Một phương án truyền dữ liệu qua kênh thoại GSM
Mobile phones and GSM technology are now very popular around the world. The demand for GSM voice signal security is urgent, while GSM's existing security solution has not yet reached the required safety level. The best solution for GSM voice signal security is to convert the signal into a digital form via a separate Vocoder, encrypt that digital signal using a strong encryption algorithm and transmit the encrypted signal through the GSM voice channel. In this contribution, we will present a solution for transmitting data via GSM voice channel which compatible with the properties of GSM voice channel, in this case, they are GSM Vocoder and voice activity detection (VAD) for GSM.