초록 ▼

A system and method are disclosed for providing a warning of, and greater immunity from, an impending call drop in a digital wireless telecommunications system. During normal operations, data is transmitted at an initial information frame rate and a corresponding initial physical frame rate. Upon th

A system and method are disclosed for providing a warning of, and greater immunity from, an impending call drop in a digital wireless telecommunications system. During normal operations, data is transmitted at an initial information frame rate and a corresponding initial physical frame rate. Upon the data transmission producing errors in excess of a threshold, which indicates an impending call drop, the initial information frame rate is reduced while error correction codes are introduced into the data transmission to maintain the initial physical frame rate. The reduction in the information frame rate produces a subtle yet noticeable change in acoustic voice quality, which serves as a warning of the impending call drop. The introduction of error correction codes into the transmission provides greater immunity to the impending call drop by improving data integrity.

대표청구항 ▼

1. In a wireless telecommunications system including a Mobile Switching Center (MSC) connected to at least one radio base station that services at least one mobile radio unit, said base station and said mobile unit communicating with each other in a digital transmission mode wherein voice data is di

1. In a wireless telecommunications system including a Mobile Switching Center (MSC) connected to at least one radio base station that services at least one mobile radio unit, said base station and said mobile unit communicating with each other in a digital transmission mode wherein voice data is digitally encoded by voice encoders located in said MSC (or said base station) and said mobile unit as a sequence of variable rate information frames, said information frames being packaged by physical layers located in said MSC (or said base station) and said mobile unit into a sequence of physical transmission frames that include said information frames with appended control and error checking bits, a method for warning a user of, and providing greater immunity from, an impending call drop, comprising the steps of:monitoring transmissions between said base station and said mobile unit for frame errors while said voice encoders are encoding voice data at an initial information frame rate and said physical layers are receiving initial rate information frames from said voice encoders and transmitting physical transmission frames at an initial physical frame rate corresponding to said initial information frame rate; upon the number of said frame errors reaching a predetermined threshold, controlling said voice encoders to reduce the information frame rate from said initial information frame rate to a reduced information frame rate such that reduced rate information frames are provided to said physical layers; controlling said physical layers to add error correction bits to said reduced rate information frames to transmit error correction enhanced physical transmission frames at said initial physical frame rate; and whereby said error correction enhanced physical transmission frames provide increased error correction robustness for greater immunity from call dropping, and result in a characteristic change in speech quality due to said reduced rate information frame being incorporated therein to serve as an impending call drop warning.