Background
The long term evolution system (LTE, long Term Evolution) in the prior art is mainly composed of three devices: a User Equipment (UE), a Core Network (CN), and a base station (eNB, enhanced Node B), wherein a Mobility management entity (MME, mobility MANAGEMENT ENTITY) in the Core Network is mainly responsible for signaling transmission, and a service gateway (SGW, serving GetWay) is mainly responsible for data transmission. The interface between the UE and the eNB is Uu, the interface between the eNB and the core network is S1, and as shown in fig. 1, the interface is a structure diagram of LTE.
And the protocol architecture of the UE, eNB and MME is shown in fig. 2. For UEs, the protocol layers RRC (Radio Resource Control ), PDCP (PACKET DATA Convergence Protocol, packet data convergence protocol), RLC (Radio Link Control, radio link layer control), MAC (Medium Access Control, media Access control) and PHY (PHYSICAL LAYER ) belong to the AS (Access Stratum) layer, while the higher layers of the AS layer are NAS (Non Access Stratum, non-intervening layer) layers.
According to the current protocol, the UE is to communicate with the eNB, and first to access the eNB, i.e. initiate a random access procedure. As shown in fig. 3, the random access procedure includes four steps, namely:
Step 1: the UE acquires available lead sequence codes for random access and time-frequency positions for sending the lead sequences through system information or RRC signaling, randomly selects the lead sequences and the time-frequency positions for sending the lead sequences in available resources, and sends the lead sequences and the time-frequency positions for sending the lead sequences to the eNB;
Step 2: the eNB deduces RA-RNTI possibly adopted by the UE through the time-frequency position adopted by the random access preamble sequence, decodes the preamble sequence by the RA-RNTI, and replies a random access response to the UE after the eNB successfully decodes the preamble sequence, wherein the response carries information such as uplink authorization and the like;
Step 3: the UE sends RRC establishment request information on the uplink authorized resources;
Step 4: and the eNB analyzes the uplink data on the uplink authorized resources, confirms the UE, solves the conflict, and sends a competition resolution identification to the UE.
Subsequently, the UE enters a connected state and then transmits/receives data.
However, this procedure requires at least four steps with long delay, and in order to simplify the steps, it is proposed that in the inactive state, the UE transmits/receives data, as shown in fig. 4, including the steps of:
Step 1: the UE sends a preamble sequence to the eNB;
Step 2: after the eNB successfully decodes the preamble sequence, replying a random access response to the UE, wherein the response carries information such as uplink authorization and the like;
step 3: the UE transmits RRC message and carries uplink data on the uplink authorized resource, or transmits uplink data and carries information such as the identification of the UE;
Step 4: and the eNB analyzes the uplink data on the uplink authorized resources, confirms the UE, solves the conflict, and sends a competition resolution identification to the UE.
It can be seen that this method of transmitting data in the inactive state is less time-delayed and more flexible than the method of transmitting data in the active state.
In the active state, to ensure the continuity of transmission, the UE needs to monitor the state of the radio link and if a radio link failure occurs, to recover in time. Similar to the active state, the UE may also experience a problem of poor radio quality when transmitting data in the inactive state. However, unlike the active state, the inactive state does not require timely restoration of the wireless link, but at the same time requires transmission of data to the network, which can result in data transmission failure.
Therefore, how to monitor the states of the wireless links in the inactive state and the light connection state, and ensure the normal transmission of data becomes the technical problem to be solved by the invention.
Disclosure of Invention
The present invention has been made in view of the above problems, and provides a radio link monitoring method and a user equipment that solve the above problems.
According to one aspect of the present invention, there is provided a radio link monitoring method comprising:
When User Equipment (UE) is in a preset state, detecting the state of a wireless link of the UE according to the data transmission condition of a user plane; wherein, the preset state refers to a state that an interface between the UE and the base station is disconnected and the base station and the core network keep the connection of the UE;
And when detecting that the radio link of the UE fails, performing radio link repair.
Optionally, the detecting the state of the radio link of the UE according to the data transmission situation of the user plane includes one or more of the following ways:
detecting whether the number of times of sending the preamble by the UE reaches a set first threshold, and judging that the radio link state of the UE is radio link failure when the number of times of sending the preamble reaches the set first threshold.
Detecting whether the retransmission times of the RLC PDU sent by the UE reach a set second threshold value, and judging that the radio link state of the UE is radio link failure when the retransmission times reach the set second threshold value;
And determining the number of times that the retransmission times of the hybrid automatic repeat request HARQ continuously reach a set threshold value, detecting whether the number of times reaches a set third threshold value, and judging that the radio link state of the UE is radio link failure when the number of times reaches the set third threshold value.
Optionally, the third threshold is threshold information configured to the UE by the base station through a broadcast or radio resource control RRC message.
Optionally, the performing radio link repair includes: initiate an application to resume RRC connection or initiate cell reselection.
Optionally, when an application for recovering the RRC connection is initiated, the application message carries indication information that the UE is in a preset state or carries cause information that data failure occurs in the preset state;
The initiating cell reselection further comprises: the cell priority of the current cell is turned down.
Optionally, the method further comprises:
And under the preset state, if the UE reselects a new cell due to movement, resetting the MAC, and resetting the retransmission times of the RLC PDU sent by the UE which is recorded currently.
According to another aspect of the present invention, there is provided a user equipment comprising:
the link detection module is used for detecting the state of the wireless link of the user equipment according to the data transmission condition of the user plane when the user equipment is in a preset state; wherein, the preset state refers to a state that an interface between the user equipment and the base station is disconnected and the base station and the core network keep the connection of the user equipment;
And the link repairing module is used for repairing the wireless link when the link detection module detects the wireless link failure of the user equipment.
Optionally, the link detection module detects the state of the radio link of the UE in one or more of the following manners:
detecting whether the number of times of sending the preamble by the UE reaches a set first threshold, and judging that the radio link state of the UE is radio link failure when the number of times of sending the preamble reaches the set first threshold.
Detecting whether the retransmission times of the RLC PDU sent by the UE reach a set second threshold value, and judging that the radio link state of the UE is radio link failure when the retransmission times reach the set second threshold value;
And determining the number of times that the retransmission times of the hybrid automatic repeat request HARQ continuously reach a set threshold value, detecting whether the number of times reaches a set third threshold value, and judging that the radio link state of the UE is radio link failure when the number of times reaches the set third threshold value.
Optionally, the third threshold is threshold information configured to the UE by the base station through a broadcast or radio resource control RRC message.
Optionally, the link repair module is specifically configured to initiate an application for recovering RRC connection or initiate cell reselection when the link detection module detects that the radio link of the user equipment fails.
Optionally, the link repair module is further configured to, when an application for recovering RRC connection is initiated, carry, in an application message, indication information that the UE is in a preset state or carry cause information that data failure occurs in the preset state; or when initiating cell reselection, the cell priority of the current cell is turned down.
Optionally, the user equipment further includes:
And the processing module is used for resetting the MAC and clearing the retransmission times of the RLC PDU sent by the UE which is currently recorded when the user equipment is in a preset state and the new cell is reselected due to movement.
The invention has the following beneficial effects:
The method and the user equipment can detect the state of the wireless link of the user equipment through the data transmission condition of the user plane when the user equipment is in a state of being disconnected with the interface of the base station and the core network keep the connection of the UE, and carry out wireless link restoration when the wireless link failure of the user equipment is detected, thereby being convenient for adapting to the mobility of the UE in an inactive state, reducing the time delay of data transmission and well solving the problem that the wireless link in the inactive state cannot be monitored and further influencing the data output in the prior art.
The foregoing description is only an overview of the present invention, and is intended to be implemented in accordance with the teachings of the present invention in order that the same may be more clearly understood and to make the same and other objects, features and advantages of the present invention more readily apparent.
Detailed Description
Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.
The embodiment of the invention provides a wireless link monitoring method and user equipment, which are used for detecting the state of a wireless link of UE according to the data transmission condition of a user plane when the UE is in a preset state (including but not limited to a non-activated state and a light connection state), and carrying out wireless link repair when the wireless link of the UE is detected to be failed. Therefore, the method and the user equipment in the embodiment of the invention can monitor the wireless link state of the user equipment in the preset state, and can repair the link in time when the wireless link failure is detected, so that the method and the user equipment are convenient for adapting to the mobility of the UE in the inactive state, and can reduce the time delay of data transmission. The implementation of the invention is described in detail below by means of several specific examples.
In a first embodiment of the present invention, there is provided a radio link monitoring method, as shown in fig. 5, including the steps of:
Step S501, when the UE is in a preset state, detecting whether the number of times of sending the preamble by the UE reaches a set first threshold, and when the number of times of sending the preamble reaches the set first threshold, determining that the radio link state of the UE is a radio link failure;
In the embodiment of the invention, the preset state refers to a state that an interface between the UE and the base station is disconnected and the base station and the core network keep the connection of the UE.
Further, in a specific embodiment of the present invention, detecting whether the number of times the UE transmits the preamble reaches a set first threshold value specifically includes:
the UE detects whether the number of times of sending the preamble reaches a set first threshold value through the MAC layer, and when the number of times of sending the preamble reaches the set first threshold value, the MAC layer indicates that the random access process is problematic to the RRC layer, and the RRC layer considers that the radio link of the UE fails.
In step S502, when a radio link failure of the UE is detected, a radio link repair is performed.
In the embodiment of the present invention, the manner of performing the radio link repair includes, but is not limited to:
mode one: initiating an application for recovering the RRC connection;
Optionally, in this embodiment, the application message for initiating the RRC connection restoration carries UE status indication information (e.g., the UE is in a preset state) or carries reestablishment reason information (e.g., the UE fails to send data in the preset state).
In this embodiment, the application message may be RRC Connection Reestablishment Request, RRC Connection Resume Request or a new message.
After receiving the application message, the base station can determine that the UE has failed in the radio link in the preset state, find the base station storing the UE context according to the UE identification information carried in the message, and then obtain the context information of the UE, and establish RRC connection for the UE. If no context information is found for the UE, the base station will re-establish the RRC connection for the UE and update the configuration of the UE.
Mode two: cell reselection is initiated. Specifically, when cell reselection is initiated, in order to avoid reselecting the current cell, the cell priority of the current cell is also lowered.
If the UE reselects a cell and the cell can support the data transmission in the preset state, the UE continues to execute the data transmission in the preset state in the cell.
In summary, in the method of the embodiment of the present invention, when the UE is in a state of being disconnected from the interface of the base station and the core network keep the connection of the UE, the state of the radio link of the UE may be detected by the transmission condition of the preamble, and when the radio link failure of the UE is detected, the radio link repair is performed, so as to not only adapt to the mobility of the UE in the inactive state, but also reduce the delay of data transmission, and well solve the problem in the prior art that the radio link in the inactive state cannot be monitored, and thus the data output is affected.
In a second embodiment of the present invention, there is provided a radio link monitoring method, as shown in fig. 6, including the steps of:
step S601, when the UE is in a preset state, detecting whether the retransmission times of the RLC PDU sent by the UE reach a set second threshold value, and when the retransmission times reach the set second threshold value, judging that the radio link state of the UE is a radio link failure;
In the embodiment of the invention, the preset state refers to a state that an interface between the UE and the base station is disconnected and the base station and the core network keep the connection of the UE.
Further, in a specific embodiment of the present invention, detecting whether the number of retransmissions of the RLC PDU sent by the UE reaches a set second threshold specifically includes:
The UE detects whether the sent RLC PDU reaches the maximum retransmission times through the RLC layer, and when the RLC layer reaches the maximum retransmission times, the RLC layer indicates the RLC layer to the RRC. After the RRC receives the indication, it considers that the radio link of the UE fails or the quality is degraded, and the current cell is not suitable for providing the data transmission service.
In step S602, when a radio link failure of the UE is detected, a radio link repair is performed.
In the embodiment of the present invention, the manner of performing the radio link repair includes, but is not limited to:
mode one: initiating an application for recovering the RRC connection;
Optionally, in this embodiment, the application message for initiating the RRC connection restoration carries UE status indication information (e.g., the UE is in a preset state) or carries reestablishment reason information (e.g., the UE fails to send data in the preset state).
In this embodiment, the application message may be RRC Connection Reestablishment Request, RRC Connection Resume Request or a new message.
After receiving the application message, the base station can determine that the UE has failed in the radio link in the preset state, find the base station storing the UE context according to the UE identification information carried in the message, and then obtain the context information of the UE, and establish RRC connection for the UE. If no context information is found for the UE, the base station will re-establish the RRC connection for the UE and update the configuration of the UE.
Mode two: cell reselection is initiated. Specifically, when cell reselection is initiated, in order to avoid reselecting the current cell, the cell priority of the current cell is also lowered.
If the UE reselects a cell and the cell can support the data transmission in the preset state, the UE continues to execute the data transmission in the preset state in the cell.
In summary, in the method of the embodiment of the present invention, when the UE is in a state of being disconnected from the interface of the base station and the core network keep the connection of the UE, the retransmission condition of the RLC PDU may be used to detect the state of the radio link of the UE, and when the radio link failure of the UE is detected, the radio link repair is performed, so as to not only adapt to the mobility of the UE in the inactive state, but also reduce the delay of data transmission, and well solve the problem in the prior art that the radio link in the inactive state cannot be monitored, thereby affecting the data output.
In a third embodiment of the present invention, there is provided a radio link monitoring method, as shown in fig. 7, including the steps of:
Step S701, when the UE is in a preset state, detecting whether the number of times of continuously reaching a set threshold value by the number of times of continuously reaching the set threshold value by the hybrid automatic repeat request HARQ reaches a set third threshold value, and when the number of times of continuously reaching the set threshold value by the UE reaches the set third threshold value, judging that the radio link state of the UE is a radio link failure;
In the embodiment of the invention, the preset state refers to a state that an interface between the UE and the base station is disconnected and the base station and the core network keep the connection of the UE.
Further, in a specific embodiment of the present invention, detecting whether the number of times of retransmission of the hybrid automatic repeat request HARQ continuously reaches the set threshold reaches the set third threshold specifically includes:
When the UE sends a data packet, the HARQ reaches the maximum retransmission times, the MAC layer indicates the HARQ to the RRC to reach the maximum retransmission times, and if the times of continuously receiving the indication of the MAC layer by the RRC layer reach a set third threshold, the radio link is considered to fail or the current cell is not suitable for providing data transmission service.
In the embodiment of the present invention, the third threshold may be broadcasted by the base station or configured to the UE through an RRC message, for example: the UE is configured with system information, RRC connection reconfiguration, RRCConnectionRelease, or a new message.
In step S702, when a radio link failure of the UE is detected, a radio link repair is performed.
In the embodiment of the present invention, the manner of performing the radio link repair includes, but is not limited to:
mode one: initiating an application for recovering the RRC connection;
Optionally, in this embodiment, the application message for initiating the RRC connection restoration carries UE status indication information (e.g., the UE is in a preset state) or carries reestablishment reason information (e.g., the UE fails to send data in the preset state).
In this embodiment, the application message may be RRC Connection Reestablishment Request, RRC Connection Resume Request or a new message.
After receiving the application message, the base station can determine that the UE has failed in the radio link in the preset state, find the base station storing the UE context according to the UE identification information carried in the message, and then obtain the context information of the UE, and establish RRC connection for the UE. If no context information is found for the UE, the base station will re-establish the RRC connection for the UE and update the configuration of the UE.
Mode two: cell reselection is initiated. Specifically, when cell reselection is initiated, in order to avoid reselecting the current cell, the cell priority of the current cell is also lowered.
If the UE reselects a cell and the cell can support the data transmission in the preset state, the UE continues to execute the data transmission in the preset state in the cell.
In summary, in the method of the embodiment of the present invention, when the UE is in a state of being disconnected from the interface of the base station and the core network keep the connection of the UE, the state of the radio link of the UE may be detected through the retransmission condition of HARQ, and when the radio link failure of the UE is detected, the radio link repair is performed, so as to not only adapt to the mobility of the UE in the inactive state, but also reduce the delay of data transmission, and well solve the problem in the prior art that the radio link in the inactive state cannot be monitored, and thus the data output is affected.
In a fourth embodiment of the present invention, there is provided a radio link monitoring method, as shown in fig. 8, including the steps of:
step S801, when the UE is in a preset state, detecting the state of a wireless link of the UE according to the data transmission condition of a user plane;
Step S802, judging whether the radio link failure of the UE is detected, if so, executing step S803, otherwise, executing step S804;
The wireless link state detection method may be any one of the methods described in the first to third embodiments.
Step S803, wireless link repair is carried out; the method for performing radio link repair is described in any of the first to third embodiments.
In step S804, it is detected whether cell reselection occurred due to UE movement, and when cell reselection occurred and other cells were reselected, the RRC instructs the MAC layer to reset the MAC and applies configuration information of the new cell.
It should be noted that the MAC is reset but the buffer is not emptied, and the data in the buffer is retransmitted as new data in the new cell. If the UE is not synchronized with the new cell, the MAC layer initiates a random access procedure.
Further, in the embodiment of the present invention, when the radio link state detection method described in the second embodiment of the present invention is adopted, after other cells are reselected, the RRC layer instructs the RLC layer to clear the number of RLC PDU retransmissions recorded by the RLC layer.
In summary, in the method of the embodiment, when the UE is in a state of being disconnected from the interface of the base station and the core network keep the connection of the UE, the state of the radio link of the UE may be detected through the data transmission condition of the user plane, and when the radio link failure of the UE is detected, the radio link repair is performed, so as to not only adapt to the mobility of the UE in the inactive state, but also reduce the delay of data transmission, and well solve the problem that in the prior art, the radio link in the inactive state cannot be monitored, and thus the data output is affected.
In a fifth embodiment of the present invention, there is provided a user equipment, as shown in fig. 9, including:
The link detection module 910 is configured to detect, when the ue is in a preset state, a state of a wireless link of the ue according to a data transmission condition of the ue; wherein, the preset state refers to a state that an interface between the user equipment and the base station is disconnected and the base station and the core network keep the connection of the user equipment;
The link repair module 920 is configured to perform radio link repair when the link detection module 910 detects that the radio link of the user equipment fails.
Further, in a specific embodiment of the present invention, the link detection module 910 detects the status of the wireless link of the UE in one or more of the following manners:
in one aspect, it is detected whether the number of times the UE transmits the preamble reaches a set first threshold, and when the number of times the UE transmits the preamble reaches the set first threshold, it is determined that the radio link status of the UE is a radio link failure.
Specifically, in this embodiment, the UE detects, through the MAC layer, whether the number of times of sending the preamble reaches a set first threshold, and when the number of times of sending the preamble reaches the set first threshold, the MAC layer indicates to the RRC layer that the random access procedure is problematic, and the RRC considers that the radio link of the UE fails.
In a second mode, whether the retransmission times of the RLC PDU sent by the UE reach a set second threshold value is detected, and when the retransmission times reach the set second threshold value, the radio link state of the UE is judged to be radio link failure;
specifically, in this embodiment, the UE detects, through the RLC layer, whether the transmitted RLC PDU reaches the maximum number of retransmissions, and when it reaches, the RLC layer indicates to the RRC that the RLC layer reaches the maximum number of retransmissions. After the RRC receives the indication, it considers that the radio link of the UE fails or the quality is degraded, and the current cell is not suitable for providing the data transmission service.
Determining the number of times that the retransmission times of the hybrid automatic repeat request HARQ continuously reach a set threshold value, detecting whether the number of times reaches a set third threshold value, and judging that the radio link state of the UE is radio link failure when the number of times reaches the set third threshold value;
specifically, in this embodiment, when the UE sends a data packet, the HARQ reaches the maximum retransmission number, the MAC layer indicates to the RRC that the HARQ reaches the maximum retransmission number, and if the number of times indicated by the RRC layer continuously receives the MAC layer reaches a set third threshold, it is considered that the radio link fails or the current cell is not suitable for providing the data transmission service.
Alternatively, the third threshold may be configured to the UE by the base station through a broadcast or radio resource control, RRC, message. For example: the UE is configured with system information, RRC connection reconfiguration, RRCConnectionRelease, or a new message.
Further, in a specific embodiment of the present invention, the link repair module 820 performs link repair by initiating an application to recover the RRC connection, or initiating a cell reselection.
Optionally, when an application for recovering the RRC connection is initiated, the application message carries indication information of the UE state or indication information of a cause of the reestablishment; or when initiating cell reselection, the cell priority of the current cell is turned down.
Optionally, in an optional embodiment of the present invention, the user equipment further includes:
A processing module 930, configured to reset the MAC and/or clear the retransmission number of the RLC PDU sent by the UE that is currently recorded when the UE is in the preset state and the new cell is reselected due to the mobile.
In summary, in the UE according to the embodiment, when the UE is in a state of being disconnected from the interface of the base station and the core network maintain the connection of the UE, the state of the radio link of the UE may be detected through the data transmission condition of the user plane, and when the radio link failure of the UE is detected, the radio link repair is performed, which is convenient for adapting to the mobility of the UE in the inactive state, and also can reduce the delay of data transmission, so that the problem in the prior art that the radio link in the inactive state cannot be monitored and further the data output is affected is well solved.
Those of ordinary skill in the art will appreciate that all or part of the steps in the various methods of the above embodiments may be implemented by a program to instruct related hardware, the program may be stored in a computer readable storage medium, and the storage medium may include: ROM, RAM, magnetic or optical disks, etc.
In summary, the foregoing description is only of the preferred embodiments of the present invention, and is not intended to limit the scope of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.