EDT transmission optimization method oriented to Internet of Things

Abstract

The invention discloses an EDT transmission optimization method for the Internet of Things. The method is suitable for a terminal, a base station and a core network in an NB-IoT system. The method comprises the following steps that: in an RRC (Radio Resource Control) connection establishment process, a terminal sends a PURConfiguration IE field to a base station through an RRC Configuration Setup Complex message, the base station reserves an uplink resource according to the field, and a subsequent base station allocates the reserved resource through the RRC Configuration Release message and releases the terminal. And the terminal performs uplink data transmission by using the EDT technology in the idle state, and the terminal returns to the idle state after the transmission is completed. Through the core network and the base station optimization strategy, the judgment process of the EDT is simplified, the situation of inconsistent judgment of three parties is avoided, and NAS signaling transmission is reduced. The data transmission efficiency is improved, the power consumption is reduced, and the system performance is optimized.

Description

Technical Field

[0001] The present invention relates to the field of wireless communication technology, and in particular to an EDT transmission optimization method for the Internet of Things. Background Art

[0002] With the rapid development of the Internet of Things (IoT), low power consumption, wide coverage, low cost and large-scale connection have become important requirements for IoT devices. Among the many IoT communication technologies, the NB-IoT (NarrowBand-IoT) system has gradually become one of the important choices for IoT communications due to its low power consumption, high security and low equipment cost. The NB-IoT system can achieve large-scale device connections and is particularly suitable for scenarios that require long-term operation and low data transmission frequency, such as smart meter reading, environmental monitoring and smart home applications.

[0003] In the NB-IoT system, low-power operation of terminal devices is particularly important. In order to extend the battery life of terminal devices, terminal devices are usually in a long sleep state and are only activated when data needs to be transmitted. However, traditional data transmission schemes have large signaling overhead during the switching process of the terminal from the sleep state to the transmission state, which increases the power consumption of the terminal and the complexity of the system. Therefore, the 3GPP protocol introduced the EDT (Early Data Transmission) technology to optimize the data transmission process of the terminal in the idle state.

[0004] EDT technology allows the terminal to carry an uplink data for transmission in the idle state without switching to the connected state. This optimization scheme reduces the number of signaling transmissions and shortens the data transmission time, thereby effectively reducing the power consumption of the terminal. However, although the initial implementation of EDT technology has improved the efficiency of data transmission, there is still room for further optimization, especially in terms of resource allocation and simplicity of data transmission.

[0005] To further improve the performance of the EDT solution, 3GPP introduced the PUR (Preconfigured Uplink Resource) strategy in Release 16. The core idea of ​​PUR is to reserve uplink resources for the terminal so that it can use these resources immediately when data transmission is needed, without waiting for dynamic resource allocation. The combination of PUR and EDT can better realize the early allocation of resources and the simplified data transmission process, thereby further reducing signaling overhead.

[0006] The specific implementation of PUR is that when the terminal is in a connected state and expects to reserve uplink resources, the terminal will apply to the base station for reserved uplink resources through PURConfigurationRequest. After receiving the request, the base station will reserve the corresponding uplink resources according to the resource requirements of the terminal, and pass these reserved uplink resources to the terminal through the RRCConnectionRelease message when the terminal needs to be released. Although the PUR strategy improves the transmission efficiency of the EDT solution, the strategy requires the addition of signaling messages, resulting in increased signaling overhead and message flow complexity, which poses certain challenges to the performance and stability of the system.

[0007] In addition, the EDT solution also has some uncertainties regarding the state switching problem after the terminal data transmission is completed. Specifically, in the EDT process, after the terminal data transmission is completed, the core network needs to decide whether the terminal returns to the idle state or restores the connected state based on whether there is downlink data. This decision-making process involves the judgment of multiple factors such as the terminal's release requirements, whether the core network has subsequent data transmission requirements, and the current status of the base station. However, these judgment processes are relatively redundant and can easily lead to inconsistent judgment results among the three parties (terminal, core network, and base station), which may in turn cause the terminal to be released in error or unnecessary NAS signaling transmission, increasing the complexity of the system.

[0008] Therefore, although the existing EDT and PUR solutions have made some progress in optimizing terminal low-power operation and simplifying data transmission, there are still problems such as large signaling overhead, redundant judgment and complex processes, and further optimization is urgently needed to improve the efficiency and reliability of the system. Summary of the invention

[0009] In view of the defects of the prior art, the present invention provides an EDT transmission optimization method for the Internet of Things.

[0010] In order to achieve the above invention object, the technical solution adopted by the present invention is as follows:

[0011] An EDT (Early Data Transmission) transmission optimization method for the Internet of Things, applicable to terminals, base stations and core networks in NB-IoT (NarrowBand IoT) systems, includes the following steps:

[0012] During the RRC (Radio Resource Control) connection establishment process, the terminal sends the PURConfiguration_IE field to the base station through the RRCConnectionSetupComplete message, and the base station reserves uplink resources based on this field; after the data transmission is completed, the base station transmits the release information of the reserved uplink resources to the terminal through the RRCConnectionRelease message, and the terminal returns to the idle state according to the message;

[0013] After the terminal completes the RRC connection establishment, it enters the idle state. At this time, the reserved uplink resources are not released, waiting for subsequent uplink data transmission needs. When the terminal needs to perform uplink data transmission, the base station uses the previously reserved uplink resources through EDT technology to achieve fast transmission of terminal uplink data, reduce data transmission delay and improve transmission efficiency.

[0014] The core network makes decisions based on the transmission of uplink data and the following conditions:

[0015] a) If there is no subsequent data transmission and no cached data, the core network sends a UE Context Release Command signaling to the base station, the base station releases the UE context, and the terminal returns to the idle state;

[0016] b) If there is no subsequent data transmission but cached data exists, the core network sends an Initial Context Setup Request signaling to the base station to re-establish the terminal context, and the terminal resumes the connected state;

[0017] c) If the subsequent data is only confirmation information of uplink data, the core network instructs the base station to release the terminal context through DL NAS Transport signaling, and the terminal returns to the idle state;

[0018] d) If there is subsequent data and it is not limited to uplink confirmation information, the core network sends an Initial Connection Setup Request signaling to the base station, and the terminal resumes the connection state.

[0019] Furthermore, upon receiving the core network DL NAS Transport signaling, the base station releases the terminal through the RRC Early Data Complete signaling, and the terminal resumes the idle state;

[0020] Furthermore, when the base station receives the UE Context Release Command signaling from the core network, it transmits a release confirmation to the terminal through Layer1Ack signaling or MAC CE signaling. After receiving the confirmation, the terminal releases the connection and returns to the idle state.

[0021] Furthermore, upon receiving the Initial Context Setup Request signaling from the core network, the base station re-establishes the RRC connection through the RRC Setup signaling, and the terminal enters the connected state.

[0022] Furthermore, the PURConfiguration_IE field is used to transmit the uplink resource requirement information of the terminal to the base station in the RRCConnectionSetupComplete message. The base station reserves uplink resources for the terminal according to the information and allocates the resources in the subsequent RRCConnectionRelease message.

[0023] Furthermore, the core network and the base station reduce redundant judgments of flags through optimized signaling processes, and do not rely on complex flags to determine the release status of the terminal, but instead execute the context release or recovery operation through clear signaling instructions.

[0024] Furthermore, the RRCConnectionRelease message includes notification information that the base station reserves uplink resources for the terminal. After receiving the message, the terminal saves the corresponding uplink resources and returns to the idle state.

[0025] Furthermore, the EDT process is combined with the PUR strategy to reduce the signaling overhead and the processing complexity of the base station by reducing the newly added signaling and flag bits in the signaling interaction process.

[0026] Compared with the prior art, the advantages of the present invention are:

[0027] 1. Reduce signaling overhead: By optimizing the combination of EDT (Early Data Transmission) and PUR (Preconfigured Uplink Resource), the existing signaling (such as Initial Context Setup Request, Initial Context Setup Response) is used to replace the newly added signaling interaction, reducing additional signaling messages, thereby effectively reducing signaling overhead, improving the overall efficiency of the system, and reducing resource waste during the communication process.

[0028] 2. Simplified signaling process: The present invention simplifies the original complex signaling process by directly transmitting the PURConfiguration_IE field in the RRCConnectionSetupComplete message, and replaces the redundant process with the existing signaling mechanism. This improvement reduces the complexity of signaling processing and reduces the processing burden of the base station.

[0029] 3. Improve power consumption efficiency: The optimized EDT process allows the terminal to transmit data in the idle state. Combined with the uplink resources reserved by the PUR strategy, the switching frequency of the terminal from the sleep state to the active state is reduced, thereby effectively reducing the power consumption of the terminal and extending the battery life of the device.

[0030] 4. Reduce misjudgment and data transmission overhead: By replacing complex flag judgments with clear signaling instructions, the problem of inconsistent judgments among the three parties (terminal, core network, and base station) is reduced, the terminal’s erroneous release or unnecessary NAS signaling transmission is avoided, and the system overhead is reduced.

[0031] 5. Optimize terminal status management: The core network can more accurately determine the terminal status (idle or connected) based on the transmission status of uplink data and specific optimization strategies, thereby improving the accuracy of terminal status management and the overall operating efficiency of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is the original design flow chart of the EDT protocol.

[0033] Figure 2 It is a PUR optimization flow chart of an embodiment of the present invention.

[0034] Figure 3 It is an EDT optimization flow chart of an embodiment of the present invention.

[0035] Figure 4 It is a flow chart of the core network optimization strategy according to an embodiment of the present invention.

[0036] Figure 5 It is a flow chart of the base station optimization strategy according to an embodiment of the present invention. DETAILED DESCRIPTION

[0037] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and examples.

[0038] Example 1: Optimized process for combining EDT with PUR

[0039] like Figure 1 As shown in the figure, in the NB-IoT narrowband Internet of Things system, if there is a small amount of uplink data transmission on the terminal side, it can be completed through the EDT process. In order to optimize the EDT transmission efficiency, Figure 2 and 3 As shown, the present invention combines EDT with PUR strategy to reduce signaling overhead and simplify the process. The specific implementation steps are as follows:

[0040] RRC access phase:

[0041] When an NB-IoT terminal needs to establish an RRC connection in the idle state, the terminal first requests an RRC connection from the base station through an RRCConnectionRequest message.

[0042] After receiving the request, the base station establishes an RRC connection through an RRCConnectionSetup message.

[0043] In this process, the terminal carries the PURConfiguration_IE field in the RRCConnectionSetupComplete message to request the base station to reserve uplink resources ( Figure 2 ). The PURConfiguration_IE field contains the uplink resource configuration information required by the terminal, which is used to simplify resource allocation for uplink data transmission.

[0044] After receiving the RRCConnectionSetupComplete message, the base station reserves the required uplink resources for the terminal based on the content of the PURConfiguration_IE field.

[0045] RRC release phase:

[0046] After the data transmission is completed, the base station transmits the reserved uplink resource information to the terminal through the RRCConnectionRelease message. At this time, the terminal releases the connection according to the content of the RRCConnectionRelease message and returns to the idle state, while retaining the reserved uplink resource information for the next uplink transmission.

[0047] Subsequently, the terminal uses these reserved uplink resources through EDT ( Figure 3 ) process completes the sending of uplink data.

[0048] Example 2: Optimization strategy for core network and base station

[0049] When the core network and base station process the EDT process, they optimize the collaborative judgment mechanism of the three parties (core network, base station, and terminal) after uplink transmission, avoiding redundant judgments and reducing the risk of erroneous release. The specific optimizations are as follows:

[0050] like Figure 4 As shown in the figure, the core network side is optimized:

[0051] When the core network receives uplink data, it determines whether there is subsequent data or cached data and makes corresponding decisions based on the following situations:

[0052] When there is no subsequent data and no cached data, the core network sends a UE Context Release Command signaling to the base station, instructing the base station to release the UE context and the terminal returns to the idle state;

[0053] When there is no subsequent data but cached data, the core network sends an Initial Context Setup Request signaling to the base station to re-establish the UE context and the terminal resumes the connected state;

[0054] When there is only ACK for uplink data and no cached data, the core network sends DL NAS Transport signaling to the base station, releases the UE context, and the terminal returns to the idle state;

[0055] When there is subsequent data and not just ACK of uplink data, the core network sends Initial Context SetupRequest signaling to the base station to re-establish the UE context and the terminal resumes the connected state.

[0056] like Figure 5 As shown, the base station side is optimized:

[0057] The base station makes corresponding processing according to the instruction signaling of the core network:

[0058] Upon receiving the DL NAS Transport signaling, the base station sends a downlink NAS message to the terminal via RRC Early Data Complete signaling, releasing the terminal and returning it to the idle state;

[0059] When receiving the UE Context Release Command signaling, the base station sends a confirmation message to the terminal through Layer 1Ack signaling (carrying Time Advance Adjustment) or MAC CE signaling (carrying Time Advance Command), and releases the terminal, and the terminal returns to the idle state;

[0060] When receiving the Initial Context Setup Request signaling, the base station re-establishes the RRC connection through the RRC Setup signaling, and the terminal enters the connected state.

[0061] Example 3: Simplification of EDT process and optimization of flag bits

[0062] like Figure 1 As shown in the figure, in the traditional EDT process, the core network, base station and terminal rely on multiple flags for judgment, which easily leads to inconsistent cooperation among the three parties, resulting in erroneous release or increased signaling overhead. The present invention reduces unnecessary overhead by simplifying the flag judgment and signaling process. The specific optimization method is as follows:

[0063] Simplification of flags:

[0064] like Figure 3 As shown, the present invention no longer relies on the redundant judgment of the flag bits of the core network, base station and terminal, but indicates the subsequent operations of the EDT process through clear signaling messages (such as UE Context Release Command, Initial Context Setup Request, etc.).

[0065] Signaling optimization:

[0066] The present invention adopts the Initial Context Setup Request message in the existing signaling to replace the original Connection Establishment Indication signaling, thereby reducing the processing complexity of the base station and improving the system adaptability.

[0067] When the terminal needs to restore the connection state, the present invention completes the context establishment by carrying NAS PDU with data through the Initial Context Setup Response message, simplifies the process of the core network repeatedly receiving the Initial UE message, and improves the signaling processing efficiency.

[0068] Example 4: Specific application scenario

[0069] In practical applications, the present invention is applicable to scenarios of large-scale IoT devices, especially NB-IoT terminals with low power consumption and high coverage requirements. Typical application scenarios include smart meter reading, environmental monitoring, asset tracking, etc.

[0070] For example, in an intelligent meter reading system, the meter reading terminal usually needs to be in a dormant state for a long time, and only transmits data periodically or when data needs to be uploaded. Through the EDT transmission optimization method of the present invention, the meter reading terminal can complete data upload without establishing a complete connection state, while saving signaling overhead, and quickly resume dormancy after data transmission, thereby greatly reducing energy consumption and extending the battery life of the device.

[0071] Those skilled in the art will appreciate that the embodiments described herein are intended to help readers understand the implementation methods of the present invention, and should be understood that the protection scope of the present invention is not limited to such special statements and embodiments. Those skilled in the art can make various other specific variations and combinations that do not deviate from the essence of the present invention based on the technical revelations disclosed by the present invention, and these variations and combinations are still within the protection scope of the present invention.

Claims

1. An EDT transmission optimization method for the Internet of Things, applicable to terminals, base stations and core networks in NB-IoT systems, characterized in that: The following steps are involved: During the RRC connection establishment process, the terminal sends the PURConfiguration_IE field to the base station through the RRCConnectionSetupComplete message, and the base station reserves uplink resources based on the field; after the data transmission is completed, the base station transmits the release information of the reserved uplink resources to the terminal through the RRCConnectionRelease message, and the terminal returns to the idle state according to the message; after the terminal completes the RRC connection establishment, it enters the idle state, at which time the reserved uplink resources are not released, waiting for subsequent uplink data transmission requirements; When the terminal needs to transmit uplink data, the base station uses the previously reserved uplink resources through EDT technology; The core network makes decisions based on the transmission of uplink data and the following conditions: a) If there is no subsequent data transmission and no cached data, the core network sends a UE Context Release eCommand signaling to the base station, the base station releases the UE context, and the terminal returns to the idle state; b) If there is no subsequent data transmission but cached data exists, the core network sends an Initial Context SetupRequest signaling to the base station to re-establish the terminal context, and the terminal resumes the connected state; c) If the subsequent data is only confirmation information of uplink data, the core network instructs the base station to release the terminal context through DL NAS Transport signaling, and the terminal returns to the idle state; d) If there is subsequent data and it is not limited to uplink confirmation information, the core network sends an Initial Connection Setup Request signaling to the base station, and the terminal resumes the connection state.

2. The EDT transmission optimization method for the Internet of Things according to claim 1 is characterized in that: When the base station receives the DL NAS Transport signaling from the core network, it releases the terminal through the RRC Early Data Complete signaling, and the terminal returns to the idle state.

3. The EDT transmission optimization method for the Internet of Things according to claim 2 is characterized in that: When the base station receives the UE Context Release Command signaling from the core network, it transmits a release confirmation to the terminal through Layer 1Ack signaling or MAC CE signaling. After receiving the confirmation, the terminal releases the connection and returns to the idle state.

4. The EDT transmission optimization method for the Internet of Things according to claim 3 is characterized in that: After receiving the Initial Context Setup Request signaling from the core network, the base station re-establishes the RRC connection through the RRC Setup signaling, and the terminal enters the connected state.

5. The EDT transmission optimization method for the Internet of Things according to claim 1 is characterized in that: The PURConfiguration_IE field is used to transmit the uplink resource requirement information of the terminal to the base station in the RRCConnectionSetupComplete message. The base station reserves uplink resources for the terminal according to the information and allocates the resources in the subsequent RRCConnectionRelease message.

6. The EDT transmission optimization method for the Internet of Things according to claim 1 is characterized in that: The core network and base station reduce redundant judgments of flags through optimized signaling processes. Instead of relying on complex flags to determine the release status of the terminal, they perform context release or recovery operations through clear signaling instructions.

7. The EDT transmission optimization method for the Internet of Things according to claim 1 is characterized in that: The RRCConnectionRelease message includes notification information that the base station reserves uplink resources for the terminal. After receiving the message, the terminal saves the corresponding uplink resources and returns to the idle state.

8. The EDT transmission optimization method for the Internet of Things according to claim 1 is characterized in that: The EDT process is combined with the PUR strategy to reduce the signaling overhead and the processing complexity of the base station by reducing the newly added signaling and flag bits in the signaling interaction process.

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