KR101419932B1 - A method and apparatus for measurement using communication gap in a wireless communications system - Google Patents

Abstract

The present invention discloses a measurement method and apparatus using a communication gap in a mobile communication system. When the terminal completes the measurement of the neighboring cells before the end of the gap interval allocated by the system, the terminal determines whether to transmit signaling informing the system of "completion of measurement before completion of gap interval" according to the valid interval of the remaining gap interval . That is, the signaling is transmitted to the system only when the effective interval of the remaining gap is equal to or greater than a predetermined comparison threshold interval X, otherwise the signaling is not transmitted.

Measurement, Gap, Early return indicator

Description

[0001] METHOD AND APPARATUS FOR MEASUREMENT USING COMMUNICATION [0002] BACKGROUND OF THE INVENTION [0003]

1 shows an example of a 3GPP LTE system structure;

2 is a diagram illustrating an example of a measurement operation using a communication gap according to the prior art;

3 is a diagram illustrating a measurement operation using a communication gap according to a preferred embodiment of the present invention.

4 is a flowchart illustrating an operation of a terminal according to a preferred embodiment of the present invention.

5 is a flow diagram illustrating operation of a network (ENB) according to a preferred embodiment of the present invention.

6 is a block diagram illustrating an apparatus of a terminal according to a preferred embodiment of the present invention.

7 is a block diagram showing an apparatus of a network (ENB) according to a preferred embodiment of the present invention.

The present invention relates to a mobile communication system, and more particularly, to an efficient measurement method and apparatus using a communication gap.

The Universal Mobile Telecommunication Service (UMTS) system is based on Global System for Mobile Communications (GSM) and General Packet Radio Services (GPRS), which are European mobile communication systems, and includes a Wideband Code Division Multiple Access (Hereinafter referred to as " third generation asynchronous mobile communication system "). In the 3rd Generation Partnership Project (3GPP), which is in charge of UMTS standardization, a discussion is underway on LTE (Long Term Evolution) system, which is a next generation mobile communication system of UMTS system. LTE is a technology that realizes high-speed packet-based communication with transmission speed of up to 100Mbps with commercialization target of about 2010. Various methods are discussed for this purpose. For example, there are discussions such as reducing the number of nodes located on the communication path by simplifying the network structure, or approaching wireless protocols to the wireless channel as much as possible.

FIG. 1 shows an example of a 3GPP LTE system structure that is evolved.

1, an Evolved UMTS Radio Access Network (E-UTRAN) 110 includes a plurality of Evolved Node B (ENB) 120, 122, 124, 126, and 128 and two nodes of anchor nodes 130 and 132, Structure. The upper nodes 130 and 132 are connected to a Mobility Management Entity (MME) responsible for a control plane such as a mobility and context of a UE (User Equipment) And a User Plane Entity (UPE) responsible for a user data plane such as data transmission and routing. The user terminal (UE) 101 accesses the Internet Protocol (IP) network 114 by the E-UTRAN 110. [ The ENBs 120 to 128 correspond to the existing Node B of the UMTS system and are connected to the UE 101 through a wireless channel.

Unlike the existing node ratio, the ENB 120-128 performs a more complex role. In LTE, since all user traffic including a real-time service such as VoIP (Voice over IP) over the Internet protocol is serviced through a shared channel, a device for collecting and scheduling situation information of UEs is required. 128). One ENB typically controls multiple cells.

In the ENBs 120 to 128, adaptive modulation and coding (AMC) is performed to determine a modulation scheme and a channel coding rate according to a channel state of a UE. (Hybrid ARQ) is performed between the ENBs 120 to 128 and the UE 101 in LTE as in HSDPA (High Speed Downlink Packet Access), HSUPA (High Speed Uplink Packet Access) and E-DCH (Enhanced Dedicated Channel) , And an outer ARQ may be performed. In addition, the ENBs 120 to 128 transmit and receive measurement control, setup and transmission of system information, a terminal context and a state, which are performed by an RNC (Radio Network Controller) of a UMTS system, (Radio Resource Control) functions such as management and control of the mobile station, handover, and the like. In 3GPP LTE, it is expected that Orthogonal Frequency Division Multiplexing (OFDM) will be used as a radio access technology in a 20MHz bandwidth in order to realize a transmission rate of up to 100Mbps.

The measurement is a series of processes for measuring the strength of a pilot of neighboring cells to support the mobility of the terminal, and there is a measurement method using a gap and a gap without using a communication gap . A gap using a gap is a measure of the strength of the pilot of neighboring cells during a gap that temporarily interrupts communication with the serving cell. The UE measures a gap between neighboring cells that can not simultaneously perform measurement during a communication with a Serving cell. As an example of the 'adjacent cell that can not simultaneously perform measurement during communication with the serving cell', if the frequency band of the adjacent cell is different from the frequency band of the serving cell and the terminal can not simultaneously receive two frequency bands, And scenarios belonging to an access technology (RAT: Radio Access Technology) system.

A gap pattern indicating time intervals during which the terminal temporarily suspends communication with a serving cell is generally allocated from a network node (i.e., an ENB), but the terminal may automatically generate a gap pattern. When a gap is allocated, the ENB, which controls the serving cell and is responsible for scheduling for the data / signaling transmissions of the terminal, may result in the terminal measuring the neighboring cells during the gap interval by excluding the terminal from scheduling during the gap interval Thereby preventing packet loss (packet loss). If the terminal is excluded from the scheduling of the ENB, the terminal does not transmit or receive any data with the serving cell. At this time, the gap pattern to be used by the UE should be promised to each other either through explicit signaling between the UE and the ENB or by an implicit rule.

2 shows an example of a measurement operation using a communication gap according to the prior art.

Referring to FIG. 2, reference numeral 211 denotes a gap interval allocated to a UE, and the UE performs a measurement on adjacent cells during a gap period 211. If the measurement of the neighboring cells is completed 213 before the end of the gap interval 211, the UE informs the ENB through the signaling that the measurement has been completed before the end of the gap interval 211. Then, the ENB does not have to wait for the gap interval 211 to end, but allocates resources for scheduling to the UE as soon as it receives the signaling, thereby reducing delay of data / signaling transmission.

However, the conventional method has a problem that it has signaling overhead by performing signaling to notify the ENB each time the terminal completes the measurement before the end of the gap interval. This additional overhead is undesirable in practice if a very limited scheduling delay gain is obtained. For example, if the signaling that the terminal completes and transmits the measurement is received at the ENB at the point when the actual gap interval is almost over, there is substantially no scheduling delay gain, but only overhead due to additional signaling.

Therefore, the present invention provides a method and apparatus for performing efficient measurement while minimizing overhead due to additional signaling in a mobile communication system.

A preferred embodiment of the present invention is a method of using a communication gap in a mobile communication system,

Performing a measurement on frequency bands other than a serving frequency band during an allocated gap period;

Calculating an effective gap remaining period until the gap interval is completed when the measurement is completed before the gap interval ends;

Determining whether to transmit signaling indicating that the measurement is completed before the end of the gap interval according to the valid gap remaining period;

And selectively transmitting the signaling according to the determination result.

A preferred embodiment of the present invention is a method of using a communication gap in a mobile communication system,

Setting a comparison threshold interval value to be compared with an effective gap remaining interval estimated by the terminal when the terminal determines that allocation of a gap pattern for the measurement is required;

And transmitting the comparison threshold value to the MS.

The operation principle of the preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear. The following terms are defined in consideration of the functions of the present invention, and may be changed according to the intentions or customs of the user, the operator, and the like. Therefore, the definition should be based on the contents throughout this specification.

Hereinafter, the 3GPP LTE system evolved in the 3GPP UMTS (Universal Mobile Telecommunication Service) system will be described as an example, but the present invention can be applied to other mobile communication systems without adding or subtracting it.

The main point of the invention is to minimize the signaling overhead in the measurement using the communication gap. In particular, it does not cause overhead due to signaling when there is little delay gain in the scheduling. Or the ENB may control the signaling overhead by Radio Resource Management (RRM).

In order to achieve this, when the terminal completes the measurement before the end of the gap interval allocated by the system, the terminal estimates the reception time point at which the ENB receives the signaling informing of "completion of the measurement before the end of the gap interval" The effective gap remaining period is calculated by using the end point of the gap interval. If the effective gap remaining period is greater than or equal to a predetermined comparison threshold X value, the terminal transmits to the ENB a signaling message indicating " completion of measurement before completion of gap interval ". On the other hand, if the effective gap remaining period is less than or equal to the comparative threshold period X value, the terminal does not transmit signaling to the ENB indicating "completion of measurement before completion of gap period".

The effective gap remaining period is calculated as an example (gap end point) - (reception point of the signaling estimated by the terminal), or as another example (gap end point) - (time point when the terminal transmits signaling) , Or (gap end point) - (time point when the measurement is completed).

FIG. 3 illustrates a measurement operation using a communication gap according to a preferred embodiment of the present invention.

Referring to FIG. 3, reference numeral 311 denotes a gap interval allocated to a UE, and the UE performs a measurement on adjacent cells during a gap interval 311. [0031] Referring to FIG. If the measurement of neighboring cells is completed 313 before the end of the gap interval 311, the terminal informs the ENB of the reception time point at which the ENB receives the signaling indicating that the measurement has been completed before the end of the gap interval 311 .

The reception time may be different depending on how the signaling is transmitted. For example, if the UE requests scheduling for the signaling in the uplink, allocates the uplink resource on the downlink, and transmits the uplink resource using the RRC message including the signaling, the scheduling (uplink) , The resource allocation (downlink), the RRC message transmission (uplink), and the time required for additional HARQ retransmission, and estimates the reception time at which the ENB receives the signaling.

As another example, if the terminal transmits the signaling using an L1 / L2 dedicated channel such as periodically available pre-allocated channel quality information (CQI) channel (from the measurement completion time 313 to the next (Time to the allocation time of the dedicated channel) and (L1 / L2 transmission time) to estimate the reception time at which the ENB receives the signaling. As another example, if the UE transmits the signaling using a random access channel (time from the measurement completion time 313 to the allocation time of the next random access channel), and And the time it takes for the signaling to be transmitted to the ENB) to estimate the reception time point at which the ENB will receive the signaling. The signaling reception time estimated by the terminal is denoted by reference numeral 321. The measurement completion time 313 and the estimated signaling reception time 321 may have a form such as a frame number indicating a system time.

The terminal calculates an effective gap remaining interval using the estimated signaling reception time point 321 and the gap ending time point 323. The effective gap remaining period is calculated as an example (gap end point 323) - (estimated signaling reception point 321).

The terminal compares the effective gap remaining period with the signal threshold value X that is signaled or hard-coded from the ENB, and if the effective gap residual period is greater than or equal to the comparison threshold period X, (RRC message, L1 / L2 dedicated channel, or RACH) to the ENB in a predetermined manner. On the other hand, if the effective gap remaining interval is less than or equal to the comparison threshold interval X, the terminal determines that it is not necessary to transmit the signaling indicating completion of the measurement before the end of the gap interval.

4 is a flowchart illustrating an operation of a terminal according to a preferred embodiment of the present invention.

Referring to FIG. 4, in step 401, the measurement of neighboring cells is completed before the allocated gap period ends. In step 403, the terminal estimates the reception time at which the ENB receives the signaling informing of "completion of the measurement before the end of the gap interval ". Estimation of the signaling reception time point depends on how the signaling is transmitted.

In step 405, the terminal calculates an effective gap remaining period using the estimated signaling reception time point and an already known gap ending time point. As an example, the effective gap remaining period is calculated as (gap end point) - (estimated signaling point in time). As another example, the effective gap remaining interval is calculated as (gap end point) - (signaling point transmission point) or (gap end point) - (measurement completion point). When the signaling transmission time point is used, the signaling transmission time point is estimated in step 403. When the measurement completion time point is used, step 403 is omitted.

In step 407, the terminal compares the valid gap remaining period with a pre-signaled or hard-coded comparison critical section X. If the effective gap remaining period is greater than or equal to the comparison threshold period X, the MS proceeds to step 411 and transmits to the ENB a signaling message informing the ENB that "measurement completion is completed before the end of the gap period" in a predetermined manner. Here, the comparison threshold section X may be signaled through system information that is signaled through a dedicated channel or broadcast in a cell. On the other hand, if the effective gap remaining period is less than or equal to the comparison threshold period X, the MS proceeds to step 413 and determines that the MS does not transmit the signaling indicating " completion of measurement before ending gap period ".

5 is a flowchart illustrating an operation of an ENB according to a preferred embodiment of the present invention. Here, the case where the comparison threshold section X is signaled through a dedicated channel assigned to the terminal is shown.

Referring to FIG. 5, in step 501, the ENB determines that it is necessary to allocate a gap pattern for a measurement to a terminal. In step 503, the ENB sets a comparison threshold section X value in consideration of the load status of the cell, the class or capability of the terminal, and transmits the comparison threshold section X to the terminal in step 505 do. As a modified embodiment, in step 503, the UE temporarily stops the communication with the serving cell and gap pattern information indicating gap intervals, which are time points for performing measurement on frequency bands other than the frequency band of the serving cell, is set And in step 505, the gap pattern information may be transmitted to the terminal.

6 is a block diagram illustrating an apparatus of a terminal according to a preferred embodiment of the present invention.

Referring to FIG. 6, the transmitter / receiver 601 receives gap pattern information indicating a position of a gap interval or a pilot channel signal for a comparison threshold section X or a measurement from the ENB. When the measurement is completed before the gap interval ends And transmits the corresponding signaling to the ENB. The gap pattern information and the comparison threshold section X are stored in the gap management / control section 603.

The gap management / control unit 603 changes the frequency band of the transmission / reception unit 601 according to the gap pattern information. For example, during the gap period indicated by the gap pattern information, the transmission / reception unit 601 is controlled to receive frequency bands of neighboring cells to be measured, which are not frequency bands of the serving cell. The measurement for the neighboring cells using the received signal during the gap period is performed in the measurement unit 605. If the measurement is completed in the neighboring cells in the measurement unit 605 before the end of the gap interval, the effective gap remaining interval calculation / determination unit 611 calculates the effective gap remaining interval as described above, / Control unit 603 with the calculated effective gap remaining period to control the measurement completion signaling generation unit 613. [

The measurement complete signaling generation unit 613 determines / determines generation of signaling completion completion signaling before completion of the gap interval, based on the comparison result of the effective gap remaining interval calculation / determination unit 611. [ Specifically, the measurement completion signaling generation unit 613 generates the signaling only when the effective gap remaining interval is equal to or greater than the comparison threshold interval X. [ The signaling is transmitted to the ENB through the transmission / reception unit 601 in a predetermined manner.

7 is a block diagram showing an apparatus of an ENB according to a preferred embodiment of the present invention.

Referring to FIG. 7, the comparison threshold interval setting unit 701 sets a value of a comparison threshold interval X to be compared with an effective gap remaining interval calculated in the terminal. The X value is set in consideration of a cell load state managed by the RRM 703, a terminal class managed by the terminal context management unit 705, terminal capability information, and the like. The comparison threshold section X is transmitted to the terminal through the transceiver 711.

While the present invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not limited to the disclosed embodiments, but is capable of various modifications within the scope of the invention. Therefore, the scope of the present invention should not be limited by the illustrated embodiments, but should be determined by the scope of the appended claims and equivalents thereof.

In the present invention that operates as described in detail above, the effects obtained by the representative ones of the disclosed inventions will be briefly described as follows.

The present invention minimizes the signaling overhead for notifying the ENB when the measurement of neighboring cells is completed before the end of the actual gap interval, thereby improving communication efficiency.

Claims (7)

A method of using a communication gap in a mobile communication system, Performing a measurement on frequency bands other than a serving frequency band during an allocated gap period; Calculating an effective gap remaining period until the gap interval is completed when the measurement is completed before the gap interval ends; Comparing the valid gap remaining period with a predetermined comparison threshold period before the gap period ends according to the valid gap remaining period; Determining if the effective gap remaining period is greater than or equal to the comparison threshold period and signaling that the measurement is completed; And transmitting the signaling according to the determination result, Wherein the effective gap remaining period is set considering at least one of a load state in a cell and a class and a capability of a terminal. delete 2. The method of claim 1, Coded to the terminal, or signaled to the terminal from the system. The method of claim 1, wherein the effective gap remaining period includes: (Gap end point) - (reception point of the signaling estimated by the terminal), (Gap end timing) - (transmission timing of the signaling), or (Gap end point) - (measurement completion point). 5. The method of claim 4, A time required for transmission of a radio resource control (RRC) message including the signaling, and a time required for additionally HARQ retransmission, or is estimated by summing up scheduling on the uplink, resource allocation on the downlink, The time from the completion of the measurement to the allocation time of the next dedicated channel and the transmission time of the L1 / L2 message including the signaling, The time from the completion of the measurement to the allocation time of the next random access channel and the time taken for the signaling to reach the system according to the random access procedure. A method of using a communication gap in a mobile communication system, Setting a comparison threshold interval value to be compared with an effective gap remaining interval estimated by the terminal when the terminal determines that allocation of a gap pattern for the measurement is required; And transmitting the comparison threshold value to the MS. 7. The method of claim 6, wherein the UE temporarily stops communication with the serving cell and sets gap pattern information indicating gap intervals that are time points for performing measurement on frequency bands other than the frequency band of the serving cell, The method of claim 1, further comprising the step of transmitting to the terminal.

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