KR101994235B1 - Method and device for performing uplink time alignment - Google Patents
Method and device for performing uplink time alignment Download PDFInfo
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- KR101994235B1 KR101994235B1 KR1020150093891A KR20150093891A KR101994235B1 KR 101994235 B1 KR101994235 B1 KR 101994235B1 KR 1020150093891 A KR1020150093891 A KR 1020150093891A KR 20150093891 A KR20150093891 A KR 20150093891A KR 101994235 B1 KR101994235 B1 KR 101994235B1
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- random access
- base station
- serving cell
- uplink
- access preamble
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- 238000000034 method Methods 0.000 title claims abstract description 63
- 230000004044 response Effects 0.000 claims description 49
- 230000003213 activating effect Effects 0.000 claims description 5
- 230000005540 biological transmission Effects 0.000 description 16
- 239000000969 carrier Substances 0.000 description 12
- 230000002776 aggregation Effects 0.000 description 8
- 238000004220 aggregation Methods 0.000 description 8
- 230000008859 change Effects 0.000 description 7
- 238000013468 resource allocation Methods 0.000 description 7
- 239000000470 constituent Substances 0.000 description 5
- 238000010586 diagram Methods 0.000 description 2
- 238000007726 management method Methods 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 230000004913 activation Effects 0.000 description 1
- 230000009849 deactivation Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000001228 spectrum Methods 0.000 description 1
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W56/00—Synchronisation arrangements
- H04W56/004—Synchronisation arrangements compensating for timing error of reception due to propagation delay
- H04W56/005—Synchronisation arrangements compensating for timing error of reception due to propagation delay compensating for timing error by adjustment in the receiver
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- H04W72/1294—
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W74/00—Wireless channel access
- H04W74/08—Non-scheduled access, e.g. ALOHA
- H04W74/0833—Random access procedures, e.g. with 4-step access
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Abstract
A method for performing uplink time synchronization of a UE according to various embodiments of the present invention includes: performing uplink granting for a serving cell in a sub-time forward group from a base station in a secondary timing advance group in an uplink asynchronous state; selecting a contention-based random access preamble when a physical downlink control channel including uplink grant information is received, and performing a random access procedure using the selected random access preamble . ≪ / RTI >
Description
The present invention relates to a method for performing uplink time synchronization in a multi-carrier system.
In a typical wireless communication system, although a bandwidth between an uplink and a downlink is set to be different from each other, only one carrier is mainly considered. In the 3GPP (3rd Generation Partnership Project) LTE (Long Term Evolution), the number of carriers constituting the uplink and the downlink is 1 based on a single carrier, and the bandwidths of the UL and the DL are generally symmetrical to be. In this single carrier system, random access is performed using one carrier. However, as a multi-carrier system has been recently introduced, random access can be implemented through a plurality of component carriers.
A multi-carrier system refers to a wireless communication system capable of supporting carrier aggregation. Carrier aggregation is a technique for efficiently using a fragmented small band so as to achieve the same effect as using a logically large band by bundling a plurality of physically non-continuous bands in the frequency domain.
In order for a terminal to access a network, a random access process is performed. The random access procedure may be classified into a contention based random access procedure and a noncontention based random access procedure.
The BS allocates a dedicated preamble for the serving cell of the sTAG when the secondary timing advance group (sTAG) requires uplink scheduling from the asynchronous state to the sTAG serving cell, and allocates a dedicated preamble for the allocated preamble And transmits a random access order including information to the terminal. The MS may adjust the sTAG uplink transmission timing by transmitting a dedicated preamble to the BS according to the random access command to perform a random access procedure.
The number of available dedicated preambles of the base station is specified in the specification, and the base station can allocate a dedicated preamble for the random access procedure of the UE even in an event such as handover or DL data resume. Therefore, in a base station in which a mobile station moves frequently, a dedicated preamble resource may be insufficient. In a base station, a dedicated preamble resource may be preferentially allocated for a procedure with a high priority.
If there is no allocable dedicated preamble for time alignment of the sTAG of the UE, the BS can not issue a random access instruction for time alignment of the sTAG and wait until the dedicated preamble can be allocated. Also, the UE can immediately recognize the uplink asynchronous time of the sTAG by a time alignment timer (TAT) expiration event, but the base station determines the uplink synchronization status based on the uplink signal quality of the sTAG serving cell It is recognized later than the terminal.
Accordingly, the terminal has to wait for a random access instruction of the sTAG transmitted from the base station even when the time alignment timer of the sTAG expires and the number of uplink transmission data is large. In addition, if there is no available dedicated preamble resource, the base station must wait until a dedicated preamble can be allocated even in a situation where there are many uplink transmission data of the UE.
It is another object of the present invention to provide a method for solving a delay problem which may occur in uplink time adjustment of a secondary serving cell in a multi-carrier aggregation system and enabling data distribution to a secondary serving cell without delay .
A method for performing uplink time synchronization of a UE according to various embodiments of the present invention includes: performing uplink granting for a serving cell in a sub-time forward group from a base station in a secondary timing advance group in an uplink asynchronous state; selecting a contention-based random access preamble when a physical downlink control channel including uplink grant information is received, and performing a random access procedure using the selected random access preamble Step < / RTI >
Wherein the step of performing the random access procedure comprises: transmitting the selected random access preamble to a base station through a serving cell of the sub-time forward group; transmitting a random access response to the random access preamble from a base station adjusting a time of an uplink of a serving cell of the sub-time forward group according to a timing advance command included in the random access response when the response is received, And activating a time alignment timer.
Wherein the step of performing the random access procedure comprises: transmitting Msg3 based on a temporary cell radio network temporary identifier (C-RNTI) included in the random access response and uplink grant information; When a contention resolution timer is activated and a physical downlink control channel to a C-RNTI including uplink grant information for the serving cell is received while the contention resolution timer is operating, Step < / RTI >
The method may further comprise changing a state of the sub-time forward group to an uplink asynchronous state when the time alignment timer of the sub-time forward group expires.
Wherein the step of selecting the random access preamble comprises the steps of: when a secondary timing advance group is in an uplink asynchronous state and a physical uplink grant information Upon receiving the physical downlink control channel, the contention-based random access preamble may be selected.
A method for performing uplink time synchronization of a UE according to various embodiments of the present invention includes: providing a serving cell of a sub-time forward group including a preamble index indicating that there is no dedicated preamble available from the base station; Selecting a contention-based random access preamble when a physical downlink control channel for the random access preamble is received, and performing a random access procedure using the selected random access preamble .
Wherein the random access procedure comprises: transmitting the selected random access preamble to a base station; receiving a random access response for the random access preamble from the base station, Adjusting the uplink time of a serving cell of the sub-time forward group according to a timing advance command and operating a time alignment timer of the serving cell. have.
Wherein the step of performing the random access procedure comprises: transmitting Msg3 based on a temporary cell radio network temporary identifier (C-RNTI) included in the random access response and uplink grant information; When a contention resolution timer is activated and a physical downlink control channel to a C-RNTI including uplink grant information for the serving cell is received while the contention resolution timer is operating, The method comprising the steps of:
A UE according to various embodiments of the present invention includes a communication unit for performing communication with a base station and a communication unit for performing uplink acknowledgment for a serving cell of a sub-time forward group from a base station in a secondary timing advance group in an uplink asynchronous state, a random access preamble is selected when a physical downlink control channel including uplink grant information is received and a random access procedure is performed using the selected random access preamble And a control unit.
Wherein the control unit controls the selected random access preamble to be transmitted to a base station through a serving cell of the sub time forward group and receives a random access response for the random access preamble from the base station Time adjusts the uplink time of the serving cell of the sub-time forward group according to a timing advance command included in the random access response.
The control unit controls to transmit Msg3 based on a temporary cell radio network temporary identifier (C-RNTI) included in the random access response and uplink grant information, and when the Msg3 is transmitted, When a contention resolution timer is activated and a physical downlink control channel to a C-RNTI including uplink grant information for the serving cell is received while the contention resolution timer is operating, .
Wherein the controller is configured to transmit a physical downlink control channel physical uplink grant information including uplink grant information for a serving cell of a sub-time forward group from a base station in a secondary timing advance group in an uplink asynchronous state, downlink control channel is received, the contention-based random access preamble may be selected.
A terminal according to various embodiments of the present invention includes a communication unit for performing communication with a base station of the present invention and a sub-time forward group including a preamble index indicating that there is no dedicated preamble available from the base station Based random access preamble when a physical downlink control channel for the serving cell of the serving cell is received and a random access procedure using the selected random access preamble can do.
Wherein the control unit controls the selected random access preamble to be transmitted to the base station and transmits a timing advance command included in the random access response when a random access response to the random access preamble is received from the base station, the time of the uplink of the serving cell of the sub-time forward group can be adjusted according to the command.
According to various embodiments of the present invention, it is possible to solve the delay problem that may occur in the uplink time adjustment of the secondary serving cell in the multi-carrier aggregation system, and to enable the data distribution to the secondary serving cell without delay.
1 shows a wireless communication system according to an embodiment of the present invention.
2 illustrates a protocol structure for supporting multi-carrier according to an embodiment of the present invention.
3 illustrates a frame structure for a multi-carrier operation according to an embodiment of the present invention.
4 is a flowchart illustrating a method of performing uplink synchronization according to an embodiment of the present invention.
5 is a flowchart illustrating an uplink synchronization performing method according to an embodiment of the present invention.
6 is a block diagram illustrating a configuration of a terminal and a base station according to various embodiments of the present invention.
Hereinafter, some embodiments will be described in detail with reference to exemplary drawings. It should be noted that, in adding reference numerals to the constituent elements of the drawings, the same constituent elements are denoted by the same reference symbols as possible even if they are shown in different drawings. In the following description of the embodiments 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 disclosure rather unclear.
In describing the components of the present specification, terms such as first, second, A, B, (a), and (b) may be used. These terms are intended to distinguish the constituent elements from other constituent elements, and the terms do not limit the nature, order or order of the constituent elements. When a component is described as being "connected", "coupled", or "connected" to another component, the component may be directly connected or connected to the other component, Quot; may be "connected," "coupled," or "connected. &Quot;
In addition, the present invention will be described with respect to a wireless communication network. The work performed in the wireless communication network may be performed in a process of controlling a network and transmitting data by a system (e.g., a base station) Work can be done at a terminal connected to the network.
1 shows a wireless communication system according to an embodiment of the present invention.
Referring to FIG. 1, the
A mobile station (MS) 100 may be fixed or mobile and may be a user equipment (UE), a mobileeterminal (MT), a user terminal (UT), a subscriber station (SS), a wireless device, a PDA a personal digital assistant, a wireless modem, a handheld device, and the like. The
The downlink means communication from the
A carrier aggregation (CA) supports a plurality of carriers and is also referred to as spectrum aggregation or bandwidth aggregation. The individual unit carriers tied by carrier aggregation are called component carriers (CCs). Each element carrier can be defined as a bandwidth and a center frequency. For example, if five elementary carriers are allocated as the granularity of a carrier unit having a bandwidth of 20 MHz, it can support a bandwidth of up to 100 MHz.
2 illustrates a protocol structure for supporting multi-carrier according to an embodiment of the present invention.
Referring to FIG. 2, a common Medium Access Control (MAC)
There are a plurality of physical control channels used in the
3 illustrates a frame structure for a multi-carrier operation according to an embodiment of the present invention.
Referring to FIG. 3, a frame is composed of 10 subframes. The subframe includes a plurality of OFDM symbols. Each carrier may have its own control channel (e.g., PDCCH). The multi-carriers may or may not be adjacent to each other. The terminal may support one or more carriers according to its capabilities.
Element carriers can be divided into Primary Component Carrier (PCC) and Secondary Component Carrier (SCC) depending on whether they are active or not. The primary carrier is always the active carrier, and the sub-carrier is the carrier that is activated / deactivated according to certain conditions. Activation means that the transmission or reception of traffic data is performed or is in a ready state. Deactivation means that transmission or reception of traffic data is impossible and measurement or transmission / reception of minimum information is possible. The terminal may use only one major carrier or use one or more sub-carrier with carrier. A terminal may be allocated a primary carrier and / or secondary carrier from a base station.
4 is a flowchart illustrating a method of performing uplink synchronization according to an embodiment of the present invention.
Referring to FIG. 4, when the time alignment timer of the secondary timing advance group (sTAG) has expired (S401), the
The
If the PDCCH including the uplink grant information is received from the
When the random access preamble is received, the
When the random access response is received, the
When the random access response is received, the terminal 100 can transmit Msg3 (S419). According to one embodiment, the terminal 100 may transmit Msg3 based on the temporary C-RNTI and uplink grant information included in the random access response. After transmitting the Msg3, the
The
When the PDCCH to the C-RNTI including the uplink grant information for the serving cell that transmitted the random access preamble is received while the contention resolution timer is operating, the
According to the above-described embodiment, even if the
5 is a flowchart illustrating an uplink synchronization performing method according to an embodiment of the present invention.
Referring to FIG. 5, the
An uplink scheduling request may be generated from the
The
If the PDCCH including the preamble index indicating that there is no dedicated preamble index available from the
When the random access preamble is received, the
When the random access response is received, the
When the random access response is received, the terminal 100 can transmit Msg3 (S519). According to one embodiment, the terminal 100 may transmit Msg3 based on the temporary C-RNTI and uplink grant information included in the random access response. After transmitting the Msg3, the
The
When the PDCCH to the C-RNTI including the uplink grant information for the serving cell that transmitted the random access preamble is received while the contention resolution timer is operating, the
According to the above-described embodiment, the
6 is a block diagram illustrating a configuration of a terminal and a base station according to various embodiments of the present invention.
Referring to FIG. 6, the
The
The
The
According to one embodiment, the
Referring to FIG. 6, the
The
The
According to one embodiment, the
According to one embodiment, when an uplink scheduling request is generated from the sTAG of the
While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention.
100: terminal 200: base station
Claims (14)
Recognizing that the time alignment timer of the secondary timing advance group has expired;
When a physical downlink control channel including uplink grant information for a serving cell of a sub-time forward group is received from a base station, a dedicated random access preamble for an uncontroversial random access from the base station Selecting one random access preamble among the contention-based random access preamble without waiting for reception;
And proceeding with a random access procedure using the selected random access preamble.
Wherein the step of performing the random access procedure comprises:
Transmitting the selected random access preamble to a base station through a serving cell of the sub-time forward group;
When a random access response for the selected random access preamble is received from a base station, a random access response for the selected random access preamble is received from the serving cell of the sub-time forward group according to a timing advance command included in the random access response. Adjusting an uplink time; And
And activating a time alignment timer of the serving cell.
Wherein the step of performing the random access procedure comprises:
Transmitting Msg3 based on a temporary cell radio network temporary identifier (C-RNTI) included in the random access response and uplink grant information;
Activating a contention resolution timer for the serving cell; And
And determining that the contention resolution procedure is successful if the physical downlink control channel to the C-RNTI including the uplink grant information for the serving cell is received while the contention resolution timer is operating.
And changing the state of the sub-time forward group to an uplink asynchronous state when the time alignment timer of the sub-time forward group expires.
When a physical downlink control channel for a serving cell of a sub-time forward group including a preamble index indicating that there is no dedicated preamble available from the base station is received, Selecting a random access preamble;
And performing a random access procedure using the selected random access preamble.
Wherein the step of performing the random access procedure comprises:
Transmitting the selected random access preamble to a base station;
When a random access response for the selected random access preamble is received from a base station, a random access response for the selected random access preamble is received from the serving cell of the sub-time forward group according to a timing advance command included in the random access response. Adjusting an uplink time; And
And activating a time alignment timer of the serving cell.
Wherein the step of performing the random access procedure comprises:
Transmitting Msg3 based on a temporary cell radio network temporary identifier (C-RNTI) included in the random access response and uplink grant information;
Activating a contention resolution timer for the serving cell; And
And determining that the contention resolution procedure is successful if a physical downlink control channel including uplink grant information for the serving cell is received while the contention resolution timer is operating.
Time up timer of the secondary timing advance group has expired and the uplink grant information for uplink grant information for the serving cell of the sub- Upon receiving a physical downlink control channel, a random access preamble is selected from a contention-based random access preamble without waiting for reception of a dedicated random access preamble for a contention-free random access from the base station. And a random access procedure is performed using the selected random access preamble.
Wherein,
Wherein the control unit controls the selected random access preamble to be transmitted to a base station through a serving cell of the sub-time forward group, and when a random access response for the selected random access preamble is received from the base station, And adjusts the uplink time of the serving cell of the sub-time forward group according to a timing advance command included in the access response.
Wherein,
(MCSG3) based on a temporary C-RNTI (Temporary Cell Radio Network Temporary Identifier) included in the random access response and uplink grant information. When the Msg3 is transmitted, a contention resolution timer, and determines that the contention resolution procedure is successful when the physical downlink control channel to the C-RNTI including the uplink grant information for the serving cell is received while the contention resolution timer is operating.
When a physical downlink control channel for a serving cell of a sub-time forward group including a preamble index indicating that there is no dedicated preamble available from the base station is received, And a controller for selecting a random access preamble and performing a random access procedure using the selected random access preamble.
Wherein,
Wherein the control unit controls to transmit the selected random access preamble to the base station and transmits a random access response to the selected random access preamble from the base station to a timing advance command included in the random access response And adjusts uplink time of a serving cell of the sub-time forward group according to the uplink time.
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JP6977066B2 (en) | 2017-08-11 | 2021-12-08 | エルジー エレクトロニクス インコーポレイティドLg Electronics Inc. | A method for adjusting the uplink timing in a wireless communication system, and a device for this purpose. |
KR102460782B1 (en) | 2018-01-10 | 2022-10-31 | 삼성전자 주식회사 | The method for efficient system information request in the next generation wireless communication systems |
CN110536470B (en) * | 2019-01-21 | 2024-05-07 | 中兴通讯股份有限公司 | Timing advance TA processing and indication information sending method and device |
KR102482490B1 (en) * | 2020-11-06 | 2022-12-28 | 한국전자통신연구원 | Method and apparatus for acquiring and maintaining synchronization in communication systems |
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US20130114574A1 (en) | 2011-11-04 | 2013-05-09 | Samsung Electronics Co., Ltd. | Apparatus and method for defining timing reference for secondary cells in a secondary timing advance group |
US20130258958A1 (en) * | 2012-04-01 | 2013-10-03 | Esmael Hejazi Dinan | Timing Advance Timer Configuration in a Wireless Device and a Base Station |
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KR20130032178A (en) * | 2011-09-22 | 2013-04-01 | 주식회사 팬택 | Apparatus and method for performing random access procedure in multiple component carrier system |
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US20130114574A1 (en) | 2011-11-04 | 2013-05-09 | Samsung Electronics Co., Ltd. | Apparatus and method for defining timing reference for secondary cells in a secondary timing advance group |
US20130258958A1 (en) * | 2012-04-01 | 2013-10-03 | Esmael Hejazi Dinan | Timing Advance Timer Configuration in a Wireless Device and a Base Station |
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