INTERFERENCE MEASUREMENT METHOD AND APPARATUS FOR USER EQUIPMENT HAVING MULTIPLE HETEROGENEOUS COMMUNICATION MODULES IN WIRELESS COMMUNICATION SYSTEM

Abstract

An interference measurement method and a user equipment supporting the method are provided. The method enables the user equipment having multiple heterogeneous communication modules for Long Term Evolution (LTE), WiFi, Bluetooth and Global Positioning System (GPS) to perform interference measurement so as to avoid coexistence interference. The user equipment may perform effective communication by identifying non-preferred frequency bands and avoiding coexistence interference caused by the heterogeneous communication modules.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit under 35 U.S.C. §119(e) of a U.S. provisional application filed on Jan. 18, 2011 in the U.S. Patent and Trademark Office and assigned Ser. No. 61/433,651, and under 35 U.S.C. §119(a) of a Korean patent application filed on Dec. 21, 2011 in the Korean Intellectual Property Office and assigned Serial No. 10-2011-0139376, the entire disclosures of which are hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a wireless communication system. More particularly, the present invention relates to an interference measurement method that enables a user equipment having multiple heterogeneous communication modules to avoid coexistence interference.

2. Description of the Related Art

In recent years, smartphones having WiFi, Bluetooth and Global Positioning System (GPS) modules have been rapidly popularized. With this trend, various communication technologies (for example, Long Term Evolution (LTE)/Universal Mobile Telecommunication System (UMTS) for cellular network communication, WiFi for wireless local area communication, Bluetooth for short-range wireless communication, and GNSS/GPS for location-based services, etc.) may coexist in the same user equipment. When heterogeneous communication technologies are simultaneously used in the same user equipment, a problem of interference therebetween may arise. This problem has been discussed under the name of In-Device Coexistence (IDC) in 3GPP.

While LTE/UMTS communication operates in various frequency bands, Bluetooth or WiFi communication operates in the Industrial Scientific Medical (ISM) band of 2400-2483.5 MHz. In particular, Band 40 (2300-2400 MHz) and Band 7 Uplink (2500-2570 MHz) among multiple LTE/UMTS frequency bands are adjacent to the ISM band for Bluetooth or WiFi communication. Hence, when LTE/UMTS communication and Bluetooth or WiFi communication are simultaneously conducted, a transmit signal for one communication technology may be received as a receive signal for another communication technology, thereby causing serious interference.

FIG. 3 illustrates 3GPP frequency bands for mobile communication around the ISM band. As indicated by FIG. 3, use of WiFi channel 1 while Band 40 is used for a mobile communication cell may cause serious interference, and use of WiFi channel 13 or 14 while Band 7 is used for a mobile communication cell may cause serious interference.

Hence, it is necessary to identify such mutual interference through precise measurement in the event of interference.

SUMMARY OF THE INVENTION

Aspects of the present invention are to address at least the above-mentioned problems and/or disadvantages and to provide at least the advantages described below. Accordingly, an aspect of the present invention is to provide a method and apparatus that enable a user equipment having multiple heterogeneous communication modules for LTE, WiFi, Bluetooth and GPS to perform interference measurement so as to avoid coexistence interference.

In order to solve the above problems, a user equipment identifies at least one frequency that is likely to be affected by interference and notifies such frequency to a base station, so that the base station can configure suitable measurement. The user equipment may also notify non-preferred frequency bands to the base station so that the base station may take actions to avoid interference.

In accordance with an exemplary embodiment of the present invention, a measurement method for a user equipment in a wireless communication system is provided. The measurement method includes identifying, upon detection of activation of an interfering communication technology that potentially causes interference to cellular communication of the user equipment, at least one frequency that is likely to be affected by the potential interference, sending a measurement configuration request message including the identified at least one frequency that is likely to be affected by the potential interference to a base station, and performing, upon reception of a measurement configuration message from the base station, measurement according to measurement configurations included in the measurement configuration message.

In accordance with another exemplary embodiment of the present invention, a user equipment capable of interference measurement in a wireless communication system is provided. The user equipment includes a transceiver unit sending and receiving a signal to and from a base station, and a control unit controlling a process of identifying, upon detection of activation of an interfering communication technology that potentially causes interference to cellular communication of the user equipment, at least one frequency that is likely to be affected by the potential interference caused by the interfering communication technology, for sending a measurement configuration request message including the identified list of at least one frequency that is likely to be affected by the potential interference to the base station, and for performing, upon reception of a measurement configuration message from the base station, measurement according to measurement configurations specified in the received message.

In accordance with another exemplary embodiment of the present invention, a system for coordinating measurement of in-device interference is provided. The system comprises a base station, and a terminal that communicates with the base station, wherein the base station instructs the terminal to measure in-device interference if the terminal determines that an interfering communication technology is activated as the terminal is communicating with the base station.

Other aspects, advantages, and salient features of the invention will become apparent to those skilled in the art from the following detailed description, which, taken in conjunction with the annexed drawings, discloses exemplary embodiments of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features, and advantages of certain exemplary embodiments of the present invention will be more apparent from the following description taken in conjunction with the accompanying drawings, in which:

FIG. 1 illustrates an LTE system architecture according to an exemplary embodiment of the present invention;

FIG. 2 illustrates a hierarchy of wireless protocols in an LTE system according to an exemplary embodiment of the present invention;

FIG. 3 illustrates 3GPP frequency bands for mobile communication around the ISM band according to an exemplary embodiment of the present invention;

FIG. 4 is a message sequence chart illustrating an interference measurement method according to an exemplary embodiment of the present invention;

FIG. 5 is a flowchart of a procedure performed by a user equipment such as, for example the user equipment provided in FIG. 4 according to an exemplary embodiment of the present invention;

FIG. 6 is a message sequence chart illustrating an interference measurement method according to an exemplary embodiment of the present invention;

FIG. 7 is a flowchart of a procedure performed by a user equipment such as, for example, the user equipment provided in FIG. 6 according to an exemplary embodiment of the present invention; and

FIG. 8 is a block diagram of a user equipment according to an exemplary embodiment of the present invention.

Throughout the drawings, it should be noted that like reference numbers are used to depict the same or similar elements, features, and structures.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of exemplary embodiments of the invention as defined by the claims and their equivalents. It includes various specific details to assist in that understanding but these are to be regarded as merely exemplary. Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the embodiments described herein can be made without departing from the scope and spirit of the invention. In addition, descriptions of well-known functions and constructions may be omitted for clarity and conciseness.

The terms and words used in the following description and claims are not limited to the bibliographical meanings, but, are merely used by the inventor to enable a clear and consistent understanding of the invention. Accordingly, it should be apparent to those skilled in the art that the following description of exemplary embodiments of the present invention is provided for illustration purpose only and not for the purpose of limiting the invention as defined by the appended claims and their equivalents.

It is to be understood that the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “a component surface” includes reference to one or more of such surfaces.

In the description, cellular communication (or mobile communication) is focused on the Long Term Evolution (LTE) system. However, various exemplary embodiments of the present invention are applicable to any type of cellular communication. As an example, an “interfering communication technology” refers to WiFI, Bluetooth or GPS technology (e.g., a WiFI, a Bluetooth or a GPS module) other than LTE technology (e.g., a LTE module). An LTE terminal may be referred to as a User Equipment (UE), and an LTE base station may be referred to as an evolved Node B (eNB).

FIG. 1 illustrates an LTE system architecture according to an exemplary embodiment of the present invention.

Referring to FIG. 1, an LTE radio access network is composed of eNBs 105, 110, 115 and 120, a Mobility Management Entity (MME) 125 and a Serving-Gateway (S-GW) 130. A User Equipment (UE) 135 may connect to an external network through at least one of the eNBs 105 to 120 and the S-GW 130.

The eNBs 105 to 120 correspond to Node Bs of the Universal Mobile Telecommunication System (UMTS). The eNB is connected to the user equipment 135 through a wireless channel, and may perform complex functions in comparison to an existing Node B. With regard to a Long Term Evolution (LTE) system, because all user traffic including real-time services such as Voice over IP (VoIP) services is served by shared channels, it is necessary to perform scheduling on the basis of collected status information regarding buffers, available transmit powers, and channels of user equipments. Each of the eNBs 105 to 120 performs such a scheduling function. In most cases, a single eNB controls multiple cells. To achieve a data rate of 100 Mbps, the LTE system utilizes orthogonal frequency division multiplexing (OFDM) in a 20 MHz bandwidth as radio access technology. The LTE system employs adaptive modulation and coding (AMC) to determine the modulation scheme and channel coding rate according to channel states of user equipments. The S-GW 130 provides data bearers, and creates and removes a data bearer under control of the MME 125. The MME 125 performs various control functions including mobility management for user equipments, and is connected to multiple eNBs.

FIG. 2 illustrates a hierarchy of wireless protocols in an LTE system according to an exemplary embodiment of the present invention.

Referring to FIG. 2, in the LTE system, a user equipment (UE) and an eNB each include a wireless protocol stack composed of a Packet Data Convergence Protocol (PDCP) layer 205 or 240, a Radio Link Control (RLC) layer 210 or 235, a Medium Access Control (MAC) layer 215 or 230, and a physical (PHY) layer 220 or 225. The PDCP layer 205 or 240 performs compression and decompression of IP headers. The RLC layer 210 or 235 reconfigures PDCP Protocol Data Units (PDUs) to a suitable size to conduct, for example, Automatic Repeat-reQuest (ARQ) operations. The MAC layer 215 or 230 is connected to multiple RLC layer devices in a user equipment, and multiplexes RLC PDUs into MAC PDUs or demultiplexes MAC PDUs into RLC PDUs. The physical layer 220 or 225 converts upper layer data into OFDM symbols by means of channel coding and modulation and transmits the OFDM symbols through a wireless channel, or converts OFDM symbols received through a wireless channel into upper layer data by means of demodulation and channel decoding and forwards the data to upper layers.

FIG. 4 is a message sequence chart illustrating an interference measurement method according to an exemplary embodiment of the present invention.

When an interfering communication technology causes interference in an operating frequency band, the user equipment needs to report such interference to a corresponding eNB. For reporting this coexistence interference using a measurement option defined in the standard, the eNB needs to notify the user equipment of a suitable measurement configuration.

In LTE, an A3 measurement event is commonly used for measurement triggering. An A3 event triggers when “Neighbor becomes offset better than serving”. That is, measurement reporting is triggered when channel quality of a neighbor cell is better than that of the serving cell by a preset threshold. However, the A3 measurement event is not suitable for solving a problem of interference between interfering communication technologies coexisting in the same user equipment. This is because an interfering communication technology transmitting signals may affect not only the serving cell but also neighbor cells through interference.

Hence, it is necessary to configure measurement settings in consideration of an A2 measurement event (“Serving becomes worse than threshold”). In other words, it is necessary to trigger measurement reporting when signal quality of the serving cell becomes worse than a preset threshold.

As a precondition for measurement configuration based on an A2 measurement event, it is necessary for the user equipment to report activation of an interfering communication technology to the eNB. Upon reception of the activation report, the eNB notifies the user equipment of appropriate measurement objects and a reporting configuration.

Referring to FIG. 4, the UE 401 detects activation of an interfering communication technology at step 405. Here, the UE 401 may detect activation of or an activation request for an interfering communication module. The UE 401 needs to detect activation of an interfering communication technology that may potentially interfere with cellular communication like LTE operation. To achieve this, the UE 401 may detect activation of a GPS module, a WiFi module, or a Bluetooth module by the user, or may detect potential interference while measuring quality of a received signal from a base station.

The UE 401 checks possibility of interference caused by the interfering communication technology, and identifies, when the interfering communication technology may cause interference, at least one frequency that is likely to be affected by the interfering communication technology at step 407. Among frequencies supported by the UE 401 (including the serving frequency), a frequency supported by the system that is not sufficiently separated from the frequency of the interfering communication technology may be regarded as a frequency that is likely to be affected by interference. For example, a frequency that is likely to be affected by interference indicates a frequency that may disrupt communication of a user equipment at present or in the near future if used by the user equipment.

For step 407, the eNB 403 uses system information blocks (SIB) to provide information regarding frequencies supported by the system to the UE 401. For example, SIB 5 may include information on frequencies used by neighbor E-UTRA (LTE) cells or other E-UTRA cells; SIB 6 may include information on frequencies used by neighbor UTRA (3G) cells or other UTRA cells; SIB 7 may contain information on frequencies used by neighbor GERAN (2G) cells or other GERAN cells; and SIB 8 may include information on frequencies used by neighbor CDMA2000 cells or other CDMA2000 cells.

A reason for examining those frequencies supported by the system among the frequencies supported by the user equipment is that it is possible for the user equipment in motion to perform handover to one of the frequencies supported by the system. Here, sufficiency of separation to avoid coexistence interference depends upon a filtering capability of the user equipment.

When at least one frequency that is likely to be affected by interference is present, the UE 401 sends a measurement configuration request message to the eNB 403 at step 409. Here, the measurement configuration request message is an RRC message including a list of frequencies that are likely to be affected by interference, and requests the eNB 403 to specify measurement objects and reporting configurations. As an example, entries of the list of frequencies that are likely to be affected by interference may correspond to frequencies to be specified as a measurement object.

Upon reception of the RRC message (e.g., the measurement configuration request message), the eNB 403 determines necessity of measurement configuration for the UE 401 in consideration of the frequencies that are likely to be affected by interference at step 411. When the serving frequency of the UE 401 is a frequency that is likely to be affected by interference, the eNB 403 may configure measurement based on an A2 measurement event.

When a measurement configuration is necessary, the eNB 403 sends a measurement configuration message to the UE 401 at step 413. Here, the measurement configuration message is an RRC message including information on a measurement configuration. More than one measurement may be configured. The measurement configuration may include an indication indicating measurement of in-device interference caused by an interfering communication technology in the UE 401.

The UE 401 performs measurement according to the measurement configuration specified by the eNB 403 at step 415.

In WiFi or Bluetooth communication, as uplink transmission is not continuous, some (e.g., not all) LTE subframes may be affected by interference caused by WiFi or Bluetooth transmission. If the UE 401 produces a measurement result by averaging measurement values for all subframes, the eNB 403 may not receive an appropriate measurement result. In other words, the eNB 403 may receive only a measurement result obtained by averaging measurement values for all subframes, but such a measurement result does not indicate severity and frequency of interference.

In an exemplary embodiment, to solve the above problem, if an indication indicating measurement of in-device interference caused by an interfering communication technology is received from the eNB 403, then the UE 401 maintains two measurement results: one measurement result for subframes not affected by in-device interference and another measurement result for subframes affected by in-device interference.

In the event that LTE downlink signal reception is affected by in-device interference caused by an interfering communication technology, the UE 401 starts to conduct inter-frequency measurement even though signal quality of the serving cell is greater than an “s-Measure” value received from the eNB 403. The UE 401 determines necessity of reporting based on an A2 measurement event by comparing the measurement result for subframes affected by the interfering communication technology with a threshold received from the eNB 403.

When the trigger condition for measurement as to the interfering communication technology is met, the UE 401 sends a measurement report message including a measurement report to the eNB 403 at step 417. Here, the measurement report includes a measurement result for subframes affected by in-device interference and another measurement result for subframes not affected by in-device interference.

In an exemplary embodiment, the measurement report may include a ratio of subframes affected by in-device interference to subframes not affected by in-device interference. The measurement report may include a measurement result for all subframes without classifying subframes according to in-device interference. The measurement report may further include measurement results for available frequencies (e.g., inter-frequency measurement). Specifically, the measurement report may include measurement results for N cells exhibiting best signal qualities corresponding to available frequencies.

Upon reception of the measurement report, the eNB 403 determines necessity of handover of the UE 401. If handover of the UE 401 is necessary, then the eNB 403 determines a target cell to which the UE 401 is to be handed over, performs operations necessary for handover, and sends a handover command to the UE 401 at step 419.

FIG. 5 is a flowchart of a procedure performed by an UE 401 such as, for example, the user equipment provided in FIG. 4 according to an exemplary embodiment of the present invention.

Referring to FIG. 5, the UE 401 detects activation of an interfering communication technology at step 503. Upon detection of activation of an interfering communication technology, the UE 401 identifies at least one frequency that is likely to be affected by the interfering communication technology at step 505. If at least one frequency that is likely to be affected by interference is present, then the UE 401 sends a measurement configuration request message to the eNB 403 at step 507. Here, the measurement configuration request message is an RRC message including a list of frequencies that are likely to be affected by interference, and requests the eNB 403 to specify measurement objects and measurement configurations.

Thereafter, the UE 401 receives a measurement configuration message including information on measurement objects and measurement configurations from the eNB 403 at step 509. The UE 401 performs measurement according to the measurement configurations specified in the measurement configuration message at step 511.

When a trigger condition is met during measurement, the UE 401 sends a measurement report message to the eNB 403 at step 513.

If a handover command message is received from the eNB 403, then the UE 401 performs handover according to the handover command message at step 515.

The UE 401 starts the interfering communication technology if necessary at step 517. Thereafter, the UE 401 returns to step 503 and performs requested operations (such as detection of activation or stoppage of interfering communication technologies).

FIG. 6 is a message sequence chart illustrating an interference measurement method according to an exemplary embodiment of the present invention.

Referring to FIG. 6, a UE 601 performs a procedure for RRC connection setup with an eNB 603 through a network access process at step 605. The UE 601 detects activation of or an activation request for an interfering communication technology that may affect LTE communication or may be affected by LTE communication through coexistence interference at step 607. As previously described in connection with FIG. 4, the UE 601 needs to detect activation of an interfering communication technology that may potentially interfere with cellular communication like LTE operation. To achieve this, the UE 601 may sense activation of a GPS module, a WiFi module, a Bluetooth module, or the like by the user or may detect potential interference while measuring quality of a received signal from a base station.

The UE 601 communicates with the eNB 603 so as not to use an LTE frequency band that may potentially interfere with the interfering communication technology. To achieve this, the UE 601 selects a preferred frequency that does not interfere with the interfering communication technology, and sends an RRC message to the eNB 603 to notify the same of the preferred frequency at step 609.

In step 609, the UE 601 identifies the operating frequency (or frequency band) of the interfering communication technology. This frequency (or frequency band) is referred to as frequency A (or frequency band A).

The UE 601 also identifies the frequency (or frequency band) supported by the current cellular system (e.g., LTE, UMTS or GSM) among frequencies supported by the UE 601. The frequency (or frequency band) supported by the system is referred to as frequency B (or frequency band B).

The UE 601 may obtain information on frequency B from the cellular system, and may receive information on supported frequencies therefrom. More specifically, if a measurement object is configured for the UE 601 in the current cell, then the UE 601 may consider the frequency associated with the measurement object as frequency B. When SIB 5 including an inter-frequency carrier frequency list (InterFreqCarrierFreqList) is received from the cellular system and stored, the UE 601 may consider a frequency included in the inter-frequency carrier frequency list among downlink carrier frequencies (dl-CarrierFreq) supported by the UE 601 as frequency B. UTRA frequencies belonging to a UTRA-FDD carrier frequency list (carrierFreqListUTRA-FDD) or UTRA-TDD carrier frequency list (carrierFreqListUTRA-TDD) included in SIB 6 may be considered as frequency B if such frequencies are supported by the UE 601. GSM frequencies included in SIB 7 may also be considered as frequency B if such frequencies are supported by the UE 601.

The UE 601 selects preferred frequencies among those frequencies regarded as frequency B (i.e., among frequencies supported by both the UE 601 and the system) in consideration of those frequencies regarded as frequency A. For example, the UE 601 may select one of the frequencies regarded as frequency B that is sufficiently separated from frequency A as a preferred frequency. Alternatively, the UE 601 may select one of the frequencies regarded as frequency B that is not sufficiently separated from frequency A as a non-preferred frequency. For example, sufficiency of separation to avoid coexistence interference depends upon a filtering capability of the UE 601.

Thereafter, the UE 601 creates a preferred frequency list (or a non-preferred frequency list) according to the above described scheme. The UE 601 sends an RRC message including the preferred frequency list (or the non-preferred frequency list) to the eNB 603 at step 609.

Upon reception of the RRC message, the eNB 603 stores the preferred frequency list (or the non-preferred frequency list) included in the RRC message. The eNB 603 checks whether the frequency currently used by the UE 601 is on the preferred frequency list.

If the frequency currently used by the UE 601 is not on the preferred frequency list, then the eNB 603 instructs the UE 601 to conduct handover to one frequency of the preferred frequency list at step 611.

If the frequency currently used by the UE 601 is on the preferred frequency list, then the eNB 603 may not instruct the UE 601 to conduct immediate handover. Later, when handover is requested, the eNB 603 may instruct the UE 601 to conduct handover to another eNB using a frequency on the preferred frequency list, which has been stored.

In other words, if the current operating frequency of the UE 601 is not a preferred frequency, the eNB 603 checks possibility of handover of the UE 601 to a preferred frequency and initiates a handover procedure when handover of the UE 601 to a preferred frequency is possible.

If handover of the UE 601 to a preferred frequency is not possible (for example, lack of resources in eNBs using preferred frequencies, or absence of neighbor eNBs using preferred frequencies), the eNB 603 may send an RRC message to the UE 601 to notify of impossibility of handover to a preferred frequency. Upon reception of the RRC message, the UE 601 may provide the RRC message to the user, so that the user may decide whether to start the interfering communication technology if it is not yet started.

After handover to a preferred frequency (or while already using a preferred frequency), the UE 601 starts the interfering communication technology at step 613. Here, two collocated communication technologies (for example, LTE and Bluetooth) may operate simultaneously.

When stoppage or turning off of the interfering communication technology is detected at step 615, the UE 601 sends an RRC message to the eNB 603 to notify stoppage of the interfering communication technology or an updated preferred frequency list (or non-preferred frequency list) at step 617. Upon reception of the RRC message, the eNB 603 removes restrictions on the corresponding frequency and stores the updated preferred frequency list (or non-preferred frequency list) for later use.

FIG. 7 is a flowchart of a procedure performed by an UE such as, for example, the UE 601 provided in FIG. 6 according to an exemplary embodiment of the present invention.

Referring to FIG. 7, the UE 701 detects activation of an interfering communication technology at step 703. Upon detection of activation of an interfering communication technology, the UE 701 identifies at least one frequency that is likely to be affected by the interfering communication technology at step 705.

If at least one frequency that is likely to be affected by interference is present, then the UE 701 sends an RRC message including a list of frequencies that are likely to be affected by interference to the eNB at step 707.

The eNB may send a handover command. When a handover command message is received from the eNB, the UE 701 performs handover according to the handover command message at step 709.

The UE 701 starts the interfering communication technology if necessary at step 711. Thereafter, the UE 701 returns to step 703 and performs requested operations (such as detection of activation or stoppage of interfering communication technologies).

FIG. 8 is a block diagram of a user equipment according to an exemplary embodiment of the present invention.

Referring to FIG. 8, the user equipment may include a transceiver unit 801, a mux/demux unit 803, an upper layer unit 805, a control message handler 807, a control unit 809, an interfering technology detector/determiner 811, and an interfering communication module 813.

In the user equipment, data is sent and received through the upper layer unit 805, and control messages are sent and received through the control message handler 807. For transmission, data is multiplexed by the mux/demux unit 803 and sent through the transceiver unit 801 under control of the control unit 809. For reception, a message signal received by the transceiver unit 801 is demultiplexed by the mux/demux unit 803 and forwarded to the upper layer unit 805 or the control message handler 807 according to the message type, under control of the control unit 809.

As an example, the interfering communication module 813 may directly send notification of a power on or start of operation to the interfering technology detector/determiner 811. The interfering technology detector/determiner 811 may already be aware of the interfering communication module 813. When a transmit signal 815 sent by the interfering communication module 813 is received by the transceiver unit 801 as a strong interference signal 817, the control unit 809 may recognize this situation and notify the interfering technology detector/determiner 811 of in-device interference.

To avoid in-device interference, the interfering technology detector/determiner 811 notifies the control message handler 807 of information on the interfering communication module 813. Then, the control message handler 807 creates an RRC message including a measurement configuration request and a preferred frequency list (or a non-preferred frequency list, and sends the RRC message to a corresponding eNB.

When a measurement configuration message is received as a control message from the eNB, the control unit 809 controls an operation to perform measurement according to the measurement configuration. When a handover command message is received as a control message from the eNB, the control unit 809 controls an operation to perform handover according to the handover command. After successfully performing handover, the control unit 809 notifies the interfering technology detector/determiner 811 of handover completion so as to start the interfering communication module 813 if not yet started. Thereafter, the control unit 809 controls an operation to detect activation or stoppage of interfering communication technologies, and the user equipment may repeat the above process.

Although the user equipment is depicted as including multiple blocks having different functions in the above description, it is not necessarily limited to such a configuration.

For example, the user equipment may be composed of a transceiver unit to send and receive a signal to and from an eNB, and a control unit to control interference measurement.

In this case, the control unit may control a process of identifying, upon detection of activation of an interfering communication technology, those frequencies that are likely to be affected by interference caused by the interfering communication technology, sending a measurement configuration request message including a list of frequencies that are likely to be affected by interference to a corresponding eNB, and performing, upon reception of a measurement configuration message from the eNB, measurement according to measurement configurations specified in the received message.

For example, the measurement configuration message may include an indication indicating measurement of in-device interference caused by an interfering communication technology in the user equipment.

The control unit may control an operation to separately store a measurement result for subframes not affected by in-device interference and another measurement result for subframes affected by in-device interference. The control unit may regard a frequency that is supported by the user equipment and is not separated by a preset gap or more from the frequency of the interfering communication technology as a frequency that is likely to be affected by interference.

When a trigger condition in the measurement configuration message is met, the control unit may control an operation to send a measurement report message including measurement results to the eNB. Here, the measurement report message may separately include a measurement result for subframes not affected by in-device interference and another measurement result for subframes affected by in-device interference.

When a handover command based on the transmitted measurement results is received from the eNB, the control unit may control an operation to perform handover according to the handover command.

As described above, a user equipment supporting the proposed method may perform effective measurement as to a present or potential interference factor, report measurement results to a corresponding base station, and perform handover to another cell so as to reduce in-device interference. Hence, the user equipment may conduct smooth communication while avoiding coexistence interference caused by an interfering communication technology.

In a feature of various exemplary embodiments of the present invention, a user equipment supporting the proposed method may provide information regarding a frequency band that can be affected by interference to a corresponding base station, which is then recommended to send a command for guiding interference avoidance to the user equipment. Hence, it is possible for the user equipment to perform smooth communication by reducing interference between communication modules.

While the invention has been shown and described with reference to certain exemplary embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims and their equivalents.

Claims

1. A measurement method for a user equipment in a wireless communication system, the measurement method comprising:

identifying, upon detection of activation of an interfering communication technology that potentially causes interference to cellular communication of the user equipment, at least one frequency that is likely to be affected by the potential interference;

sending a measurement configuration request message including the identified frequency that is likely to be affected by the potential interference to a base station; and

performing, upon reception of a measurement configuration message from the base station, measurement according to measurement configurations included in the measurement configuration message.

2. The measurement method of claim 1, wherein the received measurement configuration message includes an indication indicating measurement of in-device interference caused by the interfering communication technology in the user equipment.

3. The measurement method of claim 2, wherein the performing of the measurement according to the measurement configurations comprises separately storing a measurement result for subframes not affected by in-device interference and another measurement result for subframes affected by in-device interference.

4. The measurement method of claim 1, wherein the identifying of at least one frequency that is likely to be affected by the potential interference comprises determining a frequency that is supported by the user equipment and that is not separated by a preset gap or more from the frequency of the interfering communication technology as a frequency that is likely to be affected by the potential interference.

5. The measurement method of claim 1, further comprising creating, when a trigger condition specified in the measurement configuration message is met, a measurement report message including measurement results, and sending the measurement report message to the base station.

6. The measurement method of claim 5, wherein the measurement report message separately includes a measurement result for subframes not affected by in-device interference and another measurement result for subframes affected by in-device interference.

7. The measurement method of claim 6, further comprising:

receiving a handover command reflecting the measurement results from the base station; and

performing handover according to the received handover command.

8. A user equipment capable of interference measurement in a wireless communication system, the user equipment comprising:

a transceiver unit for sending and receiving a signal to and from a base station; and

a control unit for controlling a process of identifying, upon detection of activation of an interfering communication technology that potentially causes interference to cellular communication of the user equipment, at least one frequency that is likely to be affected by the potential interference caused by the interfering communication technology, for sending a measurement configuration request message including the identified list of at least one frequency that is likely to be affected by the potential interference to the base station, and for performing, upon reception of a measurement configuration message from the base station, measurement according to measurement configurations specified in the received message.

9. The user equipment of claim 8, wherein the control unit receives, through the transceiver unit, a measurement configuration message including an indication indicating measurement of in-device interference caused by the interfering communication technology in the user equipment.

10. The user equipment of claim 9, wherein the control unit controls an operation to separately store a measurement result for subframes not affected by in-device interference and another measurement result for subframes affected by in-device interference.

11. The user equipment of claim 8, wherein the control unit determines a frequency that is supported by the user equipment and is not separated by a preset gap or more from the frequency of the interfering communication technology as a frequency that is likely to be affected by the potential interference.

12. The user equipment of claim 8, wherein the control unit controls, when a trigger condition specified in the measurement configuration message is met, an operation to create a measurement report message including measurement results, and to send the measurement report message to the base station.

13. The user equipment of claim 12, wherein the control unit sends, through the transceiver unit, a measurement report message separately including a measurement result for subframes not affected by in-device interference caused by the interfering communication technology and another measurement result for subframes affected by in-device interference.

14. The user equipment of claim 13, wherein the control unit controls, upon reception of a handover command reflecting the measurement results from the base station, an operation to perform handover according to the received handover command.

15. A system for coordinating measurement of in-device interference, the system comprising:

a base station; and

a terminal that communicates with the base station,

wherein the base station instructs the terminal to measure in-device interference if the terminal determines that an interfering communication technology is activated as the terminal is communicating with the base station.

16. The system of claim 15, wherein upon detection of the activation of the interfering communication technology, the terminal identifies at least one frequency that is likely to be affected by potential interference from the interfering communication technology.

17. The system of claim 16, wherein the terminal identifies at least one frequency that is likely to be affected by potential interference from the interfering communication technology by determining frequencies over which the terminal communicates that are within a predefined threshold from the frequency over which the interfering communication technology is capable of communicating.

18. The system of claim 15, wherein the base station coordinates a handover with the terminal to a frequency which will likely not suffer interference from the interfering communication technology.

19. The system of claim 15, wherein the terminal, upon receipt of instructions from the base station to measure in-device interference, transmits a message which separately indicates a measurement result for subframes not affected by in-device interference and a measurement result for subframes affected by in-device interference.