WO2010011091A2 - Apparatus and method for detecting interference in heterogeneous network of mobile communication system - Google Patents

Abstract

The present invention relates to an apparatus and a method for detecting interference in a heterogeneous system of a mobile communication system using an ISM (Industrial, Scientific and Medical) frequency band. Specifically, the invention concerns the apparatus and the method for detecting interference in a heterogeneous system by: confirming the start and end points of a packet based on AGC gain variation in a Zigbee communication system that uses the ISM frequency band, and using a packet-receiving rate and an interference occurrence rate depending on whether or not a synchronization process happens during a confirmed interval. The system includes an interference detection unit that: judges the packet-receiving interval by confirming the start and end points of a received packet, confirms whether or not the packet is synchronized during the judged interval, and checks the interference occurrence rate and the packet-receiving rate depending on whether or not the packet is synchronized.

Description

Apparatus and method for detecting interference in heterogeneous networks in mobile communication systems

The present invention relates to an apparatus and method for detecting interference of heterogeneous systems in a mobile communication system using an ISM frequency band (Industrial, Scientific and Medical band), and in particular to a AGC gain change in a Zigbee communication system using the ISM frequency band. An apparatus and method for checking the start and end of a packet and detecting interference of a heterogeneous system by using a packet reception rate and an interference occurrence rate according to a synchronization process during the identified period.

Recently, with the rapid development of mobile communication, a portable terminal capable of wireless voice call and information exchange has become a necessity. In the early days of the portable terminal, it was recognized that the user could simply carry the mobile phone and make a wireless call. However, with the development of the technology and the introduction of the wireless Internet, the portable terminal may not only be used for simple phone calls or schedule management, Increasingly, applications such as image capture, satellite broadcasting, games, and remote control using near field communication are increasing.

Among the above functions, the short-range communication function provides the advantage of being able to communicate wirelessly with a peripheral device. The portable terminal manufacturers include Bluetooth, Zigbee, Ultra-Wideband, UWB, Wireless LAN, Rubee is launching a handheld terminal with short-range wireless communication.

Among the short range communication technologies described above, Zigbee is a communication method using the ISM band (Industrial, Scientific and Medical band), which can provide data rates of up to 250kbps, and can configure up to 65,535 sensor networks.

However, since the Zigbee communication uses the ISM band, it may receive a communication failure due to interference by another heterogeneous system, for example, wireless LAN or Bluetooth. Accordingly, in the Zigbee communication, it is necessary to select a frequency channel having relatively little interference in order to ensure stable data transmission and reception. In this case, the portable terminal identifies a channel with less interference through the following interference component detection method.

First, the first method of detecting the interference component is to determine that there is interference when the received signal strength indication (RSSI) level of the received signal exceeds a certain threshold, and the second method is to determine whether the RSSI exceeds the threshold. When receiving the start-of-frame delimiter (SFD) of the ZigBee packet, it is determined that there are ZigBee signals in the current frequency channel. Finally, the method of detecting the interference component is to determine that there are Zigbee signals in the frequency channel currently used when the RSSI receives the SFD while exceeding the threshold.

However, the RSSI measurement method of the above methods cannot determine whether there is a heterogeneous system other than the Zigbee system in the current channel, and the method of determining whether there is a Zigbee packet includes an operation for receiving the packet, that is, a reception mode state. The problem is that it must be kept constant.

The present invention was derived to solve the above problems, and an object of the present invention is to provide an apparatus and method for detecting interference of heterogeneous systems in a mobile communication system of an ISM frequency band (Unlicensed Industrial, Scientific and Medical band). In providing.

Another object of the present invention is to provide an apparatus and method for identifying the start and end of a packet by AGC gain change in a portable terminal supporting an ISM frequency band.

It is still another object of the present invention to provide an apparatus and method for detecting interference of a heterogeneous system using a packet reception rate and an interference occurrence rate according to whether a synchronization process is performed during a packet reception period in a portable terminal supporting an ISM frequency band. .

According to a first aspect of the present invention for achieving the above objects, the apparatus for detecting interference of a heterogeneous network in a mobile communication system determines the reception interval of the packet by checking the start and end of the received packet, It characterized in that it comprises an interference detector for checking the packet synchronization during the determined period, and confirms the occurrence of interference and the packet reception rate according to the packet synchronization.

According to a second aspect of the present invention for achieving the above object, a method for detecting interference of a heterogeneous network in a mobile communication system includes the steps of determining the reception interval of the packet by checking the start and end of the packet received; And checking whether the packet is synchronized during the determined period, and checking the occurrence of interference and the packet reception rate according to whether the packet is synchronized.

1 is a block diagram illustrating in detail a configuration of an interference detector of a portable terminal for detecting interference of a heterogeneous system according to an exemplary embodiment of the present invention;

2 is a flowchart illustrating a process for detecting interference of a heterogeneous system in a portable terminal according to the present invention;

3 is a flowchart illustrating a process for detecting interference of a heterogeneous system in a portable terminal according to an embodiment of the present invention;

4 is a diagram illustrating a process of detecting interference of a heterogeneous system in a portable terminal according to an exemplary embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In describing the present invention, when it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

Hereinafter, in the Zigbee communication system using the ISM frequency band, the start and end sections of the packet are identified by the AGC gain change, and the interference of the heterogeneous system is detected by using the packet reception rate and the interference occurrence rate according to the synchronization process during the checked period. An apparatus and method for detecting will be described.

In addition, in the following description, a portable terminal is a mobile communication terminal capable of video communication such as International Mobile Telecommunication-2000 (IMT-2000), a 4th generation broadband system (Broadband system) terminal, and a personal digital assistant (PDA). The portable terminal including a mobile communication terminal will be described assuming that the terminal supports the ISM frequency band (Unlicensed Industrial, Scientific and Medical band).

1 is a block diagram illustrating in detail a configuration of an interference detector of a portable terminal for detecting interference of a heterogeneous system according to an exemplary embodiment of the present invention.

Referring to FIG. 1, the interference detecting unit 100 may include a control unit 102, a packet checking unit 104, and a counter 106.

The control unit 102 of the interference detecting unit 100 determines the start and end of the packet received by the portable terminal supporting the Zigbee system according to the present invention, and determines whether the interference is detected by the success of packet synchronization during the determined period. Do it.

The detailed operation of the controller 102 will be described below.

The control unit 102 of the interference detection unit 100 determines the start and end of the received packet due to the AGC gain change, and then checks a field (SFD; start-of-frame delimiter) indicating the start of the frame upon receiving a Zigbee packet. It is determined whether there is interference of heterogeneous systems by determining whether the packet synchronization is successful during the start and end of the determined packet. For example, when the controller 102 detects a field indicating the start of a frame, the controller 102 may determine the packet synchronization success and check the packet reception rate through a CRC check. By judging failure, the occurrence of interference can be confirmed.

At this time, the control unit 102 confirms the occurrence of interference and the packet reception rate until receiving a reception signal that can determine that the information enough to confirm the interference of the heterogeneous system has been sufficiently confirmed.

Thereafter, the controller 102 detects the interference of the heterogeneous system by using the interference occurrence and the packet reception rate.

The packet checking unit 104 checks a field indicating the start of a frame upon reception of the Zigbee packet by receiving the instruction from the control unit 102 and confirms whether packet synchronization is successful. 106).

The counter 106 performs an operation of counting the number of Zigbee packets to be received, the number of interferences identified by the packet checking unit 104, and the number of packet reception failures.

That is, the control unit 102 of the interference detecting unit 100 controls the packet checking unit 104 to check the reception rate and the occurrence of interference for the received Zigbee packet and counts the interference counted by the counter 106. And detecting the interference of the heterogeneous system by using the packet reception failure number (packet reception rate).

The counter 106 and the packet checking unit 104 of the interference detecting unit 100 may be performed by the control unit 102 of the interference detecting unit 100 of the portable terminal. One is an exemplary configuration for convenience of description and is not intended to limit the scope of the invention in any way, those skilled in the art will recognize that various modifications are possible within the scope of the invention. For example, the controller 102 may be configured to process all of them.

In the Zigbee communication system using the ISM frequency band, the start and end sections of the packet are identified by the AGC gain change, and the interference of the heterogeneous system is detected by using the packet reception rate and the interference occurrence rate according to the synchronization process during the identified period. In the following description, in the Zigbee communication system using the ISM frequency band by using the device according to an embodiment of the present invention, the packet according to the synchronization process during the start and end of the packet A method for detecting interference of heterogeneous systems using the reception rate and the interference occurrence rate will be described.

2 is a flowchart illustrating a process for detecting interference of heterogeneous systems in a portable terminal according to the present invention.

Referring to FIG. 2, the portable terminal first confirms reception of a Zigbee packet in step 201, and then proceeds to step 203 to determine the start and end of the received Zigbee packet. At this time, the portable terminal can determine the start and end sections of the packet by the AGC gain change, and can reduce the power consumption of the portable terminal by processing to operate the modem only when the Zigbee packet is received. Thereafter, the portable terminal proceeds to step 205 to determine whether or not the synchronization of the received packet is successful, and proceeds to step 207 to determine the occurrence of interference and the packet reception rate according to the success of the synchronization process. At this time, the portable terminal determines whether the synchronization of the packet is successful during the determined period, and confirms the occurrence of interference and the packet reception rate accordingly.

Thereafter, the mobile terminal proceeds to step 209 to process the presence of interference using the interference occurrence and the packet reception rate identified in step 207.

That is, according to the present invention, the portable terminal checks the start and the end of a packet received by the AGC gain change, and detects the interference based on whether the synchronization process succeeds during the start and end of the packet, that is, the packet reception period.

Here, the portable terminal can check the reception rate by checking the packet reception failure for a predetermined number of received signals.

That is, when the portable terminal checks the occurrence of interference above a predetermined threshold or a reception rate below the predetermined threshold (number of packet reception failures above a threshold) in a predetermined number of received signals, the portable terminal checks the interference of the heterogeneous system and vice versa. When the occurrence of interference below a predetermined threshold or a reception rate (number of packet reception failures below a threshold) is determined in the signal, it may be determined that there is no interference of the heterogeneous system.

The portable terminal then terminates this algorithm.

An embodiment of detecting the interference of the heterogeneous system in the portable terminal will be described in detail with reference to FIG. 3.

3 is a flowchart illustrating a process for detecting interference of heterogeneous systems in a portable terminal according to an exemplary embodiment of the present invention.

Referring to FIG. 3, when the portable terminal first detects interference of a heterogeneous system, the number of received signals (#RxSigCnt), the number of interference detection (InterferenceDetect), and the number of packet reception failures (#CRCBad) proposed by the present invention are provided. To initialize (each set to "0").

Thereafter, the portable terminal calculates the AGC gain in step 301 and then proceeds to step 303 to compare the AGC gain calculated in step 301 with a predetermined threshold. Here, the predetermined threshold value compared with the AGC gain refers to a reference value for determining the start and end of packet reception.

Here, the interference detector of the portable terminal tries to maintain the AGC gain at the maximum value in order to amplify the noise component when there is no received signal. In this case, when the interference detector receives a packet having a power equal to or greater than a sleep level power (pNoiseLevel) (hereinafter, it is assumed to be a Zigbee packet), the interference detector adjusts the AGC gain to a value lower than the noise power.

In step 303, the portable terminal performing the process of comparing the AGC gain with a predetermined threshold value determines the start and end of the received packet.

If it is determined in step 305 that the AGC gain is equal to or less than a predetermined threshold value, the portable terminal proceeds to step 319 in response to determining that packet reception is terminated and operates the modem. This allows the modem to operate only upon packet reception, thus enabling a lower power of the system when performing the interference detection process.

On the other hand, if it is determined in step 305 that the AGC gain is equal to or greater than a predetermined threshold value, the portable terminal determines that the packet corresponds to the interval between the start and the end of the packet reception, that is, proceeds to step 307 to the modem. After processing to operate, the flow proceeds to step 309 to increase the number of received signals by 1 (# RxSigCnt ++).

In step 311, the portable terminal checks the received ZigBee packet to determine whether a field indicating the start of the frame has been detected. The process of checking whether the field indicating the start of the frame is detected refers to a process of determining whether a packet synchronization process is performed.

In step 313, the portable terminal checks the result of step 311.

If it is determined in step 313 that the field indicating the start of the frame is not detected, the mobile terminal proceeds to step 315 and determines that interference has been detected due to synchronization failure, thereby increasing the number of interference occurrences (# InterferenceDetect ++).

On the other hand, if it detects a field indicating the start of the frame in step 313, the portable terminal proceeds to step 321 to determine whether the packet reception is successful. In this case, when the portable terminal confirms the packet reception failure in step 321, that is, the Zigbee packet is detected and the field indicating the start of the frame is detected, the portable terminal determines the synchronization success, but fails to receive the packet due to the CRC error. Proceed to the step to increase the number of packet reception failures (#CRCBad ++). If it is determined in step 321 that the packet reception is successful, the process proceeds to step 317 and compares the number of received signals with a predetermined threshold value. In step 317, the terminal compares the number of received signals with a predetermined threshold. Here, the predetermined threshold refers to a value for determining interference of the heterogeneous system. That is, the portable terminal determines the presence or absence of interference of the heterogeneous system by using the interference and the packet reception rate of the received signal of a predetermined threshold or more.

If the received signal is not received above a predetermined threshold in step 317, the portable terminal repeats the process of step 301 to check the interference and packet reception rate for determining the interference of heterogeneous systems.

On the other hand, if it is determined in step 317 that the received signal is greater than the predetermined threshold, the portable terminal proceeds to step 325 to determine the presence or absence of interference detection of heterogeneous systems. That is, the portable terminal performs the process of FIG. 3 (b) to determine whether the interference is detected by checking the interference and the packet reception rate of the received signal above a predetermined threshold.

If the portable terminal proceeds to step 327 and as a result of the process of step 325 confirms that the interference on the received signal and the packet reception rate is greater than a predetermined threshold value that is a reference value for determining the presence or absence of interference detection, the portable terminal In step 329, the heterogeneous system determines that interference exists.

On the other hand, when the portable terminal proceeds to step 327 and confirms that the interference of the received signal and the packet reception rate are less than a predetermined threshold as a result of the process of step 325, the portable terminal proceeds to step 331 in the heterogeneous system. It is determined that interference does not exist.

The portable terminal then terminates this algorithm.

4 is a diagram illustrating a process of detecting interference of heterogeneous systems in a portable terminal according to an exemplary embodiment of the present invention. 4 is a diagram illustrating a process of detecting interference of a heterogeneous system over time according to the present invention.

As illustrated in FIG. 4, the process of detecting interference of the heterogeneous system can be described with reference to four situations.

First, the first case of receiving a ZigBee packet, the second case of receiving an interference signal, and the case of interference superimposed on the ZigBee packet will be described. The third case is a case where the interference is superimposed on the ZigBee packet. It can be divided into overlapping cases and interference cases overlapping the latter part of the packet.

When the portable terminal performs the function of detecting interference of heterogeneous systems, the portable terminal processes to initialize the number of received signals (#RxSigCnt), the number of interference detection (InterferenceDetect), and the number of packet reception failures (#CRCBad), respectively. Set to "0").

When the portable terminal does not detect the received signal, the amplification of the noise component is maintained by keeping the gain value of the AGC at the maximum value.

If the portable terminal determines that a ZigBee packet having a power of noise power (pNoiseLevel) is received, the AGC gain value is adjusted to an AGC gain value lower than the noise power.

At this time, if the portable terminal checks the AGC gain above the threshold value, it determines that a meaningful reception signal is received and operates the modem. On the contrary, when the AGC gain value is below the threshold value, the portable terminal breaks that the reception of the current signal is terminated. Stop it.

Thereafter, the portable terminal determines whether the SFD is detected for the received signal and whether the packet reception is successful.

At this time, in the state of receiving the Zigbee packet (401), if both the SFD detection (interference occurrence confirmation according to synchronization) and the packet reception are successful, the portable terminal receives the number of received signals (#RxSigCnt) and the number of interference detection (InterferenceDetect). And a packet reception failure number (#CRCBad) value.

That is, the portable terminal determines that interference is not detected according to the SFD detection, determines that packet reception has not failed, and sets values of #RxSigCnt = 1, #InterferenceDetect = 0, and #CRCBad = 0.

If the portable terminal receives an interference signal, that is, when receiving interference of a heterogeneous system (403), the SFD detection fails and the portable terminal determines the number of interference signals (#InterferenceDetect) by '1. 'Increase.

If the SFD does not detect the above situation, the packet reception failure number #CRCBad is not increased in the successful packet reception state.

Therefore, the portable terminal sets the values of #RxSigCnt = 2, #InterferenceDetect = 1, and #CRCBad = 0.

If a heterogeneous system signal is superimposed on a ZigBee packet (405), the SFD is located at the front of the ZigBee packet. In this case, the SFD is detected but packet detection fails due to a heterogeneous system interference superimposed on the rear of the packet. do. Accordingly, the portable terminal increases the value of #CRCBad without updating #InterferenceDetect. Therefore, the values are set to #RxSigCnt = 3, #InterferenceDetect = 1, and #CRCBad = 1.

Finally, if a heterogeneous system signal is superimposed before a Zigbee packet (407), the SFD is not detected, so that the portable terminal increases the value of #InterferenceDetect by '1' and does not increase #CRCBad. Therefore, it has values of #RxSigCnt = 4, #InterferenceDetect = 2, and #CRCBad = 1.

If the threshold for the transmission signal is 3 and the threshold for the number of interferences is 1, the threshold for the failure to receive a packet is set to 1, the portable terminal #RxSigCnt = 4, #InterferenceDetect = 2, # CRCBad = 1 and the threshold is compared to determine the interference of heterogeneous systems.

That is, the portable terminal can check the interference of the heterogeneous system by checking the interference of the threshold value or more.

As described above, the present invention is to detect interference of heterogeneous systems by using a reception rate and interference according to whether packet synchronization is successful during a Zigbee packet reception interval in a Zigbee communication system using an ISM frequency band. It is possible to detect the interference of the heterogeneous system by determining the presence or absence of the heterogeneous system interference without transmitting the packet. In addition, the present invention operates the modem only at the time of packet reception, thereby performing an interference detection process, thereby enabling a low power system.

Meanwhile, in the detailed description of the present invention, specific embodiments have been described, but various modifications are possible without departing from the scope of the present invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be determined not only by the scope of the following claims, but also by the equivalents of the claims.

Claims (10)

1. An apparatus for detecting interference of heterogeneous networks in a mobile communication system,

   After checking the start and end of the received packet to determine the reception interval of the packet, and to determine whether the packet is synchronized during the determined period, including the interference detection unit for identifying the occurrence of the interference and the packet reception rate according to the packet synchronization Characterized in that the device.
2. The method of claim 1,

   The interference detection unit checks the interference and the packet reception rate as described above until receiving the received signal which can determine that the information capable of confirming the interference of the heterogeneous network is sufficiently confirmed, and generates the interference according to whether the packet is synchronized. And determining the presence of interference in the heterogeneous network by using a packet reception rate.
3. The method of claim 1,

   And the interference detecting unit determines the reception period of the packet by checking the start and end of the received packet using an AGC gain change.
4. The method of claim 1,

   And the interference detecting unit determines whether a packet is synchronized during the determined period by determining whether a field (SFD; start-of-frame delimiter) indicating a start of a frame is detected.
5. The method of claim 4, wherein

   When the interference detection unit does not detect the field indicating the start of the frame, the interference detection unit determines the occurrence of interference, and when detecting the field indicating the start of the frame, the interference detection unit determines whether the packet is received successfully through CRC check to determine whether the packet is synchronized. The interference occurrence and the packet reception rate according to the apparatus.
6. In the method for detecting interference of heterogeneous networks in a mobile communication system,

   Determining a reception interval of the packet by checking a start and an end of a received packet;

   Checking whether the packet is synchronized during the determined period;

   And determining the interference occurrence and the packet reception rate according to whether the packet is synchronized.
7. The method of claim 6,

   In the mobile communication system, a method for detecting interference of a heterogeneous network includes generating the interference and receiving a packet until the received signal can be determined to have sufficiently confirmed information for identifying the interference of the heterogeneous network. To check,

   And determining the presence of interference in the heterogeneous network by using the occurrence of interference according to the packet synchronization and the packet reception rate.
8. The method of claim 6,

   The process of determining the reception interval of the packet by checking the start and end of the received packet, characterized in that the process using the AGC gain change.
9. The method of claim 6,

   The method of determining whether the packet is synchronized during the determined period includes determining whether a field (SFD; start-of-frame delimiter) indicating the start of a frame is detected.
10. The method of claim 9,

    The process of identifying the occurrence of interference and the packet reception rate according to whether the packet is synchronized,

    Determining that an interference occurs when the field indicating the start of the frame is not detected;

    And detecting a successful reception of a packet through a CRC check when detecting a field indicating the start of the frame.

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