DATA TRANSMISSION SYSTEM AND ITS COMMUNICATION UNIT

摘要

PROBLEM TO BE SOLVED: To recover the quality of reception reproduction data in a short time even when the quality of reception reproduction data is considerably deteriorated due to deterioration in the transmission quality. SOLUTION: In the case that wireless video phone communication by using the MPEG-4 between mobile phone terminals MS1 and MS2, when a reception electric field strength is decreased to a threshold value H or below consecutively for a prescribed period T3 or over during data reception by the mobile phone MS2, the recovery is monitored, and when the recovery is detected, the mobile phone terminal MS2 transmits a transmission request of an I frame to the mobile phone terminal MS1. Then the mobile phone terminal MS1 receiving this transmission request generates the I frame in place of a P frame and transmits the I frame.