CN107277939B

CN107277939B - Method for controlling UE state transition

Info

Publication number: CN107277939B
Application number: CN201610213129.XA
Authority: CN
Inventors: 王淑坤; 许瑞锋
Original assignee: Beijing Xinwei Telecom Technology Inc
Current assignee: Beijing Xinwei Telecom Technology Inc
Priority date: 2016-04-07
Filing date: 2016-04-07
Publication date: 2020-02-14
Anticipated expiration: 2036-04-07
Also published as: CN107277939A

Abstract

The invention provides a method for controlling UE state transition, which comprises the following steps: when the UE is in an RRC _ IDEL state, if service requirements exist, the UE enters an RRC _ CONNECTED state; when the UE is in the RRC _ CONNECTED state, if the time length of neither uplink data transmission nor downlink data reception exceeds a specified time length one, the UE enters the RRC _ LIGHT _ CONNECTED state; when the UE is in an RRC _ LIGHT _ CONNECTED state, if uplink data are transmitted or downlink data are received, the UE enters the RRC _ CONNECTED state; and if the time length of neither uplink data transmission nor downlink data reception exceeds the specified time length two, entering into an RRC _ IDLE state.

Description

Method for controlling UE state transition

Technical Field

The invention relates to the field of communication, in particular to a method for controlling UE state transition.

Background

With the development of wireless mobile communication technology, people put higher and higher demands on high speed, low delay and low cost. The lte (long Term evolution) project has been generated in such a context, pursuing higher peak rates and shorter transmission delays.

The main performance goals of the LTE project include: the peak rate of 100Mbps downlink and 50Mbps uplink can be provided in the 20MHz frequency spectrum bandwidth, the performance of cell edge users is improved, and the cell capacity is improved; the system delay is reduced, the one-way transmission delay inside the user plane is lower than 5ms, the transition time of the control plane from the sleep state to the active state is lower than 50ms, and the transition time from the residence state to the active state is less than 100 ms; cell coverage of 100Km radius is supported; the method can provide access service of more than 100kbps for 350Km/h high-speed mobile users; supporting paired or unpaired spectrum; supporting variable bandwidth, up to 20M bandwidth.

The LTE adopts a single-layer flat full IP network structure of an access network formed by NodeB on the network architecture, and the structure is favorable for simplifying the network and reducing the delay, thereby realizing the requirements of low time delay, low complexity and low cost. LTE reduces RNC nodes compared to traditional 3GPP access networks. The eNB not only has the functions of the original NodeB, but also can complete most of the functions of the original RNC, including a physical layer, an MAC layer, an RRC, scheduling, access control, bearer control, access mobility management, and the like. Node bs and Node bs are directly interconnected by using a Mesh (Mesh) method, which is also a significant modification of the original UTRAN structure. Approaching the typical IP broadband network architecture.

In physical layer technology, LTE adopts advanced radio transmission technologies such as ofdm (orthogonal Frequency division multiplexing), mimo (Multiple Input Multiple output), and channel-based link adaptive scheduling and interference coordination technologies. Further improving the speed of the user and the throughput of the cell, and improving the performance of the edge of the cell.

With the development of wireless communication technology and the further desire for low latency and high rate, new technologies are introduced at the LTE-a stage, such as carrier aggregation ca (carrier aggregation), Relay technology, coordinated multipoint (comp) and Enhanced Inter-Cell Interference (eICIC) wireless technologies.

In order to further increase LTE capacity, LTE proposes to use unlicensed spectrum to expand LTE capacity, such as LAA (Licensed-Assisted Access), lwa (LTE WLAN aggregation), lwip (LTE WLAN radio level Integration with IPsec tunnel), and other technologies.

Currently, in LTE technology evolution, the internet of things technology and MTC technology are rapidly developed, and future network deployment is faced with the situation of high-density network node deployment and massive terminal connection, so that it is a challenge to the signaling load on the network side, such as signaling of RRC interface and signaling of S1 interface, faced with such a huge number of terminal connections.

In order to reduce signaling load on the air interface and the network side and improve network performance, a new UE connection state is proposed in LTE R14, which is named RRC _ lighting connection and is between the original RRC _ IDLE and RRC _ CONNECTED states, so that signaling load on the air interface and the network side can be effectively reduced. However, an effective method for controlling the state transition between the CONNECTED state and the RRC _ IDLE and RRC _ CONNECTED states has not been proposed yet.

Disclosure of Invention

The invention provides a new method for converting a UE connection state RRC _ LightConnection and original RRC _ IDLE and RRC _ CONNECTED states, which comprises the following steps:

when the UE is in an RRC _ IDEL state, if service requirements exist, the UE enters an RRC _ CONNECTED state; when the UE is in the RRC _ CONNECTED state, if the time length of neither uplink data transmission nor downlink data reception exceeds a specified time length one, the UE enters the RRC _ LIGHT _ CONNECTED state; when the UE is in the RRC _ LIGHT _ CONNECTED state, if uplink data are transmitted or downlink data are received, the UE enters the RRC _ CONNECTED state, and if the duration of neither uplink data transmission nor downlink data reception exceeds a specified duration two, the UE enters the RRC _ IDLE state.

Preferably, the method may be implemented as follows:

when the UE is in the RRC _ CONNECTED state, if the time length of neither uplink data transmission nor downlink data reception exceeds a specified time length one, the eNB issues a connection state switching command to indicate that the UE enters the RRC _ LIGHT _ CONNECTED state from the RRC _ CONNECTED state, a specified region is configured for the UE and is sent to the MME for storage, when the UE is in the RRC _ LIGHT _ CONNECTED state in the specified region, measurement reporting and mobility management are not needed, the eNB issuing the connection state switching command stores the context of the UE, and meanwhile, the UE also stores the UE context before entering the RRC _ LIGHT _ CONNECTED state;

when the UE is in the RRC _ light connected state, if there is uplink data transmission, the following operation is performed: UE randomly accesses and informs an E-CGI of an original cell to a target cell, an eNB where the target cell is located obtains a previous context of the UE according to the E-CGI of the original cell, a C-RNTI and a Short MAC-I allocated by the original cell, negotiates a security key, performs GTP tunnel switching transfer on an S1 interface with an MME, then sends security activation information () and an RRC recovery command to the UE, and then the UE enters an RRC _ CONNECTED state to normally perform data service; if downlink data are received, the MME triggers a paging message, sends the paging message to a designated eNB according to the designated area, carries a target cell list for sending the paging message in the paging message, and performs the first operation after the UE receives the paging message; and if the time length of neither uplink data transmission nor downlink data reception exceeds the specified time length two, the eNB requests the MME to release the UE, and after the eNB obtains the response of the MME to release the UE, the eNB issues a connection state switching command to indicate that the UE enters an RRC _ IDEL state.

Preferably, the method further comprises: when the UE is in the RRC _ LIGHT _ TCONNECTED state, if the UE is to move out of the specified area, the UE randomly accesses to a cell in the specified area, and notifies the E-CGI of the original cell, the C-RNTI allocated by the original cell and the E-CGI of a target cell to the cell which is randomly accessed, and simultaneously indicates that the purpose of random access is specified area update, an eNB where the cell which is randomly accessed is configured with a new specified area for the UE, and the UE keeps the RRC _ LIGHT _ TCONNECTED state.

Preferably, in the above method, the manner for the eNB to issue the connection state transition command may be in a PDCCH order form, a MAC CE form, or an RRC signaling. The designated area may be issued in an rrcconnectionreconfiguration message in the RRC connection establishment procedure, or may be issued in a connection state transition command. The security activation information includes: a security parameter NCC (Next Hop Chaining Counter) and a corresponding security algorithm.

The invention determines the conversion relation and the triggering mechanism between the RRC _ LightConnection state and the RRC _ IDLE and RRC _ CONNECTED states, can control the state conversion between the RRC _ LightConnection state and the RRC _ IDLE and RRC _ CONNECTED states, and meets the service requirement.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the invention without limiting the invention. In the drawings:

FIG. 1 is a diagram of a transition constraint relationship between states in an embodiment of the present invention;

fig. 2 is a flowchart of entering an RRC _ light connected state according to an embodiment of the present invention;

fig. 3 is a flowchart illustrating that uplink service data is transmitted when the UE is in an RRC _ light connected state according to the embodiment of the present invention;

fig. 4 is a flowchart illustrating that downlink service data is received when the UE is in an RRC _ light connected state according to the embodiment of the present invention;

fig. 5 is a flowchart of UE moving out of a designated area when the UE is in RRC _ light connected state according to an embodiment of the present invention;

fig. 6 is a flowchart illustrating the UE entering the RRC _ idle state from the RRC _ light connected state according to an embodiment of the present invention.

Detailed Description

It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict. The present invention will be described in detail below with reference to the embodiments with reference to the attached drawings.

The transformation restriction relationship between RRC _ LightConnection and RRC _ IDLE and RRC _ CONNECTED states of the present invention is shown in fig. 1, and RRC _ LIGHTCONNECTED is not used in a scenario of crossing MME and S-GW. In fig. 1, when the UE is in the RRC _ IDEL state, if there is a traffic demand, the UE enters the RRC _ CONNECTED state. When the UE is in the RRC _ CONNECTED state, if the time length of neither uplink data transmission nor downlink data reception exceeds the specified time length one, the UE enters the RRC _ LIGHT _ CONNECTED state. When the UE is in an RRC _ LIGHT _ CONNECTED state, if uplink data are transmitted or downlink data are received, the UE enters the RRC _ CONNECTED state; and if the time length of neither uplink data transmission nor downlink data reception exceeds the specified time length two, entering into an RRC _ IDLE state.

The following embodiments will explain various state transition scenarios of the UE in detail.

As shown in fig. 2, when the UE is in the RRC _ IDEL state, if there is a service requirement, the UE performs a random access procedure and establishes an RRC connection with the eNB, the UE enters an RRC _ CONNECTED state, and the eNB determines to change the state of the UE from RRC _ CONNECTED to RRC _ light CONNECTED according to a service condition, for example, neither uplink service data is transmitted nor downlink service data is received for a time length exceeding a time length of a specified timer T1. The mode of issuing the command can be in a PDCCH order form, a MAC CE form or RRC signaling. Meanwhile, the eNB configures an E-CGI list or a cell ID list or an eNB ID list for the UE, and when the UE is in an RRC _ LIGHTCONNECTED state in the area, measurement and reporting are not needed, and mobility management is not needed. The E-CGI list, cell ID list, or eNB ID list may be issued in an RRC Connection Reconfiguration message in the RRC Connection establishment process, or may be issued in a UE Connection state transition command. The eNB issuing the UE connection state transition command may be responsible for storing the context of the UE. At the same time, the UE itself will also store the UE context before entering the RRC _ light connected state. When the eNB sends the UE connection state transition command, the configured E-CGI list, cell ID list, or eNB ID list is sent to the MME for storage.

As shown in fig. 3, when the UE is in the RRC _ light connected state, if there is uplink service data to be transmitted, the UE acquires system broadcast information of a current cell, performs a contention random access procedure, and carries the C-RNTI in the MSG3, the E-CGI, short MAC-I, and an uplink data transmission request indication of the cell where the UE is located before the RRC _ light connected state, where the four messages may all include one MAC CE (MAC control element) and may also use one MAC CE respectively. And the eNB in which the target cell is positioned acquires the previous context of the UE according to the E-CGI of the original cell, negotiates a security key and simultaneously performs switching transfer of a GTP tunnel on an S1 interface with the MME. And then, transmitting an MSG4 message to the UE, wherein the MSG4 message carries security activation information and an RRC recovery command thereof. The UE then enters the RRC _ CONNECTED state to enable normal data traffic. The security activation information includes: a security parameter NCC (Next Hop Chaining Counter) and a corresponding selected security algorithm.

As shown in fig. 4, when the UE is in the RRC _ light connected state, if downlink data is received, the MME triggers a paging message and sends the paging message to a designated eNB according to the E-CGI list, the cell ID list, or the eNB ID list, and if a cell list (cell list) is configured, the MME also sends the cell list to a target eNB to assist the eNB to send the paging message in a specific cell. After receiving the paging message, the UE performs a contention random access process, and carries C-RNTI and E-CGI, short MAC-I of a cell where the RRC _ LIGHT _ ONNECTED state is located and a downlink data receiving request indication in the MSG 3. And the eNB in which the target cell is positioned acquires the previous context of the UE according to the E-CGI of the original cell, negotiates a security key and simultaneously performs switching transfer of a GTP tunnel on an S1 interface with the MME. And then, transmitting an MSG4 message to the UE, wherein the MSG4 message carries security activation information and an RRC recovery command thereof. The UE then enters the RRC _ CONNECTED state to enable normal data traffic. The security activation information includes: a security parameter NCC and a corresponding selected security algorithm.

As shown in fig. 5, when the UE is in the RRC _ light connected state, the UE moves and is about to move out of the E-CGI list, the cell ID list, or the eNB ID list, before moving to the target cell, the UE performs a contention random access procedure to randomly access to the cell in the E-CGI list, the cell ID list, or the eNB ID list, and carries the E-CGI of the cell where the UE is located before the RRC _ light connected state in the MSG3, the C-RNTI allocated by the original cell, the E-CGI of the target cell, and a cell list update indication. The eNB in which the cell with random access is located configures a new designated area for the UE, that is, the MSG4 message carries new E-CGI list or cell ID list or eNB ID list information, and the UE still maintains the RRC _ light connected state.

As shown in fig. 6, when the UE is in the RRC _ light connected state, the eNB sending the UE connection state switching command starts a timer T2 after sending the connection state switching command, if T2 exceeds, the eNB sends an S1 signaling to request the MME to release the UE and delete the stored context of the UE, the MME sends a paging message to indicate that the eNB enters the RRC-IDLE state, and after the eNB receives a response from the MME to release the UE, the eNB sends the connection state switching command to indicate that the UE enters the IDLE state.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for controlling UE state transition, the method comprising:

when the UE is in an RRC _ IDEL state, if service requirements exist, the UE enters an RRC _ CONNECTED state;

when the UE is in the RRC _ CONNECTED state, if the time length of neither uplink data transmission nor downlink data reception exceeds a specified time length one, the UE enters the RRC _ LIGHT _ CONNECTED state, a specified region is configured for the UE and is sent to the MME for storage, measurement reporting and mobility management are not needed when the UE is in the RRC _ LIGHT _ CONNECTED state in the specified region, the eNB sending a connection state conversion command stores the context of the UE, and the UE also stores the UE context before entering the RRC _ LIGHT _ CONNECTED state;

when the UE is in the RRC _ light CONNECTED state, if there is uplink data transmission or downlink data reception, the UE enters the RRC _ CONNECTED state, and if the duration of neither uplink data transmission nor downlink data reception exceeds a specified duration two, the UE enters the RRC _ IDLE state, specifically:

if the uplink data is sent, the following operation is performed: UE randomly accesses and informs an E-CGI of an original cell to a target cell, an eNB where the target cell is located obtains a previous context of the UE according to the E-CGI of the original cell, a C-RNTI and a Short MAC-I distributed by the original cell, negotiates a security key, performs GTP tunnel switching transfer on an S1 interface between the eNB and an MME, then sends security activation information and an RRC recovery command to the UE, and the UE then enters an RRC _ CONNECTED state to normally perform data service;

if downlink data are received, the MME triggers a paging message, sends the paging message to a designated eNB according to the designated area, carries a target cell list for sending the paging message in the paging message, and performs the first operation after the UE receives the paging message;

and if the time length of neither uplink data transmission nor downlink data reception exceeds the specified time length two, the eNB requests the MME to release the UE, and after the eNB obtains the response of the MME to release the UE, the eNB issues a connection state switching command to indicate that the UE enters an RRC _ IDEL state.

2. The method of claim 1, further comprising:

when the UE is in the RRC _ LIGHT _ TCONNECTED state, if the UE is to move out of the specified area, the UE randomly accesses to a cell in the specified area, and notifies the E-CGI of the original cell, the C-RNTI allocated by the original cell and the E-CGI of a target cell to the cell which is randomly accessed, and simultaneously indicates that the purpose of random access is specified area update, an eNB where the cell which is randomly accessed is configured with a new specified area for the UE, and the UE keeps the RRC _ LIGHT _ TCONNECTED state.

3. The method of claim 2, wherein:

the mode of the eNB issuing the connection state transition command is in a PDCCH order form, or a MAC CE form, or RRC signaling.

4. The method of claim 2, wherein:

the designated area is issued in an RRC Connection Reconfiguration message in an RRC Connection establishment procedure, or issued in a Connection state transition command.

5. The method of claim 2, wherein:

the security activation information includes: a next hop chain count security parameter and a corresponding security algorithm.