Communication system

A communication system comprising:

• a first communication terminal to encode transmission data by using an encoding model that encodes and outputs data that has been input;
• a second communication terminal unable to perform encoding of transmission data using the encoding model;
• and
• a base station to decode data encoded with the encoding model of the first communication terminal by using a decoding model that, when encoded data is input, decodes and outputs the data, wherein
• the encoding model performs encoding on channel state-related data that is data on a channel state between the first communication terminal and the base station, and
• the base station executes machine learning using learning data to generate the encoding model and the decoding model, the learning data including the channel state-related data in an un-encoded state transmitted by the first communication terminal without performing encoding using the encoding model, and notifies the first communication terminal of a learning result of the encoding model.