KR20110038852A - Cell-reselection system and method using a system information block - Google Patents

Abstract

PURPOSE: A cell reselection method and system thereof which uses an SIB(System Information Block) are provided to inform a user terminal of information about an LTE(Long Term Evolution) neighboring cell or a dual layered cell through SIB. CONSTITUTION: A system information generating unit(510) generates an SIB which includes an FDD mode or a TDD mode. A system information transmitting unit(520) transmits the SIB to a user terminal through a shared channel. A control unit(530) controls the system information generating unit in order to generate the SIB. The system information transmitting unit generates the SIB according to an inter-frequency carrier frequency list.

Description

Cell reselection system and method using a system information block

The present invention relates to a method and system for performing cell reselection using a time division-long term evolution (TD-LTE) repeater in a frequency division duplexing (FDD) long term evolution (LTE) network. In detail, a user terminal using an LTE system and a non-traffic state through a System Information Block (SIB) for a LTE neighbor cell or a dual layered cell in a different mode. The present invention relates to a method and a system for cell reselection using a system information block, which enables a user terminal to perform cell reselection to a TD-LTE repeater in an FDD LTE network based on the received SIB.

The evolutionary roadmap for mobile technology can be divided into 3GPP camp LTE, IEEE camp 802.16x, and CDMA camp UMB. However, unlike other technologies, CDMA-based UMBs could not be selected by mobile operators, so they are now divided into LTE and WiMAX camps.

Some operators, especially in the US Sprint, chose WiMAX technology as their next-generation network standard, but almost all operators in Europe (Deutsche Telekom, France Telecom, Vodafone, Telecom Italia, Telenor, Telstra, etc.) and operators in Asia and the Americas (CMCC, NTT DoCoMo, KDDI, E-Mobile, Softbank, AT & T, Verizon, etc.) chose LTE as their next-generation technology standard.

In the case of TD-LTE, no operator has been selected except China Mobile Comm. Corp. (CMCC), but the technology is being promoted with full support from China. Since the early stages of LTE standardization and development, Chinese vendors and operators have been responsible for almost all aspects of TD-LTE (TDD mode of LTE). I'm trying to. In February 2008, at the Mobile World Congress (VWF), Vodafone-CMCC-Verizon signed a MoU and decided to cooperate with each other for the global proliferation and development of FDD / TD LTE. Is also being pushed.

Currently, the LTE deployment scenario, which is mainly discussed, constitutes a network of FDD LTE or TD-LTE technology alone, and considers femto / micro BTS for network hole, hot zone, and coverage expansion.

However, the license cost of the TDD frequency band is expected to be about 1/4 less than that of FDD, and Vodafone-CMCC-Verizon's evaluation shows that there is an excellent aspect of FDD in indoor, limited coverage, and hot zone. In this case, the macro coverage uses FDD LTE, and in the case of network hole, hot zone, etc., TD-LTE can be considered to increase the efficiency of the scenario.

In the case of handsets, the Chinese government and CMCC are trying to launch terminals that can support not only FDD but also TDD at the same time of LTE deployment.

When the operator deploys LTE, the FDD frequency band and the TDD frequency band, which is cheaper than FDD, are used at the same time and used in hot zones or relays, so that seamless interworking between FDD LTE and TD-LTE is essential. .

Although the LTE standard of 3GPP currently provides information for interworking with UMTS, CDMA2000, and WiMAX, there is a problem in that interworking between FDD and TDD between LTE and system information for an access network is not provided.

 Therefore, when the access network system does not provide information for cell reselection between the FDD LTE and the TD-LTE, the terminal should proactively perform the following procedure.

  First, the terminal needs Dual mode (supports both FDD / TD LTE), and the dual mode terminal in FDD LTE periodically (timer value set in advance) TD-LTE in addition to the FDD LTE modem and RF module that are turned on. The TD-LTE signal must be searched by turning on the modem and the RF module.

Second, if the TD-LTE signal is not detected, the TD-LTE modem and RF module should be turned off.

Third, if a TD-LTE signal is detected, it must switch to TD-LTE mode through the terminal's internal procedure and turn off the FDD LTE modem and RF module.

However, the aforementioned method has the following disadvantages.

(1) When searching the TD-LTE network periodically by the timer value set in the terminal, the terminal battery is rapidly consumed due to frequent modem / RF module ON / OFF and signal search, and during the FDD and TDD transition The disadvantage is that it takes a lot of time.

(2) In areas where FDD LTE and TD-LTE are partially overlaid, the signal strength of FDD LTE may be weaker than TD-LTE, but may be similar. Doing so may not work effectively.

(3) Even if the signal strength of FDD LTE is similar to or rather stronger than TD-LTE, it may be necessary to handover to TD-LTE for load sharing or other operational purposes. The disadvantage is that it is inefficient.

An object of the present invention for solving the above-described problems, information on the LTE neighbor cell or dual layered cell of the other mode (mode) through the system information block (SIB) to the user terminal using the LTE system and not in the traffic state By recognizing this, a cell reselection method and system using a system information block, a system and a base station and its cell reselection, so that the user terminal can perform cell reselection to the TD-LTE repeater in the FDD LTE network based on the received SIB A method, a user terminal, and a cell reselection method thereof are provided.

According to another aspect of the present invention, there is provided a cell reselection system, including: a base station generating a system information block including mode information of another LTE system and transmitting the same through a shared channel; And a user terminal for performing cell reselection to a TD-LTE repeater in an FDD LTE network based on the system information block received from the base station.

Here, the mode information includes an FDD mode or a TDD mode.

On the other hand, the base station according to the present invention for achieving the above object, the system information generating unit for generating a system information block including the FDD mode or TDD mode; A system information transmitter for transmitting the generated system information block to a user terminal through a shared channel; And a controller configured to control generation of a system information block (SIB) including the FDD mode or the TDD mode and transmission to the user terminal.

In addition, the system information generation unit may include an FDD mode or TDD mode information for another LTE of another frequency in an item called InterFreqCarrierFreqList in the system information block (SIB). Create

The apparatus may further include an information partitioner for segmenting the system information block (SIB) into a transmission block (TB) size of a broadcast channel, which is a transport channel, and transmitting the segment to the system information transmitter.

The system information generator generates the system information block (SIB) including information on a TD-LTE neighbor cell adjacent to or overlaid with the user terminal.

On the other hand, the cell reselection method using a system information block according to the present invention for achieving the above object is a cell reselection method using a system information block of a system including a user terminal and a base station, (a) Generating a system information block (SIB) including mode information of another LTE system; (b) dividing the generated system information block (SIB) into a transmission block size of a broadcast channel (BCH); (c) transmitting the divided system information block (SIB) to the user terminal; (d) receiving the system information block (SIB) at the user terminal; And (e) the user terminal performing cell reselection based on a system information block (SIB) including mode information of the other LTE system.

On the other hand, the cell reselection method using the system information block of the base station according to the present invention for achieving the above object, using the system information block of the base station for providing information for cell selection to the user terminal located in the jurisdiction cell CLAIMS 1. A cell reselection method, comprising: (a) generating a system information block comprising an FDD mode or a TDD mode; (b) dividing a system information block (SIB) including the FDD mode or TDD mode into a transmission block size of a broadcast channel; And (c) transmitting the divided system information block (SIB) to the user terminal.

In addition, the step (a) may include the FDD mode or TDD mode information for another LTE of a different frequency in an item called InterFreqCarrierFreqList in the system information block (SIB). ).

In addition, the step (a) generates the system information block (SIB) including information on the TD-LTE neighbor cell adjacent to or overlaid with the user terminal.

In addition, step (a) also generates a master information block including a scheduling block containing scheduling information of each scheduling unit.

Also, in the step (c), the master information block including the scheduling block containing the scheduling information of each scheduling unit is also transmitted to the user terminal.

In the step (c), the system information block is transmitted through a shared channel, and the master information block is transmitted through a system information dedicated channel.

According to the present invention, when FDD LTE and TD-LTE are overlaid and deployed, efficient cell-reselection can be performed between LTE of different modes using SIB5.

In addition, as cell reselection is performed using SIB5, battery consumption of the terminal can be significantly reduced and the time for transition can be shortened.

In addition, as a neighbor cell for cell-reselection to FDD LTE and TD-LTE, it is possible to distinguish between FDD LTE and TD-LTE networks which may have different cell reselection conditions.

In addition, since accurate information about the overlay cell and the neighbor cell can be identified, the operational efficiency of the next-generation technology Self Configuration / Optimization Network (SON), which is to be employed in the 4G network (4G N / W), can be improved.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout. Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

In the mobile communication system, the terminal broadcasts system information about various parameters necessary for the terminal to operate, such as initialization of the terminal by power-on or call connection. Get from

Such system information is transmitted to all cells through a broadcast channel (BCH) so that all terminals belonging to a cell can be received.

In the third generation mobile communication system, such system information is largely composed of a master information block (MIB) and a system information block (SIB).

The master information block (MIB) includes a parameter (PLMN ID) that the terminal should acquire quickly for PLMN search or scheduling information of each system information block (SIB). . A channel for transmitting such system information is a broadcast channel (BCH), which has a difference between a 3GPP WCDMA system and a 3G LTE system.

The channel structure of the 3G LTE system is as shown in FIG. The system information is a BCH (Broadcast Channel) used as a transport channel, which is divided into a common control physical channel (CCPCH) and a physical downlink shared channel (PDSCH).

That is, in a 3G LTE system, a master information block (MIB) is transmitted through a common control physical channel (CCPCH) as shown in FIG. 2, and the system information block (SIB) is shown as a physical downlink as shown in FIG. 3. Shared channel).

CCPCH is a system information dedicated channel for transmitting only a master information block (MIB), and PDSCH is a shared channel for transmitting other signals and data transmitted through a physical channel (PCH) or a downlink shared channel (DLSCH). Through the scheduling procedure of Access Control), data of several channels are transmitted together.

In the 3GPP WCDMA system, since physical channels for transmitting system information are separated, transmission of system information does not affect other traffic. However, in the 3G LTE system, since the system information block (SIB) is transmitted on the shared channel PDSCH, the transmission of the system information block (SIB) affects the transmission of other traffic.

4 is a configuration diagram schematically showing a configuration of a cell reselection system according to an embodiment of the present invention.

Referring to FIG. 4, the cell reselection system 400 according to the present invention includes a base station 410 ˜ 412, a user terminal (UE) 420, and repeaters 430 ˜ 432.

The base stations 410 to 412 generate a system information block (SIB) including mode information of another LTE system and transmit the generated system information block (SIB) to the user terminal 420 through a shared channel. Here, the mode information includes the FDD mode or the TDD mode.

The user terminal 420 performs cell reselection to the TD-LTE repeaters 430 to 432 in the FDD LTE network based on the system information block (SIB) received from the base station 410.

The repeaters 430 ˜ 432 perform a communication relay to the user terminal 420 in a time division manner using frequency resources as a TD-LTE repeater.

5 is a block diagram illustrating a functional block of a base station according to an embodiment of the present invention.

Referring to FIG. 5, the base station 410 according to the present invention includes a system information generator 510, a system information transmitter 520, a controller 530, and an information divider 540.

The system information generator 510 generates a system information block (SIB) including an FDD mode or a TDD mode.

The system information generation unit 510 may include a scheduling block (SB: Scheduling Block) including scheduling information of each scheduling unit (SU), a master information block (MIB), and a system. System information is generated by being selectively included in the first scheduling unit SU-1 of the system information block (SIB).

In addition, the system information generation unit 510 includes an FDD mode or TDD mode information for another LTE of another frequency in an item called an inter-frequency carrier frequency list (InterFreqCarrierFreqList) in the system information block (SIB). Create

The system information generator 510 generates a system information block (SIB) including information about a TD-LTE neighbor cell adjacent to or overlaid with the user terminal 420.

The system information transmitter 520 transmits the generated system information block to the user terminal 420 through a shared channel.

The system information transmitter 520 transmits a master information block MIB through a system information dedicated channel and a system information block SIB through a shared channel. In this case, the system information dedicated channel is a channel for transmitting only system information, such as Common Control Physical Channel (CCPCH), which is a physical channel of the 3G LTE system, and the shared channel is a physical downlink shared channel (PDSCH), which is a physical channel of the 3G LTE system. It is a channel where several pieces of information are shared and transmitted together.

At this time, the information dividing unit 540 segments the system information generated by the system information generating unit 510 into the transmission block (TB) size of the broadcasting channel, which is a transmission channel, to the system information transmitting unit 520. By transmitting the system information of the RLC (Radio Link Control) layer, it is possible to transmit the system information dedicated channel and shared channel of the physical layer, which is a lower layer. Here, the broadcast channel is a transport channel such as a broadcast channel (BCH) of the 3G LTE system.

The controller 530 controls generation of a system information block (SIB) including the FDD mode or the TDD mode and the transmission to the user terminal 420.

The information dividing unit 540 divides the system information block into the size of the transmission block of the broadcast channel and transmits the system information block to the system information transmitting unit 520.

6 is an overall flowchart illustrating a cell reselection method using a system information block according to an embodiment of the present invention.

Referring to FIG. 6, the base station 410 generates a system information block including mode information of another LTE system (S610).

Subsequently, the base station 420 divides the generated system information block into the size of the transmission block of the broadcast channel through the information dividing unit 540 (S620).

Subsequently, the base station 420 transmits the system information block to the user terminal 420 (S630).

When the user terminal 420 receives the system information block, the user terminal 420 performs cell reselection based on a system information block (SIB) including mode information of another LTE system (S640).

7 is a flowchart illustrating a cell reselection method using a system information block of a base station according to an embodiment of the present invention.

In 3G 3rd Generation Long Term Evolution (LTE) system, system information blocks (SIBs) having the same repetition period among the system information blocks (SIBs) are classified into one scheduling unit (SU) to be a unit of scheduling. To be treated as

Among the scheduling units SU, the first scheduling unit SU-1 is transmitted through a fast repetition period, and includes a scheduling unit including information that the user terminal 420 needs to quickly acquire and scheduling information of another scheduling unit SU. As a result, the 3G LTE standard stipulates a repeat period of 80ms.

Therefore, since the bandwidth occupied by the first scheduling unit SU-1 has a large effect on the bandwidth occupied by the system information block (SIB) in the physical downlink shared channel (PDSCH), the size of the first scheduling unit SU-1 may be reduced. As much as possible, the PDSCH load due to system information transmission can be reduced.

In the 3G LTE system standard, as shown in FIG. 8, scheduling information of each scheduling unit SU is included in the master information block MIB. 8 is a diagram illustrating an example of a system information structure in a 3G LTE system. In the scheme of FIG. 8, the size of the master information block MIB is maximum and the size of the first scheduling unit SU-1 is minimum, thereby minimizing the bandwidth occupied by the system information block SIB in the PDSCH. In addition, in the 3G LTE system specification, SIB3 includes cell reselection information related to a serving cell, SIB4 includes serving frequency / intra frequency neighboring cell information and parameter information for re-selection, and SIB5 includes inter-frequency neighboring Contains frequency information of cell and other LTE system. In addition, SIB6 includes information on UMTS neighbor cell and UMTS frequency, SIB7 includes information on GERAN neighbor cell, and SIB8 includes information on CDMA2000 neighbor cell.

Referring to FIG. 7, a base station 410 that provides information for cell selection to a user terminal located in a jurisdiction cell first includes a system information block including an FDD mode or a TDD mode through a system information generator 510. To generate (S710).

Here, the base station 410 includes the FDD mode or TDD mode information for another LTE of another frequency in an item called an inter-frequency carrier frequency list (InterFreqCarrierFreqList) in the system information block (SIB) as shown in FIG. 10. Create a system information block (SIB).

In addition, the base station 410 generates a system information block (SIB) including information on the TD-LTE neighbor cell adjacent to or overlaid with the user terminal.

The base station 410 also generates a master information block including a scheduling block containing scheduling information of each scheduling unit.

Subsequently, the base station 410 divides the system information block into the size of the transmission block of the broadcast channel through the information dividing unit 540 (S720).

9 is a diagram illustrating an entire radio frame structure of a 3G LTE system. The radio frame is composed of two-dimensional resource blocks with time on the horizontal axis and frequency on the vertical axis. One radio frame is 10ms long, one radio frame consists of 10 subframes, and one subframe consists of two slots. In this radio frame structure, the common control physical channel (CCPCH) through which the master information block (MIB) is transmitted occupies a resource block corresponding to 1.25 MHz in the first slot (Slot 0) of the radio frame. In addition, since CCPCH has a transmission time interval (TTI) of 40 ms, the same master information block (MIB) is repeated every four radio frames.

On the other hand, system information is segmented to fit the size of a transport block (TB) of a broadcast channel (BCH) in a radio resource control (RRC) protocol and transmitted. The master information block MIB is segmented in the form shown in FIG. 2 and transmitted to the CCPCH. That is, when the master information block MIB is divided into one, one of four radio frames (40 ms TTI) is used, and CCPCH corresponding to the remaining three radio frames is not transmitted any data.

Subsequently, the base station 410 transmits a system information block including the FDD mode or the TDD mode to the user terminal 420 (S730).

At this time, the base station 410 also transmits a master information block including a scheduling block containing scheduling information of each scheduling unit to the user terminal.

The base station 410 transmits a system information block through a shared channel, and transmits a master information block through a system information dedicated channel.

As described above, according to the present invention, the user by using the LTE system and not in the traffic state by informing the information about the LTE neighbor cell or dual layered cell of the other mode (mode) through the system information block (SIB), A cell reselection method and system using a system information block, a base station and its cell reselection method, a user terminal and the like, capable of performing cell reselection to a TD-LTE repeater in an FDD LTE network based on the received SIB Its cell reselection method can be realized.

As those skilled in the art to which the present invention pertains may implement the present invention in other specific forms without changing the technical spirit or essential features, the embodiments described above should be understood as illustrative and not restrictive in all aspects. Should be. The scope of the present invention is shown by the following claims rather than the detailed description, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included in the scope of the present invention. do.

The present invention is a handover from FDD (or TD) LTE to the same FDD (or TDD) LTE system, handover from FDD (or TD) LTE to UMTS (WCDMA) system, hand from FDD (or TD) LTE to CDMA system Over, FDD (or TD) can be applied to services and systems that support the handover from LTE to the GERAN system.

In addition, the present invention can be applied to a terminal to perform cell reselection between FDD LTE and TD-LTE, and a base station providing system information to the terminal.

1 is a diagram illustrating a channel structure of a 3G LTE system.

2 is a diagram illustrating a radio frame structure of a system information dedicated channel of a 3G LTE system.

3 is a diagram illustrating a radio frame structure of a shared channel of a 3G LTE system.

4 is a configuration diagram schematically showing a configuration of a cell reselection system according to an embodiment of the present invention.

5 is a block diagram illustrating a functional block of a base station according to an embodiment of the present invention.

6 is an overall flowchart illustrating a cell reselection method using a system information block according to an embodiment of the present invention.

7 is a flowchart illustrating a cell reselection method using a system information block of a base station according to an embodiment of the present invention.

8 is a diagram illustrating an example of a system information structure in a 3G LTE system.

9 is a diagram illustrating an entire radio frame structure of a 3G LTE system.

FIG. 10 is a diagram illustrating the contents of SIB5 including mode information of another LTE system according to an embodiment of the present invention.

<Description of Symbols for Main Parts of Drawings>

400: cell reselection system 410 ~ 412: base station

420: user terminal 430 ~ 432: repeater

510: system information generation unit 520: system information transmission unit

530: control unit 540: information divider

Claims (12)

A base station for generating a system information block (SIB) including an FDD mode or a TDD mode of another LTE system and transmitting the same through a shared channel; And A user terminal for performing cell reselection to a TD-LTE repeater in an FDD LTE network based on a system information block (SIB) received from the base station; Cell reselection system comprising a. A system information generator configured to generate a system information block (SIB) including an FDD mode or a TDD mode; A system information transmitter configured to transmit the generated system information block (SIB) to a user terminal through a shared channel; And A control unit for generating a system information block (SIB) including the FDD mode or the TDD mode and transmitting the generated system information block (SIB) to the user terminal; Base station comprising a. The method of claim 2, The system information generator generates the system information block (SIB) in the system information block (SIB) by including an FDD mode or TDD mode information for another LTE of another frequency in an item called an inter-frequency carrier frequency list (InterFreqCarrierFreqList). A base station characterized in that. The method of claim 2, And the system information generator generates the system information block (SIB) including information about a TD-LTE neighbor cell adjacent to or overlaid with the user terminal. The method of claim 2, An information dividing unit for dividing the system information block (SIB) into a size of a transmission block (TB) of a broadcasting channel, which is a transmission channel, and transmitting the segment to the system information transmitting unit 520; The base station further comprises. A cell reselection method using a system information block of a system including a user terminal and a base station, (a) the base station generating a system information block (SIB) including mode information of another LTE system; (b) dividing the generated system information block into a transmission block size of a broadcast channel (BCH); (c) transmitting the divided system information block (SIB) to the user terminal; (d) receiving the system information block at the user terminal; And (e) the user terminal performing cell reselection based on a system information block (SIB) including mode information of another LTE system; Cell reselection method using a system information block comprising a. A cell reselection method using a system information block of a base station providing information for cell selection to a user terminal located in a cell having jurisdiction, (a) generating a system information block (SIB) comprising an FDD mode or a TDD mode; (b) dividing a system information block (SIB) including the FDD mode or TDD mode into a transmission block size of a broadcast channel (BCH); And (c) transmitting the divided system information block to the user terminal; Cell reselection method using a system information block of a base station comprising a. The method of claim 7, wherein In step (a), the system information block (SIB) is included in the system information block (SIB) by including an FDD mode or TDD mode information for another LTE of a different frequency in an item called InterFreqCarrierFreqList. Cell reselection method using the system information block of the base station characterized in that the generation. The method of claim 7, wherein In step (a), the system information block of the base station is generated, wherein the system information block (SIB) includes information on a neighboring or overlaid TD-LTE neighbor cell. Cell reselection method used. The method of claim 7, wherein The step (a) of the cell reselection method using a system information block of the base station characterized in that it also generates a master information block including a scheduling block containing the scheduling information of each scheduling unit. The method of claim 7, wherein The step (c) of the cell reselection method using a system information block of the base station, characterized in that for transmitting the master information block including a scheduling block containing the scheduling information of each scheduling unit to the user terminal. The method of claim 11, In the step (c), the system information block (SIB) is transmitted through a shared channel, and the master information block is transmitted through a system information dedicated channel. .

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