KR101863803B1 - Method for minimizing interference caused by uplink data transmission and base station applying same - Google Patents

Abstract

A method for minimizing interference caused by uplink data transmission performed by a mobile communication base station, according to an embodiment of the present invention, may include a step of recognizing the existence of a terminal that is a subject of the periodic allocation of a radio resource for uplink data transmission, which exists in the coverage of the base station; a step of acquiring information on a radio channel environment between the terminal that is a subject of the periodic allocation and the base station at every predetermined period; and a step of allocating a small amount of radio resources for the uplink data transmission to the base station to the terminal that is a subject of the periodic allocation when the radio channel environment is better than a predetermined reference environment at every predetermined period.

Description

METHOD FOR MINIMIZING INTERFERENCE CAUSED BY UPLINK DATA TRANSMISSION AND BASE STATION APPLICATION SAME Technical Field [1] The present invention relates to a method for minimizing interference due to uplink data transmission,

The present invention relates to a method for reducing interference to neighboring cells caused by periodic allocation of uplink (UL) radio resources to a terminal and a base station to which the method is applied.

With the improvement of living standards and the development of information and communication technologies, a great number of people are receiving mobile communication services through a personal mobile communication terminal such as a smartphone. With the development of mobile communication technology, it becomes possible to provide a much wider variety of services to mobile communication subscribers at a faster rate than in the past.

In a recent LTE (Long Term Evolution) mobile communication environment, a round trip time (RTT) between a user entity (UE) and a base station (eNodeB) is about 25 ms on average. This is sufficient to use two-way communication services such as distance learning and smart work, but in some cases, the round-trip delay time needs to be shorter. For example, with regard to the autonomous driving technology, which has recently become popular, a time of 25 ms corresponds to a relatively long time such that a vehicle running at 150 km / h can travel at least 1 m.

According to the LTE environment described above, compared with downlink (DL) transmission, which is a data transmission from a base station to a terminal, a longer time is required for uplink (UL) transmission, which is data transmission from a terminal to a base station do. 1 is a diagram for explaining an uplink data transmission procedure in a mobile communication system. A terminal that wishes to transmit uplink data needs to first request a base station for radio resources for transmission of uplink data. However, such a request may be transmitted only at the time of arrival according to a predetermined period, and when the predetermined period is 10 TTI (transmission time interval, 1 TTI = 1 ms) 5 TTI should be waited for.

As described above, after a waiting time of an average of 5 TTIs, the UE can transmit a radio resource request (scheduling request) for uplink data to the base station (takes 1 TTI). The BS receiving the request can approve the allocation of radio resources for the MS (takes 3 TTIs), and can transmit the approval result to the MS (takes 1 TTI). Then, the UE transmits the uplink data to the base station through the allocated radio resources (takes 3 TTIs), processes the uplink data (takes 3 TTIs) to reach the base station (takes 1 TTI) To the core network of the system.

In the above-described sequence, it takes 17 TTIs on average. In particular, when the UE determines that uplink data transmission is necessary, it takes 10 TTIs, that is, 10 ms, until the UE receives a radio resource for uplink data transmission from the base station. . That is, it occupies 40% of the round trip delay time of 25 ms between the terminal and the base station.

In order to solve such a problem, a scheme for periodically allocating uplink radio resources to a mobile station has been devised even if there is no explicit uplink radio resource request of the mobile station. According to this, since the terminal always holds radio resources for uplink data transmission, it is possible to save the time of 10ms on average.

However, as described above, a UE that has been allocated an uplink radio resource must always transmit dummy data to the base station using the radio resource, even if there is no uplink data to be transmitted. This causes unnecessary uplink interference to the base station adjacent to the base station, resulting in a decrease in the data transmission rate of the entire mobile communication system.

Korean Unexamined Patent Publication No. 10-2011-0088977 (published on April 4, 2011)

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for preventing uplink interference to a neighboring base station from occurring due to periodic allocation of uplink radio resources to a terminal while achieving the effect of data round trip delay time, A base station to which the method is applied.

It is to be understood, however, that the present invention is not limited to the above-mentioned embodiments, but other and further objects which need not be mentioned can be clearly understood by those skilled in the art from the following description will be.

A method of minimizing interference due to uplink data transmission performed by a mobile communication base station according to an exemplary embodiment of the present invention includes the steps of periodically receiving radio resources for uplink data transmission, The method comprising the steps of: recognizing the presence of a terminal to be allocated; acquiring information on a wireless channel environment between the terminal and the base station, which are targets of the periodic allocation, every predetermined period; And allocating a predetermined amount of radio resources for the uplink data transmission to the base station to be periodically allocated if the base station is better than a predetermined reference environment.

A base station to which interference minimization due to uplink data transmission is applied according to an embodiment of the present invention includes a base station to which a radio resource for periodic allocation of uplink data for transmission of uplink data is allocated, An information acquisition unit for acquiring information on a radio channel environment between the terminal and the terminal to be periodically allocated at predetermined intervals; And allocating a predetermined amount of radio resources for the uplink data transmission to the terminals subject to the periodic allocation when the number of the radio resources is good compared to the number of the radio resources.

According to an embodiment of the present invention, a periodic allocation scheme of uplink radio resources for a UE is operated, and it is possible to determine whether the periodically allocated UE and the periodic allocation are performed based on various criteria. Thus, it is possible to prevent the side effect due to the interference to the adjacent cell caused by the periodic allocation, while achieving the effect of shortening the data round-trip delay time by the periodic allocation of the uplink radio resources.

1 is a diagram for explaining an uplink data transmission procedure in a mobile communication system.
2 is a diagram illustrating a configuration of a base station to which a method for minimizing interference due to uplink data transmission is applied, according to an embodiment of the present invention.
FIG. 3 is a diagram illustrating each step of a method for minimizing interference due to uplink data transmission according to an embodiment of the present invention. Referring to FIG.
FIG. 4 is a conceptual diagram for explaining a method for minimizing interference due to uplink data transmission according to an embodiment of the present invention. Referring to FIG.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention, and the manner of achieving them, will be apparent from and elucidated with reference to the embodiments described hereinafter in conjunction with the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. To fully disclose the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims.

In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear. The terms used in the following description are defined in consideration of the functions of the embodiments of the present invention and may vary depending on the subscriber, the intention or custom of the operator, and the like. Therefore, the definition should be based on the contents throughout this specification.

2 is a diagram illustrating a configuration of a base station to which a method for minimizing interference due to uplink data transmission is applied, according to an embodiment of the present invention. The base station 100 of FIG. 2 is a device for providing a mobile communication service to a terminal of a user subscribed to the mobile communication system. The general description of the base station 100 will be readily available to those of ordinary skill in the mobile communication arts, and a detailed description thereof will be omitted here.

The base station 100 of FIG. 2 may include a terminal recognition unit 110, an information acquisition unit 120, and a control unit 130. Each of the components may include a data bus for receiving data, a wired / wireless communication module, or the like, and may include a computing device such as a microprocessor in some cases. However, the description of the components of the base station 100 of FIG. 2 is only an embodiment of the present invention, and therefore the technical idea of the present invention is not limited to FIG. 2. Hereinafter, the operation of each component of the base station 100 will be schematically described with reference to FIG. 2. Detailed operation will be described in detail with reference to FIGS. 3 and 4. FIG.

The UE recognizer 110 recognizes the existence of a terminal (hereinafter, referred to as a "target terminal") that is a target of periodic allocation of radio resources for uplink data transmission, which is present in the coverage of the base station 100 can do. That is, the terminal recognizing unit 110 can identify the target terminal among the plurality of terminals in the coverage.

The information acquisition unit 120 may acquire information on the radio channel environment between the target terminal and the base station 100 at predetermined intervals. The information obtained by the information obtaining unit 120 may be data for determining whether or not the uplink radio resource is allocated to the target terminal in the corresponding period.

The control unit 130 controls the operation of the terminal recognition unit 110 and the information acquisition unit 120 and can perform scheduling for the terminals included in the coverage of the base station 100 including the target terminal. Specifically, the control unit 130 may transmit a predetermined amount of uplink radio resources (e.g., uplink radio resource) to the target terminal without any uplink radio resource allocation request from the target terminal, based on the information on the radio channel environment acquired by the information obtaining unit 120, It is possible to determine whether to allocate resources to the target terminal. The radio resource may be a radio resource that can be utilized for uplink data transmission from the corresponding period to the next period in which the allocation is made.

FIG. 3 is a diagram illustrating each step of a method for minimizing interference due to uplink data transmission according to an embodiment of the present invention. Referring to FIG. However, since the method shown in FIG. 3 is only one embodiment of the present invention, the concept of the present invention is not limited to FIG. 3, and each step of the method shown in FIG. And the like. The description of the elements overlapping with those of Figs. 1 and 2 may be omitted.

First, the terminal recognition unit 110 can determine whether the terminal that is initially connected to the mobile communication system (S101) is a target terminal to which the uplink radio resource is periodically allocated (S102). This is for performing periodic allocation of uplink radio resources only to necessary terminals, not all terminals within the coverage of the base station 100. [

The criterion for determining whether the target terminal is the target terminal may be set according to the mobile communication system operation policy of the mobile communication provider. For example, the terminal identification unit 110 may determine whether the initial access terminal is the target terminal, Based on the type of mobile communication service used by the terminal. For example, a service provider sets a terminal using a service requiring low latency data transmission such as a vehicle to everything (V2X) as a target terminal, and a terminal using a general web service not sensitive to delays It can be excluded from the terminal. Such a function can be implemented by using a QoS class identifier (QCI) which is given from an evolved packet core (EPC) when a mobile station accesses a call for service use. More specifically, the terminal recognition unit 110 may recognize a terminal having a specific QCI as a target terminal.

If it is determined that the initial access terminal is not the target terminal, the control unit 130 does not perform the uplink radio resource periodic allocation to the corresponding terminal, but allocates the uplink radio resource only when there is a request from the terminal Can be applied. On the other hand, the controller 130 may set a timer for counting the activation time of the mode after entering the mode for periodically allocating the uplink radio resources even if there is no request from the terminal, Can be set to 0 (S104).

For the target terminal, the controller 130 may operate the periodic allocation mode for a predetermined resource allocation time (e.g., one second). During the resource allocation time, the control unit 130 transmits a predetermined amount of uplink radio resource to the target terminal in consideration of factors such as the radio channel environment between the target terminal and the base station 100 at a predetermined resource allocation period (e.g., 5 ms) Or not.

The operation of the control unit 130 will be described in more detail below. The control unit 130 may operate the timer so that the value of the timer indicates how much time has elapsed since the timer was set to zero. If the elapsed time is less than the length of the resource allocation time (S105), the controller 130 determines whether the resource allocation period comes or not by determining whether the remainder obtained by dividing the value of the timer by the value of the resource allocation time is 0 (S106).

Whenever the resource allocation period arrives, the controller 130 can determine whether the wireless channel environment is equal to or greater than a predetermined reference environment (S107). For the determination of the controller 130, the information obtaining unit 120 may obtain information on the radio channel environment between the target terminal and the base station 100 for each resource allocation period. Then, the controller 130 can allocate a predetermined amount of uplink radio resource to the target terminal only when the radio channel environment is better than the reference environment (S109).

Specifically, the information obtaining unit 120 may obtain the uplink signal-to-noise ratio in the wireless channel, the size of the transmission output when the terminal transmits a signal, and the like as information on the wireless channel. If the uplink signal-to-noise ratio is greater than or equal to a reference value (for example, 20 dB) and / or the transmission output size is less than or equal to a reference value (for example, 22 dBm) It can be determined that what channel environment is better than the reference environment.

4 is a conceptual diagram for explaining a method for minimizing interference due to uplink data transmission according to an embodiment of the present invention. Two terminals 150 and 160 exist in the coverage 101 of the base station 100 belonging to the mobile communication system 10 and a coverage 201 adjacent to the coverage 101 of the base station 100 exists near the base station 100, It is assumed that an adjacent base station 201 exists. It is also assumed that the first terminal 150 is closer to the base station 100 than the second terminal 160.

The second terminal 160 far from the base station 100 can measure the uplink signal-to-noise ratio lower than that of the first terminal 150 because the signal strength from the base station 100 is weaker than that of the first terminal 150 have. This low value of the uplink signal-to-noise ratio means that the radio channel environment of the second terminal 160 is worse than that of the first terminal 150. In order to compensate for such a harsh environment, the second terminal 160 has a relatively higher transmission power than that of the first terminal 150, and has a larger bandwidth to transmit the same-sized data when the transmission power reaches a maximum value Lt; / RTI > For this reason, the information obtaining unit 120 can estimate the wireless channel environment through the uplink signal-to-noise ratio, the size of the transmission output of the target terminal, and the like.

In this example, the second terminal 160 is located closer to the neighbor base station 200 than the first terminal 150, uses a higher transmission power and a larger bandwidth, There is a high possibility. Therefore, even if both the first terminal 150 and the second terminal 160 are the target terminals, the controller 130 allocates uplink radio resources regardless of whether there is a radio resource request only to the first terminal 150 The problem of interference on the adjacent base station 200 can be solved while the average data round trip delay time of the mobile communication system 10 is shortened. However, the controller 130 may allocate uplink radio resources to the second terminal 160 if there is an uplink radio resource request from the second terminal 160.

By generalizing the above, the controller 130 can set the periodic radio resource allocation coverage 102, which is an area having a size smaller than the coverage 101. [ Accordingly, it is also possible that the controller 130 performs the periodic allocation of the uplink radio resources only to the target terminals existing in the periodic radio resource allocation coverage 102. [

In some cases, when there are many target terminals satisfying the condition that the radio channel environment is equal to or greater than the reference, and the radio resources are periodically allocated to all of the target terminals, the uplink radio resource is actually required, Sufficient radio resources may not be allocated to the UE requesting the radio resources. This phenomenon may cause a problem of inefficiency from the viewpoint of the entire mobile communication system.

In order to solve this problem, the controller 130 may preferentially allocate radio resources to terminals that actually request radio resources for uplink data transmission among the terminals existing in the coverage 101 of the base station 100 , And may perform periodic allocation of radio resources to a target terminal only when there is an extra uplink radio resource after the priority assignment. The control unit 130 determines whether the total amount of the radio resources preferentially allocated for each resource allocation period is less than a predetermined reference resource amount. If the total amount of radio resources is less than the reference resource amount, The link radio resource can be allocated (S108).

On the other hand, when it is impossible to allocate the predetermined amount of radio resources to all the target terminals satisfying the condition that the radio channel environment is equal to or higher than the reference level due to the lack of redundant radio resources, It is possible to allocate the predetermined amount of radio resources by selecting some target terminals in descending order of link signal-to-noise ratio.

The control unit 130 can periodically allocate radio resources to the target UE based on the principle as described above. However, when the value of the timer becomes longer than the length of the resource allocation time (i.e., (The number of resource allocation times divided by the resource allocation period), releases the periodic allocation mode of the radio resources for the target terminal, enters the mode for allocating the uplink resource only when there is a request of the target terminal (S110). This is to prevent the periodic allocation of the radio resources from being ineffective in the mobile communication system due to the period of time being excessively long.

However, if the target terminal in the idle state enters the radio resource control (RRC) connection state or the uplink radio resource request is received from the target terminal in the RRC connection state, The UE can be re-entered into the periodic allocation mode of the radio resources (S111). That is, the controller 130 may perform the above-described step S104 again from the re-entry point.

According to an embodiment of the present invention as described above, periodic allocation of radio resources is selectively applied according to a terminal according to a system operation policy of a mobile communication provider, and a terminal having a poor radio channel environment and strong interference with an adjacent base station It is possible to perform the periodic allocation with the extra radio resource remaining in the periodic allocation and preferentially allocating to the UE requesting the uplink radio resource. Accordingly, it is possible to prevent the side effect due to the interference to the adjacent cell caused by the periodic allocation while achieving the effect of shortening the data round-trip delay time through the periodic allocation of the uplink radio resources.

Combinations of each step of the flowchart and each block of the block diagrams appended to the present invention may be performed by computer program instructions. These computer program instructions may be embedded in an encoding processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus, so that the instructions, performed through the encoding processor of a computer or other programmable data processing apparatus, Thereby creating means for performing the functions described in each step of the flowchart. These computer program instructions may also be stored in a computer usable or computer readable memory capable of directing a computer or other programmable data processing apparatus to implement the functionality in a particular manner so that the computer usable or computer readable memory It is also possible for the instructions stored in the block diagram to produce a manufacturing item containing instruction means for performing the functions described in each block or flowchart of the block diagram. Computer program instructions may also be stored on a computer or other programmable data processing equipment so that a series of operating steps may be performed on a computer or other programmable data processing equipment to create a computer- It is also possible that the instructions that perform the processing equipment provide the steps for executing the functions described in each block of the block diagram and at each step of the flowchart.

Also, each block or each step may represent a module, segment, or portion of code that includes one or more executable instructions for executing the specified logical function (s). It should also be noted that in some alternative embodiments, the functions mentioned in the blocks or steps may occur out of order. For example, two blocks or steps shown in succession may in fact be performed substantially concurrently, or the blocks or steps may sometimes be performed in reverse order according to the corresponding function.

The above description is merely illustrative of the technical idea of the present invention, and various modifications and changes 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 thereof should be construed as falling within the scope of the present invention.

According to an embodiment of the present invention, an effect of shortening the data round-trip delay time through the periodic allocation of the uplink radio resources can be achieved, and side effects due to the interference to the adjacent cells caused by the periodic allocation can be prevented.

10: Mobile communication system
100: base station
110:
120: Information obtaining unit
130:
150:
160: Second terminal
200: neighbor base station

Claims (14)

A method performed by a mobile communication base station,
Determining whether the terminal connected to the base station is a terminal subject to periodic allocation of uplink radio resources;
Acquiring information on a radio channel environment between the subscriber station and the base station subject to the periodic allocation every predetermined period; And
Allocating a predetermined amount of radio resources to the base station for the uplink data transmission to the base station, which is a target of the periodic allocation, for the terminal whose radio channel environment is better than the predetermined reference environment Step
A method for minimizing interference due to uplink data transmission. The method according to claim 1,
Wherein the determining includes determining whether the terminal connected to the base station is a terminal to be periodically allocated based on the type of mobile communication service used by the terminal
A method for minimizing interference due to uplink data transmission. 3. The method of claim 2,
Wherein the step of allocating comprises the step of allocating the predetermined amount of radio resources for each of the predetermined periods to the terminal, which is better than the predetermined reference environment, regardless of whether the uplink radio resource allocation request is received from the terminal The method comprising:
The method comprises the steps of: allocating a radio resource for uplink data transmission only to a terminal other than a terminal to which the predetermined amount of radio resources are allocated among all terminals connected to the base station, RTI ID = 0.0 >
A method for minimizing interference due to uplink data transmission. The method according to claim 1,
The determining step may include the step of determining that the terminal is an object of periodic allocation when the terminal enters an RRC (radio resource control) connection state from an idle state to a terminal connected to the base station Included
A method for minimizing interference due to uplink data transmission. The method according to claim 1,
Wherein the obtaining includes obtaining at least one of a signal-to-noise ratio in the wireless channel and a size of a transmission output when the terminal transmits a signal as information on the wireless channel environment
A method for minimizing interference due to uplink data transmission. The method according to claim 1,
Wherein the allocating includes allocating a predetermined amount of radio resources to all the UEs connected to the base station when the total amount of radio resources allocated to the UE requesting the uplink data transmission is less than a predetermined reference resource amount, ≪ RTI ID = 0.0 >
A method for minimizing interference due to uplink data transmission. The method according to claim 1,
And allocating radio resources for the uplink data transmission only when there is a request from the terminal subject to the periodic allocation, when the acquisition of the information on the radio channel environment for each predetermined period is repeated a predetermined number of times Further comprising
A method for minimizing interference due to uplink data transmission. As a mobile communication base station,
A terminal determination unit for determining whether the terminal connected to the base station is a terminal subject to periodic allocation of uplink radio resources;
An information obtaining unit for obtaining information on a radio channel environment between the mobile station and the mobile station, And
Whether or not an uplink radio resource allocation request is received from the terminal, which is a target of the periodic allocation, for a terminal whose radio channel environment is better than a predetermined reference environment every predetermined period, And a control unit for allocating a predetermined amount of radio resources for link data transmission
A base station to which a method for minimizing interference due to uplink data transmission is applied. 9. The method of claim 8,
The terminal determination unit determines whether the terminal connected to the base station is the terminal that is the target of the periodic allocation based on the type of the mobile communication service used by the terminal
A base station to which a method for minimizing interference due to uplink data transmission is applied. 10. The method of claim 9,
Wherein the control unit allocates a radio resource for the uplink data transmission only when there is a request from the other terminal for a terminal other than the terminal to which the predetermined amount of radio resources are allocated among all terminals connected to the base station To do
A base station to which a method for minimizing interference due to uplink data transmission is applied. 9. The method of claim 8,
When the UE enters the RRC (radio resource control) connection state from the idle state, the UE determining unit determines that the UE is the target of the periodic allocation
A base station to which a method for minimizing interference due to uplink data transmission is applied. 9. The method of claim 8,
Wherein the information obtaining unit obtains at least one of a signal-to-noise ratio in the wireless channel and a size of a transmission output when the terminal transmits a signal as information on the wireless channel environment
A base station to which a method for minimizing interference due to uplink data transmission is applied. 9. The method of claim 8,
Wherein the control unit allocates the predetermined amount of radio resources when the total amount of the radio resources allocated to the terminals requesting the radio resources for the uplink data transmission is less than a predetermined reference amount among all the terminals connected to the base station doing
A base station to which a method for minimizing interference due to uplink data transmission is applied. 9. The method of claim 8,
Wherein the controller is configured to transmit the radio resource for the uplink data transmission only when there is a request from the terminal that is the subject of the periodic allocation if the acquisition of information on the radio channel environment for each predetermined period is repeated a predetermined number of times Perform the assignment
A base station to which a method for minimizing interference due to uplink data transmission is applied.

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