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to digital multimedia broadcasting (DMB), and more particularly to an apparatus and method for receiving DMB in a wireless terminal.

2. Description of the Related Art

Digital multimedia broadcasting (DMB) can provide compact disk (CD)-quality level sounds, data and video service, etc. DMB can also provide excellent reception quality to a moving broadcasting receiver. The DMB is classified into terrestrial DMB and satellite DMB according to transmission means (a ground wave or a satellite). That is, DMB is a digital multimedia broadcasting service for providing various high quality digital content (video/audio/data) to a receiver through a cost-effective broadcasting network. The terrestrial DMB provides music and video services using a ground-based terrestrial repeater. The satellite DMB provides a service in a band of 2.6˜2.655 GHz corresponding to the ultra high frequency (UHF). For example, when a transmitting station on a Gwanaksan mountain in Korea transmits the radio wave for the terrestrial DMB, the terrestrial DMB service is provided to metropolitan areas in Korea. When the radio wave for the satellite DMB service is transmitted from the satellite located outside the atmosphere to the Korean Peninsula, entire regions in Korea can simultaneously receive the satellite DMB service. If wireless terminals can receive the DMB, users of the wireless terminals will be able to conveniently use the DMB service.

SUMMARY OF THE INVENTION

Therefore, it is an object of the present invention to provide an apparatus and method that can receive digital multimedia broadcasting (DMB) through a wireless terminal.

In accordance with an aspect of the present invention, the above and other objects can be accomplished by an apparatus for receiving digital multimedia broadcasting (DMB) in a wireless terminal. The apparatus includes a first antenna for receiving a satellite DMB signal and a first terrestrial DMB signal; a second antenna for receiving a second terrestrial DMB signal; a satellite DMB receiver for receiving the satellite DMB signal through the first antenna; a terrestrial DMB receiver for receiving the first and second terrestrial DMB signals through the first and second antennas; and a switch for switching the satellite DMB signal and the first terrestrial DMB signal received by the first antenna to one of the satellite DMB receiver and the terrestrial DMB receiver.

In accordance with another aspect of the present invention, the above and other objects can be accomplished by a method for receiving digital multimedia broadcasting (DMB) in a wireless terminal. The method includes displaying available types of DMB, when DMB viewing is selected in a television (TV) mode; receiving and outputting a satellite DMB signal, when satellite DMB is selected by a user from the displayed types of DMB; and receiving and outputting a terrestrial DMB signal, when terrestrial DMB is selected by a user from the displayed types of DMB.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Embodiments of the present invention will be described in detail herein below with reference to the accompanying drawings. In the drawings, the same or similar elements are denoted by the same reference numerals even though they are depicted in different drawings.

In embodiments of the present invention, a DMB mode is divided into a satellite DMB mode and a terrestrial DMB mode. The terrestrial DMB mode is divided into a mode of L-Band serving as the European terrestrial DMB band (hereinafter, referred to as the “first terrestrial DMB band”), and a mode of Band-III serving as the Korean terrestrial DMB band (hereinafter, referred to as the “second terrestrial DMB band”). Here, a frequency band of the satellite DMB mode is 2.6˜2.65 GHz, a frequency band of the first terrestrial DMB mode is 1452˜1492 MHz, and a frequency band of the second terrestrial DMB mode is 174˜240 MHz.

FIG. 1is a block diagram illustrating a wireless terminal in accordance with an embodiment of the present invention, andFIG. 2is a block diagram illustrating a DMB receiver ofFIG. 1.

As illustrated inFIGS. 1 and 2, the wireless terminal includes a first antenna100, a second antenna105, a control unit110, a first memory120, a radio frequency (RF) unit121, a second memory122, a data processing unit123, an audio processing unit125, a key input unit127, a third memory129, a switch130, a tuning unit140, a DMB processing unit150, a coder-decoder (CODEC) unit160, a video processing unit170, and a display unit180.

Referring toFIGS. 1 and 2, the RF unit121performs a wireless communication function of the wireless terminal. The RF unit121includes an RF transmitter for up converting and amplifying a frequency of a signal to be transmitted, an RF receiver for low-noise amplifying a received signal and down converting a frequency of the received signal, etc. The RF unit121transmits a signal to the first antenna100through the switch130, and receives an applied signal through the switch130.

The data processing unit123includes a transmitter for coding and modulating the signal to be transmitted and a receiver for demodulating and decoding the received signal. That is, the data processing unit123can be composed of a modulator-demodulator (MODEM) and a coder-decoder (CODEC). The data processing unit123may be included in the control unit110.

The audio processing unit125reproduces a received audio signal output from the data processing unit123or outputting a transmission audio signal generated from a microphone to the data processing unit123. More specifically, when the wireless terminal performs a television (TV) mode in accordance with the embodiment of the present invention, the audio processing unit125performs a function for reproducing an audio signal of a DMB signal output from the CODEC unit160.

The key input unit127includes keys necessary for inputting number and letter information and function keys necessary for setting various functions. More specifically, the key input unit127includes various mode setup keys for processing a DMB signal in accordance with the embodiment of the present invention.

The third memory129can be composed of program and data memories, etc. The program memory can store programs for controlling the overall operation of the wireless terminal. More specifically, the program memory can store programs for processing a DMB signal in accordance with the embodiment of the present invention. The third memory129performs a function for temporarily storing data generated while the programs are executed.

The control unit110controls the overall operation of the wireless terminal in accordance with the embodiment of the present invention, and may include the data processing unit123.

When the wireless terminal performs a communication mode in accordance with the embodiment of the present invention, the control unit110controls the switch130to switch a signal received by the first antenna100to the RF unit121, such that a wireless communication function can be performed. When the wireless terminal performs a satellite DMB mode in accordance with the embodiment of the present invention, the control unit110controls the switch130to switch a satellite DMB signal received by the first antenna100to the first tuner141of the tuning unit140.

When the wireless terminal performs the first terrestrial DMB mode in accordance with the embodiment of the present invention, the control unit110controls the switch130to switch a first terrestrial DMB signal received by the first antenna100to the second tuner142.

When the wireless terminal performs the second terrestrial DMB mode in accordance with the embodiment of the present invention, the control unit110applies a second terrestrial DMB signal received by the second antenna105to the second tuner142. When the control unit110sets the DMB mode in the DMB processing unit150in accordance with the embodiment of the present invention, the control unit110controls the DMB processing unit150to turn off power for a corresponding DMB mode when not using a predetermined DMB mode. The control unit110can reduce power consumption of the CODEC unit160using parallel communication in accordance with the embodiment of the present invention.

The first antenna100receives communication signals such as code division multiple access (CDMA) and personal communication service (PCS) signals to apply the received communication signals to the switch130in accordance with the embodiment of the present invention. More specifically, the first antenna100applies the satellite DMB signal and the first terrestrial DMB signal to the switch130.

The second antenna105applies the second terrestrial. DMB signal to the second tuner142in accordance with the embodiment of the present invention.

The tuning unit140receives a selected DMB signal according to a control operation of the control unit110, and performs a function for converting a frequency of the received DMB signal. The tuning unit140includes the first tuner141and the second tuner142in accordance with the embodiment of the present invention. The first tuner141receives and frequency-converts a satellite DMB signal, and the second tuner142receives and frequency-converts a terrestrial DMB signal.

The DMB processing unit150performs a function for demodulating and decoding DMB signals output from the tuning unit140in accordance with the embodiment of the present invention. That is, the DMB processing unit150demodulates the DMB signals received by the first and second tuners141and142, separates the demodulated DMB signals into audio and video signals, and performs channel-by-channel decoding, according to a control operation of the control unit110. The channel-by-channel decoded DMB signals are stored in the first memory120serving as a buffer memory.

The CODEC unit160decodes the audio and video signals received from the DMB processing unit150into signals of the Moving Picture Experts Group (MPEG) format according to a control operation of the control unit110. The CODEC unit160outputs the decoded audio signal to the audio processing unit125, and outputs the decoded video signal to the video processing unit170. The decoded audio and video signals are stored in the second memory122. The second memory122can store various data as well as the decoded audio and video signals.

When the wireless terminal performs the DMB mode in accordance with the embodiment of the present invention, the video processing unit170processes the video signal output from the CODEC unit160and user data output from the control unit110, and displays the processed signal and the processed user data on corresponding areas of the display unit180. The video processing unit170may be included in the CODEC unit160.

When the wireless terminal operates in the communication mode, the display unit180displays the data output from the control unit110. When the wireless terminal operates in the DMB mode, the display unit180displays the DMB video data and the user data output from the video processing unit170on corresponding areas. Here, the display unit180can be a liquid crystal display (LCD). In the case of the LCD, the display unit180can include an LCD controller, a memory capable of storing video data, an LCD element, etc. When the LCD is implemented using a touch-screen system, the key input unit127and the display unit180can serve as an input unit.

FIG. 3is a block diagram illustrating details of the DMB receiver ofFIG. 2.

Referring toFIGS. 1 to 3, the first antenna100is constructed to receive the entire range of a communication signal band frequency (CDMA: 800˜900 MHz or PCS: 1850˜1990 MHz), a satellite DMB signal band frequency (2.63˜2.65 GHz), and a first terrestrial DMB signal band frequency (1.45˜1.49 GHz).

It is preferred that the first antenna100has an internal helical structure and resonates in a desired frequency band. It is preferred that the helical structure includes four helices capable of receiving four band frequencies that is, a CDMA signal, a PCS signal, a satellite DMB signal, and a first terrestrial DMB signal. When a winding interval and the number of windings in the helical structure are adjusted, a signal of a desired frequency band can be received.

The second antenna105receives band frequencies (174˜240 MHz) of the second terrestrial DMB signal, and can be constructed by a whip antenna.

While the wireless terminal operates in the communication mode, the switch130switches an RF communication signal received by the first antenna100to the RF unit121according to a control operation of the control unit110. While the wireless terminal operates in the satellite DMB mode, the switch130switches the satellite DMB signal received by the first antenna100to the first tuner141according to a control operation of the control unit110.

While the wireless terminal operates in the first terrestrial DMB mode, the switch130switches the first terrestrial DMB signal received by the first antenna100to the second tuner142according to a control operation of the control unit110.

The satellite DMB receiver includes the first tuner141, a first DMB processor157, and a first CODEC161.

The first tuner141receives the satellite DMB signal from the switch130, and then frequency-converts the received satellite DMB signal. That is, the first tuner141is an integrated circuit (IC) for down converting the satellite DMB signal frequency into an intermediate frequency (IF) signal (38 or 2 MHz).

The DMB processing unit150includes the first DMB processor157, and the second DMB processor158.

The first DMB processor157demodulates and decodes the satellite DMB signal according to a control operation of the control unit110, and includes a first demodulator151, a first channel decoder152, and a pilot channel decoder153.

The first demodulator151demodulates an analog satellite DMB signal received from the first tuner141into a digital signal. At this point, the first demodulator151uses code division multiplexing (CDM). More specifically, the first demodulator151separates the digital satellite DMB signal into audio and video signals.

The first channel decoder152decodes the digital satellite DMB signal received from the first demodulator151from each channel. The decoded digital satellite DMB signal is stored in the first memory120.

The pilot channel decoder153is provided to implement synchronization between transmission and reception operations. Because a satellite DMB coding technique is CDM, a pilot channel is needed for the synchronization between the transmission and the reception operations.

The first CODEC161decodes the audio and video signals separated from the received satellite DMB signal by the first DMB processor157according to a control operation of the control unit110. The first CODEC161outputs the decoded audio signal to a speaker through the audio processing unit125, and displays the decoded video signal on the display unit180through the video processing unit170.

The terrestrial DMB receiver includes the second tuner142, the second DMB processor158, and a second CODEC162.

The second tuner142receives the first terrestrial DMB signal from the switch130, and then frequency-converts the received first terrestrial DMB signal. The second tuner142receives the second terrestrial DMB signal from the second antenna105, and then frequency-converts the received second terrestrial DMB signal. That is, the second tuner142is an IC for down converting the first and second terrestrial DMB signal frequencies into IF signals (38 or 2 MHz).

The second DMB processor158demodulates and decodes the terrestrial DMB signals according to a control operation of the control unit110, and includes a second demodulator154, and a second channel decoder155. The second demodulator154demodulates the first and second terrestrial DMB signals into digital signals. The second demodulator154uses orthogonal frequency division multiplexing (OFDM). OFDM is to be adopted as a modulation technique in European, Japanese, and Australian digital TV standards. When the OFDM technique is used, data can be distributed to a large number of frequency carriers that are separated from each other by a predetermined interval. The OFDM technique provides orthogonality so that a corresponding demodulator will not receive a different frequency other than its own frequency.

The second demodulator154separates, into audio and video signals, the first and second terrestrial DMB signals converted into the digital signals.

The second channel decoder155decodes the first and second terrestrial DMB signals received from the second demodulator154for each channel. The decoded first and second terrestrial DMB signals are stored in the first memory120.

The second CODEC162decodes the audio and video signals separated from the received first and second terrestrial DMB signals by the second DMB processor158according to a control operation of the control unit110. The second CODEC162outputs the decoded audio signal to the speaker through the audio processing unit125, and displays the decoded video signal on the display unit180through the video processing unit170.

The following Table 1 illustrates the control signals transmitted and received between the tuner unit140(i.e. the first and second tuners141and142) and the DMB processing unit150.

TABLE 1SignalDescriptionAGCAGC is controlled in a baseband such that a constant IF signal(−6 dBm) is output even when a level of an RF level varies.SDASERIAL DATA: Tuner register setting => CH dataSCLSERIAL CLOCK: Sync signalIFIF analog signal

The following Table 2 illustrates the control signals transmitted and received between the DMB processing unit150and the CODEC unit160.

TABLE 2SignalDescriptionD(0:15)Data of 16 or 8 bitsA(0:15)Address signal: Address assignmentINTERRUPTSignal sent before sending dataamong baseband CODEC and control units.Chip SelectChip Select is a chip select signal, and access toan assigned memory address is performed whena chip is selected.RDData readWRData write

The operation of the wireless terminal in the DMB mode will be described with reference toFIG. 4.

FIG. 4is a flow chart illustrating a process for receiving DMB in the wireless terminal in accordance with an embodiment of the present invention.

Referring toFIGS. 1 to 4, when a user of the wireless terminal selects a TV mode, the control unit110senses the selected TV mode in step401, and sets the wireless terminal to the TV mode in step402.

When the user inputs a menu key while the wireless terminal is operating in the TV mode, the control unit110controls the display unit180to display selection items for TV viewing, that is, a menu for TV viewing.

When “DMB viewing”, or a similar menu item, is selected from the menu for TV viewing according to user selection information (e.g., a key input), the control unit110controls the display unit180to display the available types of DMB signals in step403. Here, the types of DMB signals are satellite DMB and terrestrial DMB.

When “satellite DMB”, or a similar menu item, is selected from the displayed types of DMB signals, the control unit110senses the selected “satellite DMB” in step404, and proceeds to step405in which a satellite DMB reception function is performed.

In step405, the control unit110controls the switch130to switch a satellite DMB signal received by the first antenna100to the first tuner141.

When the satellite DMB signal is received from the switch130, the first tuner141frequency-converts the satellite DMB signal, and then applies the frequency-converted satellite DMB signal to the first DMB processor157. The first demodulator151of the first DMB processor157demodulates an analog signal of the applied satellite DMB signal into a digital signal and then separates the digital signal into audio and video signals according to a control operation of the control unit110. The demodulated satellite DMB signal is decoded through the first channel decoder153for each channel, and the decoded satellite DMB signal is stored in the first memory120. At this point, the pilot channel decoder153performs synchronization between transmitted and received satellite DMB signals. The audio and video signals are applied from the first DMB processor157to the first CODEC161. The first CODEC161decodes the applied audio and video signals according to a control operation of the control unit110, and then stores the decoded audio and video signals in the second memory122. The first CODEC161outputs the decoded audio signal to the speaker through the audio processing unit125, and displays the decoded video signal on the display unit180through the video processing unit170.

On the other hand, when “terrestrial DMB”, or a similar menu item, is selected from the types of DMB signals according to the user selection information, the control unit110senses the selected “terrestrial DMB” in step406, and proceeds to step407in which a terrestrial DMB reception function is performed.

In step407, when the first antenna100receives a first terrestrial DMB signal, the control unit110controls the switch130to switch the received first terrestrial DMB signal to the second tuner142.

In step407, when the second antenna105receives a second terrestrial DMB signal, the control unit110controls the switch130to switch the received second terrestrial DMB signal to the second tuner142. Because the processes for receiving the first and second terrestrial DMB signals are the same as each other in the embodiment of the present invention, two signals are generally referred to as the terrestrial DMB signals.

Upon receiving the terrestrial DMB signals (i.e. the first and second terrestrial DMB signals), the second tuner142frequency-converts the terrestrial DMB signals, and applies the frequency-converted terrestrial DMB signals to the second DMB processor158.

The second demodulator154of the second DMB processor158demodulates analog signals of the applied terrestrial DMB signals into digital signals and then separates the demodulated terrestrial DMB signals into audio and video signals according to a control operation of the control unit110. The audio and video signals are output by the audio processing unit125and the display unit180through the CODEC unit160, respectively.

When the user selects to terminate a corresponding function while the satellite DMB reception function or the terrestrial DMB reception function is performed, the control unit110senses the selected function termination in step408, and proceeds to step409in which the TV mode is released.

On the other hand, when the user of the wireless terminal selects a communication mode for conducting a wireless communication, the control unit110proceeds to step411in which the communication mode is performed.

In step411, the control unit110controls the switch130to switch a communication signal received by the first antenna100to the RF unit121.

The RF unit121performs the wireless communication function through the communication signal received from the switch130.

Although certain embodiments of the present invention associated with a wireless terminal have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope of the present invention. Therefore, the present invention is not limited to the above-described embodiments, but is defined by the following claims, along with their full scope of equivalents.

As apparent from the above description, the present invention provides an apparatus for receiving digital multimedia broadcasting (DMB) in a wireless terminal that can receive DMB as well as perform a communication function using the wireless terminal, such that convenience for users can be improved.