KR20180093167A - Radio resource allocation method - Google Patents

Abstract

A radio resource allocation method according to an embodiment includes a step of allowing user equipment to store PRACH information including a physical random access channel (PRACH) repetition number used for random access, a step of determining whether the user equipment supports non-anchor carriers, and a step of allowing the user equipment to allocate an assigned non-anchor carrier with a minimum weight to a carrier for data communication of the user equipment according to at least one non-anchor carrier if the user equipment is a terminal supporting the non-anchor carrier. It is possible to allocate anchor carriers in balance.

Description

[0001] RADIO RESOURCE ALLOCATION METHOD [

BACKGROUND OF THE INVENTION 1. Field of the Invention [0002] The present invention relates to a radio resource allocation method, and more particularly, to a technique for allocating radio resources based on a radio state of a user equipment in an LTE NB-IoT (Narrow Band Internet of Thing) base station.

3GPP LTE mobile communication system defines NB-IoT technology capable of low power wide area service to support Internet of things. NB-IoT uses a band of 200kHz for wireless transmission different from the existing LTE using the 180kHz band. NB-IoT is characterized by providing an extended service area of 20db compared to GPRS. NB-IoT is designed to be more simple to use than wireless LTE, to operate in half-duplex mode, and to have longer latency to accommodate Internet services. NB-IoT supports the in-band using a part of the existing LTE, the guard-band using the guard band of LTE, and the standalone using the frequency independent of LTE.

3GPP Rel. The NB-IoT defined in 13 is composed of an anchor-carrier for transmitting broadcasting information of a base station for each cell and non-anchor-carriers as data-only transmission / reception carriers.

An anchor carrier is used by a user equipment to broadcast information for receiving transmission synchronization and cell information from a base station, and data transmission / reception for user equipment is possible through an anchor carrier. Alternatively, the anchor carrier only performs data transmission and reception with the user equipment.

Since anchor carriers need to allocate a lot of radio resources for broadcast information, radio resources may be insufficient when the number of user equipments per cell is high or the data transmission frequency is high. Therefore, a plurality of non-anchor carriers must be used for data transmission and reception.

If you are allocating user equipment with an anchor carrier, the scheduling for the UEs may be delayed if the user equipment is concentrated in some non-anchor carriers. To prevent this, the available anchor carriers may be balanced A method is required to distribute the information.

Embodiments are for balanced allocation of non-anchor carriers.

According to an embodiment of the present invention, a radio resource allocation method includes: storing PRACH information including a repetition number of PRACH (Physical Random Access Channel) used by a user equipment for random access; determining whether the user equipment supports non-anchor carriers Allocating a non-anchor carrier with a minimum weight assigned by the user equipment to at least one non-anchor carrier as a carrier for data communication of the user equipment, if the user equipment is a terminal supporting non-anchor carriers; .

According to an embodiment of the present invention, there is an advantage that a non-anchor carrier can be allocated in consideration of an actual resource utilization rate reflecting a repetition frequency.

According to the embodiments, there is an advantage that the user equipment can be prevented from being biased to some non-anchor carriers.

1 is a schematic diagram showing a network structure for data communication with an external Internet network in an NB-IoT mobile communication network.
2 is a schematic diagram showing the structure of a PRACH frame for random access.
3 is a flowchart illustrating a method of allocating carriers according to a radio resource allocation method according to an embodiment of the present invention.
FIG. 4 is a flowchart for releasing a carrier according to a radio resource allocation method according to an embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The present invention may be embodied in many different forms and is not limited to the embodiments described herein.

In order to clearly illustrate the present invention, parts not related to the description are omitted, and the same or similar components are denoted by the same reference numerals throughout the specification.

Also, throughout the specification, when an element is referred to as "including" an element, it is understood that the element may include other elements as well, without departing from the other elements unless specifically stated otherwise.

The techniques described in this specification may be used in a variety of communication systems, for example, current 2G and 3G communication systems and next generation communication systems, e.g., Global System for Mobile Communications (GSM) systems, Code Division Multiple Access , A Time Division Multiple Access (TDMA) system, a Wideband Code Division Multiple Access (WCDMA) system, a Frequency Division Multiple Access (FDMA) system, an Orthogonal Frequency-Division Multiple Access (OFDMA) system, a single- (SC-FDMA) system, a General Packet Radio Service (GPRS) system, a Long Term Evolution (LTE) system, and other communication systems.

User equipment related to the present application may be a wireless terminal or a wired terminal. A wireless terminal may refer to a device that provides a voice and / or data connection to a user, a palm-sized device with wireless connectivity, or another processing device coupled to the wireless modem. A wireless terminal may be connected to one or more core networks via a Radio Access Network (RAN). A wireless terminal may be a mobile terminal, such as a mobile phone (referred to as a "cellular" phone), capable of exchanging voice and / or data over a wireless access network, A palm-sized computer with a built-in computer, a mobile terminal, or an in-vehicle mobile device. For example, a Personal Communication Service (PCS) phone, a wireless telephone set, a Session Initiation Protocol (SIP) phone, a wireless local loop (WLL) station, ). ≪ / RTI > The wireless terminal may also be referred to as a system, a subscriber unit, a subscriber station, a mobile station, a remote station, an access point, a remote terminal, A user terminal, an access terminal, a user terminal, a user agent, a user device, or a user equipment.

A base station (e.g., an access point) associated with the present application may refer to a device that communicates with a wireless terminal via one or more sectors of an air interface in the access network. The base station may be configured to convert between frames received over the air and IP packets and may be configured to serve as a router between the wireless terminal and the rest of the access network, And an Internet Protocol (IP) network. The base station may adjust the attribute management of the air interface. For example, the base station may be a base station (base transceiver station, BTS) in GSM or in CDMA, a base station (NodeB) in WCDMA, or an evolved NodeB (NodeB, eNB, or e-NodeB, evolutionary Node B), and is not limited to the present application.

1 is a schematic diagram showing a network structure for data communication with an external Internet network in an NB-IoT mobile communication network. 1, the NB-IoT LTE mobile communication network includes a user equipment (UE) 101, a base station 102 transmitting and receiving data to and from the user equipment 101, authentication and mobility of the user equipment 101, (Mobility Management Entity) function for managing mobility and a C-SGN (Cellular IoT) Serving Gateway Node (CIoT) 103 for performing a GW (Gateway) function for distributing traffic to the base stations 102 do.

2 is a schematic diagram showing a structure of a Physical Random Access Channel (PRACH) frame for random access performed by the user equipment 101 in order to access the base station 102. As shown in FIG. The base station 102 informs the user equipment 101 of up to three PARCH resource areas for random access to SIB2 (System Information Block Type 2).

The information of each PARCH resource region includes the number of subcarriers {n12, n24, n36, n48} per PRACH resource, {r1, r2, r4, r8, r16, r32, r64, r128, r256, r512, r1024 , r2048}, a Msg3 section for multitone transmission, and a maximum random access maximum number {n3, n4, n5, n6, n7, n8, n10}.

The user equipment 101 performs random access using the PARCH resource information. For example, the user equipment 101 performs random access using the lowest number of PRACH repetition times. If the random access procedure using the lowest number of PRACH repetition times fails, the user equipment 101 performs random access using the next highest PRACH resource information.

Next, the radio resource allocation process will be described with reference to FIG.

3 is a flowchart illustrating a method of allocating carriers according to a radio resource allocation method according to an embodiment of the present invention.

First, the Nue value is initialized to 0 for all non-anchor carriers (S301). The Nue value is a weight to which the user equipment 101 is allocated for each non-anchor carrier. A large Nue value means that the radio resource utilization rate of the corresponding non-anchor carrier is high. The Nue value is proportional to the number of user equipments 101. In addition, each Nue value reflects the repetition frequency of the allocated user equipment 101, so that the actual radio resource usage rate can be reflected.

The user equipment 101 performs random access to access the base station 102 (S302). The base station 102 stores PRACH information including the number of PRACH repetitions used by the user equipment 101 for random access.

The user equipment 101 transmits the capability of the user equipment 101 to the base station 102 via an M3 message. Then, the base station 102 uses the M3 message to determine whether the user equipment 101 supports non-anchor carriers (S303).

If the user equipment 101 is a terminal that does not support non-anchor carriers, the base station 102 allocates a carrier for data communication as an anchor carrier (S304).

If the user equipment 101 is a terminal supporting non-anchor carriers, the base station 102 searches for the index value of the non-anchor carrier having the minimum Nue value (S305).

Then, the base station 102 reflects the number of random access repetitions by the user equipment 101 to the Nue value of the detected non-anchor carriers (S306). This can be expressed by the following equation (1).

In Equation (1), i is a non-anchor carrier index having a minimum value, and NumberOfRepetition is a number of repetitions of the user equipment 101 attempting random access.

Then, the base station 102 assigns the searched non-anchor carrier to the carrier for data communication of the user equipment 101 and notifies the user equipment 101 (S307).

Next, the radio resource release process will be described with reference to FIG.

FIG. 4 is a flowchart for releasing a carrier according to a radio resource allocation method according to an embodiment. The base station 102 or the core network determines (S401) the non-anchor carrier deallocation of the user equipment 101. The base station 102 or the core network may decide to release the radio resources allocated to the user equipment 101 if there is no more data to transmit to the user equipment 101. [

The base station 102 determines whether a non-anchor carrier is assigned to the user equipment 101 (S402). If the anchor carrier is allocated, the base station 102 searches for the corresponding non-anchor carrier (S403). Then, the base station 102 decreases the Nue value of the non-anchor carrier (S404). This can be expressed by the following equation (2).

In Equation (2), i is an index of a non-anchor carrier allocated to the user equipment 101, and NumberOfRepetition is a repetition number of attempts by the user equipment 101 to attempt random access.

Then, the base station 102 cancels the allocation of the non-anchor carriers allocated to the user equipment 101 (S405).

According to the radio resource allocation method of the embodiment, the non-anchor carriers can be allocated in consideration of the actual resource utilization rate reflecting the random access repetition times of the user equipment 101, and the user equipment 101 can be allocated to some non-anchor carriers The phenomenon can be prevented.

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, It belongs to the scope of right.

Claims (1)

A radio resource allocation method of a base station,
Storing PRACH information including a PRACH (Physical Random Access Channel) repetition number used for random access by the user equipment,
Determining whether the user equipment supports a non-anchor carrier, and
If the user equipment is a terminal supporting non-anchor carriers, assigning a non-anchor carrier with a minimum weight assigned by the user equipment to at least one non-anchor carrier as a carrier for data communication of the user equipment
And allocating a radio resource to the radio resource.

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