Patent ID: 7047185

Claim:
A wireless communication system comprising: a mobile unit which receives signals from a base station, the mobile unit containing a bit-exact speech coder and a non bit-exact speech coder, wherein the bit-exact speech coder is compatible with the non bit-exact speech coder, wherein the non bit-exact speech coder produces a lower quality transmit signal than the bit-exact speech coder, the mobile unit encoding voice data in a signal to transmit using either the bit-exact speech coder or the non bit-exact speech coder, wherein the bit-exact speech coder produces a first transmit signal and the non bit-exact speech coder produces a second transmit signal; a signal strength detector in the mobile unit which measures the signals received by the mobile unit to determine a bit error rate of the received signal, wherein the mobile unit averages several measurements of the received signal to determine an average bit error rate; and a coder selector in the mobile unit which is in communication with the signal strength detector in the mobile unit, the coder selector in the mobile unit compares the average bit error rate of the received signal to a predetermined threshold to calculate whether to switch between the non bit-exact speech coder and the bit-exact speech coder based on the average bit error rate of the received signals from the signal strength detector; wherein the coder selector switches from the non bit-exact speech coder to the bit-exact speech coder when the average bit error rate of the received signal exceeds the predetermined threshold and the coder selector switches from the bit-exact speech coder to the non bit-exact speech coder when the average bit error rate of the received signal is below the predetermined threshold; wherein the non bit exact speech encoder reduces power consumption in the mobile unit; and wherein the second transmit signal is more degraded than the first transmit signal.