KR20210014333A - Methods and apparatuses for random access using random power backoff - Google Patents

Abstract

The present invention relates to a random access method using random power backoff, and a device thereof. According to one embodiment of the present invention, the random access method using random power backoff comprises the steps of: receiving a first message including a preamble randomly selected from a terminal; transmitting, to the terminal, a second message including a fixed power backoff value or a power backoff range; receiving a third message by separating the same from a message received from another terminal using the received power of the third message received from the terminal; and transmitting, to the terminal, a fourth message which is a confirmation message with respect to the received third message. The present invention can improve random access efficiency.

Description

Random access method and apparatus using random power backoff TECHNICAL FIELD [METHODS AND APPARATUSES FOR RANDOM ACCESS USING RANDOM POWER BACKOFF}

The present invention relates to a random access method and apparatus using random power backoff.

In the conventional random access procedure of 4G communication, a preamble randomly selected by the terminal is transmitted to the base station through a physical random access channel (PRACH). The base station receiving the preamble may determine whether the same preamble collides with a difference in the arrival time of the preamble signal, which occurs according to the distance between the terminals. However, when UEs at a similar distance transmit the same preamble, the base station cannot detect the preamble collision even though a collision occurs. Thereafter, the base station allocates resources for transmission of a third message (Msg3) by transmitting a random access response (RAR) message to the terminal transmitting the preamble. At this time, the RAR message is transmitted only to terminals for which no collision has been detected during transmission of the preamble in order to avoid collision occurring during transmission of the third message (Msg3). Thereafter, the terminal transmits a third message (Msg3) to the base station and performs a connection request. However, if detection is not performed even though a preamble collision occurs, a plurality of terminals transmit a third message (Msg3) in the same resource to cause collision, and random access fails.

The 5G communication technology provides a non-orthogonal multiple access technology that can divide and use communication resources in the time and frequency domains as well as by using code or power. In orthogonal multiple access (OMA) used in 4G communication technology, since the terminal uses communication resources using orthogonality in a specific time and frequency band, only one terminal can use a specific communication resource. However, in the non-orthogonal multiple access technology, a plurality of terminals can use the same communication resource by using a successive interference cancellation (SIC) scheme in a receiver included in the base station.

Recently, the NORA (Non-orthogonal Rancom Access) method using a non-orthogonal technique capable of separating multiple signals within the same resource by utilizing the difference in received power has been studied. In NORA, when the base station detects a preamble collision, a new field is added to the RAR message to avoid collision with the third message (Msg3), and a power backoff value is transmitted to the terminal. Each terminal calculates transmission power based on the received power backoff value and transmits a third message (Msg3) to the base station. The base station may improve the random access collision problem by receiving a plurality of third messages Msg3 having a difference in reception power and successfully receiving the third message Msg3 using the SIC technique. However, the NORA method still has a problem in that a preamble collision occurs, but the third message (Msg3) collision problem of undetected terminals cannot be solved.

Embodiments of the present invention collide a message (eg, Msg3) for random access when a preamble collision is detected and a preamble collision is not detected using a non-orthogonal multiple access technology in a wireless network environment (eg, 5G) To provide a random access method and apparatus using random power backoff that can avoid

Embodiments of the present invention mitigate collisions of messages (eg, Msg3) occurring in a random access process performed by a terminal to access a mobile communication network in a wireless network environment, thereby mitigating a conventional random access method (eg, random access of 4G communication). Method or NORA method) to provide a random access method and apparatus using random power backoff that can improve random access efficiency and delay time performance.

According to an embodiment of the present invention, there is provided a random access method performed by a base station in a wireless network environment, the method comprising: receiving a first message including a randomly selected preamble from a terminal; Transmitting a second message including a fixed power backoff value or a power backoff range to the terminal; Receiving a third message for a base station connection request from the terminal; And transmitting a fourth message, which is a confirmation message for the received third message, to the terminal. A random access method using random power backoff may be provided.

The transmitting of the second message may include detecting whether the received preamble collides, and transmitting a second message including a fixed power backoff value or a power backoff range to the terminal according to whether the detected preamble collides. Can be transmitted.

In the transmitting of the second message, whether or not the received preamble collides may be detected through a power delay profile (PDP) of the received preamble.

In the transmitting of the second message, when a collision of the received preamble is detected, a second message including a fixed power backoff value may be transmitted to the terminal.

In the transmitting of the second message, if collision of the received preamble is not detected, a second message including a power backoff range may be transmitted to the terminal.

The power back-off range may be divided into a plurality of power back-off ranges divided for each predetermined terminal area.

The plurality of power backoff ranges may correspond to a plurality of pre-set areas according to a plurality of communication ranges based on a distance to a base station.

Meanwhile, according to another embodiment of the present invention, there is provided a random access method performed by a terminal in a wireless network environment, comprising: transmitting a first message including a preamble randomly selected from among a plurality of preambles to a base station; Receiving a second message including a fixed power backoff value or a power backoff range from the base station; Transmitting a third message to the base station with a transmission power according to the received fixed power backoff value or a power backoff range; And receiving a fourth message that is a confirmation message for the transmitted third message from the base station. A random access method using random power backoff may be provided.

In the transmitting of the third message to the base station, when a fixed power backoff value is received from the base station, transmission power may be calculated by using the received fixed power backoff value.

The step of transmitting the third message to the base station is, when receiving a power backoff range from the base station, randomly selecting a power backoff value from the received power backoff range, and using the selected power backoff value. Thus, the transmission power can be calculated.

Meanwhile, according to another embodiment of the present invention, a communication module for communicating with a terminal for random access (RA) in a wireless network environment; A memory for storing at least one program; And a processor connected to the communication module and the memory, wherein the processor receives, through the communication module, a first message including a randomly selected preamble from a terminal by executing the at least one program, and the Transmitting a second message including a fixed power backoff value or a power backoff range to the terminal, receiving a third message for a base station connection request from the terminal, and a confirmation message for the received third message to the terminal A base station may be provided that transmits the phosphorus fourth message.

The processor may detect whether the received preamble collides, and transmit a second message including a fixed power backoff value or a power backoff range to the terminal according to whether the detected preamble collides.

The processor may detect whether the received preamble collides through a power delay profile (PDP) of the received preamble.

When a collision of the received preamble is detected, the processor may transmit a second message including a fixed power backoff value to the terminal.

If the collision of the received preamble is not detected, the processor may transmit a second message including a power backoff range to the terminal.

The power back-off range may be divided into a plurality of power back-off ranges divided for each predetermined terminal area.

The plurality of power backoff ranges may correspond to a plurality of pre-set areas according to a plurality of communication ranges based on a distance to a base station.

On the other hand, according to another embodiment of the present invention, a communication module that communicates with a base station for random access (RA) in a wireless network environment; A memory for storing at least one program; And a processor connected to the communication module and the memory, wherein the processor, by executing the at least one program, transmits a first message including a preamble randomly selected from a plurality of preambles to a base station through the communication module. A third message to the base station by transmitting, receiving a second message including a fixed power backoff value or a power backoff range from the base station, and transmitting power according to the received fixed power backoff value or a power backoff range A terminal may be provided, which transmits and receives a fourth message, which is a confirmation message for the transmitted third message from the base station.

When receiving a fixed power backoff value from the base station, the processor may calculate the transmission power using the received fixed power backoff value.

When receiving a power backoff range from the base station, the processor may randomly select a power backoff value from the received power backoff range and calculate a transmission power by using the selected power backoff value. .

Embodiments of the present invention collide a message (eg, Msg3) for random access when a preamble collision is detected and a preamble collision is not detected using a non-orthogonal multiple access technology in a wireless network environment (eg, 5G) Can be avoided.

Embodiments of the present invention mitigate collisions of messages (eg, Msg3) occurring in a random access process performed by a terminal to access a mobile communication network in a wireless network environment, thereby mitigating a conventional random access method (eg, random access of 4G communication). Method or NORA method), the random access efficiency and delay time performance can be improved.

1 is a diagram showing a network structure to which a random power backoff method according to an embodiment of the present invention is applied.
2 is a flowchart illustrating an example of operations of terminals performing a random access method according to an embodiment of the present invention.
3 is a diagram illustrating a message reception operation using the SIC technique used in an embodiment of the present invention.
4 is a diagram illustrating a random access response message to which a fixed power backoff value and a power backoff range are added used in an embodiment of the present invention.
5 is a diagram showing a communication range of a base station is classified into several areas.
6 is a diagram illustrating a structure of a wireless network to which a random access method according to another embodiment of the present invention is applied.
7 is a flowchart illustrating an operation example of terminals performing a random access method according to another embodiment of the present invention.
8 is a flowchart illustrating a random access method using random power backoff performed by a base station according to an embodiment of the present invention.
9 is a flowchart illustrating a random access method using random power backoff performed by a terminal according to an embodiment of the present invention.
10 is a block diagram illustrating a configuration of a base station for random access using random power backoff according to an embodiment of the present invention.
11 is a block diagram illustrating a configuration of a terminal for random access using random power backoff according to an embodiment of the present invention.
12 is a diagram showing parameters used in a simulation according to an embodiment of the present invention.
13 is a diagram illustrating an average random access delay time according to a change in the number of competing terminals according to an embodiment of the present invention and comparison methods.
14 is a diagram illustrating random access access efficiency of a terminal according to the number of competing random access terminals according to an embodiment of the present invention and comparison methods.
15 is a diagram illustrating an average random access delay time of a terminal according to the number of competing random access terminals in random access methods according to an embodiment of the present invention and another embodiment.
16 is a diagram showing random access access efficiency of a terminal according to the number of random access competing terminals in random access methods according to an embodiment of the present invention and another embodiment.

Since the present invention can make various changes and have various embodiments, specific embodiments will be illustrated in the drawings and described in detail.

However, this is not intended to limit the present invention to a specific embodiment, it is to be understood to include all changes, equivalents, or substitutes included in the spirit and scope of the present invention.

Terms such as first and second may be used to describe various components, but the components should not be limited by the terms. These terms are used only for the purpose of distinguishing one component from another component. For example, without departing from the scope of the present invention, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element. The term and/or includes a combination of a plurality of related listed items or any of a plurality of related listed items.

When a component is referred to as being "connected" or "connected" to another component, it is understood that it may be directly connected or connected to the other component, but other components may exist in the middle. Should be. On the other hand, when a component is referred to as being "directly connected" or "directly connected" to another component, it should be understood that there is no other component in the middle.

The terms used in the present application are only used to describe specific embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In the present application, terms such as "comprise" or "have" are intended to designate the presence of features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, but one or more other features. It is to be understood that the presence or addition of elements or numbers, steps, actions, components, parts, or combinations thereof, does not preclude in advance.

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 the present invention belongs. Terms such as those defined in a commonly used dictionary should be interpreted as having a meaning consistent with the meaning in the context of the related technology, and should not be interpreted as an ideal or excessively formal meaning unless explicitly defined in this application. Does not.

Hereinafter, preferred embodiments of the present invention will be described in more detail with reference to the accompanying drawings. In describing the present invention, in order to facilitate an overall understanding, the same reference numerals are used for the same elements in the drawings, and duplicate descriptions for the same elements are omitted.

1 is a diagram showing a network structure to which a random power backoff method according to an embodiment of the present invention is applied.

A method of random power backoff according to an embodiment of the present invention will be described by taking the wireless network shown in FIG. 1 as an example. The wireless network shown in FIG. 1 includes one base station 100 and four terminals 200. Terminal 1 (UE 1) and UE 2 (UE 2) select Preamble 2, and UE 3 and UE 4 select Preamble 5 (UE 5). The base station (eNB, eNode B) 100 sensed that a collision occurred by transmitting the same preamble between terminal 1 (UE 1) and terminal 2 (UE 2), and terminal 3 (UE 3) and terminal 4 (UE 4) ) Has transmitted the same preamble, but it is assumed that the collision of the corresponding preamble has not been detected.

An embodiment of the present invention is a non-orthogonal multiple access (NOMA, Non-orthogonal Multiple Access) technology when a terminal (UE, 200) performs random access (RA) in a wireless network (eg, 5G network) environment. It is possible to improve the collision problem of the third message (Msg3) by utilizing. Here, the third message Msg3 is a message for requesting connection to the base station for uplink data transmission. Specifically, after transmission of the preamble of the terminals, the base station (eNB/gNB) 100 sets a fixed power backoff value when a preamble collision is detected when transmitting a random access response (RAR) message. It transmits to the corresponding terminals. On the other hand, when the preamble collision is not detected (Undetected collision), the base station 100 transmits the power backoff range to the corresponding terminals. Through this, the base station 100 may successfully recognize the third message Msg3 by using the difference in reception power even when receiving a plurality of third messages Msg3. An embodiment of the present invention can improve the random access access efficiency and access delay time of the terminal 200 in a 5G network environment in which a plurality of terminals 200 attempt access.

2 is a flowchart illustrating an example of operations of terminals performing a random access method according to an embodiment of the present invention.

The random access method according to an embodiment of the present invention is performed through the following steps.

In step S101, the terminal 200 first selects a preamble and transmits it to the base station 100. Terminal 1 (UE 1) and terminal 2 (UE 2) that transmitted the same preamble transmit the preamble to the base station 100 on the same resource, and terminal 3 (UE 3) and terminal 4 (UE 4) that transmitted the same preamble ) Transmits the preamble to the base station 100 in the same resource. The base station 100 determines whether the preamble received from the terminal 200 collides.

In step S102, the base station 100 detects a preamble collision and transmits a fixed power backoff value to the terminal 200, or does not detect a preamble collision and transmits a power backoff range to the terminals through an RAR message. For example, the base station 100 selects fixed power backoff values 1 and 2 to UE 1 and UE 2 in which a preamble collision is detected, and transmits the RAR message. In addition, the base station 100 transmits a random power backoff range {1, 2, ..., n} to UE 3 (UE 3) and UE 4 (UE 4) in which preamble collision is not detected.

In step S103, the terminal 200 determines the fixed power backoff value as the power backoff value, or selects a random power backoff value in the power backoff range. For example, UE 3 and UE 4 randomly select a power backoff value within the received power backoff range. Terminal 3 (UE 3) and UE 4 (UE 4) determine power backoff values as 1 and 3.

In step S104, the terminal 200 calculates transmission power based on the determined power backoff value and transmits a third message (Msg3) to the base station 100, and the base station 100 uses the SIC technique to transmit the third message. (Msg3) is received. For example, UE 1 and UE 2 calculate the transmission power of the third message Msg3 corresponding to the fixed power backoff values 1 and 2. Terminal 3 (UE 3) and UE 4 (UE 4) calculate the transmission power of the third message (Msg3) by using the determined power backoff values 1 and 3. In addition, UE 1 to UE 4 transmits the third message Msg3 to the base station 100 with the calculated transmission power of the third message Msg3. The base station 100 may separately receive all of the third messages Msg3 of terminals 1, 2, 3, and 4 by using the SIC technique.

In step S105, the base station 100 responds to the terminal 200 with a fourth message Msg4, which is a confirmation message for the third message Msg3. As an example, the base station 100 transmits a fourth message (Msg4) to terminal 1 (UE 1), terminal 2 (UE 2), terminal 3 (UE 3), and terminal 4 (UE 4), and a random access process This is done.

)을 선택한다. 단말(200)은 고정 파워 백오프 값을 수신한 경우 해당값을 파워 백오프 값(

)으로 설정한다. 단말(200)은 결정된 파워 백오프 값(

)과 하기의 [수학식 1]을 통해 Msg3 전송전력을 구할 수 있다.Meanwhile, the terminal 200 receives PRACH resource information for performing random access from the base station 100 in order to perform random access. The terminal 200 randomly selects one of the preambles available in the PRACH resource information and transmits it to the base station 100. The base station 100 that has received a plurality of the same preambles may determine the preamble collision through a power delay profile (PDP) of each preamble. When the base station 100 detects a preamble collision, a unique fixed power backoff value according to the preamble TA (Timing Advance) is added to the RAR message and transmitted to the terminal 200 through a physical downlink control channel (PDCCH). If the base station 100 does not detect the preamble collision, the same power backoff range is added to the RAR message and transmitted to the terminal 200 through the PDCCH. Upon receiving the RAR message, the terminals 200 check a fixed power backoff value or a power backoff range assigned to them according to the preamble TA value. When receiving the power backoff range through the RAR message, the terminal 200 randomly receives the power backoff value (

Select ). When the terminal 200 receives a fixed power backoff value, the terminal 200 uses the power backoff value (

). The terminal 200 determines the determined power backoff value (

) And the following [Equation 1] to obtain the Msg3 transmission power.

: 경로 손실이 0dB일 때 RB(Resource Block)당 수신 전력

: Received power per RB (Resource Block) when the path loss is 0dB

: 단말의 최대 송신전력

: Maximum transmission power of the terminal

: 상향링크에서 사용가능한 RB 개수

: Number of RBs available in uplink

: 하향링크에서 추정된 경로 손실

: Path loss estimated in downlink

: 단말(200)의 전송 전력

: Transmission power of the terminal 200

: 기지국(100)으로부터 받은 파워 백오프 값

: Power backoff value received from the base station 100

: 파워 백오프 오프셋(offset) 값

: Power backoff offset value

: 전력 제어로 인해 증가된 전송 전력 감소율

: Increased transmission power reduction rate due to power control

The terminals 200 transmit a third message (Msg3) to the base station 100 by using the transmission power of the third message (Msg3) determined through [Equation 1] in the allocated Physical Uplink Shared Channel (PUSCH) resource. . The base station 100 may sequentially separate and receive the third messages Msg3 in which the difference in reception power appears, starting from the order in which the power is large, using the SIC technique. The base station 100 transmits the fourth message (Msg4) to the terminals 200 corresponding to the received third message (Msg3), and the terminals 200 that receive the fourth message (Msg4) succeed in random access. Is done.

3 is a diagram illustrating a message reception operation using the SIC technique used in an embodiment of the present invention.

As shown in FIG. 3, the base station 100 enables a plurality of terminals 200 to use the same communication resource by using the SIC technique. The base station 100 may separate and receive all third messages having a power difference received from a plurality of terminals 200.

4 is a diagram illustrating a random access response message to which a fixed power backoff value and a power backoff range are added used in an embodiment of the present invention.

As shown in FIG. 4, in order to include a fixed power back-off value and a power back-off range in the RAR message, a power back-off value and a power back-off range as shown in FIG. off Range) field is newly defined in the RAR message.

5 is a diagram showing a communication range of a base station is classified into several areas.

Another embodiment of the present invention is to prevent a third message (Msg3) collision that occurs when a preamble collision occurs but the base station 100 does not detect it. To this end, the communication range of the base station 100 is classified into a number of zones based on the distance to the base station 100. Another embodiment of the present invention can improve the random access collision problem by allocating different random power backoff ranges to each zone.

As shown in FIG. 5, the communication range of the base station 100 is classified into several zones based on the distance to the base station 100. When a preamble collision occurs but is not detected, the base station 100 according to another embodiment of the present invention transmits a different random power backoff range for each zone to the terminals through RAR messages. Terminals with different zones have different received random power backoff ranges, and thus power backoffs randomly selected by the terminals are also different. The terminals calculate their respective third message (Msg3) transmission power with different power backoff values, and transmit the third message (Msg3) to the base station 100 with the power. Thereafter, the base station 100 may receive the third message Msg3 having a difference in reception power, and may separate the third messages Msg3 using the SIC technique. Through this, another embodiment of the present invention can improve random access delay time and access efficiency performance.

6 is a diagram illustrating a structure of a wireless network to which a random access method according to another embodiment of the present invention is applied.

The wireless network shown in FIG. 6 includes one base station 100 and four terminals 200. Among them, terminal 2 (UE 2), terminal 3 (UE 3), and terminal 4 (UE 4) are located in the same zone, and terminal 1 (UE 1) is located in a different zone. Terminal 1 (UE 1) and UE 2 (UE 2) select preamble 4, and UE 3 and UE 4 (UE 4) select preamble 2. The base station 100 assumed that UE 1 (UE 1) and UE 2 (UE 2) did not detect a preamble collision and a preamble collision between UE 3 (UE 3) and UE 4 (UE 4).

7 is a flowchart illustrating an operation example of terminals performing a random access method according to another embodiment of the present invention.

In step S201, terminal 1 (UE 1) and terminal 2 (UE 2) transmitting the same preamble transmit a third message (Msg3) in the same resource, and terminal 3 (UE 3) and terminal 4 (UE 4) Will transmit the third message (Msg3) in the same resource.

In step S202, the base station 100 is the terminal 1 (UE 1) and the terminal 2 (UE 2) a random power backoff range {1, 2, ... , 5} and a random power backoff range {6, 7,… to UE 3 and UE 4) , 10}.

In step S203, UE 1 (UE 1) randomly selects a power backoff value 2, and UE 2 (UE 2) selects a power backoff value of 7. And UE 3 (UE 3) randomly selects a power backoff value 6, and UE 4 (UE 4) randomly selects a power backoff value 9.

In step S204, the terminals each calculate the transmission power of the corresponding third message Msg3 using the selected power backoff value, and transmits the third message Msg3 to the base station 100 with the determined transmission power. Terminal 1 (UE 1) and UE 2 (UE 2) have different received powers as the selected power backoff values are 2 and 7, so the base station 100 uses the SIC technique to The third message Msg3 of UE 2 may be separated and received. In addition, since UE 3 (UE 3) and UE 4 (UE 4) have different received powers as the selected power backoff values are different from each other to 6 and 9, the base station 100 uses the SIC technique to use the terminal 3 (UE 3). ) And the third message Msg3 of UE 4 may be separately received.

Thereafter, in step S205, the base station 100 transmits a fourth message (Msg4) to terminal 1 (UE 1), terminal 2 (UE 2), terminal 3 (UE 3), and terminal 4 (UE 4), and 1 (UE 1), terminal 2 (UE 2), terminal 3 (UE 3), and terminal 4 (UE 4) complete the random access process.

8 is a flowchart illustrating a random access method using random power backoff performed by a base station according to an embodiment of the present invention.

In step S301, the base station 100 receives a first message including a randomly selected preamble from the terminal 200.

In step S302, the base station 100 checks whether a preamble collision is detected.

In step S303, when a preamble collision is detected, the base station 100 transmits a second message including a fixed power backoff value to the terminal 200.

On the other hand, in step S304, if the preamble collision is not detected, the base station 100 transmits a second message including a power backoff range to the terminal 200.

In step S305, the base station 100 receives the third message by separating it from the message received from the other terminal 200 by using the reception power of the third message received from the terminal 200.

In step S306, the base station 100 transmits a fourth message, which is a confirmation message for the third message, to the terminal 200.

9 is a flowchart illustrating a random access method using random power backoff performed by a terminal according to an embodiment of the present invention.

In step S401, the terminal 200 transmits a first message including a preamble randomly selected from among a plurality of preambles to the base station 100.

In step S402, the terminal 200 checks whether a fixed power backoff value is received from the base station 100.

In step S403, when a fixed power backoff value is received from the base station 100, the terminal 200 calculates transmission power by using the fixed power backoff value.

On the other hand, in step S404, if a fixed power backoff value is not received from the base station 100, that is, when a power backoff range is received, the terminal 200 randomly selects a power backoff value from the received power backoff range. do.

In step S405, the terminal 200 calculates transmission power using the selected power backoff value.

In step S406, the terminal 200 transmits a third message to the base station 100 with the calculated transmission power.

In step S407, the terminal 200 receives a fourth message, which is a confirmation message for the third message, from the base station 100.

10 is a block diagram illustrating a configuration of a base station for random access using random power backoff according to an embodiment of the present invention.

As shown in FIG. 10, the base station 100 according to an embodiment of the present invention includes a communication module 110, a memory 120, and a processor 130. However, not all of the illustrated components are essential components. The base station 100 may be implemented by more components than the illustrated components, or the base station 100 may be implemented by fewer components than the illustrated components.

Hereinafter, a detailed configuration and operation of each component of the base station 100 of FIG. 10 will be described.

The communication module 110 communicates with the terminal 200 for random access (RA) in a wireless network environment.

The memory 120 stores at least one program.

The processor 130 is connected to the communication module 110 and the memory 120.

By executing the at least one program, the processor 130 receives, through the communication module 110, a first message including a randomly selected preamble from the terminal 200, and provides a fixed power to the terminal 200. A second message including a backoff value or a power backoff range is transmitted, and the third message is separated from the message received from the other terminal 200 by using the received power of the third message received from the terminal 200. A message is received, and a fourth message, which is a confirmation message for the received third message, is transmitted to the terminal 200.

According to embodiments, the processor 130 detects whether the received preamble collides, and according to whether the detected preamble collides, the terminal 200 includes a fixed power backoff value or a power backoff range. 2 Can send messages.

According to embodiments, the processor 130 may detect whether a received preamble collides through a power delay profile (PDP) of the received preamble.

According to embodiments, when a collision of a received preamble is detected, the processor 130 may transmit a second message including a fixed power backoff value to the terminal 200.

According to embodiments, if the collision of the received preamble is not detected, the processor 130 may transmit the second message including the power backoff range to the terminal 200.

According to embodiments, the power back-off range may be divided into a plurality of power back-off ranges divided for each zone of the terminal 200 set in advance.

According to embodiments, a plurality of power backoff ranges may correspond to a plurality of preset areas according to a plurality of communication ranges based on a distance to the base station 100.

11 is a block diagram illustrating a configuration of a terminal for random access using random power backoff according to an embodiment of the present invention.

As shown in FIG. 11, the terminal 200 according to an embodiment of the present invention includes a communication module 210, a memory 220, and a processor 230. However, not all of the illustrated components are essential components. The terminal 200 may be implemented by more components than the illustrated components, or the terminal 200 can be implemented by fewer components.

Hereinafter, a detailed configuration and operation of each component of the terminal 200 of FIG. 11 will be described.

The communication module 210 communicates with the base station 100 for random access (RA) in a wireless network environment.

The memory 220 stores at least one program.

The processor 230 is connected to the communication module 210 and the memory 220.

By executing the at least one program, the processor 230 transmits a first message including a preamble randomly selected among a plurality of preambles to the base station 100, and transmits a fixed power backoff value or power from the base station 100. Receives a second message including a backoff range, calculates a transmission power using the received fixed power backoff value or a power backoff range, and transmits a third message to the base station 100 using the calculated transmission power Then, a fourth message, which is a confirmation message for the transmitted third message, is received from the base station 100.

According to embodiments, when receiving a fixed power backoff value from the base station 100, the processor 230 may calculate the transmission power by using the received fixed power backoff value.

When receiving the power backoff range from the base station 100, the processor 230 may randomly select a power backoff value from the received power backoff range, and calculate the transmission power using the selected power backoff value. have.

12 is a diagram showing parameters used in a simulation according to an embodiment of the present invention.

The random access delay time and access efficiency were compared between the random access method according to an embodiment of the present invention, the random access method in 4G (Comparative Method 1) and the random access method (Comparative Method 2) proposed by NORA. The parameters used in the simulation were set as shown in FIG. 12. Performance was evaluated by changing the number of terminals participating in random access competition from 10 to 200, and the distance between the terminal 200 and the base station 100 was set to be random. In addition, if the RAR message is not received within 5 ms after transmission of the preamble, the preamble is retransmitted, and when the third message Msg3 collides, the terminal 200 retries random access after a random time within 0 to 20 ms.

13 is a diagram illustrating an average random access delay time according to a change in the number of competing terminals according to an embodiment of the present invention and comparison methods.

In both the random access method (invention 1) and the comparison method according to an embodiment of the present invention, it can be seen that as the number of terminals increases, the average access delay time increases in an exponential function. In the random access method (invention 1) according to an embodiment of the present invention, it is possible to improve the performance of the random access procedure when the base station 100 detects a preamble collision as well as when it does not. Accordingly, it was confirmed that the random access method (invention 1) according to an embodiment of the present invention decreases the average random access delay time compared to other comparison methods. As the random access average delay time performance is improved through the random access method (invention 1) according to an embodiment of the present invention, the energy efficiency of the terminal 200 is saved by saving energy consumed by the terminal 200 in random access. Can increase

14 is a diagram showing random access access efficiency of a terminal according to the number of competing random access terminals according to an embodiment of the present invention and comparison methods.

It was confirmed that the random access method according to an embodiment of the present invention (the present invention 1) has higher random access access efficiency than the comparison methods. In addition, it can be seen that the random access method (invention 1) and the comparison method according to an embodiment of the present invention increase access efficiency and then decrease again as the number of terminals increases. When the number of terminals is less than the number of preambles, access efficiency is low due to the presence of unused preambles, and as the number of terminals increases, the number of unused preambles decreases, but collisions increase during preamble transmission, thereby reducing access efficiency.

15 is a diagram illustrating an average random access delay time of a terminal according to the number of competing random access terminals in random access methods according to an embodiment of the present invention and another embodiment.

It can be seen that the random power backoff method according to the distance difference (Invention 2) has a lower average random access delay time than the random access method (Invention 1) according to an embodiment of the present invention.

16 is a diagram illustrating random access access efficiency of a terminal according to the number of random access competing terminals in random access methods according to an embodiment of the present invention and another embodiment.

It can be seen that the random power backoff method according to the distance difference (Invention 2) has higher random access access efficiency than the random access method (Invention 1) according to an embodiment of the present invention.

The random access method using random power backoff according to the above-described embodiments of the present invention may be implemented as a computer-readable code on a computer-readable recording medium. The random access method using random power backoff according to the embodiments of the present invention may be implemented in the form of program instructions that can be executed through various computer means and recorded in a computer-readable recording medium.

A non-transitory computer-readable storage medium including at least one program executable by a processor, wherein when the at least one program is executed by the processor, the processor causes: a preamble randomly selected from a terminal through a communication module Receiving the included first message, transmitting a second message including a fixed power backoff value or power backoff range to the terminal, and using the received power of the third message received from the terminal from another terminal A non-transitory computer-readable storage medium comprising instructions for receiving the third message separately from the received message, and transmitting a fourth message, which is a confirmation message for the received third message, to the terminal. I can.

Meanwhile, as a non-transitory computer-readable storage medium including at least one program executable by a processor, when the at least one program is executed by the processor, the processor causes: a preamble randomly selected from a plurality of preambles Transmitting the included first message to the base station, receiving a second message including a fixed power backoff value or power backoff range from the base station, and using the received fixed power backoff value or power backoff range Non-temporary, including instructions for calculating transmission power, transmitting a third message to the base station with the calculated transmission power, and receiving a fourth message, which is a confirmation message for the transmitted third message from the base station A computer-readable storage medium may be provided.

The above-described method according to the present invention may be implemented as a computer-readable code on a computer-readable recording medium. The computer-readable recording medium includes all types of recording media in which data that can be decoded by a computer system is stored. For example, there may be read only memory (ROM), random access memory (RAM), magnetic tape, magnetic disk, flash memory, optical data storage device, and the like. In addition, the computer-readable recording medium can be distributed in a computer system connected through a computer communication network, and stored and executed as code that can be read in a distributed manner.

Although described above with reference to the drawings and examples, it does not mean that the protection scope of the present invention is limited by the drawings or examples, and those skilled in the art It will be appreciated that various modifications and changes can be made to the present invention without departing from the spirit and scope.

Specifically, the described features may be implemented in digital electronic circuitry, or computer hardware, firmware, or combinations thereof. Features may be executed in a computer program product implemented in storage in a machine-readable storage device, for example, for execution by a programmable processor. And the features can be performed by a programmable processor executing a program of directives to perform the functions of the described embodiments by operating on input data and generating output. The described features include at least one programmable processor, at least one input device, and at least one output coupled to receive data and directives from the data storage system and to transmit data and directives to the data storage system. It can be executed within one or more computer programs that can be executed on a programmable system including the device. A computer program includes a set of directives that can be used directly or indirectly within a computer to perform a specific action on a given result. A computer program is written in any form of a programming language, including compiled or interpreted languages, and is included as a module, element, subroutine, or other unit suitable for use in another computer environment, or as a independently operable program. It can be used in any form.

Suitable processors for execution of a program of directives include, for example, both general and special purpose microprocessors, and either a single processor or multiple processors of a different kind of computer. Storage devices suitable for implementing computer program directives and data implementing the described features are, for example, semiconductor memory devices such as EPROM, EEPROM, and flash memory devices, magnetic devices such as internal hard disks and removable disks. Devices, magneto-optical disks, and all types of non-volatile memory including CD-ROM and DVD-ROM disks. The processor and memory may be integrated within application-specific integrated circuits (ASICs) or added by ASICs.

The present invention described above is described on the basis of a series of functional blocks, but is not limited by the above-described embodiments and the accompanying drawings, and various substitutions, modifications and changes within the scope not departing from the technical spirit of the present invention It will be apparent to those of ordinary skill in the art to which this invention pertains.

Combinations of the above-described embodiments are not limited to the above-described embodiments, and combinations of various types as well as the above-described embodiments may be provided according to implementation and/or need.

In the above-described embodiments, the methods are described on the basis of a flow chart as a series of steps or blocks, but the present invention is not limited to the order of steps, and certain steps may occur in a different order or concurrently with other steps as described above. I can. In addition, those of ordinary skill in the art understand that the steps shown in the flowchart are not exclusive, other steps are included, or one or more steps in the flowchart may be deleted without affecting the scope of the present invention. You can understand.

The foregoing embodiments include examples of various aspects. Although not all possible combinations for representing the various aspects can be described, those of ordinary skill in the art will recognize that other combinations are possible. Accordingly, the present invention will be said to cover all other replacements, modifications and changes falling within the scope of the following claims.

100: base station
200: terminal
110: communication module
120: memory
130: processor
210: communication module
220: memory
230: processor

Claims (20)

In a random access method performed by a base station in a wireless network environment,
Receiving a first message including a randomly selected preamble from a terminal;
Transmitting a second message including a fixed power backoff value or a power backoff range to the terminal;
Receiving a third message for a base station connection request from the terminal; And
And transmitting a fourth message, which is a confirmation message for the received third message, to the terminal. The method of claim 1,
Transmitting the second message,
Random using random power backoff for detecting whether the received preamble collides, and transmitting a second message including a fixed power backoff value or a power backoff range to the terminal according to whether the detected preamble collides Access method. The method of claim 2,
Transmitting the second message,
A random access method using random power backoff for detecting whether the received preamble collides through a power delay profile (PDP) of the received preamble. The method of claim 2,
Transmitting the second message,
When the collision of the received preamble is detected, transmitting a second message including a fixed power backoff value to the terminal, a random access method using random power backoff. The method of claim 2,
Transmitting the second message,
If the collision of the received preamble is not detected, transmitting a second message including a power backoff range to the terminal, random access method using random power backoff. The method of claim 1,
The power back-off range is,
Random access method using random power backoff, which is divided into a plurality of power backoff ranges divided for each predetermined terminal area. The method of claim 6,
The plurality of power backoff ranges,
A random access method using random power backoff corresponding to a plurality of preset areas according to a plurality of communication ranges based on a distance to a base station. In a random access method performed by a terminal in a wireless network environment,
Transmitting a first message including a preamble randomly selected from among a plurality of preambles to a base station;
Receiving a second message including a fixed power backoff value or a power backoff range from the base station;
Transmitting a third message to the base station with a transmission power according to the received fixed power backoff value or a power backoff range; And
And receiving a fourth message, which is a confirmation message for the transmitted third message, from the base station. The method of claim 8,
Transmitting the third message to the base station,
When a fixed power backoff value is received from the base station, a transmission power is calculated using the received fixed power backoff value. The method of claim 8,
Transmitting the third message to the base station,
When a power backoff range is received from the base station, random power backoff is performed by selecting a power backoff value at random from the received power backoff range and calculating transmission power using the selected power backoff value. Random access method used. A communication module that communicates with a terminal for random access (RA) in a wireless network environment;
A memory for storing at least one program; And
And a processor connected to the communication module and the memory,
The processor, by executing the at least one program,
Through the communication module, receiving a first message including a randomly selected preamble from the terminal,
Transmitting a second message including a fixed power backoff value or power backoff range to the terminal,
Receiving a third message for a base station connection request from the terminal,
The base station transmitting a fourth message that is a confirmation message for the received third message to the terminal. The method of claim 11,
The processor,
The base station for detecting whether the received preamble collides, and transmitting a second message including a fixed power backoff value or a power backoff range to the terminal according to whether the detected preamble collides. The method of claim 12,
The processor,
The base station for detecting whether or not the received preamble collides through a power delay profile (PDP) of the received preamble. The method of claim 12,
The processor,
When a collision of the received preamble is detected, transmitting a second message including a fixed power backoff value to the terminal. The method of claim 12,
The processor,
When the collision of the received preamble is not detected, transmitting a second message including a power backoff range to the terminal. The method of claim 11,
The power back-off range is,
The base station divided into a plurality of power back-off ranges divided by preset terminal zones. The method of claim 16,
The plurality of power backoff ranges,
A base station corresponding to a plurality of preset areas according to a plurality of communication ranges based on a distance to the base station. A communication module communicating with a base station for random access (RA) in a wireless network environment;
A memory for storing at least one program; And
And a processor connected to the communication module and the memory,
The processor, by executing the at least one program,
Transmitting a first message including a preamble randomly selected from among a plurality of preambles to the base station through the communication module,
Receiving a second message including a fixed power backoff value or a power backoff range from the base station,
Transmitting a third message to the base station with a transmission power according to the received fixed power backoff value or power backoff range,
Receiving a fourth message, which is a confirmation message for the transmitted third message from the base station. The method of claim 18,
The processor,
When receiving a fixed power backoff value from the base station, calculating a transmission power by using the received fixed power backoff value. The method of claim 18,
The processor,
When a power backoff range is received from the base station, a power backoff value is randomly selected from the received power backoff range, and transmission power is calculated using the selected power backoff value.

Images