An Improved MCPTT System File Breakpoint Resuming Algorithm

For the time-varying channel quality of MCPTT system, in order to successfully transmit large multimedia files, an improved file breakpoint retransmission algorithm in MCPTT system is proposed. By jointly considering the user channel quality and file size, adaptively fragments large multimedia files and selects the appropriate number of retransmissions, which can improve the transmission success rate and transmission rate of large multimedia files. Theoretical analysis and simulation results show that compared with the traditional breakpoint resuming algorithm, the algorithm can not only improve the transmission success rate, but also reduce the file transmission time of large multimedia files.