4G LTE modem is an Internet of things communication terminal, which uses a wireless network to provide users with long-distance data transmission functions, and uses a high-performance industrial communication processor and an industrial wireless module. The stability of 4G LTE modem is the primary consideration when we choose and buy products. Only a stable signal can bring better transmission effect.
Four ways to test 4G LTE modem signal stability:
Test the ability of 4G LTE modem to maintain the established link by itself. When there is no data, 4G LTE modem maintains its own connection through heartbeat. 4G LTE modems should be able to maintain an average link duration of at least 1 hour without disconnection and reconnection.
Test method: connect the 4G LTE modem to the data center without sending any data, and observe how long it can maintain the link, the longer the better.At the end of this test, several data packets shall be sent to the data center and the 4G LTE modem respectively to verify that the idle link maintained by the 4G LTE modem is really available. If either the 4G Lte modem or the data center cannot receive the data packet from the other party, it is not qualified.
During the future operation and maintenance of the data center, the service will definitely be suspended temporarily, so it is necessary to test the rapid recovery ability of 4G LTE modem after the recovery of the data center.
Test method: Shut down the data center for a short time, such as 1 minute, and then restore the data center to see if the 4G LTE modem can be connected quickly. The recovery time should be within 5 minutes, the faster the better. Repeat the test for many times. The 4G LTE modem must be able to restore 100% of the connection. As long as the 4G LTE modem can not restore the connection once, it is not qualified.The 4G LTE modem quality can be judged by this example.
Test the ability of 4G LTE modem to send and receive small data packets frequently, because the daily operation is mainly the frequent two-way sending and receiving of small data packets.
Test method: at the data center and the 4G LTE modem, send a data packet of about 100 bytes to the other party every 10 seconds for 10 minutes. At the same time, count whether the network is disconnected or the data is lost. The best result is that there is no disconnection and reconnection, and no data packet is lost. If the 4G LTE modem/RTU is disconnected and never comes online,Or if it is unable to continue to send and receive data in both directions after going online, it is unqualified. In addition, during the small data volume test, you can observe whether there is packet loss or data content error. If there is frequent packet loss or content error, it is unqualified.
Some applications need to temporarily transfer large amounts of data, so this test is also very necessary.
Test method: at the data center and the 4G LTE modem, send a data packet of about 1000 bytes to each other every 2 seconds for 30 minutes, and count whether the network is disconnected and whether the data packet is lost.Generally speaking, under the stress test, the 4G LTE modem may be disconnected and reconnected, and data packets may also be lost, but the number of times of disconnection and reconnection should not exceed 10, and the smaller the number of times, the better. If the 4G LTE modem is disconnected and cannot be connected again, or cannot continue to send and receive data in both directions after being connected, it is not qualified.In addition, the index of data transmission performance can be observed during the big data stress test. In general, the speed of 4G LTE modem data transmission is within the range of 300 ~ 1500 bytes per second, which is normal, but the faster the speed, the better the transmission performance. If the transmission capacity of the 4G LTE modem is significantly lower than this range, it is not qualified.
