GB/T 44087-2024Technical requirements and test methods for BDS-3 regional short message communication user terminal (English PDF)

3 Terms, definitions and abbreviations

3.1.1 regional short message communication (RSMC): the communication service providing users with short message communication, emergency search and rescue and position reporting within a given coverage area through the BeiDou geostationary orbit satellites.

3.1.2 to 3.1.5 The document distinguishes a smart terminal, which separates the operating system from the application software and allows both to be configured dynamically; a handheld terminal, operated while held in the hand; an ordinary user terminal, which can receive broadcast information, communicast, multicast and unicast messages and can send unicast and multicast messages, also called user terminal or user set; and a management terminal, which has all the functions of an ordinary user terminal and can additionally receive and query the BeiDou short message information of its subordinate users and communicast to them.

3.1.6 to 3.1.7 unicast is point-to-point communication over the BDS-3 regional short message link; communicast is the mode in which a management terminal broadcasts the same short message information to all its subordinate users in a single short message transmission.

3.1.8 to 3.1.9 address: the unique number identifying an entity taking part in the BDS-3 regional short message service, divided into an intranet part and an extranet part. The extranet address is the unique number identifying an external user exchanging information with the BDS-3 system by unicast; a note gives mobile telephone numbers, WeChat user numbers and Weibo numbers as examples.

3.2 The abbreviations used are EIRP for equivalent isotropically radiated power and SAR for specific absorption rate.

4 Technical requirements

4.1 By function, BDS-3 regional short message communication user terminals are divided into management terminals and ordinary user terminals; by the way they are installed and used, into handheld, vehicle-mounted, ship-borne and airborne terminals; and by whether they support dynamic configuration of the operating system and the addition or removal of application software, into smart and non-smart terminals.

4.2 to 4.5 The outer surface of the terminal shall be free from defects such as dents, scratches, cracks and deformation; coatings and platings shall not blister, craze or peel; metal parts shall not corrode. The rated voltage range for normal operation is laid down in the product standard. The main unit, the antenna and other main parts shall carry a marking and a nameplate that are clear, conspicuous, firm and durable; the nameplate shall include the manufacturer name, the equipment serial number and the date of manufacture and shall comply with GB/T 13306-2011. The terminal shall have at least one input/output data interface.

4.6.1 The short message service functions are: it shall be able to send short messages supporting Chinese characters and codes; it shall be able to receive them; it shall have a communication receipt function; a management terminal shall have communicast and joint reception functions; it may be able to send messages to extranet addresses; and it may be able to receive information sent from extranet addresses.

4.6.2 For communication control the terminal shall have a frequency control function, able to control inbound applications according to the service rate (inbound transmissions that do not consume the rate, such as communication receipts, excepted), limiting over-rate inbound applications and giving a corresponding prompt; a parameter update function, able to respond to system access management commands, to adjust parameters such as transmission rate, communication grade and inbound power and to work with the adjusted parameters while prompting the user; and an electromagnetic silence function, able to set itself to the electromagnetic silence state, to send a silence inbound application and to receive and signal the silence confirmation message.

4.6.3 For communication management the terminal shall have four transmission rates, 2 kbit/s, 4 kbit/s, 8 kbit/s and 16 kbit/s, and shall select the matching inbound rate automatically according to the message length; it shall have a no-response-beam inbound function, transmitting the inbound signal directly when it cannot lock any outbound beam; and it shall have a power-on report function, sending a power-on report automatically when switched on.

4.6.4 to 4.6.5 The information security requirements for smart terminals are: an application software security configuration capability, providing a mechanism to configure the behaviour of installed third-party application software when it calls the sending and receiving of short messages; pre-installed application software containing signature information that is genuine and valid; and a prohibition on processing transmitted information or transmitting false information in a way that makes the receiver identify a particular communicating party wrongly, on pre-installing application software able to alter short message prompt information or to serve the dissemination of information forbidden by national laws and regulations, and on pre-installing content forbidden by national laws and regulations, including but not limited to pictures, texts, menus, audio and video and applications. The terminal shall have a human-machine interaction function.

4.7.1 The transmission performance indicators are: EIRP not more than 36 dBm; transmission frequency accuracy not more than 0.5 parts per million; occupied bandwidth of the transmitted signal not more than 8.2 MHz; transmitted signal frequency range from 1610 MHz to 1626.5 MHz with centre frequencies of 1614.26 MHz and 1618.34 MHz; spurious emission meeting table 1; and protection of special frequency bands meeting table 2. Table 1 sets, for both the band from 30 MHz to 1580 MHz and the band from 1650 MHz to 12.75 GHz, a maximum level limit of minus 50 dBm measured in a 4 kHz bandwidth with root-mean-square detection. Table 2 sets a limit of minus 54 dBm measured in a 100 kHz bandwidth with root-mean-square detection for the bands 48.5 MHz to 72.5 MHz, 76 MHz to 118 MHz, 167 MHz to 223 MHz and 470 MHz to 702 MHz, and a limit of minus 40 dBm measured in a 1 MHz bandwidth for the bands 5725 MHz to 5850 MHz and 5905 MHz to 5925 MHz.

4.7.2 The reception performance indicators are: with a received signal level of minus 121.8 dBm, a bit error rate of not more than 1 in 100 000, with antenna elevation from 70 degrees to 90 degrees for handheld terminals and from 30 degrees to 90 degrees for other terminals, azimuth from 0 degrees to 360 degrees and a data segment information rate of 24 kbit/s; not fewer than four channels for receiving satellite signals; in conducted mode, with a reference sensitivity signal level of minus 127 dBm, a bit error rate of not more than 1 in 100 000; and receiver blocking meeting table 3. Table 3 gives two interference cases, one at 2472 MHz with a 20 MHz interference bandwidth and an interference level of minus 80 dBm, the other at 2520 MHz with a 10 MHz bandwidth and a level of minus 76 dBm; the wanted signal power, sensitivity plus 6 dB, and the bit error rate limit of not more than 1 in 100 000 appear once for the two rows.

4.7.3 to 4.7.4 The electromagnetic compatibility indicators refer the radiated emission limits below 1 GHz to A4.1 and A4.2 of table A.4 of GB/T 9254.1-2021 and those above 1 GHz to table A.5 of the same standard, the conducted emission limits to its table A.10, the electrostatic discharge immunity to contact discharge level 2 and air discharge level 3 of table 1 of GB/T 17626.2-2018 with the result meeting clause 9 b) of that standard, the radiated immunity to test level 2 of table 1 of GB/T 17626.3-2016 and, for terminals with an AC or DC power port with cables longer than 3 m, the conducted immunity to test level 1 of table 1 of GB/T 17626.6-2017; the terminal shall also withstand adjacent-channel interference from mobile communications, WLAN and Bluetooth, receiving and processing outbound communication correctly with a success rate of not less than 95 %. For terminals used within 20 cm of the human body, the electromagnetic radiation exposure limit shall meet the local SAR requirement of table 1 of GB 21288-2022.

4.8 The environmental adaptability requirements are an operating temperature from minus 20 degrees Celsius to 55 degrees Celsius and a storage temperature from minus 40 degrees Celsius to 70 degrees Celsius.

5 Test methods

5.1 The instruments and equipment used shall have been verified or calibrated, shall meet the measurement requirements and shall be within their validity period. Table 4 lists ten items with their descriptions and indicators: a BDS-3 regional short message signal broadcasting simulator, a BDS-3 regional short message inbound signal receiving simulator, test control and evaluation equipment, a rotatable test table, a spectrum analyser, a detector, an electromagnetic radiation specific absorption rate test system, a high and low temperature test chamber, a combiner and a blocking signal generator.

5.2 Table 5 maps the test items to the requirement clause, the test method clause and the test scenario, covering appearance, power supply, marking, interfaces, the five functional items (short message service, communication control, communication management, information security and human-machine interaction), the four performance items (transmission, reception, electromagnetic compatibility and electromagnetic field exposure) and environmental adaptability. Test environment one of figure 1 is used for the tests of 5.4.1, 5.4.2, 5.4.3, 5.5.1, 5.5.2 a), 5.5.2 b) and 5.5.2 c), and test environment two of figure 2 for the test of 5.5.2 d); the other test items use the test environments set up according to the relevant standards.

5.3 Appearance is checked by eye and by hand. For the power supply test the terminal under test is supplied at the voltage determined by the product standard and it is checked whether it works normally. Marking and interfaces are checked by eye.

5.4.1 In the short message service function test the test system broadcasts the test signal and the terminal is switched on and locks the signal; it is then checked whether the terminal can carry out human-machine interaction in graphic and code form, whether the inbound signal is correct when the terminal applies for inbound transmission in Chinese characters and in codes, whether the terminal receives and processes unicast communication correctly and sends the receipt correctly, and, for management terminals, whether communicast inbound applications and outbound communicast reception are correct. It is further checked whether inbound transmission to an extranet user address is correct, whether unicast outbound communication from an extranet sender address is received and processed correctly, and whether a management terminal correctly receives and processes unicast outbound communication addressed to one of its subordinate users.

5.4.2 The communication control tests cover frequency control, parameter update and electromagnetic silence. For frequency control the terminal transmits inbound signals continuously at a rate above the reference rate and it is checked whether the inbound rate is the reference rate and whether the terminal gives the corresponding prompt, and then whether it can transmit at the adjusted rate after the test system has broadcast a frequency control command. For parameter update the same procedure is followed for rate and for communication grade, and for power control the inbound power P1 is measured, a power control command with a power change is broadcast covering all adjustment values from the largest to the smallest, the inbound power P2 is measured and it is checked whether the terminal adjusts its inbound power according to the command with an adjustment deviation of less than 0.5 dB. For electromagnetic silence the terminal sends a silence application to set itself in the silence state and it is checked whether the inbound signal is correct, whether the terminal receives and processes the silence inbound confirmation correctly and gives a silence prompt, and whether it is unable to send a communication receipt when a unicast outbound communication is broadcast.

5.4.3 The communication management tests cover inbound rate selection, no-response-beam inbound transmission and the power-on report. For rate selection the terminal sends messages of 2 047 bit, 4 095 bit, 8 191 bit and 14 000 bit and it is checked whether it selects the matching transmission rate automatically according to the message length, 2 047 bit corresponding to 2 kbit/s, 4 095 bit to 4 kbit/s, 8 191 bit to 8 kbit/s and 14 000 bit to 16 kbit/s. For the no-response-beam function the terminal applies for inbound transmission in Chinese characters and in codes with no outbound signal present and the correctness of the inbound signal is checked. For the power-on report the terminal is set to the off state and, after it is switched on and locks the signal, it is checked whether it transmits the power-on report inbound correctly.

5.4.4 The information security test checks whether the operating system supports the installation of third-party application software and provides development functions for sending and receiving short messages; a third-party application is installed and developed, and it is checked whether its calls to send and receive short messages can be configured, what the application actually does when those calls are disabled and when they are enabled, and whether the security configuration is unchanged after the application has been upgraded and run. It is also checked whether the pre-installed short message applications contain signature information that is genuine and valid, whether functions exist that could make the receiver identify the sender wrongly, such as changing the short message user ID number, or that could alter short message prompt information, and, by going through the menus and the pre-installed applications, whether they contain content forbidden by national laws and regulations or can serve the dissemination of such content.

5.5.1 In the transmission performance test the terminal transmits inbound at maximum power and a spectrum analyser measures the EIRP not fewer than 20 times, the mean being checked against the limit of not more than 36 dBm. Frequency accuracy is calculated by formula (1) from 20 measurements of the inbound signal centre frequency; in its legend the frequency accuracy is a dimensionless quantity, the measured centre frequency and the nominal centre frequency are in hertz and n is the number of measurements. Occupied bandwidth is measured five times using the marker function of the spectrum analyser between the two points 10 dB below the peak power spectral density and averaged. The lowest frequency corresponding to 99 % of the power on the lowest supported channel and the highest frequency corresponding to 99 % of the power on the highest supported channel are recorded five times and averaged. Spurious emission and special band protection are checked by configuring the spectrum analyser according to tables 1 and 2 and marking the largest level measured.

5.5.2 In the reception performance test the signal power, data segment rate and antenna elevation and azimuth are set as required, with not fewer than three elevation angles covering the boundary values, cyclic azimuth movement at a rotation rate of not more than 5 degrees per second, not fewer than one million navigation messages collected and at least one full azimuth revolution; the bit error rate is calculated by formula (2) as the number of messages in error divided by the total number of samples. Reception of not fewer than four beams is checked by broadcasting unicast outbound communication, at least two messages per beam and not fewer than ten in total, with a success rate of not less than 95 %. The conducted reference sensitivity test connects the receiving port to the test system by cable and repeats the bit error rate measurement. The blocking test is set up according to figure 2, with the blocking signal set according to table 3 and the wanted signal at sensitivity plus 6 dB, the bit error rate being read and stored by the host computer.

5.5.3 The electromagnetic compatibility tests are run according to the facilities, equipment and procedures of clause 6 of GB/T 9254.1-2021 for radiated and conducted emission, GB/T 17626.2-2018 for electrostatic discharge immunity, GB/T 17626.3-2016 for radiated immunity and GB/T 17626.6-2017 for conducted immunity, with the additional conditions given in the clause: for radiated emission the transmitter and transceiver working frequencies and their spurious emissions are ignored but recorded in the test report, the tests are run in the typical configuration of the auxiliary equipment, common mode absorbing devices meeting GB/T 6113.104-2021 may be used and their use recorded, and above 1 GHz both average and peak detectors are used, a peak result meeting the average limit being taken to satisfy both. For radiated immunity the test runs from 80 MHz to 6 GHz with a frequency step of 1 % of the preceding frequency, a dwell time of not less than 0.5 s, a field strength of 3 V/m and 80 % amplitude modulation by a 1 kHz sine wave, the exempt bands of receivers and transceivers being excluded and narrowband responses at discrete frequencies ignored but recorded. For conducted immunity the test runs from 150 kHz to 80 MHz with the same step and dwell time, a test level of 3 V root mean square and the same modulation. Adjacent-channel interference is checked by radiating 4G and 5G mobile communication, WLAN and Bluetooth interference at the powers of table 6 while outbound communication is broadcast, over 20 tests, with a success rate of not less than 95 %. Table 6 gives the interference signal power arriving at the antenna aperture for seven bands: minus 26.6 dBm from 2010 MHz to 2025 MHz, minus 27.0 dBm from 2110 MHz to 2130 MHz, minus 27.1 dBm from 2130 MHz to 2155 MHz, minus 22.8 dBm from 2400 MHz to 2453.5 MHz, minus 32.8 dBm from 2412 MHz to 2472 MHz, minus 28.6 dBm from 2530 MHz to 2615 MHz and minus 28.8 dBm from 2575 MHz to 2635 MHz.

5.5.4 The electromagnetic field exposure tests follow YD/T 1644.1-2020 for terminals used close to the ear, tested in the cheek and tilt positions on the left and the right side of the head phantom, YD/T 1644.4-2020 for limb-worn terminals, tested in the in-front-of-the-face mode at 10 mm from the phantom surface where no use distance is specified and in contact where the terminal touches the cheek in use, and YD/T 1644.2-2011 for other terminals held in front of the face, at 25 mm where no distance is specified. Where a terminal is used both close to the ear and in front of the face, only the close-to-the-ear mode need be tested. For body-worn terminals the test distance is 15 mm for terminals with a screen diagonal larger than 200 mm and 5 mm for others. For limb-worn terminals in the wrist exposure scenario the contact mode is measured, a flat body phantom being usable where no wrist phantom is available. A note states that during these tests the terminal is operated as specified in 5.4.1 c).

5.6 The environmental adaptability tests are: low temperature storage according to test Ab of GB/T 2423.1-2008, with the unpacked and unpowered terminal at room temperature placed in a chamber at room temperature, the temperature lowered at a rate of not more than 1 degree Celsius per minute averaged over not more than 5 min to minus 40 degrees Celsius plus or minus 3 degrees Celsius, held for 48 h after temperature stabilisation, recovered at normal temperature for at least 2 h and then tested according to 5.4.1 against the requirements of 4.6.1; low temperature operation according to test Ad of the same standard at minus 20 degrees Celsius plus or minus 3 degrees Celsius for 24 h with the terminal powered and working normally; high temperature storage according to test Bb of GB/T 2423.2-2008 at 70 degrees Celsius plus or minus 2 degrees Celsius for 48 h, following the steps of the low temperature storage test; and high temperature operation according to test Bd of GB/T 2423.2-2008 at 55 degrees Celsius plus or minus 2 degrees Celsius for 24 h.