Patent EA-001342-B1 (EA)
Title: Conference calling system and method for a wireless communications channel
Inventor: KIMBALL ROBERT H
IPC: H04W88/02
Filed: 1997-09-11
Abstract: 1. An apparatus for a wireless communications channel, said apparatus having first, second and third participants communicating via first, second and third transmitters and receivers respectively said apparatus comprising: means for receiving variable rate vocoded signals each having a rate from at least one of said transmitters; means for determining said rate of each received vocoded signal; means for selecting only one of said received vocoded signals based upon the rate of each received vocoded signal; and means for re-transmitting the selected received vocoded signal to the other participants. 2. The apparatus recited in claim 1 wherein said variable rate vocoded signals have speech vocoded at a first rate and silence vocoded at a second rate. 3. The apparatus recited in claim 2 wherein said means for re-transmitting the encoded signal received from the speaking participant to the other participants includes switch means for selecting for re-transmission between first, second and third receivers adapted to receive signals transmitted by said first, second and third participant transmitters, respectively. 4. The apparatus recited in claim 5 wherein said means for re-transmitting the encoded signal received from the first participant to the other participants further includes control means for activating said switch means in response to the output of said means for determining the rate of the vocoded signal. 5. An apparatus for a CDMA communications channel having first, second and third participants communicating via first, second and third transmitters and receivers respectively, said apparatus comprising:  means for receiving variable rate vocoded signals from each of said transmitters; means for determining which of said participants is speaking by determining a rate of encoding of each of said vocoded signals; and means for re-transmitting the vocoded signal received from the speaking participant to the other participants, said means for re-transmitting including: switch means for selecting for re-transmission between first, second and third receivers adapted to receive signals transmitted by said first, second and third participant transmitters respectively; and control means for activating said switch means in response to the output of said means for determining the rate of each vocoded signal. 6. A method for a wireless communications channel having first, second and third participants communicating via first, second and third transmitters and receivers respectively, said method comprising the steps of: receiving variable rate vocoded signals each having a rate from at least one of said transmitters; determining from the rate of each of said received vocoded signals, selecting only one of said received vocoded signals based upon the rates; and re-transmitting the selected received vocoded signal to the other participants. 7. An apparatus for conference calling systems having first, second and third participants communicating via first, second and third transmitters and receivers, respectively, comprising: a receiver which receives variable rate vocoded signals from at least one of the transmitters, each received signal having a rate; a rate determination circuit which determines the rate of each of the received vocoded signals; a switch for selecting only one of the received vocoded signals based on the rates determined by the rate determination circuit; and a transmitter which re-transmits to the other participants, the selected one of the received vocoded signals. 8. The apparatus of claim 7 wherein the variable rate vocoded signals have speech vocoded at a first rate and silence vocoded at a second rate. 9. A conference calling apparatus for a CDMA communications channel having first, second and third participants communicating via first, second ant third transmitters and receivers, respectively, comprising: a receiver which receives variable rate vocoded signals from each of the transmitters; a rate determination circuit that determines which of said participants is speaking by determining a rate of encoding of each of the vocoded signals; a transmitter which re-transmits to the other participants, the vocoded signal received; a switch, coupled to the first, second and third receivers, adapted to receive signals transmitted by the first, second and third participant transmitters, respectively; and control means for activating said switch in response to the output of said rate determination circuit. 10. A conference calling method for a wireless communications channel having first, second and third participants communicating via first, second and third transmitters and receivers respectively, wherein two of said participants are speaking, said conference calling method including the steps of: receiving variable rate vocoded signals each having a rate from a plurality of transmitters; determining the rate of each of said received vocoded signals; selecting only one of said received vocoded signals based on the highest rate and based upon which participant was most recently speaking when it has been determined that a tie for the highest rate has occurred; and re-transmitting the selected received vocoded signal to the other participants.