KR20120092044A - Method for controlling random access, base station and terminal in mobile communication system - Google Patents

Abstract

PURPOSE: A random access control method, a base station supporting the same, and a terminal are provided to reduce load of a base station based on ranging configuration information allocated to an M2M terminal. CONSTITUTION: A terminal receives a broadcasting message including random access related parameters from a base station(S100). The terminal receives information for indicating the random access related parameters from the base station in an idle mode(S120). The terminal attempts to access the base station by using information for indicating the random access related parameters(S130).

Description

Random access control method in mobile communication system, base station and terminal supporting it {METHOD FOR CONTROLLING RANDOM ACCESS, BASE STATION AND TERMINAL IN MOBILE COMMUNICATION SYSTEM}

The present invention relates to a mobile communication system. Specifically, the present invention relates to a method for controlling random access in a broadband mobile communication system.

Broadband mobile communication systems are being used for high speed data communication or voice communication via a computer or terminal controlled by a user. On the other hand, in recent years, there is an increasing market demand for realizing machine-to-machine communication (M2M) that occurs without user intervention. Accordingly, efforts are being actively made to support existing inter-object communication (hereinafter, may be mixed with M2M communication) by changing an existing broadband mobile communication system.

In inter-object communication, a large number of terminals are considered in comparison with a conventional broadband mobile communication system. That is, a very large number of M2M terminals are connected to one base station. And, terminals providing the same M2M service tends to attempt network reconnection at the same time.

For example, a terminal providing a remote meter reading service (hereinafter referred to as a terminal for remote meter reading) operates in idle mode after initial network access and periodically reports the remote meter reading result to a server in the core network. Attempt to reconnect to the network. In general, an M2M terminal providing the same M2M service is allocated the same network reconnection period (eg, a period for reporting a remote meter reading result in the case of a remote meter terminal).

In addition, conventionally, random access configuration information for network reconnection is commonly given for each base station or cell. That is, all terminals in the cell attempt to reconnect to the network using the same random access configuration information. Here, the random access configuration information may be various parameters (for convenience, referred to as random access related parameters) for performing random access (eg, sequence information for random access, time / frequency resource information for random access, backoff information, etc.). It includes.

Accordingly, a large number of M2M terminals attempt network reconnection at the same time using the same random access configuration information, which may cause a load on the base station and delay network reconnection.

Accordingly, there is a need for a method for distributing random access of multiple M2M terminals.

An object of the present invention is to provide a method for controlling random access of a terminal in a broadband mobile communication system.

In a mobile communication system according to an aspect of the present invention, a method for performing random access by a terminal includes: receiving a broadcast message including a random access related parameter from a base station; random access to the terminal from the base station when entering a dormant mode; Receiving information indicating a related parameter, and attempting random access using the information indicating the random access related parameter and the random access related parameter for the terminal upon network reconnection.

In a mobile communication system according to an aspect of the present invention, a method for controlling a random access of a terminal by a base station periodically transmitting a broadcast message including a random access related parameter to at least one terminal, a terminal to enter idle mode Transmitting information indicating the random access related parameter to the terminal to the user; and reconnecting the network according to the random access attempt of the terminal based on the random access related parameter and the information indicating the random access related parameter to the terminal. Performing a step.

A terminal for use in a mobile communication system according to an aspect of the present invention includes a radio frequency (RF) unit and a processor, and the processor receives a broadcast message including a random access related parameter from a base station and pauses. Receives information indicating a random access related parameter for the terminal from the base station when entering the mode, and random access using the information indicating the random access related parameter and the random access related parameter for the terminal upon network reconnection. Is set to try.

A base station for use in a mobile communication system according to an aspect of the present invention includes a radio frequency (RF) unit and a processor, and the processor periodically transmits a broadcast message including a random access related parameter to at least one terminal. And transmitting information indicating a random access related parameter for the terminal to a terminal that intends to enter idle mode, and the terminal based on the information indicating the random access related parameter and the random access related parameter for the terminal. It is set to perform the network reconnection procedure according to the random access attempt of.

According to a feature of the present invention, ranging configuration information for a large number of M2M terminals can be allocated. Accordingly, a large number of M2M terminals can attempt random access by distributing based on the allocated ranging configuration information, reduce the load of the base station, and reduce the delay time when reconnecting the network.

1 is a flowchart illustrating a network reconnection procedure according to an embodiment of the present invention.
2 illustrates a terminal and a base station that can be applied to an embodiment of the present invention.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention, and like reference numerals designate like parts throughout the specification.

Throughout the specification, when a part is said to "include" a certain component, it means that it can further include other components, without excluding other components unless specifically stated otherwise.

Throughout the specification, a mobile station (MS) is a terminal, a mobile terminal (MT), a subscriber station (SS), a portable subscriber station (PSS), an access terminal (access) It may refer to a terminal (AT), a user equipment (UE), or the like, and may include all or some functions of the terminal, MT, SS, PSS, AT, UE, and the like.

In addition, the base station (BS) is a node B (eB), an evolved node B (eNodeB), an access point (AP), a radio access station (radio access station (RAS)), a base transceiver station may refer to a base transceiver station (BTS), a mobile multihop relay (MMR) -BS, or the like, and may include all or a part of functions of a NodeB, an eNodeB, an AP, a RAS, a BTS, an MMR-BS, and the like.

In addition, the random access procedure may be referred to by various names according to the communication system. For example, the random access process may be referred to as a contention-based access process, a random access channel (RACH) process, a ranging process, and the like. For convenience, in the present specification, the ranging is described as an example, but the ranging may be replaced with the various terms described above.

1 is a flowchart illustrating a network reconnection procedure according to an embodiment of the present invention.

Referring to FIG. 1, the base station periodically transmits a broadcast message to a terminal in an active mode after initial network access or initial network access (S100). In this case, the broadcast message includes a random access related parameter for network reconnection. The random access related parameter may include a random access parameter for each priority. The random access parameter for each priority may include at least one of backoff information for each priority and ranging code information for each priority. The random access parameter for each priority may further include at least one of ranging channel information for each priority and backoff time offset information for each priority.

Details of the random access parameter for each priority will be described later.

When the terminal wants to enter the idle mode, the terminal transmits a idle mode entry request message to the base station (S110). In addition, the base station transmits an idle mode entry permission message to the terminal in response to the idle mode entry request message (S120). The idle mode entry permission message may include information indicating a random access related parameter for the corresponding terminal. For example, the idle mode entry permission message may include priority information for random access. Priority information for random access may be assigned by the base station. Priority information for random access may be allocated for an individual terminal or for a terminal group including a plurality of terminals. The base station may allocate priority information for random access in consideration of characteristics of individual terminals or groups of terminals.

In this specification, information (eg, priority information) indicating a random access related parameter for a corresponding UE is described as being transmitted through an idle mode entry permission message, but this is only an example. That is, information indicating a random access related parameter for the terminal may be transmitted through various messages according to the system design.

In addition, the present specification describes a case in which information indicating a random access related parameter for a corresponding UE is explicitly transmitted from the base station to the terminal, but this is only an example. For example, the information indicating the random access related parameter for the terminal is based on the type / characteristic of the terminal (eg, general terminal, M2M terminal), the urgency of the message to be sent by the terminal, and the type of message to be sent by the terminal. It may be confirmed indirectly in consideration of the priorities.

Thereafter, when the terminal receives the paging message from the base station or when uplink data to be transmitted to the base station occurs, the terminal performs a network reconnection procedure with the base station (S130). To this end, the terminal may attempt random access using priority information allocated from the base station and random access parameters for each priority. That is, random access may be attempted according to the random access parameter corresponding to the priority information allocated in step S120 among random access parameters for each priority in the broadcast message received in step S100. In detail, the terminal may attempt random access through the ranging channel corresponding to the priority information allocated through step S120. Alternatively, when the random access fails, the terminal may perform the backoff according to the backoff information corresponding to the priority information allocated through step S120. After the backoff, the UE may retry random access by transmitting a ranging code corresponding to the priority information through the ranging channel corresponding to the priority information.

Table 1 shows random access parameters for each priority according to an embodiment of the present invention.

Parameter you Note Number of Random access priority 3 Priority of random access during network reentry For (i = 0, i <Number of Random access priority; i ++) { priority 3 0 is the highest priority Ranging backoff start 4 Initial backoff window size for contention based ranging during network reentry Ranging backoff end 4 Final backoff window size for contention based ranging during network reentry Start of ranging code group 8 Indicates the start number of the group of codes used for random access during network reentry Number of ranging codes 8 The number of codes used for random access during network reentry Mode index 8 Moduler index. If ranging channel index MOD (mode index + 1) = 0, then, this ranging channel is allowed for random access from AMS with this priority.
}

Referring to Table 1, the random access parameters for each priority level include the Number of Random Access Priority field, Priority field, and Ranging backoff start and Ranging backoff end. And ranging code information for each priority (Number of ranging codes) and ranging channel information for each priority (Mode index).

The number of random access priorities may be represented by, for example, 3 bits. The number of random access priorities means the number of priorities for random access during network reentry.

Priority may be represented by 3 bits. If the priority value is 0, it may represent the highest priority.

The priority-based backoff information designates the size of the priority-based backoff window and may include a ranging backoff start field and a ranging backoff end field. The ranging backoff start field indicates an initial backoff window size for contention based ranging (or random access) during network reconnection. The ranging backoff end field refers to the final backoff window size of contention based ranging (or random access) during network reconnection. When performing the backoff, the terminal may retry the random access at any point within the given backoff window.

The ranging code information for each priority designates a ranging code that can be used to reconnect a network according to the priority assigned by the terminal, and includes a start of ranging code group field and a number of ranging codes. of ranging codes) field. The Start of ranging code group field indicates a ranging code number at which the corresponding ranging code group starts in the entire ranging code used for random access during network reentry. The Number of ranging codes field means the number of ranging codes used for random access during network reentry, and can be counted starting from the ranging codes indicated by the start field of the ranging code group. have.

The ranging channel information for each priority designates a ranging channel for transmitting a ranging code designated for each priority after the backoff window designated for each priority. For example, ranging channel information for each priority may be represented by a mode index field. To this end, a unique index may be allocated to each ranging channel. The ranging channel may be configured to enable random access in the ranging channel where the index value of the ranging channel and the result of the modular operation of (N * mode index + M) become zero. N and M are positive integers. For example, when N = M = 1 and the mode index value is set to 2, the ranging channel 3 and the number 6 where the index value of the ranging channel and the result of the modular operation of (N * mode index + M) become 0. Random access is possible through a ranging channel, a ranging channel 9, and the like. As another example, when the mode index value is set to 0, the UE may randomly access through any ranging after the backoff window.

In Table 1, if a random access parameter for each priority exists in the order of increasing / decreasing priority and is continuous, the priority field may be omitted.

And a ranging backoff start field, a ranging backoff end field, a starting of ranging code group field, and a number of ranging codes. ) And Mode Index fields are set for each priority, but some of them may be given as common values regardless of priority, and only some values may be given for each priority.

This modification can be equally applied to Tables 2 and 3 below.

Table 2 shows random access parameters for each priority according to another embodiment of the present invention.

Parameter you Note Number of Random access priority 3 Priority of random access during network reentry For (i = 0, i <Number of Random access priority; i ++) { priority 3 0 is the highest priority Ranging backoff start 4 Initial backoff window size for contention based ranging during network reentry Ranging backoff end 4 Final backoff window size for contention based ranging during network reentry Start of ranging code group 8 Indicates the start number of the group of codes used for random access during network reentry Number of ranging codes 8 The number of codes used for random access during network reentry Ranging Channel offset 8 Ranging channel offset. M2M device transmits ranging code on (Ranging channel offset + 1) th ranging channel after backoff }

Referring to Table 2, the random access parameters for each priority level include the number of random access priorities, ranging backoff information (Ranging backoff start, Ranging backoff end), and ranging code information for each priority. (Start of ranging code group, Number of ranging codes) and ranging channel information for each priority (Ranging channel offset).

Except that the ranging channel information for each priority is represented by a ranging channel offset field, it is shown in Table 1 below. Therefore, the description duplicated with Table 1 will be omitted.

The ranging channel offset field means that the ranging code is transmitted through the (ranging channel offset + 1) th ranging channel after the backoff. That is, after performing the backoff according to the priority assigned by the terminal, the ranging code may be transmitted through the (ranging channel offset + 1) th ranging channel. For example, when the ranging channel offset is set to 0, the terminal may perform a backoff and then transmit a ranging code through the first ranging channel. When the ranging channel offset is set to 3, the terminal performs the backoff. After that, the ranging code may be transmitted through the fourth ranging channel.

Table 3 shows random access parameters for each priority according to another embodiment of the present invention.

Parameter you Note Number of Random access priority 3 Priority of random access during network reentry For (i = 0, i <Number of Random access priority; i ++) { priority 3 0 is the highest priority Ranging backoff start 4 Initial backoff window size for contention based ranging during network reentry Ranging backoff end 4 Final backoff window size for contention based ranging during network reentry Start of ranging code group 8 Indicates the start number of the group of codes used for random access during network reentry Number of ranging codes 8 The number of codes used for random access during network reentry Ranging Backoff Time offset 8 Ranging backoff time offset. M2M device performs backoff after Ranging time offset }

Referring to Table 3, the random access parameters for each priority level include the number of random access priorities, ranging backoff information (Ranging backoff start, Ranging backoff end), and ranging code information for each priority. (Start of ranging code group, Number of ranging codes) and ranging backoff time offset information for each priority (Ranging backoff time offset).

Except that the ranging channel information for each priority is replaced by the ranging backoff time offset for each priority, it is the same as Table 1 below. Therefore, the description duplicated with Table 1 will be omitted.

The ranging backoff time offset information for each priority may be instructed to perform the backoff after the ranging time offset. Accordingly, a backoff time point of an individual terminal or a terminal group can be set differently, and a collision probability at random access can be lowered. The ranging time offset may be applied not only before the backoff but also after the backoff.

Meanwhile, after the base station broadcasts a random access parameter for each priority to the terminal, the random access information for each priority may be changed. In this case, the base station may broadcast the changed random access parameter for each priority to the terminal. When the terminal receives the changed random access parameter for each priority, the terminal may update the random access parameter by using the corresponding information.

In addition, the priority information allocated to each terminal may be fixed for each terminal or may be changed every time the terminal enters the idle mode. For example, when the terminal reenters the idle mode after performing network reconnection according to the priority information allocated when entering the idle mode, the base station may allocate the changed priority information to the terminal.

In the above description, Tables 1 to 3 assume random access parameters given for each priority. Generalizing this, for example, in Tables 1 to 3, "Number of Random access priority" may be replaced by "Number of Random access configurations", and "Priority" may be replaced by "Configuration Number".

2 illustrates a terminal and a base station that can be applied to an embodiment of the present invention.

Referring to FIG. 2, the mobile communication system includes a terminal 1200 and a base station 1300. The terminal 1200 and the base station 1300 include a processor 1210 and 1310, a memory 1220 and 1320, and a radio frequency (RF) unit 1230 and 1330, respectively. The processors 1210 and 1310 may be configured to implement the procedures and / or methods proposed by the present invention. The memories 1220 and 1320 are connected to the processors 1210 and 1310 and store various information related to the operation of the processors 1210 and 1310. The RF units 1230 and 1330 are connected to the processors 1210 and 1310 and transmit and / or receive a radio signal. The base station 1300 and / or the terminal 1200 may have a single antenna or multiple antennas.

The embodiments of the present invention described above are not only implemented through the apparatus and the method, but may be implemented through a program for realizing a function corresponding to the configuration of the embodiments of the present invention or a recording medium on which the program is recorded.

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 (17)

In the method of the user equipment random access in the mobile communication system,
Receiving a broadcast message including a random access related parameter from a base station,
Receiving information indicating a random access related parameter for the terminal from the base station when entering the idle mode, and
Attempting random access using information indicating the random access related parameter and the random access related parameter for the terminal upon network reconnection;
&Lt; / RTI &gt; The method of claim 1,
The random access related parameters are random access parameters for each priority.
The information indicating the random access related parameter for the terminal is priority information allocated for the terminal. The method of claim 2,
The random access parameter for each priority includes backoff information for each priority and ranging code information for each priority. The method of claim 3,
The random access parameter for each priority may further include at least one of ranging channel information for each priority and backoff time offset information for each priority. The method of claim 4, wherein
Attempting the random access is
Performing backoff according to backoff information corresponding to the priority information; and
Transmitting a ranging code corresponding to the priority information through a ranging channel corresponding to the priority information.
&Lt; / RTI &gt; The method of claim 4, wherein
Attempting the random access is
Performing a backoff according to backoff information corresponding to the priority information after a backoff time offset corresponding to the priority information, and
Transmitting a ranging code corresponding to the priority information to the base station
&Lt; / RTI &gt; A method for controlling a random access of a terminal by a base station in a mobile communication system,
Periodically transmitting a broadcast message including a random access related parameter to at least one terminal;
Transmitting information indicating a random access related parameter to the terminal to the terminal to enter the idle mode, and
Performing a network reconnection procedure according to a random access attempt of the terminal based on the random access related parameter and information indicating the random access related parameter for the terminal;
&Lt; / RTI &gt; The method of claim 7, wherein
The random access related parameters are random access parameters for each priority.
The information indicating the random access related parameter for the terminal is priority information allocated for the terminal. The method of claim 8,
The random access parameter for each priority includes backoff information for each priority and ranging code information for each priority. 10. The method of claim 9,
The priority-based backoff information includes initial backoff window size information and final backoff window size information for contention-based random access during network reconnection. 10. The method of claim 9,
The ranging code information for each priority is ranging code number information starting with the corresponding ranging code group in all ranging codes used for contention-based random access during network reconnection and the lane included in the corresponding ranging code group. Method for including the count information of the gong code. 10. The method of claim 9,
The random access parameter for each priority may further include at least one of ranging channel information for each priority and backoff time offset information for each priority. The method of claim 12,
The ranging channel information for each priority is represented by a mode index.
And a ranging channel to which random access is attempted based on a result of the modular operation of the ranging channel and the index value of the ranging channel. The method of claim 12,
The ranging channel information for each priority includes ranging channel offset information after backoff. The method of claim 12,
And the priority-based backoff time offset information includes time offset information before or after backoff. In the terminal for use in a mobile communication system,
A radio frequency (RF) unit; And
Includes a processor,
The processor receives a broadcast message including a random access related parameter from a base station, receives information indicating a random access related parameter for the terminal from the base station when entering a dormant mode, and receives the random access related at network reconnection. And a terminal configured to attempt random access using information indicating a parameter and a random access related parameter for the terminal. A base station for use in a mobile communication system,
A radio frequency (RF) unit; And
Includes a processor,
The processor periodically transmits a broadcast message including a random access related parameter to at least one terminal, and transmits information indicating a random access related parameter to the terminal to a terminal to enter idle mode, and the random access. And a base station configured to perform a network reconnection procedure according to the random access attempt of the terminal based on the related parameter and information indicating the random access related parameter for the terminal.

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