Quectel BC95 G BC68 Application Design Guide V1.1
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BC95&BC95-G&BC68 Application Design Guide NB-IoT Module Series Rev. BC95&BC95-G&BC68_Application_Design_Guide _V1.1 Date: 2018-06-21 Status: Released www.quectel.com NB-IoT Module Series BC95&BC95-G&BC68 Application Design Guide Our aim is to provide customers with timely and comprehensive service. For any assistance, please contact our company headquarters: Quectel Wireless Solutions Co., Ltd. 7th Floor, Hongye Building, No.1801 Hongmei Road, Xuhui District, Shanghai 200233, China Tel: +86 21 5108 6236 Email: info@quectel.com Or our local office. For more information, please visit: http://quectel.com/support/sales.htm For technical support, or to report documentation errors, please visit: http://quectel.com/support/technical.htm Or email to: support@quectel.com GENERAL NOTES QUECTEL OFFERS THE INFORMATION AS A SERVICE TO ITS CUSTOMERS. THE INFORMATION PROVIDED IS BASED UPON CUSTOMERS’ REQUIREMENTS. QUECTEL MAKES EVERY EFFORT TO ENSURE THE QUALITY OF THE INFORMATION IT MAKES AVAILABLE. QUECTEL DOES NOT MAKE ANY WARRANTY AS TO THE INFORMATION CONTAINED HEREIN, AND DOES NOT ACCEPT ANY LIABILITY FOR ANY INJURY, LOSS OR DAMAGE OF ANY KIND INCURRED BY USE OF OR RELIANCE UPON THE INFORMATION. ALL INFORMATION SUPPLIED HEREIN IS SUBJECT TO CHANGE WITHOUT PRIOR NOTICE. COPYRIGHT THE INFORMATION CONTAINED HERE IS PROPRIETARY TECHNICAL INFORMATION OF QUECTEL WIRELESS SOLUTIONS CO., LTD. TRANSMITTING, REPRODUCTION, DISSEMINATION AND EDITING OF THIS DOCUMENT AS WELL AS UTILIZATION OF THE CONTENT ARE FORBIDDEN WITHOUT PERMISSION. OFFENDERS WILL BE HELD LIABLE FOR PAYMENT OF DAMAGES. ALL RIGHTS ARE RESERVED IN THE EVENT OF A PATENT GRANT OR REGISTRATION OF A UTILITY MODEL OR DESIGN. Copyright © Quectel Wireless Solutions Co., Ltd. 2018. All rights reserved. BC95&BC95-G&BC68_Application_Design_Guide 1 / 22 NB-IoT Module Series BC95&BC95-G&BC68 Application Design Guide About the Document History Revision Date Author Description 1.0 2018-06-20 Hayden WANG/ Evan WU Initial 2018-06-21 Hayden WANG/ Evan WU Updated description of unsolicited information about firmware upgrade state in the process of firmware upgrade via DFOTA 1.1 BC95&BC95-G&BC68_Application_Design_Guide 2 / 22 NB-IoT Module Series BC95&BC95-G&BC68 Application Design Guide Contents About the Document ................................................................................................................................... 2 Contents ....................................................................................................................................................... 3 Table Index ................................................................................................................................................... 4 Figure Index ................................................................................................................................................. 5 1 Introduction .......................................................................................................................................... 6 2 Application Design Guidelines ........................................................................................................... 7 2.1. Fixed Applications with Data Transmission ............................................................................... 7 2.1.1. Requirements on Network Configurations....................................................................... 7 2.1.2. Application Design Guidelines ......................................................................................... 8 2.1.3. Flowchart of Design Guidelines ..................................................................................... 10 2.2. Fixed Applications with Remote Control .................................................................................. 11 2.2.1. Requirements on Network Configurations..................................................................... 11 2.2.2. Application Design Guidelines ....................................................................................... 11 2.2.3. Flowchart of Design Guidelines ..................................................................................... 13 2.3. Mobile Applications with Data Transmission ........................................................................... 14 2.3.1. Requirements on Network Configurations..................................................................... 14 2.3.2. Application Design Guidelines ....................................................................................... 14 2.3.3. Flowchart of Design Guidelines ..................................................................................... 16 2.4. Mobile Applications with Remote Control ................................................................................ 17 2.4.1. Requirements on Network Configurations..................................................................... 17 2.4.2. Application Design Guidelines ....................................................................................... 17 2.4.3. Flowchart of Design Guidelines ..................................................................................... 19 3 Supplementary Notes ........................................................................................................................ 20 3.1. Conventional Maintenance and Test Means ........................................................................... 20 3.2. Brief Introduction of Related AT Commands ........................................................................... 20 4 Appendix A References..................................................................................................................... 22 BC95&BC95-G&BC68_Application_Design_Guide 3 / 22 NB-IoT Module Series BC95&BC95-G&BC68 Application Design Guide Table Index TABLE 1: REQUIREMENTS ON NETWORK CONFIGURATIONS FOR FIXED APPLICATIONS WITH DATA TRANSMISSION ................................................................................................................................ 7 TABLE 2: DESIGN GUIDELINES FOR FIXED APPLICATIONS WITH DATA TRANSMISSION ........................ 8 TABLE 3: REQUIREMENTS ON NETWORK CONFIGURATIONS FOR FIXED APPLICATIONS WITH REMOTE CONTROL ......................................................................................................................... 11 TABLE 4: DESIGN GUIDELINES FOR FIXED APPLICATIONS WITH REMOTE CONTROL .......................... 11 TABLE 5: REQUIREMENTS ON NETWORK CONFIGURATIONS FOR MOBILE APPLICATIONS WITH DATA TRANSMISSION ............................................................................................................................... 14 TABLE 6: DESIGN GUIDELINES FOR MOBILE APPLICATIONS WITH DATA TRANSMISSION ................... 14 TABLE 7: REQUIREMENTS ON NETWORK CONFIGURATIONS FOR MOBILE APPLICATIONS WITH REMOTE CONTROL ........................................................................................................................ 17 TABLE 8: DESIGN GUIDELINES FOR MOBILE APPLICATIONS WITH REMOTE CONTROL ...................... 17 TABLE 9: BRIEF INTRODUCTION OF RELATED AT COMMANDS ................................................................ 20 TABLE 10: REFERENCE DOCUMENTS .......................................................................................................... 22 TABLE 11: TERMS AND ABBREVIATIONS ...................................................................................................... 22 BC95&BC95-G&BC68_Application_Design_Guide 4 / 22 NB-IoT Module Series BC95&BC95-G&BC68 Application Design Guide Figure Index FIGURE 1: FLOWCHART OF DESIGN GUIDELINES FOR FIXED APPLICATIONS WITH DATA TRANSMISSION ............................................................................................................................ 10 FIGURE 2: FLOWCHART OF DESIGN GUIDELINES FOR FIXED APPLICATIONS WITH REMOTE CONTROL ....................................................................................................................................... 13 FIGURE 3: FLOWCHART OF DESIGN GUIDELINES FOR MOBILE APPLICATIONS WITH DATA TRANSMISSION ............................................................................................................................. 16 FIGURE 4: FLOWCHART OF DESIGN GUIDELINES FOR MOBILE APPLICATIONS WITH REMOTE CONTROL ....................................................................................................................................... 19 BC95&BC95-G&BC68_Application_Design_Guide 5 / 22 NB-IoT Module Series BC95&BC95-G&BC68 Application Design Guide 1 Introduction At present, Quectel NB-IoT modules are mainly applied to following application scenarios: ⚫ ⚫ ⚫ ⚫ Fixed applications with data transmission: such as water meters, gas meters and smoke detectors. Fixed applications with remote control: such as street lights and shared laundry machines. Mobile applications with data transmission: such as shared bicycles and activity trackers. Mobile applications with remote control: such as electric motor controllers. This document illustrates design guidelines for the four application scenarios mentioned above in order to help customers deploy NB-IoT terminals based on Quectel NB-IoT modules under different network deployment environments, such as a change on EARFCN (E-UTRA Absolute Radio Frequency Channel Number) values and a switch from intra-frequency to inter-frequency. This document is applicable to following Quectel NB-IoT modules: ⚫ ⚫ ⚫ BC95 B657SP5 version or later BC95-G B300 version or later BC68 B300 version or later BC95&BC95-G&BC68_Application_Design_Guide 6 / 22 NB-IoT Module Series BC95&BC95-G&BC68 Application Design Guide 2 Application Design Guidelines This chapter provides design guidelines and recommendations for different application scenarios of Quectel NB-IoT modules. 2.1. Fixed Applications with Data Transmission Fixed applications with data transmission feature a fixed deployment location and periodic data transmission service. They are kept in sleep mode most of the time, and they only receive downlink data when an uplink data transmission is initiated (no need for receiving paging messages). Such terminals have high requirements on power consumption and success rate of data transmission rather than the timeliness of data transmission. Therefore, it is recommended to comply with the following design requirements. 2.1.1. Requirements on Network Configurations Table 1: Requirements on Network Configurations for Fixed Applications with Data Transmission No. Parameter Configuration Requirement 1 eDRX Disabled 2 PSM Enabled NOTE Please confirm the configuration settings of these parameters with corresponding network operators since they are determined by the core network. BC95&BC95-G&BC68_Application_Design_Guide 7 / 22 NB-IoT Module Series BC95&BC95-G&BC68 Application Design Guide 2.1.2. Application Design Guidelines Table 2: Design Guidelines for Fixed Applications with Data Transmission No. 1 Design Guideline Description Timeout period for the MCU to register on network after start-up It may take a long time for the MCU to register on network when in deep coverage or when the network changes, so the timeout period for the MCU to register on network after start-up is recommended to be at least 300s. a) 2 Enable cell reselection function b) In order to ensure that the module can be camped on a better cell in terms of signal strength and quality, it is recommended to enable the cell reselection function of the module. For BC95 B657SP5 or later versions, BC95-G B300 or later versions, and BC68 B300 or later versions, the cell reselection function is enabled by default. If the cell reselection function is disabled, make sure the module is in minimum functionality mode (can be queried by AT+CFUN? command), and then the MCU sends AT+NCONFIG=CELL_RESELECTION,TRUE to enable the cell reselection function. 3 Start an uplink data transmission with RAI identifiers Start an uplink data transmission with RAI identifiers (e.g.: AT+QLWULDATAEX=3,AA34BB,0x0001) for indicating the core network to release the current RRC connection immediately so as to let the module enter idle mode. Then the module will automatically enter PSM after the idle timer expires. 4 If it needs to power off the module, it must delay for at least 15s after the module enters idle mode After the module enters idle mode, it must wait for at least 15s before powering off the module, so that the network can configure the T3324 timer to ensure the module has enough time to complete the cell reselection procedure. 5 If it needs to power off the module, AT+CFUN=0 must be executed before power-off. Before powering off the module, the MCU needs to send AT+CFUN=0 command to the module to trigger the module to save the EARFCN values and send a message to detach from network. a) 6 Data transmission service When starting a data transmission via Huawei OceanConnect IoT platform, if "+CME ERROR: 513" error is returned (AT+CMEE=1 has been set; 513: TUP not registered), the MCU will attempt to re-send the data after a delay of 20s; if the re-send is failed for 3 times continuously, the MCU will enter the exception handling process (Refer to No.7 below). BC95&BC95-G&BC68_Application_Design_Guide 8 / 22 NB-IoT Module Series BC95&BC95-G&BC68 Application Design Guide b) 7 8 During a normal data transmission, if no downlink data is received within 60s in data interaction process, it will be regarded as a data service failure due to timeout, and the MCU will attempt to re-send the data; if the re-send is failed for 3 times continuously, the MCU will enter the exception handling process (Refer to No.7 below). Exception handling process If it fails to register on network or transmit data, then the MCU executes AT+NRB (Reboot the module) → AT+CFUN=0 (Enter minimum functionality mode) → AT+NCSEARFCN (Clear Stored EARFCN values) → AT+CFUN=1 (Enter full functionality mode) → AT+CGATT=1 (Attach to network), and tries to register on network and re-sends the data. If the re-registration or re-send still fails, it will retry for 3 times according to the back off algorithm. If it still fails, the MCU will power off the module. In such case, the module will try to register on network when the next round of data transmission is initiated. Support the module’s firmware upgrade via DFOTA During a firmware upgrade process via DFOTA, no AT command can be sent and the module cannot be powered off. It is recommended that the uninterruptible power supply time should be 30 minutes. The module outputs "FIRMWARE DOWNLOADING" via the main port to indicate that the firmware has started upgrading, "FIRMWARE UPDATE SUCCESS" to indicate that the upgrade is successful and "FIRMWARE UPDATE OVER" to indicate that the upgrade is completed. BC95&BC95-G&BC68_Application_Design_Guide 9 / 22 NB-IoT Module Series BC95&BC95-G&BC68 Application Design Guide 2.1.3. Flowchart of Design Guidelines Power on the module Set to manually register on network AT+NCONFIG=AUTOCONNECT,FALSE Set CDP server address AT+NCDP=[, ] Skip this step for UDP/TCP server Reboot the module by software AT+NRB Specify band values AT+NBAND= Skip this step for BC95 module Enter full functionality mode AT+CFUN=1 Disable eDRX function of the module AT+CEDRXS=0,5 Trigger network attachment AT+CGATT=1 Network attachment Data transmission service Yes Query whether successfully registered on network AT+CGATT? Execute AT+CGATT? after 300s, "+CGATT:1" is not returned. Reboot the module AT+NRB Trigger network attachment AT+CFUN=1 Enter minimum AT+CGATT=1 functionality mode Fail to receive downlink data 3 times continuously due to timeout (60s). Whether the data is No transmitted successfully? Yes No Start an uplinlk data transmission with RAI identifiers. AT+CFUN=0 Idle mode Clear stored EARFCN values AT+NCSEARFCN Whether to power off the module? N PSM Whether retry to register on network? It is recommended to enter the PSM. If it needs to power off the module, it is recommended to wait for at least 15s after entering idle mode, and execute AT+CFUN=0 before powering off the module. Y AT+CFUN=0 No Yes Failed after 3 times of retries according to the back off algorithm. Exception Handling Power off Figure 1: Flowchart of Design Guidelines for Fixed Applications with Data Transmission BC95&BC95-G&BC68_Application_Design_Guide 10 / 22 NB-IoT Module Series BC95&BC95-G&BC68 Application Design Guide 2.2. Fixed Applications with Remote Control Fixed applications with remote control feature a fixed deployment location. They are usually powered with an external power supply and kept in connected mode most of the time. Meanwhile, they are required to receive real-time downlink data. Such terminals have high requirements on timeliness of data transmission rather than power consumption. Therefore, it is recommended to comply with the following design requirements. 2.2.1. Requirements on Network Configurations Table 3: Requirements on Network Configurations for Fixed Applications with Remote Control No. Parameter Configuration Requirement 1 eDRX Disabled 2 PSM Disabled NOTE Please confirm the configuration settings of these parameters with corresponding network operators since they are determined by the core network. 2.2.2. Application Design Guidelines Table 4: Design Guidelines for Fixed Applications with Remote Control No. Design Guideline Description 1 Timeout period for the MCU to register on network after start-up It may take a long time for the MCU to register on network when in deep coverage or when the network changes, so the timeout period for the MCU to register on network after start-up is recommended to be at least 300s. a) 2 Enable cell reselection function In order to ensure that the module can be camped on a better cell in terms of signal strength and quality, it is recommended to enable the cell reselection function of the module. For BC95 B657SP5 or later versions, BC95-G B300 or later versions, and BC68 B300 or later versions, the cell reselection function is enabled by default. BC95&BC95-G&BC68_Application_Design_Guide 11 / 22 NB-IoT Module Series BC95&BC95-G&BC68 Application Design Guide b) 3 If it needs to power off the module, AT+CFUN=0 must be executed before power-off. Before powering off the module, the MCU needs to send AT+CFUN=0 command to the module to trigger the module to save the EARFCN values and send a message to detach from network. a) 4 Data transmission service b) 5 6 If the cell reselection function is disabled, make sure the module is in minimum functionality mode (can be queried by AT+CFUN? command), and then the MCU sends AT+NCONFIG=CELL_RESELECTION,TRUE to enable the cell reselection function. When starting a data transmission via Huawei OceanConnect IoT platform, if "+CME ERROR: 513" error is returned (AT+CMEE=1 has been set; 513: TUP not registered), the MCU will attempt to re-send the data after a delay of 20s; if the re-send is failed for 3 times continuously, the MCU will enter the exception handling process (Refer to No.5 below). During a normal data transmission, if no downlink data is received within 60s in data interaction process, it will be regarded as a data service failure due to timeout, and the MCU will attempt to re-send the data; if the re-send is failed for 3 times continuously, the MCU will enter the exception handling process (Refer to No.5 below). Exception handling process If it fails to register on network or transmit data, then the MCU executes AT+NRB (Reboot the module) → AT+CFUN=0 (Enter minimum functionality mode) → AT+NCSEARFCN (Clear Stored EARFCN values) → AT+CFUN=1 (Enter full functionality mode) → AT+CGATT=1 (Attach to network), and tries to register on network and re-sends the data. If the re-registration or re-send still fails, it will retry for 3 times according to the back off algorithm. If it still fails, the MCU will power off the module. In such case, the module will try to register on network when the next round of data transmission is initiated. Support the module’s firmware upgrade via DFOTA During a firmware upgrade process via DFOTA, no AT command can be sent and the module cannot be powered off. It is recommended that the uninterruptible power supply time should be 30 minutes. The module outputs "FIRMWARE DOWNLOADING" via the main port to indicate that the firmware has started upgrading, "FIRMWARE UPDATE SUCCESS" to indicate that the upgrade is successful and "FIRMWARE UPDATE OVER" to indicate that the upgrade is completed. BC95&BC95-G&BC68_Application_Design_Guide 12 / 22 NB-IoT Module Series BC95&BC95-G&BC68 Application Design Guide 2.2.3. Flowchart of Design Guidelines Power on the module Set to manually register on network AT+NCONFIG=AUTOCONNECT,FALSE Set CDP server address AT+NCDP= [, ] Skip this step for UDP/TCP server Reboot the module by software AT+NRB Specify band values AT+NBAND= Skip this step for BC95 module Enter full functionality mode AT+CFUN=1 Disable eDRX function of the module AT+CEDRXS=0,5 Disable the use of PSM AT+CPSMS=0 Trigger network attachment AT+CGATT=1 Network attachment Data transmission service Yes Query whether successfully registered on network AT+CGATT? Execute AT+CGATT? after 300s, "+CGATT:1" is not returned. Reboot the module AT+NRB Trigger network attachment AT+CFUN=1 Enter minimum AT+CGATT=1 functionality mode Fail to receive downlink data 3 times continuously due to timeout (60s). Whether the data is No transmitted successfully? No Yes AT+CFUN=0 Idle mode Clear stored EARFCN values AT+NCSEARFCN Whether retry to register on network? No Yes Failed after 3 times of retries according to the back off algorithm. Exception Handling Power off Figure 2: Flowchart of Design Guidelines for Fixed Applications with Remote Control BC95&BC95-G&BC68_Application_Design_Guide 13 / 22 NB-IoT Module Series BC95&BC95-G&BC68 Application Design Guide 2.3. Mobile Applications with Data Transmission Mobile applications with data transmission will start a data transmission while they are moving. They only receive downlink data when an uplink data transmission is initiated (no need for receiving paging messages). Such terminals have high requirements on power consumption rather than timeliness of data transmission. Therefore, it is recommended to comply with the following design requirements. 2.3.1. Requirements on Network Configurations Table 5: Requirements on Network Configurations for Mobile Applications with Data Transmission No. Parameter Configuration Requirement 1 eDRX Disabled 2 PSM Enabled NOTE Please confirm the configuration settings of these parameters with corresponding network operators since they are determined by the core network. 2.3.2. Application Design Guidelines Table 6: Design Guidelines for Mobile Applications with Data Transmission No. Design Guideline Description 1 Timeout period for the MCU to register on network after start-up It may take a long time for the MCU to register on network when in deep coverage or when the network changes, so the timeout period for the MCU to register on network after start-up is recommended to be at least 300s. a) 2 Enable cell reselection function b) In order to ensure that the module can be camped on a better cell in terms of signal strength and quality, it is recommended to enable the cell reselection function of the module. For BC95 B657SP5 or later versions, BC95-G B300 or later versions, and BC68 B300 or later versions, the cell reselection function is enabled by default. If the cell reselection function is disabled, make sure the module is in minimum functionality mode (can be queried by BC95&BC95-G&BC68_Application_Design_Guide 14 / 22 NB-IoT Module Series BC95&BC95-G&BC68 Application Design Guide AT+CFUN? command), and then the MCU sends AT+NCONFIG=CELL_RESELECTION,TRUE to enable the cell reselection function. 3 Start an uplink data transmission with RAI identifiers Start an uplink data transmission with RAI identifiers (e.g.: AT+QLWULDATAEX=3,AA34BB,0x0001) for indicating the core network to release current RRC connection immediately so as to let the module enter idle mode. Then the module will automatically enter PSM after the idle timer expires. 4 If it needs to power off the module, AT+CFUN=0 must be executed before power-off. Before powering off the module, the MCU needs to send AT+CFUN=0 command to the module to trigger the module to save the EARFCN values and send a message to detach from network. a) 5 Data transmission service b) 6 7 When starting a data transmission via Huawei OceanConnect IoT platform, if "+CME ERROR: 513" error is returned (AT+CMEE=1 has been set; 513: TUP not registered), the MCU will attempt to re-send the data after a delay of 20s; if the re-send is failed for 3 times continuously, the MCU will enter the exception handling process (Refer to No.6 below). During a normal data transmission, if no downlink data is received within 60s in data interaction process, it will be regarded as a data service failure due to timeout, and the MCU will attempt to re-send the data; if the re-send is failed for 3 times continuously, the MCU will enter the exception handling process (Refer to No.6 below). Exception handling process If it fails to register on network or transmit data, then the MCU executes AT+NRB (Reboot the module) → AT+CFUN=0 (Enter minimum functionality mode) → AT+NCSEARFCN (Clear Stored EARFCN values) → AT+CFUN=1 (Enter full functionality mode) → AT+CGATT=1 (Attach to network), and tries to register on network and re-sends the data. If the re-registration or re-send still fails, it will retry for 3 times according to the back off algorithm. If it still fails, the MCU will power off the module. In such case, the module will try to register on network when the next round of data transmission is initiated. Support the module’s firmware upgrade via DFOTA During a firmware upgrade process via DFOTA, no AT command can be sent and the module cannot be powered off. It is recommended that the uninterruptible power supply time should be 30 minutes. The module outputs "FIRMWARE DOWNLOADING" via the main port to indicate that the firmware has started upgrading, "FIRMWARE UPDATE SUCCESS" to indicate that the upgrade is successful and "FIRMWARE UPDATE OVER" to indicate that the upgrade is completed. BC95&BC95-G&BC68_Application_Design_Guide 15 / 22 NB-IoT Module Series BC95&BC95-G&BC68 Application Design Guide 2.3.3. Flowchart of Design Guidelines Power on the module Set to manually register on network AT+NCONFIG=AUTOCONNECT,FALSE Set CDP server address AT+NCDP= [, ] Skip this step for UDP/TCP server Reboot the module by software AT+NRB Specify band values AT+NBAND= Skip this step for BC95 module Enter full functionality mode AT+CFUN=1 Disable eDRX function of the module AT+CEDRXS=0,5 Trigger network attachment AT+CGATT=1 Network attachment Data transmission service Yes Query whether successfully registered on network AT+CGATT? Execute AT+CGATT? after 300s, "+CGATT:1" is not returned. Reboot the module AT+NRB Trigger network attachment AT+CFUN=1 Enter minimum AT+CGATT=1 functionality mode Fail to receive downlink data 3 times continuously due to timeout (60s). Whether the data is No transmitted successfully? Yes No Start an uplink data transmission with RAI identifiers. AT+CFUN=0 Idle mode PSM Clear stored EARFCN values AT+NCSEARFCN Whether retry to register on network? No Yes Failed after 3 times of retries according to the back off algorithm. Exception Handling Power off Figure 3: Flowchart of Design Guidelines for Mobile Applications with Data Transmission BC95&BC95-G&BC68_Application_Design_Guide 16 / 22 NB-IoT Module Series BC95&BC95-G&BC68 Application Design Guide 2.4. Mobile Applications with Remote Control Mobile applications with remote control are kept in a moving state and in connected mode most of the time. They are required to receive real-time downlink data and report real-time uplink data. Such terminals are usually rechargeable and have high requirements on timeliness of data transmission rather than power consumption. Therefore, it is recommended to comply with the following design requirements. 2.4.1. Requirements on Network Configurations Table 7: Requirements on Network Configurations for Mobile Applications with Remote Control No. Parameter Configuration Requirement 1 eDRX Disabled 2 PSM Disabled NOTE Please confirm the configuration settings of these parameters with corresponding network operators since they are determined by the core network. 2.4.2. Application Design Guidelines Table 8: Design Guidelines for Mobile Applications with Remote Control No. Design Guideline Description 1 Timeout period for the MCU to register on network after start-up It may take a long time for the MCU to register on network when in deep coverage or when the network changes, so the timeout period for the MCU to register on network after start-up is recommended to be at least 300s. a) 2 Enable cell reselection function b) In order to ensure that the module can be camped on a better cell in terms of signal strength and quality, it is recommended to enable the cell reselection function of the module. For BC95 B657SP5 or later versions, BC95-G B300 or later versions, and BC68 B300 or later versions, the cell reselection function is enabled by default. If the cell reselection function is disabled, make sure the module is in minimum functionality mode (can be queried by BC95&BC95-G&BC68_Application_Design_Guide 17 / 22 NB-IoT Module Series BC95&BC95-G&BC68 Application Design Guide AT+CFUN? command), and then the MCU sends AT+NCONFIG=CELL_RESELECTION,TRUE to enable the cell reselection function. 3 Start an uplink data transmission with RAI identifiers Start an uplink data transmission with RAI identifiers (e.g.: AT+QLWULDATAEX=3,AA34BB,0x0001) for indicating the core network to release the current RRC connection immediately so as to let the module enter idle mode. Then the module will automatically enter PSM after the idle timer expires. 4 If it needs to power off the module, AT+CFUN=0 must be executed before power-off. Before powering off the module, the MCU needs to send AT+CFUN=0 command to the module to trigger the module to save the EARFCN values and send a message to detach from network. a) 5 Data transmission service b) 6 7 When starting a data transmission via Huawei OceanConnect IoT platform, if "+CME ERROR: 513" error is returned (AT+CMEE=1 has been set; 513: TUP not registered), the MCU will attempt to re-send the data after a delay of 20s; if the re-send is failed for 3 times continuously, the MCU will enter the exception handling process (Refer to No.6 below). During a normal data transmission, if no downlink data is received within 60s in data interaction process, it will be regarded as a data service failure due to timeout, and the MCU will attempt to re-send the data; if the re-send is failed for 3 times continuously, the MCU will enter the exception handling process (Refer to No.6 below). Exception handling process If it fails to register on network or transmit data, then the MCU executes AT+NRB (Reboot the module) → AT+CFUN=0 (Enter minimum functionality mode) → AT+NCSEARFCN (Clear Stored EARFCN values) → AT+CFUN=1 (Enter full functionality mode) → AT+CGATT=1 (Attach to network), and tries to register on network and re-sends the data. If the re-registration or re-send still fails, it will retry for 3 times according to the back off algorithm. If it still fails, the MCU will power off the module. In such case, the module will try to register on network when the next round of data transmission is initiated. Support the module’s firmware upgrade via DFOTA During a firmware upgrade process via DFOTA, no AT command can be sent and the module cannot be powered off. It is recommended that the uninterruptible power supply time should be 30 minutes. The module outputs "FIRMWARE DOWNLOADING" via the main port to indicate that the firmware has started upgrading, "FIRMWARE UPDATE SUCCESS" to indicate that the upgrade is successful and "FIRMWARE UPDATE OVER" to indicate that the upgrade is completed. BC95&BC95-G&BC68_Application_Design_Guide 18 / 22 NB-IoT Module Series BC95&BC95-G&BC68 Application Design Guide 2.4.3. Flowchart of Design Guidelines Power on the module Set to manually register on network AT+NCONFIG=AUTOCONNECT,FALSE Set CDP server address AT+NCDP= [, ] Skip this step for UDP/TCP server Reboot the module by software AT+NRB Specify band values AT+NBAND= Skip this step for BC95 module Enter full functionality mode AT+CFUN=1 Disable eDRX function of the module AT+CEDRXS=0,5 Disable the use of PSM AT+CPSMS=0 Trigger network attachment AT+CGATT=1 Network attachment Data transmission service Yes Query whether successfully registered on network AT+CGATT? Execute AT+CGATT? after 300s, "+CGATT:1" is not returned. Reboot the module AT+NRB Trigger network attachment AT+CFUN=1 Enter minimum AT+CGATT=1 functionality mode Fail to receive downlink data 3 times continuously due to timeout (60s). Whether the data is No transmitted successfully? Yes No Start an uplink data transmission with RAI identifiers. AT+CFUN=0 Clear stored EARFCN values AT+NCSEARFCN Idle mode Whether retry to register on network? No Yes Failed after 3 times of retries according to the back off algorithm. Exception Handling Power off Figure 4: Flowchart of Design Guidelines for Mobile Applications with Remote Control BC95&BC95-G&BC68_Application_Design_Guide 19 / 22 NB-IoT Module Series BC95&BC95-G&BC68 Application Design Guide 3 Supplementary Notes 3.1. Conventional Maintenance and Test Means ⚫ ⚫ The terminals should be capable of reporting network-related information and such information can be displayed on the platform: such as EARFCN values, cell ID, enhanced coverage level (ECL), signal strength (RSRP) and signal noise ratio (SNR), which can be obtained via AT+NUESTATS command. A local port is available on the terminals for the module to upgrade the firmware, view log information and modify the configurable parameters. 3.2. Brief Introduction of Related AT Commands This chapter briefly introduces some related AT commands regarding to the application design guidelines. For more details, please refer to document [1]&[2]. Table 9: Brief Introduction of Related AT Commands No. AT Command Description 1 AT+NCONFIG=CELL_RESELECTION,TRUE Enable cell reselection function of the module 2 AT+NCONFIG=AUTOCONNECT,FALSE Disable automatic network registration of the module 3 AT+CEDRXS=0,5 Disable eDRX function of the module 4 AT+CGATT=1 Trigger the module for network attachment 5 AT+CGATT? Query whether the module is registered on network successfully 6 AT+NRB Reboot the module 7 AT+CPSMS=0 Disable the use of PSM for the module BC95&BC95-G&BC68_Application_Design_Guide 20 / 22 NB-IoT Module Series BC95&BC95-G&BC68 Application Design Guide AT+NSOSTF= , , , , , Can be used to send UDP data with flags for indicating the core network to release the current RRC connection immediately so as to let the module enter idle mode. AT+QLWULDATAEX= ,, Can be used to send CoAP data with RAI identifiers for indicating the core network to release the current RRC connection immediately so as to let the module enter idle mode. AT+NUESTATS Query EARFCN values, cell ID, ECL, RSRP and SNR information of the last cell that is camped on. 11 AT+NCSEARFCN Clear EARFCN values stored by the module. This command takes effect only when AT+CFUN=0. 12 AT+CFUN= Set the functionality level of the module 8 9 10 BC95&BC95-G&BC68_Application_Design_Guide 21 / 22 NB-IoT Module Series BC95&BC95-G&BC68 Application Design Guide 4 Appendix A References Table 10: Reference Documents SN Document Note [1] Quectel_BC95_AT_Commands_Manual BC95 AT commands manual [2] Quectel_BC95-G&BC68_AT_Commands_Manual BC95-G&BC68 AT commands manual [3] Quectel_BC95_DFOTA_User_Guide BC95 DFOTA upgrade guidance [4] Quectel_BC95&BC95-G&BC68_RAI_Application_Note BC95&BC95-G&BC68 RAI application note Table 11: Terms and Abbreviations Abbreviation Description CoAP Constrained Application Protocol EARFCN E-UTRA Absolute Radio Frequency Channel Number ECL Enhanced Coverage Level eDRX Extended Discontinuous Reception MCU Microprogrammed Control Unit PSM Power Saving Mode RAI Release Assistant Indication RSRP Reference Signal Received Power SNR Signal Noise Ratio UDP User Datagram Protocol BC95&BC95-G&BC68_Application_Design_Guide 22 / 22
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