TWI502950B - Hand-held electronic apparatus and method for detecting sim card using the same - Google Patents

Description

Handheld electronic device and method for detecting user identification card

The present invention relates to an electronic device and a method for detecting the same, and more particularly to a method for detecting a handheld electronic device and its user identification card.

Generally, in a mobile communication system, a user obtains a Subscriber Identity Module (SIM) card when applying for a mobile phone number. The user identification card must be placed in the user identification card slot of the handheld electronic device. Its function is to identify legitimate users, which is an important basis for calling and billing, and can store relevant identification information of the user on the communication network. That is to say, the handheld electronic device must have the user's identification card to use the call function, and the different mobile phone door numbers have different user identification cards. Therefore, for users who have multiple user identification cards at the same time, there is often a need to replace the user identification card of the handheld electronic device.

When the user removes the user identification card, if the power of the user identification card has not been turned off, the user identification card may be short-circuited, causing damage to the user identification card. Therefore, in order to avoid the above situation, the existing handheld electronic device prevents the user from removing the user identification card when the power of the user identification card is not turned off by designing the configuration of the battery and the user identification card slot. Please refer to FIG. 1A to FIG. 1C . FIG. 1A to FIG. 1C illustrate the arrangement of the battery and the user identification card slot of the handheld electronic device.

As shown in FIG. 1A, the slot 18 of the handheld electronic device 10 is disposed under the battery 12, that is, after the user opens the back cover, the battery 12 must be removed before the slot 18 is located under the battery 12 and placed. The subscriber identity card 5 is located within the slot 18. That is, the user must first remove the battery 12 before inserting or removing the user identification card 5. As shown in FIG. 1B, the slot 28 of the handheld electronic device 10 is juxtaposed with the battery 12. When the user needs to insert or remove the user identification card 5, the insertion direction D1 and the removal direction D2 as shown in FIG. 1B must be followed. . In other words, the user must first remove the battery 22 before inserting or removing the user identification card 5. Therefore, the arrangement of the battery and the subscriber identification card slot as shown in FIGS. 1A and 1B can prevent the user from moving the subscriber identity card before the battery is removed.

However, as shown in FIG. 1C, the arrangement of the slot 38 and the battery 32 of the handheld electronic device 30 is independent, that is, regardless of whether the battery 32 is unplugged or not, the user can follow the insertion direction D3 and the removal direction. D4 moves the subscriber identity card 5. As such, the configuration shown in FIG. 1C will easily cause the user to insert and remove the user identification card 5 without the battery 32 being removed. A method for detecting whether the user identification card 5 shown in FIG. 1C has been removed is to add a sensing device (not shown) in the slot 38. However, the sensing device increases the handheld electronic device 30. Manufacturing costs and occupying the internal space of the handheld electronic device 30.

The invention provides a handheld electronic device, which can prevent a user from reinserting a user identification card when the power of the handheld electronic device is not turned off. The resulting short circuit condition.

The invention provides a method for detecting a user identification card, which can detect whether the user identification card has been removed from the handheld electronic device, so as to prevent the short circuit caused by the re-insertion of the handheld electronic device when the user identification card is not turned off. .

The present invention provides a handheld electronic device that includes an antenna, a subscriber identification card, and a processor. The antenna is disposed on the removable back cover of the handheld electronic device for receiving the wireless signal. The processor is coupled to the subscriber identity card, wherein the processor detects the signal strength and signal variation of the wireless signal received by the antenna. If the signal strength is less than the first threshold or the absolute value of the signal change is greater than the second threshold, the processor polls the subscriber identity card to detect if the subscriber identity card has been removed.

In an embodiment of the invention, the processor sends a status query command to the user identification card, and detects whether the response data from the user identification card is received, thereby determining whether the user identification card has been removed.

In an embodiment of the invention, if the processor does not receive the response data, the power of the user identification card is turned off.

In an embodiment of the present invention, the handheld electronic device further includes a display unit coupled to the processor, wherein after the processor turns off the power of the user identification card, the control display unit displays a prompt that the user identification card has been removed. message.

In an embodiment of the present invention, the handheld electronic device further includes a timer coupled to the processor, wherein the processor polls the user identification card according to the signal timing of the timer. When the signal strength is less than the first threshold Or the signal change amount is greater than the second threshold value, and when the processor receives the response data, the polling time interval of the timer is shortened.

In one embodiment of the present invention, the handheld electronic device further includes a radio frequency module coupled between the antenna and the processor, wherein the radio frequency module performs frequency reduction processing on the wireless signal received by the antenna to be converted into The baseband signal is transmitted to the processor for processing.

In an embodiment of the present invention, the handheld electronic device further includes a user identification card interface coupled between the processor and the user identification card, wherein the processor accesses the user identification card through the user identification card interface.

The invention provides a method for detecting a user identification card, which is suitable for a handheld electronic device, and the detection method comprises the following steps. Receiving a wireless signal through the antenna, wherein the antenna is disposed on the removable back cover of the handheld electronic device. Detects the signal strength and signal variation of wireless signals. Determine whether the signal strength is less than the first threshold, and determine whether the signal change amount is greater than the second threshold. If the signal strength is less than the first threshold or the absolute value of the signal change is greater than the second threshold, the user identification card of the handheld electronic device is polled to detect whether the user identification card has been removed.

In an embodiment of the invention, the step of polling the user identification card of the handheld electronic device to detect whether the user identification card has been removed comprises transmitting a status inquiry command to the user identification card. It is detected whether the response data from the user identification card is received, and it is determined whether the user identification card has been removed.

In an embodiment of the invention, if the response data from the subscriber identity card is not detected, the power of the subscriber identity card is turned off.

In an embodiment of the invention, after the step of turning off the power of the user identification card, the method further includes displaying, by the display unit, a prompt message that the user identification card has been removed.

In an embodiment of the present invention, the method for detecting a user identification card further includes periodically polling the user identification card. When the signal strength is less than the first threshold or the absolute value of the signal change is greater than the second threshold, and the response data is received, the polling time interval for polling the subscriber identity card is shortened.

In an embodiment of the present invention, the method for detecting a user identification card further includes: performing frequency reduction processing on the wireless signal received by the antenna to convert to a baseband signal, thereby performing judgment and signal processing on the baseband signal. .

Based on the above, the handheld electronic device of the present invention and the method for detecting the user identification card can detect whether the user identification card has been moved, by monitoring the difference of the received signal strength as the basis for whether the state of the user identification card needs to be queried. In addition, to avoid the short circuit caused by the user inserting the user identification card into the handheld electronic device again when the power is not turned off.

The above described features and advantages of the present invention will be more apparent from the following description.

First embodiment

2A is a block diagram of a handheld electronic device in accordance with a first embodiment of the present invention. 2B to 2C are schematic perspective views of a handheld electronic device according to a first embodiment of the present invention. Please refer to Figure 2A below. As shown in FIG. 2C, the handheld electronic device 200 is, for example, a handheld electronic device such as a mobile phone, a personal digital assistant (PDA) mobile phone, or a smart phone, and is not limited to the above. It is noted that the handheld electronic device 200 includes a removable back cover 202 , a body 204 , and a latch mechanism 201 , wherein the latch mechanism 201 is disposed between the removable back cover 202 and the body 204 . When the latch mechanism 201 is triggered, the buckle mechanism 201 can be released from the buckle between the body 204 and the removable back cover 202, so that the removable back cover 202 is separated from the body 204 (as shown in FIG. 2B and FIG. 2C). Shown).

Referring to FIG. 2A, the handheld electronic device 200 includes an antenna 210, a user identification card 220, and a processor 230. The function of the antenna 210 is as follows: The antenna 210 of the present invention is disposed on the removable back cover 202 of the handheld electronic device 200. Used to receive or send wireless signals. Generally, the common manufacturing method is to fix the metal piece to the removable back cover 202 of the handheld electronic device 200 by plastic hot melt or to directly attach the metal piece to the removable back cover 202. The Laser Direct Structuring (LDS) technique directly exposes the antenna 210 to the removable back cover 202. The manner in which such an antenna is disposed on the removable back cover 202 can be used to reduce the volume of the handheld electronic device 200. Accordingly, the antenna 210 of the present embodiment is, for example, a laser engraved antenna, a chip antenna, an F-shaped circuit antenna, or the like. In addition, for convenience of explanation, only one antenna 210 is shown here, but the embodiment is not limited thereto. In other embodiments, the number of antennas 210 may also be multiple.

The subscriber identity card 220 may also be referred to as a SIM card, which is, for example, a microprocessor chip. The piece is used to store relevant identification data of the user on the wireless communication network, such as a mobile phone number, communication parameters, and a memory space for storing a personal phone book or other personal information.

The processor 230 is coupled to the user identification card 220, wherein the processor 230 is used to control the overall operation of the handheld electronic device 200, such as the communication function of the handheld electronic device 200. For example, the processor 230 can detect the signal strength of the wireless signal received by the antenna 210 and the signal variation of the wireless signal, and access the user identification card 220, and is not limited to the above. In addition, the processor 230 is, for example, a central processing unit (CPU), or other programmable microprocessor (Microprocessor), a digital signal processor (DSP), a programmable controller, Application Specific Integrated Circuits (ASICs), Programmable Logic Devices (PLDs), or the like.

In addition, the handheld electronic device 200 of the present embodiment can be configured with a radio frequency module 240 coupled between the antenna 210 and the processor 230. The radio frequency module 240 can perform frequency down or up-conversion processing of the wireless signal. For example, the radio frequency module 240 can down convert the high frequency radio frequency (RF) signal received from the antenna 210 into a baseband signal, and transmit the baseband signal to the processor. 230 for processing. Alternatively, the RF module 240 can upconvert the baseband signal from the processor 230 to a high frequency RF signal. In addition, when the number of the antennas 210 is multiple, the radio frequency module 240 may include a front end device (not shown) for timely switching different antennas to receive or transmit signals.

FIG. 3 is a flow chart of a method for detecting a user identification card according to an embodiment of the invention. Referring to FIG. 2A and FIG. 3 simultaneously, the detection method of the present embodiment is applicable to the handheld electronic device 200 in the above embodiment, wherein the antenna 210 of the handheld electronic device 200 is disposed on the removable back cover 202. The detailed steps of the display method of this embodiment will be described below in conjunction with the components in the handheld electronic device 200 of FIG. 2A.

In step S302, the antenna 210 receives the wireless signal. In detail, since the wireless signal received by the antenna 210 is a high frequency signal, the radio frequency module 240 down-converts the wireless signal (ie, the high-frequency signal) received by the antenna 210 to be converted into a baseband signal. . Moreover, the radio frequency module 240 transmits the baseband signal to the processor 230 for processing.

Next, in step S304, the processor 230 detects the signal strength and the signal change amount of the wireless signal. Further, since the antenna 210 of the embodiment is disposed on the removable back cover 202, the signal strength and signal detected by the processor 230 when the removable back cover 202 is separated from the body 204. The amount of change will vary greatly. On the other hand, when the signal of the wireless communication service at the location where the handheld electronic device 200 is located is weak, the signal strength and signal variation detected by the processor 230 are also affected.

For example, when the signal strength received by the handheld electronic device 200 is greater than -75 dBm (decibel relative to one milliwatt, dBm), the reception quality is excellent, and if the call service is performed at this time, the call is stable and the voice is clear; When the signal strength received by the handheld electronic device 200 is between -75 dBm and -90 dBm, the reception quality is normal. If the call service is performed at this time, the call is stable and the voice is unclear; when the handheld electronic device 200 The received signal strength is between -90dBm and -105dBm, which means that the receiving quality is acceptable. If the call service is performed at this time, the call can still be called but some voices are unclear; when the handheld electronic device 200 If the received signal strength is less than -105dBm, it means that the reception quality is poor. At this time, there is no way to make a call service or a clear conversation.

In general, in the case where the environment of the handheld electronic device 200 is not significantly changed, the signal strength and signal variation detected by the processor 230 do not vary greatly. For example, if the user is fixed in the office and uses the handheld electronic device 200, if the receiving quality is normal, the signal strength of the handheld electronic device 200 will be substantially between -75 dBm and -90 dBm. If the user does not change the position of the handheld electronic device 200, but the signal strength detected by the processor 230 suddenly drops below -90 dBm, that is, the amount of signal change in a short time is too large, it means that the handheld electronic device 200 can The removable back cover 202 may have detached from the body 204. Since the antenna 210 is disposed on the removable back cover 202, if the removable back cover 202 is farther from the body 204 of the handheld electronic device 200, the signal strength detected by the processor 230 is worse.

Therefore, in step S306, the processor 230 determines whether the signal strength received in step S304 is less than the first threshold, and determines whether the signal change amount is greater than the second threshold. It is explained here that the setting of the first critical value and the second critical value differs depending on the specifications of the handheld electronic device 200. Specifically, due to the different specifications of the handheld electronic device, the signal strength of the wireless signal that can be received by the antenna is also different. Therefore, those skilled in the art can, for example, pre-empt the handheld electronic device 200. The number is measured to obtain information such as average received signal strength, maximum received signal strength, or minimum received signal strength to assist in setting the first and second threshold values.

In this embodiment, the first threshold value can be set, for example, to -105 dBm, because when the signal strength is less than -105 dBm, it is highly probable that the removable back cover 202 has been separated from the body 204, resulting in poor reception quality. On the other hand, those skilled in the art can detect, for example, the average signal strength Avg1 when the removable back cover 202 of the handheld electronic device 200 is in close contact with the body 204, and detect the removal of the removable back cover 202. The average signal strength Avg2 after the body 204 is taken as the second critical value by the absolute value |Avg2-Avg1| of the change amount of the signal strength of the two. In this embodiment, the second threshold value is, for example, 15 dBm. That is, when the signal strength of the handheld electronic device 200 drops by more than 15 dBm, it is highly probable that the removable back cover 202 has been separated from the body 204, resulting in receipt. The quality of the message deteriorates instantly. For example, if the signal strength is -75 dBm at time t, and the signal strength becomes -95 dBm at time (t+1), the absolute value of the signal change is 20 dBm (greater than the second threshold 15 dBm). Where t is a positive integer greater than zero.

Accordingly, in step S306, if the signal strength is not less than the first threshold and the absolute value of the signal change is not greater than the second threshold, the process returns to step S304 to continue detecting the signal strength and signal variation of the wireless signal.

However, in step S306, if the signal strength detected by the processor 230 is less than the first threshold or the absolute value of the signal variation is greater than the second threshold, the processor 230 may hold the electronic device as shown in step S308. The user identification card 220 of the device 200 performs polling to detect the user identification card. 220 has been removed.

In detail, when the removable back cover 202 disposed on the antenna 210 is separated from the body 204, or the antenna 210 cannot obtain the wireless communication service, the signal strength detected by the processor 230 may be changed or a signal may be generated. The amount of change. Therefore, if the processor 230 determines that the signal strength is less than the first threshold, or determines that the absolute value of the signal change is greater than the second threshold, the processor 230 further sends a status query command to the user identification card 220, and detects It is determined whether a response data from the subscriber identity card 220 is received. The status query instruction is, for example, an access instruction executed by the processor 230 to the user identification card 220, and the response data is, for example, information corresponding to the access instruction. As such, if the processor 230 receives the response data of the user identification card 220, it indicates that the user identification card 220 has not been removed.

In addition, if the processor 230 does not receive the response data of the user identification card 220 in step S308, the user identification card 220 has been removed on behalf of the user identification card 220. Therefore, following step S310, the processor 230 turns off the power of the user identification card 220. In this way, whether the user inserts the subscriber identity card 220 back into the slot 208 of the subscriber identity card, the situation in which the subscriber identity card 220 is short-circuited can be avoided, thereby protecting the information in the subscriber identity card 220.

Based on the above, if the signal strength received by the processor is less than the first threshold, or the absolute value of the signal change amount is greater than the second threshold, the processor polls the user identification card to detect the user identification card. Whether it is removed, and when the processor determines that the user identification card has been removed, the power can be turned off immediately to protect the user identification card.

Second embodiment

4 is a block diagram of a handheld electronic device in accordance with a second embodiment of the present invention. Referring to FIG. 2A and FIG. 4 simultaneously, the handheld electronic device 400 of FIG. 4 is similar to the handheld electronic device 200 of FIG. 2A, and the difference is that the handheld electronic device 400 of FIG. 4 further includes a display unit 250 and a user identification card. The functions of interface 260 and timer 270 are described as follows: The display unit 250 is coupled to the processor 230, wherein the display unit 250 can display the message generated by the processor 230. In addition, the display unit 250 of the embodiment is, for example, various touch screens, such as a resistive touch screen, a capacitive touch screen, an optical touch screen, and an acoustic wave. A touch screen, an electromagnetic touch screen, etc., but is not limited thereto. In another embodiment, the display unit 250 may also be a liquid crystal screen that has only a display function.

The subscriber identity card interface 260 is coupled between the processor 230 and the subscriber identity card 220. The processor 230 accesses the subscriber identity card 220 through the subscriber identity card interface 260. In addition, the subscriber identity card interface 260 and the processor 230 can be implemented as a chip circuit (e.g., virtual frame 265).

The timer 270 is coupled to the processor 230. The timer 270 can be a separate chip composed of one or several logic gates, and coupled to the processor 230 to control the independent wafer through the processor 230. Alternatively, the timer 270 can be a code written in a programming language, and the code is stored in a storage unit (not shown) for execution by the processor 230. The above storage unit is, for example, a non-volatile memory, a flash memory or a hard Dish and so on.

In addition, the materials, arrangement relationships, uses, and functions of the other components of the handheld electronic device 400 in FIG. 4 are similar to those of the handheld electronic device 200 in FIG. 2A, and thus are not described herein.

FIG. 5 is a flow chart of a method for detecting a user identification card according to a second embodiment of the present invention. The detection method of the embodiment is applicable to the handheld electronic device 400 in the above embodiment, wherein the antenna 210 of the handheld electronic device 400 is disposed on the removable back cover 202. The detailed steps of the display method of this embodiment will be described below in conjunction with the components in the handheld electronic device 200 of FIGS. 4 and 5.

Referring to FIG. 4 and FIG. 5 simultaneously, in step S502, the antenna 210 receives the wireless signal. In step S504, the processor 230 detects the signal strength and the signal change amount of the wireless signal. Steps S502 and S504 of the present embodiment are the same as steps S302 and S304 of the first embodiment, and thus are not described herein again.

In step S506, the processor 230 determines whether the signal strength is less than the first threshold, and determines whether the absolute value of the signal change amount is greater than the second threshold. Here, when the signal strength determined by the processor 230 is not less than the first threshold and the absolute value of the signal change is not greater than the second threshold, the processor 230 may follow the signal of the timer 270 as shown in step S508. The user identification card 220 is periodically polled to detect whether the user identification card 220 has been removed. For example, timer 270 can provide a polling time interval (eg, 20 seconds), causing processor 230 to periodically transmit a status query command to user identification card 220 in accordance with the polling time interval, and to cause processor 230 to time It is detected whether a response data from the subscriber identity card 220 is received. Then, if the processor 230 does not receive the response data from the subscriber identity card 220, the processor 230 will turn off the power of the subscriber identity card 220 as shown in step S510. However, if the processor 230 still receives the response data from the subscriber identity card 220, and the signal strength and its amount of change both vary within the normal range of values, then return to step S504.

Going back to step S506, when the processor 230 determines that the signal strength is less than the first threshold or the absolute value of the signal change is greater than the second threshold, the processor 230 immediately acts on the handheld electronic device 200 as shown in step S512. The subscriber identity card 220 performs polling to detect if the subscriber identity card 220 has been removed.

Here, if the processor 230 detects that the user identification card 220 has not been removed, as shown in step S514, the timer 270 shortens the polling time interval for polling the user identification card 220, and performs step S508, timing. The timer 270 will cause the processor 230 to send a status query command to the user identification card 220 according to the shortened polling time interval to detect whether the user identification card 220 has been removed. For example, if the preset polling time interval is preset to 20 seconds, at this time, the timer 270 will shorten the preset polling time interval to 5 seconds, and the timer 270 will cause the processor every 5 seconds. 230 detects if the user identification card 220 has been removed. In other words, when the signal strength detected by the processor 230 is less than the first threshold or the absolute value of the signal change is greater than the second threshold, and the response data is received, the timer 270 will raise the round of the user identification card 220. The frequency of the inquiry.

Going back to step S512, if the processor 230 detects the user identification card 220 has been removed, as shown in step S516, the processor 230 immediately turns off the power of the subscriber identity card 220 to avoid a situation in which the subscriber identity card 220 is reinserted into the slot of the subscriber identity card.

In addition, in the above steps, after the processor 230 turns off the power transmitted to the user identification card 220, the processor 230 can also control the display unit 250 to display a prompt message that the user identification card has been removed, such as a "user identification card. The text message has been removed to alert the user.

Based on the above, the processor periodically polls the subscriber identity card, and if the signal strength received by the processor is less than the first threshold, or the absolute value of the signal variation is greater than the second threshold, the processor The polling time interval for polling the subscriber identity card row is shortened to detect if the subscriber identity card has been removed. Thereby, when the processor determines that the user identification card has been removed, the power can be turned off immediately to protect the user identification card.

In summary, in the above method and the handheld electronic device, the processor detects the signal strength and the signal variation of the wireless signal, and determines whether the received signal strength is less than the first threshold, or determines the received signal change. When the absolute value of the quantity is greater than the second threshold, the processor polls the subscriber identity card to detect whether the subscriber identity card has been removed. In this way, when the processor detects that the user identification card has been removed, the power can be turned off immediately, thereby preventing the short circuit condition caused by the user identification card being inserted into the handheld electronic device again.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the invention, and any one of ordinary skill in the art can make some modifications and refinements without departing from the spirit and scope of the invention. this The scope of the invention is defined by the scope of the appended claims.

5‧‧‧User Identification Card

10, 20, 30‧‧‧ handheld electronic devices

12, 22, 32‧‧‧ batteries

18, 28, 38‧‧‧ slots

200, 400‧‧‧ handheld electronic devices

201‧‧‧Latch mechanism

202‧‧‧Removable back cover

204‧‧‧ body

206‧‧‧Battery

210‧‧‧Antenna

220‧‧‧User Identification Card

230‧‧‧ processor

240‧‧‧RF Module

250‧‧‧ display unit

260‧‧‧User Identification Card Interface

265‧‧‧Dummy box

270‧‧‧Timer

Directions D1, D2, D3, D4‧‧

S302~S310, S502~S516‧‧‧ steps

1A-1C illustrate a configuration of a battery and a subscriber identification card slot of a handheld electronic device.

2A is a block diagram of a handheld electronic device in accordance with a first embodiment of the present invention.

2B to 2C are schematic perspective views of a handheld electronic device according to a first embodiment of the present invention.

FIG. 3 is a flow chart of a method for detecting a user identification card according to an embodiment of the invention.

4 is a block diagram of a handheld electronic device in accordance with a second embodiment of the present invention.

FIG. 5 is a flow chart of a method for detecting a user identification card according to a second embodiment of the present invention.

S302~S310‧‧‧Steps

Claims (9)

A handheld electronic device includes: an antenna disposed on a removable back cover of the handheld electronic device, the antenna is configured to receive a wireless signal; a user identification card; and a processor coupled to the user An identification card, the processor detecting a signal strength and a signal variation of the wireless signal received by the antenna, if the signal strength is less than a first threshold or the absolute value of the signal variation is greater than a second threshold The processor polls the user identification card to detect whether the user identification card has been removed, wherein: the processor sends a status query command to the user identification card and detects whether the user identification is received. A response data of the card is used to determine whether the user identification card has been removed; and if the processor does not receive the response data, the processor turns off the power of the user identification card. The handheld electronic device of claim 1, further comprising: a display unit coupled to the processor, wherein the processor controls the display unit to display the power after the processor turns off the power of the user identification card A prompt message that the user identification card has been removed. The handheld electronic device of claim 1, further comprising: a timer coupled to the processor, the processor polling the user identification card according to the signal timing of the timer, When the signal strength is less than the first threshold or the signal variation is greater than the second threshold, and the processor receives the response data, shortening one of the timer polling time intervals. The handheld electronic device of claim 1, further comprising: a radio frequency module coupled between the antenna and the processor, and the radio signal received by the antenna is down-converted to convert It is a fundamental frequency signal, and the fundamental frequency signal is transmitted to the processor for processing. The handheld electronic device of claim 1, further comprising: a user identification card interface coupled between the processor and the user identification card, the processor accessing the user through the user identification card interface Identification card. A method for detecting a user identification card is applicable to a handheld electronic device. The detection method includes: receiving a wireless signal through an antenna, wherein the antenna is disposed on a removable back cover of the handheld electronic device; detecting the a signal strength and a signal change amount of the wireless signal; determining whether the signal strength is less than a first threshold value, and determining whether the absolute value of the signal change amount is greater than a second threshold value; and if the signal strength is less than the first The threshold value or the signal change amount is greater than the second threshold value, and polling a user identification card of the handheld electronic device to detect whether the user identification card has been removed, including: sending a status query command to the user identification Card detecting whether a response data from the user identification card is received, thereby determining whether the user identification card has been removed; If the response data from the subscriber identity card is not detected, the power of the subscriber identity card is turned off. The method for detecting a user identification card according to claim 6, wherein the step of turning off the power of the user identification card further comprises: displaying, by a display unit, a prompt message that the user identification card has been removed. . The method for detecting a subscriber identity card according to claim 6 further includes: periodically polling the subscriber identity card, wherein when the signal strength is less than the first threshold or the absolute value of the signal variation is greater than The second threshold value, and when the response data is received, shortens a polling time interval for polling the user identification card. The method for detecting a subscriber identity card according to claim 6 further includes: down-converting the wireless signal received by the antenna to be converted into a baseband signal, thereby determining the baseband signal And signal processing.