초록 ▼

A system and method for determining the data rate of a frame of data at a receiver of a variable rate communications system. A vocoder at a transmitter encodes a frame of data at one of the rates of a predetermined set of rates. The data rate is dependent on the speech activity during the time frame

A system and method for determining the data rate of a frame of data at a receiver of a variable rate communications system. A vocoder at a transmitter encodes a frame of data at one of the rates of a predetermined set of rates. The data rate is dependent on the speech activity during the time frame of the data. The data frame is also formatted with overhead bits, including bits for error detection and detection. At the receiver, the data rate for the frame is determined based on hypothesis testing. Because the data rate is based on speech activity, a hypothesis test may be designed based on the statistics of speech activity. The received data frame is first decoded into information bits at the most probable rate as provided by the hypothesis test. Error metrics are generated for the decoded information bits. If the error metrics indicate that the information bits are of good quality, then the information bits are presented to a vocoder at the receiver to be processed for interface with the user. If the error metrics indicate that the information bits have not been properly decoded, then the received data frame is decoded at the other rates of the set of rates until the actual data rate is determined.

대표청구항 ▼

[ We claim:] [1.] In a variable rate communications system, a sub-system for determining, at a receiver, the data rate of a received data frame, comprising:a processor for generating a signal indicating the most likely rate of said received data frame in accordance with a predetermined hypothesis te

[ We claim:] [1.] In a variable rate communications system, a sub-system for determining, at a receiver, the data rate of a received data frame, comprising:a processor for generating a signal indicating the most likely rate of said received data frame in accordance with a predetermined hypothesis test;a decoder for receiving said most likely rate signal and for decoding said received data frame into a decoded frame of bits at said most likely rate;a data check element for receiving said decoded bits, generating error metrics characterizing said decoded bits, and generating a quality indication based on said error metrics for said decoded bits;a vocoder for receiving said decoded bits and processing said decoded bits to provide speech to a user upon generation of a positive quality indication; andwherein upon generation of a negative quality indication, said processor further causes said decoder to perform additional decoding of said received data frame in accordance with at least one rate other than said most likely rate.