Abstract: This application discloses a NB-IoT-based communication method and an apparatus, to evolve a NB-IoT communication technology into an NTN. The method is as follows: A terminal device generates an uplink signal, including a superframe which includes a synchronization sequence located in first duration of the superframe and a data frame located in second duration which is after the first duration, the synchronization sequence successively includes a first sequence repeated Ni times and a second sequence repeated N2 times, the second sequence is obtained by multiplying the first sequence by ?1, a part of consecutive sequences of the synchronization sequence are used as a first synchronization reference sequence that is obtained based on the second sequence repeated N2 times and one or more first sequences that are sorted from back to front in the first sequence repeated N1 times. The terminal device sends the uplink signal to a network device.

Abstract: An information transmission method and an apparatus. The information transmission method includes: a receive end sends first indication information, where the first indication information indicates a target receiving mode of the receive end, and the target receiving mode is one of a plurality of receiving modes. The receive end receives service information based on the target receiving mode. The receive end performs decoding processing on the service information based on the target receiving mode. In this way, power consumption can be further reduced, and information transmission of a plurality of service types can be supported, thereby improving information transmission flexibility and user experience.

Abstract: The present disclosure provides an experiment platform for simulating fire in an underground traffic conversion channel, including: a model body configured to simulate fire in the an underground traffic conversion channel; a burner connected to the model body and configured to generate smoke; and a smoke imaging system including laser sheet light sources and image recording devices configured to record smoke distribution images. The laser sheet light sources are in the model body, and plane laser light emitted by the laser sheet light sources is parallel to a flow direction of the smoke. The image recording devices are in one-to-one correspondence to the laser sheet light sources and are arranged outside an observation window of the model body. One laser sheet light source and one image recording device corresponding thereto each have a filter configured to filter out laser light of a same wavelength.

Abstract: The present disclosure provides an experiment platform for simulating fire in an underground traffic conversion channel, including: a model body configured to simulate fire in the an underground traffic conversion channel; a burner connected to the model body and configured to generate smoke; and a smoke imaging system including laser sheet light sources and image recording devices configured to record smoke distribution images. The laser sheet light sources are in the model body, and plane laser light emitted by the laser sheet light sources is parallel to a flow direction of the smoke. The image recording devices are in one-to-one correspondence to the laser sheet light sources and are arranged outside an observation window of the model body. One laser sheet light source and one image recording device corresponding thereto each have a filter configured to filter out laser light of a same wavelength.