KR101216092B1 - Modem for mobile station supporting a plurality of communication standards - Google Patents

Abstract

The present invention relates to a mobile terminal supporting at least two communication standards, and more particularly, to a modem of a mobile terminal supporting an interface of various radio frequency integrated circuits (RFICs). According to the present invention, a modem for a mobile terminal supporting a plurality of communication standards includes a first frequency control module for controlling a clock provided from an external device according to a specific first communication standard; A second frequency control module for controlling a clock provided from the outside according to a specific second communication standard; And a first selection module for selecting any one of outputs of the first frequency control module and the second frequency control module and inputting the selected module to a specific module on the modem.

GSM, WCDMA, PLL, Specification, Clock

Description

Modem for mobile station supporting a plurality of communication standards

1 is a configuration diagram of a modem included in a mobile terminal supporting a GSM / GPRS standard according to the prior art.

2 is a block diagram of a mobile terminal supporting both WCDMA and GSM / GPRS standards according to the prior art.

3 is a block diagram of a modem according to an embodiment of the present invention.

4 is a block diagram of a modem according to an embodiment of the present invention.

The present invention relates to a mobile terminal supporting at least two communication standards, and more particularly, to a modem and a peripheral device of a mobile terminal supporting interfaces of various radio frequency integrated circuits (RFICs).

Recent mobile communication systems have been developed in the direction of integrating various multimedia technologies. In particular, recent communication systems provide various types of communication standard interfaces. That is, the technology is developed to provide various communication standard interfaces such as UMTS (WCDMA), GSM and CDMA, rather than supporting one standard in one communication system. The development of such technology is to meet various needs of users, and for this purpose, a communication device such as a mobile terminal should be designed to simultaneously support various interfaces.

Hereinafter, a mobile terminal according to the prior art will be described. A conventional mobile terminal may be divided into a terminal supporting one standard and a terminal supporting a plurality of standards.

Hereinafter, a terminal supporting one standard will be described. 1 is a configuration diagram of a modem included in a mobile terminal supporting a GSM / GPRS standard according to the prior art.

As shown, the modem receives a signal of a specific clock through an oscillator located outside and controls the received signal to generate signals of various clocks required by the modem. The modem of FIG. 1 receives a signal corresponding to a reference clock provided from the temperature compensation crystal oscillator 20 provided outside the modem. A phase locked loop (PLL) included in the clock controller 10 of FIG. 1 generates signals of various clocks by using the signal received from the temperature compensated crystal oscillator 20 as a reference clock.

Hereinafter, a terminal supporting a plurality of standards will be described. 2 is a block diagram of a mobile terminal supporting both WCDMA and GSM / GPRS standards according to the prior art.

As shown, the terminal of FIG. 2 includes a PLL 100 inside the modem 400. The PLL 100 included in the modem is provided with a reference clock by the VCTCXO 200 provided outside the modem 400. The conventional terminal has a PLL (100) which is a device for supporting a WCDMA interface in the modem 400, and a UHF PLL (300) for supporting a GSM interface on the outside of the modem (400). In addition, the VCTCXO (Voltage Controlled Temperature Compensated Crystal Oscillator) serves as a source for supplying a reference clock for the PLL 100 and performs a function of maintaining synchronization with an RFIC included in the terminal. A voltage controlled temperature compensation crystal oscillator).

The terminal of FIG. 2 must support a plurality of interface specifications, and each interface specification requires a different clock source because different clocks are required. That is, since the clock source required by the mobile system is different according to a communication standard, the required clock source is different according to the system.

Although the terminal of FIG. 1 generates a specific clock required by one interface standard, the terminal of FIG. 2 should generate a specific clock required by a plurality of interface standards. Therefore, the method of controlling the clock in the terminal of FIG. 2 is relatively complicated. Hereinafter, a clock control operation performed in the terminal of FIG. 2 will be described.

In the terminal of FIG. 2, the VCTCXO 200 provides a signal of a specific clock frequency to the PLL 100 and the UHF PLL 300. Although the PLL 100 and the UHF PLL 300 support different standards, the PLL 100 and the UHF PLL 300 receive signals of a reference clock from the VCTCXO 200. The PLL 100 controls the clock of the signal received from the VCTCXO 200 and supplies the signal of the controlled clock to a specific device located in the modem. The PLL 100 is a device that supports the WCDMA standard, and the WCDMA standard uses 15.36MHZ as a base clock frequency, so that the PLL 100 can generate a specific clock frequency. Generate the clock signal. The UHF PLL 300 is a device that supports the GSM / GPRS standard, and the GSM / GPRS standard uses 26 MHZ as the base clock frequency, so that the UHF PLL receives a signal of a specific clock capable of generating the base clock frequency. Create

As described above, a mobile terminal supporting a plurality of standards should be provided with various devices capable of supporting different basic clock frequencies.

The present invention has been proposed to improve the prior art, and an object of the present invention is to provide a mobile terminal supporting different interface standards.

Another object of the present invention is to provide a modem supporting various RFIC interfaces.

It is still another object of the present invention to provide a modem that can operate regardless of the specifications of a particular communication device.

According to the present invention, a modem for a mobile terminal supporting a plurality of communication standards includes a first frequency control module for controlling a clock provided from an external device according to a specific first communication standard; A second frequency control module for controlling a clock provided from the outside according to a specific second communication standard; And a first selection module for selecting any one of outputs of the first frequency control module and the second frequency control module and inputting the selected module to a specific module on the modem.

The present invention proposes a modem considering different clock source interfaces for various RFIC (Radio Frequency IC) interfaces. In addition, the present invention proposes a mobile terminal including a modem part according to a flexible clock configuration method. The present invention implements a device in a modem section that considers a clock source interface different for each communication standard. This supports various configurations of the RFIC part located outside the modem. This invention can solve that the design and development of a mobile terminal are restrict | limited by the specification and setting of a specific RFIC.

Modem according to the invention has an additional frequency control device according to the communication standard supported by the mobile terminal. The additional frequency control device preferably includes a phase-locked loop (PLL). In addition, the mobile terminal and modem according to the invention support a digital interface. The modem according to the present invention performs data transmission and reception using an RFIC and an analog interface or a digital interface provided outside the modem.

The operation, features and effects of the present invention will be further embodied by one embodiment of the present invention described below. Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

The modem according to the present embodiment includes a plurality of frequency control devices according to a communication standard supported by the mobile terminal. The frequency control device is a module that generates signals of various clocks according to a provided reference clock. The frequency control device preferably includes a PLL.

As shown in FIG. 2, the conventionally proposed mobile terminal includes a PLL in each of a modem and a communication device except the modem to support a plurality of standards. Since each PLL receives a reference clock by one oscillator, the oscillator and each PLL operate in pairs. That is, when a mobile terminal is designed using a conventional modem and a conventional communication device (for example, RFIC), a problem arises in that the mobile terminal must be designed according to a specific modem and oscillator setting. In other words, you should only use solutions offered by specific vendors. However, the modem according to this embodiment has a plurality of frequency control devices.

Hereinafter, the structure of the modem according to the present embodiment will be described with reference to FIGS. 3 and 4. The modem according to the present embodiment may receive a signal from a digital RFIC located outside, or may receive a signal through a dual mode analog front end (AFE). Hereinafter, the structure of the modem according to the present embodiment connected to the digital RFIC will be described with reference to FIG. 3, and the structure of the modem according to the present embodiment connected to the dual mode AFE will be described with reference to FIG. 4.

3 is a block diagram of a modem according to an embodiment of the present invention. 3 illustrates a mobile terminal supporting a WCDMA interface and a GSM / GPRS interface. Modem 500 according to the example of FIG. 3 supports at least two communication standards. In addition, the modem 500 of FIG. 3 includes a first frequency control module 520 supporting a WCDMA interface and a second frequency control module 530 supporting a GSM / GPRS interface. 3 shows an example of the modem 500 connected to a digital RFIC 510 supporting a digital interface.

As shown in FIG. 3, the modem 500 according to the present invention is connected to the RFIC 510 through a digital interface. The digital interface is preferably a Low Voltage Differential Signals (LVDS) interface. In the case of the LVDS interface, fast data transmission is possible by a very small voltage swing to perform communication with wide bandwidth, and high-speed data transmission is possible. Currently, the LVDS interface is used in the interface parts of LCDs and cameras, and when the LVDS technology is applied, the number of lines for communication can be reduced compared to the existing analog interface, and HSDPA (High-Speed Downlink Packet Access) and The same high speed data transfer can be enabled.

As shown in FIG. 3, the modem 500 according to the present invention includes frequency control modules 520 and 530 corresponding to an interface standard supported by the mobile terminal. The frequency control modules 520 and 530 generate signals according to the basic clock frequency required by each interface standard. The output of each frequency control module 520, 530 is input to the clock generation module 540. That is, the outputs of the frequency control modules 520 and 530 are used as a master clock of the clock generation module 540 to generate clocks required by the WCDMA or GSM / GPRS standard.

The first frequency control module 520 controls the input reference clock to generate a signal of a new clock and a first PLL 521 and a first mux to select an output of the first frequency control module 520. 522. Preferably, the first PLL 521 is activated or not by an external control signal PLLRSTN0, and the first MUX 522 selects an output by an external control signal PLLBYPSN0. .

The second frequency control module 530 controls the input reference clock to generate a signal of a new clock and a second PLL 531 and a second mux to select an output of the second frequency control module 530. 532. Preferably, the second PLL 531 is activated or not by an external control signal PLLRSTN1, and the second MUX 532 preferably selects an output by an external control signal PLLBYPSN1. .

As described above, the outputs of the frequency control modules 520 and 530 are input to the clock generation module 540, and each output is controlled by the third MUX 550 controlled by the external control signal CK_SEL. .

4 is a block diagram of a modem according to an embodiment of the present invention. The modem 500 proposed in this embodiment performs data communication with the WCDMA RFIC controlling the WCDMA interface and the GSM RFIC controlling the GSM / GPRS interface. In addition, the WCDMA RFIC may perform data communication with the modem 500 through a digital interface or an analog interface, and the GSM RFIC may perform data communication with the modem 500 through a digital interface or an analog interface. have. That is, the modem 500 may perform data communication with an external device such as an RFIC through various interfaces. In this case, the modem 500 performs data communication with the WCDMA RFIC and the GSM RFIC through the dual mode AFE 560.

In summary, the WCDMA RFIC in FIG. 4 may use a digital interface including an LVDS interface, and the GSM RFIC supporting GSM / GPRS may selectively use digital and analog interfaces. Due to the characteristics of the above-described RFICs, a dual mode AFE 560 is preferably added between the RFICs and the modem 500. The dual mode AFE 560 is a device for converting an analog signal transmitted from an RFIC into a digital signal to support the interface of WCDMA and GSM / GPRS together. If a GSM RFIC using an analog interface is used, the dual mode AFE 560 may transfer the analog signal transmitted from the RFIC to the modem 560 as it is.

As described above, it is preferable that the PLLs 521 and 531 proposed in the present embodiment are activated by a control signal. When a plurality of PLLs are included in a general mobile terminal and each PLL supports a specific air interface standard, there is a problem in that power consumption increases. That is, the mobile terminal includes a plurality of PLLs to support a plurality of standards, but even if a company providing a communication service uses one standard, all PLLs have to be activated and perform an operation. Therefore, the present embodiment controls the operation of the PLL through the control signal.

That is, when the mobile terminal is designed using the modem 500 proposed in this embodiment, and all the PLLs 521 and 531 do not need to be used when the mobile terminal uses only a specific standard, each PLL needs to be used. Set the control signal PLLRSTN0,1 that can be turned off. In addition, when a malfunction of each PLL occurs and the dual mode AFE 560 provides a signal of a basic clock frequency (for example, 26 MHz) required by GSM, an external clock source (External) is turned off after each PLL is turned off. It is preferable to add the first mux 522 and the second mux 532 to bypass the Clock Source to the modem part including the clock generation module 540. In addition, since a particular PLL does not perform an operation, signals input from the outside may be passed to the modem portion. In this case, regardless of which of the first frequency control module 520 and the second frequency control module 530 is used, it is necessary to provide a clock required for a core such as a CPU included in the clock generation module 540. Therefore, it is preferable that a third mux 550 for selecting one of the outputs of the first frequency control module 520 and the second frequency control module 530 is added.

As described above, the first mux 522 and the second mux 532 may bypass the signal when the PLL malfunctions. That is, separate paths are formed in the frequency control modules 520 and 530 by the first mux 522 and the second mux 532. The route can be used for various purposes. First, the path can also be used for testing the modem after modem completion. In other words, if the PLL of the manufactured modem chip does not work, there is no way to verify the function of the entire modem chip. That is, it is impossible to test whether the frequency control module that implements functions other than the PLL is operated. In this case, you can create a bypass path. That is, without using a PLL, an external clock may be applied to other data processing blocks through specific test equipment, etc., to test the inside of the modem chip. That is, the bypass path may be used for testing the modem chip or applying an external clock.

The modem and the mobile terminal proposed in this embodiment are as described above. Hereinafter, specific operations of the above-described modem and mobile terminal will be described.

First, the case where the modem 500 performs data communication with the digital RFIC 510 through a digital interface will be described.

In this case, the clock configuration is performed in the environment as shown in FIG. 3. In this case, the WCDMA RFIC and the GSM RFIC supporting GSM / GPRS use a digital interface instead of the conventional analog method. The digital RFIC 510 converts an analog signal received from an antenna into a digital signal and transmits the analog signal to the modem 500, thereby enabling digital communication between the above-described RFICs and the modem 500.

As described above, the first and second frequency control modules 520 and 530 are provided with a reference clock from the outside, and the reference clock frequency provided is 19.2 MHz. The frequency control module receives a clock of 19.2Mhz and generates a clock required by each core included in the modem and the WCDMA standard and the GSM / GPRS standard.

The base clock frequency used in the WCDMA standard is 15.36 MHz. The first frequency control module 520 according to the present embodiment receives a signal of 19.2Mhz and generates a 307.2Mhz signal having a 16 times clock of 19.2Mhz. In general, the core clock frequency required by the communication terminal is different from system to system, such as 150Mhz to 230Mhz. The modem 500 divides a signal of 307.2 Mhz by 20 minutes (307.2Mhz / 20 = 15.36Mhz) to generate a signal of a basic clock frequency of 15.36Mhz.

That is, the clock relationship of the first frequency control module 520 supporting the WCDMA interface is as follows.

That is, the digital RFIC 510 provides a reference clock of 19.2 MHz to the first PLL 521 for signal generation according to the WCDMA standard. The first PLL 521 generates a clock of 307.2 MHz that is 16 times faster than the reference clock. A 307.2 MHz clock is input to the clock generation module 540. That is, the 307.2 MHz clock is used as the master clock of the clock generation module 540 which generates the clock required by the WCDMA standard. This operation generates clocks required for WCDMA (15.36MHz), as well as the clocks for the LVDS and the various cores (ARM, DSP, and memory) that are responsible for the digital interface.

Hereinafter, an operation of generating a clock required for the GSM / GPRS standard will be described.

The base clock frequency used in the GSM / GPRS system is 26 MHz. The second frequency control module 530 according to the present embodiment receives a signal of 19.2Mhz and generates a 312Mhz signal having a 65/4 times clock of 19.2Mhz. In general, the core clock frequency required by the communication terminal is different from system to system, such as 150Mhz to 230Mhz. The modem 500 divides the signal of 312 Mhz into 12 divisions (312Mhz / 12 = 26Mhz) to generate a signal of a basic clock frequency of 26Mhz. That is, the clock relationship of the second frequency control module 530 supporting the GSM / GPRS interface is as follows.

That is, a reference clock of 19.2 MHz is provided to the second PLL 531 to generate a signal of a basic clock used in GSM / GPRS. The second PLL 531 generates a clock of 312 MHz that is about 16 times faster than the reference clock. The 312 MHz clock is input to the clock generation module 540. That is, the 312 MHz clock is used as the master clock of the clock generation module 540 which generates the clock required by the GSM / GPRS standard. This operation generates clocks required for WCDMA (26MHz), as well as clocks for LVDS, the module responsible for the digital interface, and various cores (ARM, DSP, Memory).

As described above, since the modem according to the present embodiment includes a plurality of PLLs, it is possible to control whether the PLLs are activated to prevent unnecessary power waste. That is, if the WCDMA interface or GSM / GPRS is selected according to the service area, the PLL which does not need to operate according to the provided service is turned off by the control signal PLLRSTN0,1 to reduce unnecessary power consumption. prevent. That is, when located in the WCDMA service area, the first PLL 521 switches to an inactive mode including a power save mode or the like under the control of PLLRSTN1. In the case of supporting multi-mode, it is preferable to use one of the modes as the default (Default). In the case of the WCDMA mode, the second PLL 531 is used as the power saving mode. In the GSM mode mode, however, it is highly desirable to operate all PLLs in order to provide a continuous clock for various cores. That is, when the mobile terminal is located in the GSM / GPRS service area, it is preferable that both the first PLL 521 and the second PLL 531 operate. Therefore, the modem and the mobile terminal according to the present embodiment have a more advantageous effect when operating based on the WCDMA system.

Hereinafter, the case where the modem 500 performs data communication with the RFIC through the dual mode AFE 560 described above.

In this case, the clock is configured in the environment as shown in FIG. 4. In this case, the WCDMA RFIC and the GSM RFIC supporting GSM / GPRS may perform data communication through a digital or analog interface. It is desirable to use the dual mode AFE 560 to selectively use different interfaces.

If the RFIC 510 communicating with the modem 500 through the dual mode AFE 560 supports a digital interface, the RFIC 510 and the modem 500 communicate through the digital interface.

That is, when the dual mode AFE 560 supports only a clock source of 19.2 MHz, even though the dual mode AFE 560 receives a clock, the same operation as that of FIG. 3 is performed in the modem 500. Is performed. That is, each frequency control module controls the reference clock to generate the basic clock frequency required by each interface specification. In this case, the RFIC 510 converts the analog signal received from the antenna into a digital signal through the dual mode AF 560 and transmits the analog signal to the modem 500. As a result, the RFIC 510 and the modem 500 communicate through a digital interface, and the operation shown in FIG. 3 is performed in the modem.

As mentioned above. The RFIC supporting the digital interface and the modem 500 may perform digital communication. If a digital RFIC interface is used, the LVDS module must be implemented in advance for transmission / reception in the modem 500, and the module for the digital interface (eg, LVDS interface logic) in the RFIC 510 is also included. ) Should be implemented. When using a mobile terminal using an RFIC that does not meet these requirements, it should be possible to use the analog RFIC interface as before, without using the digital interface provided in the modem 500. To this end, the present invention uses the dual mode AFE 560. The dual mode AFE 560 supports an analog interface as well as a digital interface. Through this, the analog signal received from the RFIC 510 is converted and provided to the modem 510.

Hereinafter, a case in which a reference clock is received through the dual mode AFE 560 but a reference clock of a different clock from the related art will be described.

For example, a problem may occur when the modem 500 does not receive a reference clock of 19.2 MHz as in the prior art, but receives a signal of another clock (for example, a reference clock of 26 MHz used by GSM / GPRS). Can be. That is, it is preferable to change the design of the modem 500 in preparation for using a plurality of reference clocks. That is, the dual mode AFE 560 according to the present embodiment is not configured as an oscillator (for example, a conventional TCXO) that merely provides a specific frequency, and 26Mhz used in GSM / GPRS in addition to the basic clock of 19.2 MHz Can support the clock directly. In this case, the modem 500 should be able to interface between the RFIC 510 and the modem 500 located outside the modem 500 without operating the second PLL 531. Therefore, in this case, the second PLL 531 switches to an inactive mode such as a power saving mode by the control signal PLLRSTN1. In this case, it is preferable that the second mux 532 selects a clock of 26 Mhz provided from the outside without selecting the second PLL 531. In this case, the second mux 532 selects the output by controlling the control signal PLLBYPSN1. If the second mux selects a clock of 26 MHz according to the control signal, as shown in FIG. 4, the output of the second frequency control module 530 becomes a clock of 26 MHz. As described above, when the clock that is externally studied in the second frequency control module is passed as it is, that is, when bypassing, the core clock inputted to the cores of the clock generation module 540 is stored. Must be set to the output of the first frequency control module. That is, when a specific frequency control module bypasses an external clock, a control signal selected to use the output of the other frequency control module as a core clock and a mux operating according to the control signal are required. In the example of FIGS. 3 and 4, the output of the frequency control module is selected by CK_SEL, and the output of the frequency control module is used as the core clock by the third mux 550 controlled by the CK_SEL.

In conclusion, the dual mode AFE used in this embodiment supports an interface between an RFIC and a modem supporting an analog interface and a digital interface. In addition, the mobile terminal system and the modem according to the present embodiment are designed to supply all the reference clocks required by the WCDMA and GSM / GPRS standards. In addition, the modem can flexibly support various clocks required by each core located in the modem even if a clock source exists externally.

Those skilled in the art through the above description can be seen that various changes and modifications can be made without departing from the spirit of the present invention. Therefore, the technical scope of the present invention is not limited to the contents described in the detailed description of the specification but by the claims.

The present invention proposes an apparatus for a mobile terminal supporting various standards. That is, a modem and a mobile terminal for controlling a PLL supporting multiple standards such as WCDMA and GSM / GPRS are proposed. According to the present invention, RFICs conforming to various standards can be freely used. In addition, the power consumption can be efficiently controlled according to the present invention. A developer developing a mobile terminal through the present invention can solve the problem of RFIC dependency only by using a specific RFIC interface. This has the beneficial effect that developers can greatly reduce the development risk associated with the application of RFIC.

Claims (10)

In the modem for a mobile terminal supporting a plurality of communication standards, A first frequency control module for controlling a clock provided from the outside according to a specific first communication standard; A second frequency control module for controlling a clock provided from the outside according to a specific second communication standard; And And a first selection module for selecting one of the outputs of the first frequency control module and the second frequency control module and inputting the selected module to a specific module on the modem, the second frequency control module according to the second communication standard. When a signal of a base clock frequency is input, the first selection module selects an output of the first frequency control module.  Modem for mobile terminals supporting multiple communication standards. The method of claim 1, The first frequency control module may include a phase locked loop (PLL) circuit. Modem for a mobile terminal that supports a plurality of communication standards characterized in that. 3. The method of claim 2, The PLL circuit determines that activation is determined by a control signal. Modem for a mobile terminal that supports a plurality of communication standards characterized in that. 3. The method of claim 2, The first frequency control module includes a second selection module for selecting any one of a clock provided from the outside and a clock by the PLL circuit. Modem for a mobile terminal that supports a plurality of communication standards characterized in that. The method of claim 1, The first selection module selects an output according to a communication standard of an area where the mobile terminal is located. Modem for a mobile terminal that supports a plurality of communication standards characterized in that. The method of claim 1, The first frequency control module and the second frequency control module is configured to receive the same external clock. Modem for a mobile terminal that supports a plurality of communication standards characterized in that. The method of claim 1, The first frequency control module and the second frequency control module perform data communication with an external radio frequency integrated circuit (RFIC) according to a low voltage differential signals (LDVS) standard. Modem for a mobile terminal that supports a plurality of communication standards characterized in that. delete The method of claim 1, When the mobile terminal is located in the area according to the first communication standard, The second frequency control module enters a power saving mode, The first selection module selects an output of the first frequency control module. Modem for a mobile terminal that supports a plurality of communication standards characterized in that. The method of claim 1, The first frequency control module and the second frequency control module perform data communication with an analog front end (AFE) for converting an analog signal into a digital signal according to an interface of an external radio frequency integrated circuit (RFIC). Modem for a mobile terminal that supports a plurality of communication standards characterized in that.

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