KR101610069B1 - dynamic resource allocating method in LTE wireless backhaul system - Google Patents

Abstract

The present invention can dynamically allocate resources for a backhaul terminal in consideration of a variable traffic state of a general terminal connected to a backhaul base station and a general terminal connected to a backhaul terminal in a wireless backhaul system using LTE or LTE-A wireless transmission technology And more particularly, to an apparatus and method for allocating resources for operating an LTE wireless backhaul system.

Description

Technical Field [0001] The present invention relates to a dynamic resource allocation method in a wireless backhaul system,

In particular, in a wireless backhaul system using an LTE or LTE-A radio transmission technology, a general terminal connected to a backhaul base station, and a general terminal connected to a backhaul terminal, And allocating resources to the backhaul terminals dynamically in consideration of the resources allocated to the backhaul terminals.

As is well known, a femto cell base station (hereinafter, simply referred to as a 'femto base station') is a very small mobile communication base station connected to a mobile communication core network through a broadband network installed in a house or an office. These femto base stations have various advantages such as expanding indoor coverage, improving call quality, and efficiently providing various wired / wireless convergence services.

A base station called an evolved NodeB (eNB) and a home evolved NodeB (HeNB) are used in 3GPP Long Term Evolution (LTE) or LTE Advanced (LTE-A) I have defined it. The eNB is a macro base station that manages a general macro cell and the home eNB is a femto base station that controls a femtocell. That is, 3GPP considers an environment in which a femto base station that can be connected to only a specific user is installed separately from an existing macro base station. At this time, the femto base station may be installed by a user or a provider for the purpose of increasing coverage, increasing capacity, or providing other differentiated services. The service coverage of a femto base station can be considered from a minimum of several meters to a maximum macro service coverage degree.

On the other hand, in a wireless communication system, when a base station and a core network are connected by wire, a wired installation cost is required, and additional costs are increased each time the base stations are installed. In order to solve this problem, a wireless backhaul repeater is installed between the base station and the core network, so that the installation cost for the base station can be minimized whenever the base station is installed even though the wireless backhaul repeater and the core network are connected by wire.

1 is a network configuration diagram of a conventional LTE wireless backhaul system. 1, a conventional LTE wireless backhaul system includes a WiFi AP (Access Point) 30 for exchanging data wirelessly with a user terminal 60 in a house or a building, a 3G femto base station A backhaul base station 10 and a WiFi AP 30 which are connected to a core network while having a wireless backhaul function and a 3G femto base station The LTE femto base station 50 or the LTE femto base station 50. The backhaul base station 10 and the backhaul terminal 20 constitute a backhaul network.

The backhaul terminal 20 transmits data generated in the user terminal 60 in service to the backhaul base station 10 or transmits data received from the backhaul base station 10 to the WiFi APs 30, To the user terminal 60 in service via the 3G femto base station 40 or the LTE femto base station 50.

FIG. 2 is a sequence chart for explaining an operation procedure of the conventional LTE wireless backhaul system shown in FIG. 2, when the power of the backhaul terminal 20 is turned on, an RRC connection establishment procedure is performed between the backhaul terminal 20 and the backhaul base station 10 according to the conventional LTE wireless backhaul system And then a terminal authentication and location registration procedure is performed with the LTE core network. In this location registration process, the backhaul terminal 20 is recognized as one terminal in the LTE core network.

After the location registration is performed, the LTE core network transmits an Initial Context Setup Request, which is an S1 control message, to the backhaul base station 10, so that the LTE core network allocates radio link resources to the backhaul terminal 20, Conventionally, no reservation is made for radio resources or fixed resources are allocated.

Next, the backhaul base station 10 performs resource allocation so as to satisfy the required service quality for both the user terminal connected to the base station 10 and the backhaul terminal 20. In the case of the backhaul terminal 20, Many resources must be allocated fixedly because they must be exchanged.

Next, the backhaul base station 10 receives its capability information from the backhaul terminal 10 through the RRC procedure with the backhaul terminal 20, and receives the RRC connection shape change RRC Connection Reconfiguration procedure to obtain the latest terminal capability from the backhaul terminal. Then, the backhaul base station transmits Initial Context Setup Response, which is an S1 control message including the terminal capability information, to the LTE core network.

On the other hand, the LTE core network checks whether the connected terminal is a backhaul terminal based on the Initial Context Setup Response, and allocates additional resources when the terminal is a backhaul terminal. To this end, the LTE core network transmits an E-RAB Setup Request message to the backhaul base station 10 in which additional resources are reserved, and then the backhaul base station 10 transmits an E-RAB Setup Request message And then transmits an E-RAB Setup Response message to the LTE core network as a result of performing an RRC connection configuration change procedure with the backhaul terminal 20 for setting up an additional link with the LTE core network.

According to the conventional LTE wireless backhaul system as described above, since the backhaul network can be configured without modifying existing equipment of the backhaul base station and the LTE core network, the resources for the backhaul terminals are not reserved or fixed values are used It is advantageous that system software is easy to implement.

However, if the resources are not reserved for the backhaul terminals, the service quality deteriorates for the user terminals exchanging data through the backhaul terminals. On the contrary, when many resources are reserved for the backhaul terminals, data is exchanged through the backhaul terminals The service quality of the user terminal may be improved, but the service quality of the user terminal connected to the backhaul base station deteriorates.

Prior Art: 10-2014-0077327 Disclosure of the Invention Problems to be Solved by the Invention A method of allocating resources between a backhaul repeater and a base station in a wireless backhaul system

SUMMARY OF THE INVENTION The present invention has been conceived to solve the above-mentioned problems, and it is an object of the present invention to provide a wireless backhaul system using an LTE or LTE-A wireless transmission technology in consideration of a variable traffic state of a general terminal connected to a backhaul base station, And to provide a method of allocating an operation resource of a wireless backhaul system capable of dynamically allocating resources for a backhaul terminal.

According to another aspect of the present invention, there is provided a method of allocating resources for a wireless backhaul system, the method comprising: wirelessly connecting a backhaul base station and a backhaul base station, which are macro base stations connected to a mobile communication core network, A wireless backhaul system including a backhaul terminal for transmitting data of a user terminal between a base station and a mobile communication base station or a WiFi AP, the base station comprising: a backhaul agent provided in a mobile communication core network or a backhaul base station, (A) checking whether a connected terminal is a user terminal or a backhaul terminal, and allocating additional resources when the terminal is a backhaul terminal; (C) dynamically allocating resources to the backhaul terminal according to the checking result of the service condition of the backhaul terminal and the checking result of the step (b).
In the above-described configuration, the checking whether the backhaul terminal is in the step (a) is performed by the unique ID of the backhaul terminal in the process of performing the terminal authentication and location registration procedure.
In the step (a), the additional resource allocation is performed based on a QoS class identifier (QCI) or an aggregated maximum bit rate (AMBR).
The service situation of the backhaul terminal is a service time of the backhaul terminal and the backhaul agent dynamically allocates the entire radio link resources of the backhaul base station to the user terminal connected to the backhaul base station and the backhaul terminal based on the service time .
The service situation of the backhaul terminal is a service location of the backhaul terminal, and the backhaul agent includes a lookup table for each location of the backhaul terminal, so that the entire radio link resources of the backhaul base station are transmitted to the user terminal connected to the backhaul base station, And the service location of the backhaul terminal is confirmed by the location registration procedure or by the cell ID information of the backhaul base station to which the backhaul terminal is connected.
The service situation of the backhaul terminal is the number of the user terminals that the backhaul terminal is servicing and the backhaul agent calculates the ratio of the number of the user terminals that the backhaul base station is serving to the number of the user terminals that are being serviced by the backhaul base station, And allocates resources to the resource.
The service situation of the backhaul terminal is a transmission rate of the backhaul terminal. The backhaul agent dynamically allocates resources to the backhaul terminal based on the total transmission rate of the user terminals being served by the backhaul base station and the transmission rate of the user terminals being served by the backhaul terminal .

According to the operation resource allocation method of the wireless backhaul system of the present invention, considering a variable traffic state of a general terminal connected to a backhaul base station and a general terminal connected to a backhaul terminal in a wireless backhaul system using LTE or LTE-A radio transmission technology By dynamically allocating resources for backhaul terminals, it is possible to more efficiently manage limited resources.

1 is a network configuration diagram of a conventional LTE wireless backhaul system.
FIG. 2 is a sequence chart illustrating an operation procedure of the conventional LTE wireless backhaul system shown in FIG. 1. FIG.
3 is a sequence chart illustrating an operational procedure of the LTE wireless backhaul system of the present invention.
4 is a diagram for explaining a dynamic resource allocation algorithm in the LTE wireless backhaul system according to the present invention;

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a preferred embodiment of a method for allocating resources for operation of a wireless backhaul system according to the present invention will be described in detail with reference to the accompanying drawings.

3 is a sequence chart illustrating an operation procedure of the LTE wireless backhaul system according to the present invention. The LTE wireless backhaul system of the present invention does not include operations related to a separate backhaul network configuration because the conventional LTE wireless backhaul system is not designed considering a backhaul terminal. However, the LTE wireless backhaul system of the present invention includes a backhaul agent module, And is configured to operate efficiently in a network environment. The backhaul agent module may be implemented as a software module in the LTE core network or the backhaul base station, or as a separate device.

According to the LTE wireless backhaul system of the present invention, in order to solve the disadvantage that only the base link which is not reserved in the past is activated when the backhaul terminal is activated, after checking that the backhaul agent is a backhaul terminal, And initiates a radio link (E-RAB) assignment in which the resource is reserved.

More specifically, according to the LTE wireless backhaul system of the present invention, when the power of the backhaul terminal is turned on, an RRC connection establishment procedure is performed between the backhaul terminal and the backhaul base station, A location registration procedure is performed. In this location registration process, the backhaul terminal 20 is recognized as one terminal in the LTE core network.

Meanwhile, the backhaul agent according to the present invention requests a unique ID for a corresponding terminal through a downlink (NAS) non-access stratum (NAS) transport procedure to the backhaul base station in association with the terminal performing the registration procedure. In response to this, the backhaul base station performs a NAS transmission procedure with the backhaul terminal to acquire the unique ID of the backhaul terminal and then reports it to the backhaul agent through a UL (Uplink) NAS transmission procedure. The agent can check whether the terminal registered in the current LTE core network is a backhaul terminal based on the received ID.

Meanwhile, apart from the above-described backhaul terminal checking process, the LTE core network allocates radio link resources to the backhaul terminals by transmitting an Initial Context Setup Request, which is an S1 control message, to the backhaul base station via the backhaul agent. It does not reserve radio resources or allocates fixed resources.

Here, the backhaul base station performs resource allocation so as to satisfy the required service quality for both the user terminal connected to the backhaul terminal and the backhaul terminal. In the case of the backhaul terminal, since data of a plurality of user terminals must be exchanged, .

Next, the backhaul base station receives the capability information from the backhaul terminal through the RRC procedure with the backhaul terminal 20, and performs an RRC connection reconfiguration procedure using the received terminal capability information To obtain the latest terminal capability from the backhaul terminal. The backhaul base station then transmits an Initial Context Setup Response, which is an S1 control message including the terminal capability information, to the LTE core network via the backhaul agent.

Meanwhile, the backhaul agent allocates additional resources to the backhaul base station when the currently registered terminal is a backhaul terminal. The amount and characteristics of the resources reserved in the backhaul base station are classified into a QoS Class Identifier (QCI) and an Aggregated Maximum Bit Rate (AMBR) . ≪ / RTI > Here, QCI is a quality-of-service class identifier parameter used to indicate a service level in an LTE service, and can be used for priority-based traffic scheduling in a transit interval as well as a gateway. The AMBR is the maximum aggregate bit rate. In order to prevent multiple bearers from using excessive network resources in the LTE service, the sum of bandwidths of multiple EPS bearers can be prevented from exceeding a certain level through the AMBR.

Referring back to FIG. 3, the backhaul agent transmits an E-RAB Setup Request message to the backhaul base station in order to allocate resources to the backhaul base station. In response, the backhaul base station adds an additional resource reservation After the RRC connection configuration change procedure with the backhaul terminal is performed to establish the link, the E-RAB Setup Response message is transmitted to the backhaul agent as a result.

Next, the backhaul agent performs a shape change (E-RAB Modification) procedure for a radio link (E-RAB) already allocated to the backhaul base station according to a dynamic resource allocation algorithm described below when a change to the reserved resource is required The amount and nature of resources that are changed at the backhaul base station can be determined using QCI and AMBR as in the initial setting. The E-RAB configuration change procedure can be performed through an E-RAB Modification Request from the backhaul agent to the backhaul base station, an RRC connection between the backhaul base station and the backhaul terminal, and an E-RAB Modification response from the backhaul base station to the backhaul agent have. Further, the E-RAB configuration change procedure is repeatedly performed according to the traffic condition monitoring result of the backhaul base station and the backhaul terminal.

4 is a diagram for explaining a dynamic resource allocation algorithm in the LTE wireless backhaul system according to the present invention. As shown in FIG. 4, in the LTE wireless backhaul system according to the present invention, the dynamic resource allocation algorithm for the backhaul terminal includes time, location of the backhaul terminal, and the number of user terminals And data rate.

First, a time-based algorithm is a method of varying the amount of resources allocated to a backhaul terminal at specific time zones. For example, when a backhaul network is configured in a suburban complex area, While keeping it small after the end of the working hours. To this end, the backhaul agent may include a system timer and a lookup table according to the time zone, thereby allocating resources to the backhaul terminal in a time-based manner. In this case, time-based weighting may be applied.

Equations (1) and (2) below represent a time-based dynamic resource allocation algorithm in the LTE wireless backhaul system of the present invention.

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In the above Equations 1 and 2, "RB_tot" represents the total amount of radio link resources of the backhaul base station, and "RB_tot_gue" represents the total amount of radio link resources allocated to the user terminal of the backhaul base station among all the radio links of the backhaul base station. "RB_tot_bue" represents the total amount of radio link resources allocated to the backhaul terminal of the backhaul base station among the total radio links of the backhaul base station, "Ratio_t_gue" and "Ratio_t_bue" represent the ratio of the backhaul base station and the backhaul terminal at a specific time, The sum is 1.

Next, the position-based algorithm is a method of varying the amount of resources allocated to the backhaul terminal according to specific locations of the backhaul base station. The location of the backhaul terminal is obtained by a location based service procedure, The cell ID of the backhaul agent may be determined based on the cell ID of the backhaul agent. In this case, the backhaul agent includes lookup data for each location of the terminal, May be applied.

Equations (3) and (4) below represent a location based dynamic resource allocation algorithm in the LTE wireless backhaul system of the present invention.

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In Equations (3) and (4) above, "Ratio_l_gue" and "Ratio_l_bue" are the ratio of the backhaul base station and the backhaul terminal at a specific location,

Next, an algorithm based on the number of terminals is a method of varying the amount of resources allocated to the backhaul terminals based on the number of user terminals being serviced by the backhaul base station and the number of user terminals being serviced by the backhaul terminal. For this, the backhaul agent monitors the number of user terminals in the backhaul base station, calculates the ratio of the number of user terminals in service of the backhaul base station to the number of user terminals in service of the backhaul terminal, The number of UE-based weights may be applied in this process.

Equations 5 to 8 below represent the UE-based dynamic resource allocation algorithm in the LTE wireless backhaul system of the present invention.

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In the above Equations 5 to 8, "UE_tot_n_benb" indicates the total number of user terminals being serviced by the backhaul base station, and "UE_tot_n_bue" indicates the total number of user terminals serviced by the backhaul terminal.

Finally, the algorithm based on the data rate is a method of varying the amount of resources allocated to the backhaul terminal based on the overall transmission rate of the user terminals being served by the backhaul base station and the transmission rate of the user terminals being served by the backhaul terminal. For this, the backhaul agent monitors the rate of the user terminal in the backhaul base station and the backhaul terminal, calculates the ratio between the two, and allocates the resource allocation to the backhaul terminal based on the result. In this process, Weights may be applied.

Equations (9) to (12) below represent a data rate based dynamic resource allocation algorithm in the LTE wireless backhaul system of the present invention.

"UE_tot_r_benb" in Equations (9) to (12) represents the sum of all the user terminal transmission rates being serviced by the backhaul base station, and "UE_tot_r_bue" represents the sum of all the user terminal transmission rates serviced by the backhaul terminal.

According to the operation resource allocation method of the LTE wireless backhaul system of the present invention, efficient resource allocation is possible based on a variable traffic state of a user terminal in a backhaul base station and a user terminal connected to a backhaul terminal. This is expected to satisfy the service requirements of user terminals and improve the resource utilization efficiency. Further, the present invention is considered to contribute to the configuration of a backhaul network based on LTE and LTE-A technologies.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. . Accordingly, the scope of the present invention should be determined by the following claims.

Claims (7)

delete delete delete A backhaul base station and a backhaul base station, which are macro base stations connected to a mobile communication core network, are wirelessly connected to a mobile communication base station or a WiFi AP, and are connected by a backhaul base station and a mobile communication base station or a WiFi AP, A backhaul agent provided in a mobile communication core network or a backhaul base station in a wireless backhaul system,
(A) communicating with a backhaul base station to determine whether a terminal connected to a backhaul base station is a user terminal or a backhaul terminal, and allocating additional resources if the terminal is a backhaul terminal;
(B) confirming a service situation of the backhaul terminal and
And (c) dynamically allocating resources to the backhaul terminal according to the result of the checking in the step (b)
The service status of the backhaul terminal is a service time of the backhaul terminal,
Wherein the backhaul agent dynamically allocates the entire radio link resources of the backhaul base station to the user terminal and the backhaul terminal connected to the backhaul base station based on the service time. A backhaul base station and a backhaul base station, which are macro base stations connected to a mobile communication core network, are wirelessly connected to a mobile communication base station or a WiFi AP, and are connected by a backhaul base station and a mobile communication base station or a WiFi AP, A backhaul agent provided in a mobile communication core network or a backhaul base station in a wireless backhaul system,
(A) communicating with a backhaul base station to determine whether a terminal connected to a backhaul base station is a user terminal or a backhaul terminal, and allocating additional resources if the terminal is a backhaul terminal;
(B) confirming a service situation of the backhaul terminal and
And (c) dynamically allocating resources to the backhaul terminal according to the result of the checking in the step (b)
The service status of the backhaul terminal is a service location of the backhaul terminal,
The backhaul agent dynamically allocates the entire radio link resources of the backhaul base station to the user terminal and the backhaul terminal connected to the backhaul base station based on the location,
Wherein the service location of the backhaul terminal is verified by the location registration procedure or by the cell ID information of the backhaul base station to which the backhaul terminal is connected. delete delete

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