KR20160116793A - Method for selecting operating channel considering intermodulation distortion in unlicensed band - Google Patents
Method for selecting operating channel considering intermodulation distortion in unlicensed band Download PDFInfo
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- KR20160116793A KR20160116793A KR1020150045049A KR20150045049A KR20160116793A KR 20160116793 A KR20160116793 A KR 20160116793A KR 1020150045049 A KR1020150045049 A KR 1020150045049A KR 20150045049 A KR20150045049 A KR 20150045049A KR 20160116793 A KR20160116793 A KR 20160116793A
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- H04W72/085—
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W28/00—Network traffic management; Network resource management
- H04W28/16—Central resource management; Negotiation of resources or communication parameters, e.g. negotiating bandwidth or QoS [Quality of Service]
- H04W28/18—Negotiating wireless communication parameters
- H04W28/20—Negotiating bandwidth
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W72/00—Local resource management
- H04W72/02—Selection of wireless resources by user or terminal
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Abstract
A method for selecting an operation channel considering intermodulation distortion in a license-exempted band according to an embodiment of the present invention is a method for selecting a license-exempted band operation channel of a wireless communication device using a licensed band and a license-exempted band at the same time, ; Calculating or measuring the intermodulation distortion according to the license band and the carrier aggregation in the license-exempted band; And applying the intermodulation distortion to determine an operating channel within the license-exempt band.
Description
The present invention relates to an operation channel selection method considering intermodulation distortion in a license-exempted band, and more particularly, to a method for selecting an operation channel in a license-exempted band by using a licensed band and a license- To minimize the deterioration of system performance due to intermodulation distortion by selecting an operation channel.
Conventional wireless communication terminals such as mobile phones have a communication module using a license band such as LTE (long term evolution) and a communication module using a license-exempt band such as a WiFi. The communication module using the license band performed communication using the designated channel in the authorized license band and additionally provided the function of collecting the carriers and performing communication in order to increase the data transmission rate. On the other hand, in the collection of carriers within the licensed band, a carrier aggregation capable of aggregating between license bands separated from each other in frequency due to problems such as intermodulation distortion is defined as a standard form, and carrier aggregation is considered only for the corresponding aggregation Respectively.
In this case, the intermodulation distortion refers to a combination of harmonic frequencies of signals having two or more different input frequencies during a signal process through a nonlinear element. In this case, . For example, when the signal having the input frequency f1 and the signal having the frequency f2 are simultaneously passed through the nonlinear element, the harmonic components f1, 2 * f1, 3 * f1, ... of the frequency f1, the harmonic components f2, (F1 + f2, f1-f2) and the third-order intermodulation component (2 * f1-f2) for the f1 signal and the f2 signal, f2, 2 * f1 + f2, 2 * f2-f1, 2 * f2 + f1).
Meanwhile, the communication module using the license-exempted band can perform communication using any channel in the license-exempt band of a certain band. At this time, communication is performed using a channel having a good channel quality among a plurality of channels in the license-exempt band, and generally only the current channel status information such as RSSI (Received Signal Strength Indicator) information of the channel is used. In addition, the carrier aggregation technology in the license-exempt band is also considered and used, and the carrier aggregation at this time considers only the carrier aggregation within a given license-exempted band.
In recent technologies such as LTE-Unlicensed spectrum (LTE-U) discussed in the 3GPP (3 rd Generation Partnership Project), LTE modules are considering using an additional license-exempt band in addition to the license band conventionally used. The technology currently being considered considers a general technique of using a channel with superior channel quality among a plurality of available channels in a license-exempt band.
1 shows an example of a channel selection method in a general license-exempt band. Assuming that there are four channels from Uf1 to Uf4 available in the license-exempt band, the license-exempt device selects the channel with the highest channel quality as the operating channel and performs communication. At this time, the channel quality can be determined according to the RSSI in the corresponding channel, the size of the interference signal from the other device, the length of time occupied by the other channel, and the like. In the case of FIG. 1, it is determined that Uf1 channel has the best channel quality. Therefore, Uf1 is selected as an operation channel in the case of a device using a conventional license-exempt band to perform communication.
In this conventional method, only the channel quality according to the external device and the external environment is evaluated regardless of the change of the channel quality according to the operation of the device, and the operation channel is selected based on the evaluation. In the case where the license band and the license-exempted band are used in a carrier aggregation, an operation channel in the license-exempt band should be selected in consideration of influence due to the carrier aggregation of the own device, in addition to the external variables caused by the other device and channel environment.
FIG. 2 shows an example of a license-exempt band channel selection process when carriers of a general license band and a license-exempt band are used together. In the case of conventional license-exemption devices, Uf1 to Uf4 have selected channels with good channel quality among the four channels, but when using license-exempted bands with license band Lf1, problems such as intermodulation distortion should be considered.
FIG. 3 shows an example of a problem that may occur in the general license band and license-exempt band carrier aggregation. Since the signals of the license band (Lf) and the license-exempt band (Uf) received by the same antenna in the communication device have different frequencies, they pass through different bandpass filters and process signals of the respective bands. In this case, if the characteristics of the bandpass filter are poor, or if isolation between the license band and the license-exempted band signal path is not perfect, there may be a license-exempted band signal in the licensed band signal path and a licensed band signal in the non- Can exist.
In the case where the license band frequency is a multiple of the license-exempt band frequency or vice versa, the problem as shown in FIG. 3 may occur when the non-linear block such as a mixer passes through this state. As shown in the upper part of FIG. 3, a signal generated by the second-order intermodulation is generated in the vicinity of the license band signal, such as Uf-Lf, so that the license band signal can be distorted and the harmonic component of Lf, And can distort the license-exempted band signal. At this time, the positions of the licensed band and the license-exempted band may be changed.
FIG. 4 shows a problem due to third-order intermodulation distortion that may occur when a general license band and a license-exempt band are adjacent to each other. The cause of the interference between the license band signal and the license-exempt band signal is the same as in FIG. 3, but in the case of FIG. 3, the frequency of the license band and the license-exempt band are multiples or the like. And frequencies are adjacent to each other.
As shown in FIG. 4, when the frequencies of the license band Lf and the license-exempt band Uf are adjacent to each other, a third-order intermodulation distortion component such as 2Lf-Uf is generated near Lf as shown in the upper part of FIG. Lt; / RTI > Also, a third-order intermodulation distortion component such as 2Uf-Lf may be generated in the vicinity of the license-exempted band signal as shown in the lower part of FIG. 4, thereby causing distortion of the license-exempted band signal.
In the conventional operation channel selection method, only the channel quality according to other devices and the external environment is evaluated regardless of the change of the channel quality according to the operation of the own device, and the operation channel is selected based on the evaluation result. There is a problem in that there is no consideration of a problem of intermodulation distortion caused by carrier waves.
The present invention minimizes deterioration of system performance due to intermodulation distortion by selecting an operation channel in consideration of intermodulation distortion with a license band in determining a license-exiting band operation channel of a wireless communication device using a license band and a license-exempt band at the same time The present invention provides a method of selecting an operation channel considering intermodulation distortion in a license-exempt band that maximizes the improvement of system performance due to simultaneous use of the band and the license-exempt band.
The technical problems of the present invention are not limited to the above-mentioned technical problems, and other technical problems which are not mentioned can be understood by those skilled in the art from the following description.
A method for selecting an operation channel considering intermodulation distortion in a license-exempted band according to an embodiment of the present invention is a method for selecting a license-exempted band operation channel of a wireless communication device using a licensed band and a license-exempted band at the same time, ; Calculating or measuring the intermodulation distortion according to the license band and the carrier aggregation in the license-exempted band; And applying the intermodulation distortion to determine an operating channel within the license-exempt band.
This technology minimizes deterioration of system performance due to intermodulation distortion by determining license-exempt band operation channel in consideration of intermodulation distortion due to carrier integration of licensed and unlicensed bands, thereby improving system performance due to simultaneous use of licensed and licensed bands Can be maximized.
FIG. 1 is a diagram for explaining a channel selection method of a general license-exempt band.
Figure 2 is an example of a general licensing band and license-exempt band carrier aggregation usage.
FIG. 3 is a diagram for explaining a problem caused by the general licensed band and the license-exempted band carrier aggregation.
FIG. 4 is a view for explaining a problem due to third-order intermodulation distortion in a general license band and a license-exempt band carrier aggregation.
FIG. 5 is a diagram illustrating an example of a license-unlicensed band operation channel selection when carriers are accumulated in a license band and a license-exempt band according to an embodiment of the present invention.
FIG. 6 is a diagram illustrating an example of a license-license carrier aggregation and a license-exclusion zone operation channel determination in a license-exempt band carrier aggregation according to an embodiment of the present invention.
7 is a configuration diagram of a communication system for determining a license-exempt band operation channel according to an embodiment of the present invention.
8 is a flowchart illustrating a method of determining a license-exempt band operation channel according to an embodiment of the present invention.
Hereinafter, some embodiments of the present invention will be described in detail with reference to exemplary drawings. It should be noted that, in adding reference numerals to the constituent elements of the drawings, the same constituent elements are denoted by the same reference symbols as possible even if they are shown in different drawings. In the following description of the embodiments of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the difference that the embodiments of the present invention are not conclusive.
In describing the components of the embodiment of the present invention, terms such as first, second, A, B, (a), and (b) may be used. These terms are intended to distinguish the constituent elements from other constituent elements, and the terms do not limit the nature, order or order of the constituent elements. Also, unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the relevant art and are to be interpreted in an ideal or overly formal sense unless explicitly defined in the present application Do not.
The present invention discloses a method for determining an operation channel of a license-exempt band in consideration of intermodulation distortion that may occur when carriers of a licensed band and a license-exempted band coalesce in a device using both licensed and unlicensed bands simultaneously. By using the present invention, it is possible to maximize the performance improvement of the communication system due to the simultaneous utilization of the license band and the license-exempt band by determining the optimal operation channel within the license-exempt band.
Hereinafter, embodiments of the present invention will be described in detail with reference to FIGS. 5 to 8. FIG.
FIG. 5 is a diagram illustrating an example of a license-unlicensed band operation channel selection when carriers are accumulated in a license band and a license-exempt band according to an embodiment of the present invention.
Referring to FIG. 5, performance degradation is determined for each license-exempted channel considering the channel quality and the intermodulation distortion that may occur depending on the carrier aggregation of the license band and the license-exempt band, and reflects the performance degradation to the channel quality.
In the conventional method of FIG. 2, Uf1 having the best channel quality is set as the operation channel of the license-exempt band. However, according to the present invention, performance deterioration due to intermodulation distortion is expected to occur in Uf1 and the channel quality index of Uf1 is subtracted In the present invention, Uf3 is set as the operation channel of the license-exempt band.
In addition, the signal component distortion (ID1) of the licensed band due to the frequency component of the license-exempt band should be considered, as well as the distortion of the license-exempted band signal component according to the licensed band frequency component in carrier integration of licensed and unlicensed bands.
For example, in the case of FIG. 5, when one of the channels Uf2 to Uf4 in the license-exempted band operates, the intermodulation distortion does not occur in the license band frequency Lf1. However, when Uf1 is used, Should be calculated by lowering the channel quality index in consideration of the amount that is not used or causes intermodulation distortion in Lf1. In this case, Uf1 can be completely excluded from the operation channel selection when the license band signal transmission is important due to the importance of the license band, and the amount of generating intermodulation distortion in the license band is reflected in the license- Can be lowered, which may vary depending on the implementation.
FIG. 6 is a diagram illustrating an example of a license-license carrier aggregation and a license-exclusion zone operation channel determination in a license-exempt band carrier aggregation according to an embodiment of the present invention.
In the case of communication systems such as the existing LTE, a large number of carriers are collected and used even within the license band. FIG. 6 shows an application example of the present invention in the case of determining the operation channel among the license-exempt bands Uf1 to Uf4 in the communication system using the license band Lf1 and Lf2.
In other words, the application of carrier aggregation in the licensed band will increase the number of possible intermodulation distortion cases, which should be additionally considered. In the example of FIG. 5, only intermodulation distortion occurs only in Uf1 using only license band Lf1. However, in case of using Lf1 and Lf2 as carrier aggregation as shown in FIG. 6, additional intermodulation distortion due to Lf2 and carrier aggregation of Lf1 and Lf2 Can cause additional intermodulation distortion in the license-exempt band. Accordingly, it is expected that serious intermodulation distortion (ID1, ID2) occurs in Uf1 and Uf3 in FIG. 6, thereby lowering the channel quality index of the corresponding channel, and the communication system determines Uf4 as the operation channel in the license-exempt band.
7 is a configuration diagram of a communication system for determining a license-exempt band operation channel according to an embodiment of the present invention.
Referring to FIG. 7, a license-exclusion zone operation channel determination system according to an embodiment of the present invention includes a
The
The intermodulation distortion calculator 200 calculates or measures the frequency of the license band used by the device and the intermodulation distortion that may occur when the carriers are collected for the available channels in the license-exempt band.
The
Hereinafter, a method for determining a license-exempt band operation channel according to an embodiment of the present invention will be described in detail with reference to FIG.
The
In the reflection of the intermodulation distortion, it is possible to measure all the channels in the license-exempted band. However, for ease of implementation, it is possible to calculate the intermodulation distortion due to the use of each channel in the license-exempted band. For example, when the channel quality index is C for a total of N license-exempted channels, C is present from C1 to CN. In this case, if the intermodulation distortion occurring when using the channel i in the license-exempt band is represented as Di, the channel quality index Q considering the intermodulation distortion can be expressed by Equation 1 below.
In this case, the method of calculating the intermodulation distortion Di may be expressed as a product of the intermodulation distortion occurrence ratio Mi with respect to the transmission output Pi of the license band or the license-exempted band signal. Therefore, Di at this time can be expressed by the following equation (2).
On the other hand, in the generation of the intermodulation distortion that can be calculated as above, it is possible to generate intermodulation distortion of the license band by the license-exempt band signal and intermodulation distortion of the license-exemption band by the license band signal. . When calculating the intermodulation distortion D value of Equation (1) for N available channels in the license-exempted band, the intermodulation distortions DU generated in the license-exempted band and the intermodulation distortion generated in the license band The intermodulation distortion D can be expressed by Equation (3) given below by giving a weight a to DL.
Although the licensed band and the license-exempted band have been described in order to facilitate the description of the present invention, the present invention is applicable to all wireless communication systems using carrier aggregation. The terms and parameters used for the description of the present invention may be changed depending on the system to which the present invention is applied.
When the calculation of the intermodulation distortion is completed, the
As described above, according to the present invention, in an apparatus using both a licensed band and a license-exempt band, an operation channel of a license-exempt band is determined in consideration of intermodulation distortion that may occur when carriers of a licensed band and a license- By determining the operating channel, system performance improvement due to simultaneous utilization of licensed and unlicensed bandwidths can be maximized.
The foregoing description is merely illustrative of the technical idea of the present invention, and various changes and modifications may be made by those skilled in the art without departing from the essential characteristics of the present invention.
Therefore, the embodiments disclosed in the present invention are intended to illustrate rather than limit the scope of the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The scope of protection of the present invention should be construed according to the following claims, and all technical ideas within the scope of equivalents should be construed as falling within the scope of the present invention.
Claims (1)
Measuring quality per channel in the license-exempt band;
Calculating or measuring the intermodulation distortion according to the license band and the carrier aggregation in the license-exempted band; And
Determining an operating channel within the license-exempt band by applying the intermodulation distortion;
A method for selecting an operating channel in consideration of intermodulation distortion in a license-exempted band.
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| KR20140086999A (en) | 2011-11-01 | 2014-07-08 | 톰슨 라이센싱 | Profiling wi-fi channel congestion and interference to optimize channel selection |
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| KR20140086999A (en) | 2011-11-01 | 2014-07-08 | 톰슨 라이센싱 | Profiling wi-fi channel congestion and interference to optimize channel selection |
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