KR102153589B1 - Radio resource allocation method - Google Patents

Abstract

The radio resource allocation method of the embodiment includes storing PRACH information including the number of repetitions of a PRACH (Physical Random Access Channel) used by a user equipment for random access, determining whether the user equipment supports a non-anchor carrier, and the user If the equipment is a terminal supporting a non-anchor carrier, allocating a non-anchor carrier having a minimum weight assigned to the user equipment for each of at least one non-anchor carrier as a carrier for data communication of the user equipment.

Description

Radio resource allocation method {RADIO RESOURCE ALLOCATION METHOD}

The present disclosure relates to a radio resource allocation method, and more particularly, to a technology 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.

The 3GPP LTE mobile communication system is defining NB-IoT technology that enables low-power wide area services to support the Internet of Things. NB-IoT uses a 200kHz band as a wireless transmission method different from the existing LTE that uses a 180kHz band. NB-IoT has the feature of providing an extended service area of 20db compared to GPRS. NB-IoT is implemented with a simpler wireless transmission technology than LTE, operates in a half-duplex transmission method, and is designed to have a longer waiting time to be suitable for IoT services. NB-IoT supports an in-band using some bands of existing LTE, a guard-band using a guard band of LTE, and a standalone method using a frequency independent of LTE.

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

The anchor carrier is used for the user equipment to broadcast information for receiving transmission synchronization and cell information from the base station, and data transmission/reception for the user equipment is possible through the anchor carrier. In contrast, the non-anchor carrier only performs data transmission/reception with the user equipment.

Since the anchor carrier needs to allocate a large number of radio resources for broadcast information, radio resources may be insufficient when the number of user equipment per cell is large or the data transmission frequency is high. Therefore, it is necessary to use a plurality of non-anchor carriers for data transmission and reception.

In the case of allocating user equipments as non-anchor carriers, if user equipments are concentrated on some non-anchor carriers, scheduling for terminals may be delayed. To prevent this, available anchor carriers are balanced to user equipments. There is a need for a way to distribute it.

The embodiments are for balancing non-anchor carriers.

According to an embodiment of the present invention, the radio resource allocation method includes storing PRACH information including the number of repetitions of a PRACH (Physical Random Access Channel) used by a user equipment for random access, and determining whether the user equipment supports a non-anchor carrier. And if the user equipment is a terminal supporting a non-anchor carrier, allocating a non-anchor carrier having a minimum weight assigned to the user equipment for each non-anchor carrier as a carrier for data communication of the user equipment Includes.

According to an embodiment, there is an advantage of allocating a non-anchor carrier in consideration of an actual resource utilization rate reflecting the number of repetitions.

According to embodiments, there is an advantage of preventing a phenomenon in which user equipment is biased toward 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 for allocating a carrier according to a radio resource allocation method according to an embodiment.
4 is a flowchart for releasing a carrier according to a radio resource allocation method according to an embodiment.

Hereinafter, various embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those of ordinary skill in the art may easily implement the present invention. The present invention may be implemented in various different forms and is not limited to the embodiments described herein.

In order to clearly describe the present invention, parts irrelevant to the description have been omitted, and the same reference numerals are assigned to the same or similar components throughout the specification.

In addition, throughout the specification, when a part "includes" a certain component, it means that other components may be further included rather than excluding other components unless otherwise stated.

The technology described in this specification is a variety of communication systems, for example, current 2G and 3G communication systems and next generation communication systems, for example, Global System for Mobile Communications (GSM) systems, Code Division Multiple Access (CDMA) systems. , TDMA (Time Division Multiple Access) system, WCDMA (Wideband Code Division Multiple Access Wireless) system, FDMA (Frequency Division Multiple Addressing) system, OFDMA (Orthogonal Frequency-Division Multiple Access) system, single-carrier (single-carrier) FDMA It can be applied to a (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 connected to a wireless modem. The wireless terminal may be connected through one or more core networks and a radio access network (RAN). A wireless terminal is a mobile terminal, such as a mobile phone (referred to as a “cellular” phone), capable of exchanging voice and/or data over a radio access network, and, for example, portable, pocket-sized, It could be a palm-sized, embedded in a computer, a computer with a mobile terminal, or a mobile device in a vehicle. It can be, for example, a PCS (Personal Communication Service) phone, a wireless telephone set, a Session Initiation Protocol (SIP) phone, a wireless local loop (WLL) station, or a Personal Digital Assistant (PDA). ) Can be the same device. The wireless terminal is also a system, a subscriber unit, a subscriber station, a mobile station, a remote station, an access point, a remote terminal, and an access terminal. It may be referred to as (Access Terminal), user terminal (User Terminal), user agent (User Agent), user device (User Device), or user equipment (User Equipment).

A base station (eg, access point) related to the present application may refer to a device that communicates with a wireless terminal via one or more sectors of an air interface in an access network. The base station may be configured to mutually convert 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, where the rest of the access network It may include an Internet Protocol (IP) network. The base station may coordinate attribute management of the air interface. For example, the base station may be a base station (Base Transceiver Station, BTS) in GSM or CDMA, and may also be a base station (NodeB) in WCDMA, or an enhanced NodeB (evolved NodeB) in LTE. ) (NodeB, eNB, or e-NodeB, evolutional Node B), and is not limited in this 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. As shown in FIG. 1, the NB-IoT LTE mobile communication network includes a user equipment (UE) 101, a base station 102 for transmitting and receiving data with the user equipment 101, and authentication and mobility of the user equipment 101. Including a C-SGN (Cellular IoT (Cellular IoT) Serving Gateway Node) 103 that performs a mobility management entity (MME) function that manages (mobility) and a gateway (GW) function that distributes traffic to the base stations 102 do.

Next, FIG. 2 is a schematic diagram showing the structure of a PRACH (Physical Random Access Channel) frame for random access performed to access the base station 102 by the user equipment 101. The base station 102 transmits information of up to three PARCH resource areas for random access to a system information block type 2 (SIB2) in order to inform the user equipment 101.

The information of each PARCH resource region includes the number of subcarriers per PARCH resource {n12, n24, n36, n48}, the number of PRACH repetitions {r1, r2, r4, r8, r16, r32, r64, r128, r256, r512, r1024 , r2048}, Msg3 interval for multi-tone transmission, and information such as the maximum number of random accesses {n3, n4, n5, n6, n7, n8, n10}.

User equipment 101 performs random access using the PARCH resource information. For example, the user equipment 101 performs random access using the lowest PRACH repetition number. If the random access process using the lowest PRACH repetition number fails, the user equipment 101 performs random access using the next highest PRACH resource information.

Next, a radio resource allocation process will be described with reference to FIG. 3.

3 is a flowchart for allocating a carrier according to a radio resource allocation method according to an embodiment.

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

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.

User equipment 101 transmits the capabilities of user equipment 101 to base station 102 via M3 messages. Then, the base station 102 determines whether the user equipment 101 supports the non-anchor carrier using the M3 message (S303).

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

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

Then, the base station 102 reflects the number of repetitions of random access by the user equipment 101 to the Nue value of the searched non-anchor carrier (S306). This can be represented by Equation 1 below.

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

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

Next, a radio resource release process will be described with reference to FIG. 4.

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 the release of the non-anchor carrier assignment of the user equipment 101 (S401). The base station 102 or the core network may determine to release radio resources allocated to the user equipment 101 when there is no more data to be transmitted to the user equipment 101.

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

In Equation 2, i is an index of a non-anchor carrier allocated to the user equipment 101, and NumberOfRepetition is the number of repetitions at which the user equipment 101 attempts random access.

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

According to the radio resource allocation method of the embodiment, a non-anchor carrier may be allocated in consideration of an actual resource utilization rate reflecting the number of random access repetitions of the user equipment 101, and the user equipment 101 is biased to some non-anchor carriers. It can prevent the phenomenon.

Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements by those skilled in the art using the basic concept of the present invention defined in the following claims are also provided. It belongs to the scope of rights.

Claims (6)

As a radio resource allocation method of a base station,
Storing PRACH information including the number of repetitions of a PRACH (Physical Random Access Channel) used by the user equipment for random access,
Determining whether the user equipment supports a non-anchor carrier,
If the user equipment is a terminal supporting a non-anchor carrier, allocating a non-anchor carrier having a minimum weight assigned to the user equipment for each of at least one non-anchor carrier as a carrier for data communication of the user equipment,
Determining whether a non-anchor carrier is assigned to the user equipment,
If a non-anchor carrier is assigned to the user equipment, searching for the assigned non-anchor carrier,
Decreasing the Nue value of the searched non-anchor carrier, and
Releasing allocation of non-anchor carriers allocated to the user equipment
Radio resource allocation method comprising a. The method of claim 1,
Prior to the step of storing the PRACH information, initializing the Nue value to 0 for all non-anchor carriers
Radio resource allocation method further comprising a. The method of claim 1,
The step of determining whether the user equipment supports a non-anchor carrier,
Receiving an M3 message from the user equipment, and
Further comprising the step of determining whether the user equipment supports a non-anchor carrier using the M3 message,
Radio resource allocation method. The method of claim 1,
If the user equipment is a terminal that does not support a non-anchor carrier, allocating a carrier for data communication of the user equipment as an anchor carrier
Radio resource allocation method further comprising a. The method of claim 1,
The step of allocating a non-anchor carrier having a minimum weight assigned to a user equipment for each of the at least one non-anchor carrier as a carrier for data communication of the user equipment,
Retrieving an index value of a non-anchor carrier whose current Nue value is the minimum,
Reflecting the number of repetitions of random access by the user equipment to the Nue value of the searched non-anchor carrier, and
Allocating the searched non-anchor carrier as a carrier for data communication of the user equipment,
Radio resource allocation method. delete

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