Method for a wireless communications channel

• US 5,881,053 A
• Filed: 09/13/1996
• Issued: 03/09/1999
• Est. Priority Date: 09/13/1996
• Status: Expired due to Term

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Kimball, Robert H.
• Primary Examiner(s): NGUYEN, CHAU T
• Application Number:
  US08/718,039
• Time in Patent Office: 907 Days
• Field of Search: 370/252, 370/260-263, 370/320, 370/335, 370/342, 370/468, 370/267, 370/477, 379/202, 379/203, 379/206, 375/200, 375/225, 455/416
• US Class Current: 370/260
• CPC Class Codes: H04M 3/56 Arrangements for connecting several subscribers to a common circuit, i.e. affording conference facilities video conference systems H04N7/15
• CPC Class Codes: H04M 3/564 whereby the feature is a sub-conference

Abstract

A conference calling system for a wireless communications channel. The system is adapted for use with a channel having first, second and third participants communicating via first, second and third transmitters and receivers respectively. The system includes a circuit for receiving an encoded signal from at least one of the transmitters. A second circuit determines which of the participants is speaking from the received encoded signal. A third circuit is provided for re-transmitting an encoded signal received from the speaking participant to the other participants. In the illustrative implementation, the encoded signals are variable rate speech vocoded signals in which speech is vocoded at full rate, silence is vocoded at 1/8th rate and the 1/2 and 1/4 rates are used as transitional rates. In the illustrative implementation, the speaker'"'"'s signal is identified by examining the rate of the received vocoded signals. When the speaker'"'"'s vocoded signal is identified, it is re-transmitted without de-vocoding to the non-speaking participants in the conference call. By re-transmitting the speaker'"'"'s signal without de-vocoding, the quality of the received signal is preserved.

Claims

1. A conference calling system for a wireless communications channel having first, second and third participants communicating via first, second and third transmitters and receivers respectively, said conference calling system 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 conference calling system of claim 1 wherein said variable rate vocoded signals have speech vocoded at a first rate and silence vocoded at a second rate.

3. A conference calling system for a CDMA communications channel having first, second and third participants communicating via first, second and third transmitters and receivers respectively, wherein one of said participants is speaking and said conference calling system 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.

4. 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 one of said participants is speaking and said conference calling method including the steps of:

receiving variable rate vocoded signals each having a rate from at least one of said transmitters;

determining 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.

5. A conference calling system 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.

6. The system of claim 5 wherein the variable rate vocoded signals have speech vocoded at a first rate and silence vocoded at a second rate.

7. A conference calling system for a CDMA communications channel 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 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.

8. A conference calling system for a wireless communications channel having first, second and third participants communicating via first, second and third transmitters and receivers respectively, wherein one of said participants is speaking and said conference calling system comprising:

means for receiving variable rate vocoded signals from at least one of said transmitters, said vocoded signals have speech vocoded at a first rate and silence vocoded at a second rate;

means for determining which of said participants is speaking from said received vocoded signals by determining the rate of each vocoded signal and providing an output in response thereto; and

means for re-transmitting said received vocoded signal received from the speaking participant to the other participants, wherein said means for re-transmitting 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; and

control means for activating said switch means in response to the output of said means for determining the rate of each vocoded signal.

9. 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 and 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.