Method for improving the quality of voice transmission via a radio interface

1. A method for improving a speech transmission quality via a radio interface in a communications network wherein the speech transmission is in the form of voice data packets, the method comprising:

compressing a voice data packet;

transmitting the compressed voice data packet via the radio interface by a sending device;

receiving the transmitted voice data packet by a receiving device;

storing the transmitted voice data packet by the receiving device;

automatically re-transmitting the compressed voice data packet after a time delay from the transmission of the voice data packet;

receiving the re-transmitted voice data packet by the receiving device;

determining a measure of the quality of the voice data packets by the receiving device; and

selecting the packet having a better speech transmission quality for use by the receiving device;

wherein a compression ratio for the voice data packet is selected such that the voice data packet and the re-transmitted voice data packet occupy a bandwidth less than or equal to a bandwidth occupied by the voice data packet prior to the step of compressing, wherein if a compression ratio that permits the voice data packet and the re-transmitted voice data packet to occupy a bandwidth less than or equal to the bandwidth occupied by the voice data packet prior to the step of compressing is not available, then the step of transmitting the voice data packet further comprises transmitting the voice data packet on a first transmission channel or a first logical link of the radio interface and the step of re-transmitting the voice data packet further comprise re-transmitting the voice data packet on a second transmission channel or a second logical link of the radio interface.

2. The method according to claim 1 , further comprising a step of decompressing the voice data packet at the receiving device.

3. The method according to claim 1 , wherein the voice data is compressed at least by a factor of 2.

4. The method according to claim 1 ,

wherein the measure of the transmission quality is determined by forming and checking a checksum from data contained in the voice data packet or

wherein the measure of the transmission quality is determined by forming and checking a Cyclic Redundancy Check (CRC) control bit pattern from data contained in the voice data packet or

wherein the measure of the transmission quality is determined by forming and checking a checksum and a Cyclic Redundancy Check (CRC) control bit pattern from data contained in the voice data packet.

5. The method according to claim 1 ,

wherein the data to be transmitted is checked to see if it is voice data, and

wherein the re-transmission step, the receiving the re-transmission step, the determining step, and the selecting step are bypassed for non voice data.

6. A sending device for improving a speech transmission quality via a radio interface, wherein the speech transmission is in the form of voice data packets, the sending device comprising:

a codec that compresses voice data;

a transmitter that transmits a first transmission of a voice data packet and a second transmission of the same voice data packet, wherein the voice data packet comprises compressed voice data;

a delay module that delays the second transmission of the voice data packet by a delay time after the first transmission;

wherein a compression ratio of the codec for compressing the voice data packet is selected such that the first and the delayed transmissions of the voice data packet occupy a bandwidth less than or equal to a bandwidth occupied by the first transmission of the voice data packet;

wherein the first transmission and the delayed transmission of the voice data packet are transmitted on a first transmission channel of the radio interface;

wherein if a compression ratio that permits the first and the second transmissions of the voice data packet to occupy a bandwidth less than or equal to the bandwidth occupied by the first transmission of the voice data packet is not available, then the first transmission of the voice data packet is transmitted on the first transmission channel or a first logical link of the radio interface and the delayed transmission of the voice data packet is transmitted on a second transmission channel or a second logical link of the radio interface.

7. The device according to claim 6 , wherein the compressed voice data is compressed at least by a factor of 2.

8. The device according to claim 6 , wherein the delay time is greater or equal to a time corresponding to a length of a radio frame of the radio interface.

9. The device according to claim 8 , wherein the delay time is a multiple of the frame length time.

10. The device according to claim 6 , wherein the codec and the delay module are bypassed by non-voice data.

11. A receiving device for improving a speech transmission quality via a radio interface comprising:

a codec for compressing a first packet and a second packet;

a receiver that receives the first packet including a first voice data and the second packet including a second voice data,

wherein the second packet is received after a time delay from the receipt of the first packet;

an error detection device that determines a measure of the quality of the voice data for each packet;

a comparator that compares the measure of the quality of the first voice data with the measure of quality of the second voice data;

a selector that selects the voice data with a better transmission quality for use;

wherein the first voice data and the second voice data are the same data having different transmission quality; and

wherein a compression ratio for the first packet and the second packet is selected such that the first packet and the second packet occupy a bandwidth less than or equal to a bandwidth occupied by the first packet prior to compressing by the codec, wherein if a compression ratio that permits the first packet and the second packet to occupy a bandwidth less than or equal to the bandwidth occupied by the first packet prior to compressing is not available, then the first packet is transmitted on a first transmission channel or a first logical link of the radio interface and the second packet is transmitted on a second transmission channel or a second logical link of the radio interface.

12. The device according to claim 11 , further comprising a memory for storing the first voice data.

13. The device according to claim 11 , wherein the time delay is greater or equal to a time corresponding to a length of a radio frame of the radio interface.

14. The device according to claim 11 , wherein the codec compresses the first packet and the second packet at least by a factor of 2.

15. The method according to claim 11 ,

wherein the measure of the transmission quality is determined by forming and checking a checksum from data contained in the voice data packet or

wherein the measure of the transmission quality is determined by forming and checking a Cyclic Redundancy Check (CRC) control bit pattern from data contained in the voice data packet or

wherein the measure of the transmission quality is determined by forming and checking a checksum and a Cyclic Redundancy Check (CRC) control bit pattern from data contained in the voice data packet.