SYSTEM AND METHOD FOR ADAPTIVE MULTI-RATE (AMR) VOCODER RATE ADAPTATION

• US 20080049661A1
• Filed: 10/31/2007
• Published: 02/28/2008
• Est. Priority Date: 05/15/1998
• Status: Active Grant

• Current Assignee: Jaleh Komaili, Yongbing Wan
• Original Assignee: Jaleh Komaili, Yongbing Wan
• Inventors: Komaili, Jaleh, Wan, Yongbing
• Granted Patent: US 8,265,220 B2
• Time in Patent Office: Days
• US Class Current: 370/321
• CPC Class Codes: G10L 19/24 Variable rate codecs, e.g. for generating different qualities using a scalable representation such as hierarchical encoding or layered encoding
• CPC Class Codes: H04L 1/0011 applied to payload information
• CPC Class Codes: H04L 1/0014 by adapting the source coding
• CPC Class Codes: H04L 1/0025 Transmission of mode-switching indication
• CPC Class Codes: H04L 1/0026 Transmission of channel quality indication
• CPC Class Codes: H04L 1/0059 Convolutional codes
• CPC Class Codes: H04W 28/22 Negotiating communication rate
• CPC Class Codes: H04W 88/181 Transcoding devices; Rate adaptation devices
• CPC Class Codes: Y10S 370/914 Rate converter

Abstract

The present invention includes a time-division-multiple-access (TDMA) communication system having a base station and at least one mobile station, each transmitting and receiving an analog radio-frequency signal carrying digitally coded speech. The speech is encoded using a vocoder which samples a voice signal at variable encoding rates. During periods when the radio-frequency channel is experiencing high levels of channel interference, the encoded voice channel having a lower encoding rate is chosen. This low-rate encoded voice is combined with the high degree of channel coding necessary to ensure reliable transmission. When the radio-frequency channel is experiencing low levels of channel interference, less channel coding is necessary and the vocoder having a higher encoding rate is used. The high-rate encoded voice is combined with the lower degree of channel coding necessary to ensure reliable transmission. The appropriate levels of channel coding necessary for reliable transmission are determined by various channel metrics, such as frame erase rate and bit error rate. The determination of the appropriate vocoder rate and level of channel coding for both the uplink and downlink may be determined centrally at the base station, with the vocoder rate and level of channel coding for the uplink being relayed to the mobile station. Alternatively, the appropriate vocoder rate and level of channel coding for the downlink may be determined by the mobile station, and the appropriate vocoder rate and level of channel coding for the uplink may be determined by the base station.

Claims

1-37. -37. (canceled)

38. A method of controlling adaptive data transmission at a receiving side in a wireless communication system, the method comprising:

determining a quality indicator of a communication channel by measuring a channel quality metric;

obtaining quantization bits corresponding to the quality indicator, the quantization bits indicating a vocoder rate to be used in a transmitting side;

transmitting a first data frame including the quantization bits to the transmitting side; and

receiving a second data frame including voice data encoded by a vocoder in the transmitting side at the vocoder rate indicated by the quantization bits.

39. The method of claim 38, wherein the second data frame further includes rate bits indicating the vocoder rate.

40. The method of claim 39, wherein the rate bits are soft-coded.

41. The method of claim 38, wherein the quantization bits are convolutionally encoded to be transmitted to the transmitting side.

42. The method of claim 38, wherein the quantization bits are obtained by a measure of hysteresis.

43. The method of claim 38, wherein the transmitting side is a base station and the receiving side is a mobile station.

44. The method of claim 38, wherein the transmitting side is a mobile station and the receiving side is a base station.

45. A method of controlling adaptive data transmission at a receiving side in a wireless communication system, the method comprising:

determining a quality indicator of a communication channel by measuring a channel quality metric;

obtaining quantization bits corresponding to the quality indicator, the quantization bits providing information on a vocoder rate to be used in a transmitting side;

transmitting a first data frame including the quantization bits to the transmitting side; and

receiving a second data frame including voice data encoded by a vocoder in the transmitting side at the vocoder rate determined based on the quantization bits.

46. The method of claim 45, wherein the second data frame further includes rate bits indicating the vocoder rate.

47. The method of claim 46, wherein the rate bits are soft-coded.

48. The method of claim 45, wherein the quantization bits are convolutionally encoded to be transmitted to the transmitting side.

49. The method of claim 45, wherein the quantization bits are obtained by a measure of hysteresis.

50. The method of claim 45, wherein the transmitting side is a base station and the receiving side is a mobile station.

51. The method of claim 45, wherein the transmitting side is a mobile station and the receiving side is a base station.