Data transmission method, device, and system

A data transmission method, comprising:

• receiving, by user equipment UE in a first subframe in a first radio frame and a first subframe in a second radio frame, a narrowband primary synchronization signal (NPSS) from a base station, wherein the first radio frame and the second radio frame are consecutive;
• receiving, by the UE in a second subframe in the first radio frame and a second subframe in the second radio frame, a narrowband physical broadcast channel (NPBCH) from the base station;
• receiving, by the UE in a third subframe in the first radio frame, a narrowband secondary synchronization signal (NSSS) from the base station;
• receiving, by the UE in a third subframe in the second radio frame, a system information block Type1-NB (SIB1-NB) from the base station;
• and
• in response to that the first subframe and the third subframe in the first radio frame are separated by a subframes, determining, by the UE, that both the first radio frame and the second radio frame use a time division duplex (TDD) uplink-downlink subframe configuration, wherein a is a natural number, a is not equal to 3 and is less than 9.

An apparatus, comprising:

• at least one processor coupled to a non-transitory memory and configured to execute instructions stored in the non-transitory memory, wherein the instructions cause the apparatus to:
• receive, in a first subframe in a first radio frame and a first subframe in a second radio frame, a narrowband primary synchronization signal (NPSS) from a base station, wherein the first radio frame and the second radio frame are consecutive;
• receive, in a second subframe in the first radio frame and a second subframe in the second radio frame, a narrowband physical broadcast channel (NPBCH) from the base station;
• receive, in a third subframe in the first radio frame, a narrowband secondary synchronization signal (NSSS) from the base station;
• receive, in a third subframe in the second radio frame, a system information block Type1-NB (SIB1-NB) from the base station;
• and
• in response to that the first subframe and the third subframe in the first radio frame are separated by a subframes, determine that both the first radio frame and the second radio frame use a time division duplex (TDD) uplink-downlink subframe configuration, wherein a is a natural number, a is not equal to 3 and is less than 9.

An apparatus, comprising:

• at least one processor coupled to a non-transitory memory and configured to execute instructions stored in the non-transitory memory, wherein the instructions cause the apparatus to:
• send a narrowband primary synchronization signal (NPSS) to user equipment (UE) using a first subframe in a first radio frame and a first subframe in a second radio frame, wherein the first radio frame and the second radio frame are consecutive, and both the first radio frame and the second radio frame use a time division duplex (TDD) uplink-downlink subframe configuration;
• send a narrowband physical broadcast channel (NPBCH) to the UE using a second subframe in the first radio frame and a second subframe in the second radio frame;
• send a narrowband secondary synchronization signal (NSSS) to the UE using a third subframe in the first radio frame;
• and
• send a system information block Type1-NB (SIB1-NB) to the UE by using a third subframe in the second radio frame.