FM system modes for HD radio

Patent metadata

Field	Value
Publication number	US-11038622-B2
Application number	US-201916277598-A
Country	US
Kind code	B2
Filing date	Feb 15, 2019
Priority date	Feb 17, 2018
Publication date	Jun 15, 2021
Grant date	Jun 15, 2021

Abstract

Service modes specify how digital content is formatted in sidebands of an FM radio channel. In an improved service mode, encoded bits can be distributed between an in-band encoded component and a cross-band encoded component, where the encoded bits in the in-band encoded component are desynchronized by a specified duration with respect to the encoded bits in the cross-band encoded component. The encoded bits in the in-band encoded component can be allocated into frequency partitions that are used by a legacy service mode, such as MP1 or MP3, which can provide backward compatibility with the legacy service mode. The encoded bits in the cross-band encoded component can be allocated into frequency partitions that are not used by the legacy service mode, and are found in the opposite sideband, compared with the legacy service mode, which can provide time diversity within a single sideband.

First claim

What is claimed is:

1. A radio transmitter, comprising:
transmitting circuitry configured to broadcast over a frequency modulation (FM) radio channel, the FM radio channel having a center frequency and a sideband, the FM radio channel including digital data in a plurality of partitions, each partition being broadcast at a specified frequency within the sideband; and
processing circuitry configured to:
receive input bits for transmitting;
encode the input bits using forward error correction encoding to form encoded bits;
distribute the encoded bits between an in-band encoded component and a cross-band encoded component, the encoded bits in the in-band encoded component being desynchronized by a specified duration with respect to the encoded bits in the cross-band encoded component;
allocate the encoded bits of the in-band encoded component into a first group of partitions of the sideband, the first group corresponding to partitions in a sideband of a service mode that specifies how digital content is formatted in sidebands of the FM radio channel;
allocate the encoded bits of the cross-band encoded component into a second group of partitions of the sideband, the second group corresponding to partitions that are absent from the service mode;
modulate the encoded bits for transmitting; and
direct the modulated encoded bits to the transmitting circuitry for broadcasting in the sideband of the FM radio channel.

2. The radio transmitter of claim 1 , wherein the service mode includes an MP 1 service mode and the first group of partitions of the sideband extends from 130 kHz away from the center frequency to 200 kHz away from the center frequency.

3. The radio transmitter of claim 2 , wherein the first group of partitions includes ten partitions.

4. The radio transmitter of claim 1 , wherein the service mode includes an MP 1 service mode and the second group of partitions of the sideband extends from 100 kHz away from the center frequency to 130 kHz away from the center frequency.

5. The radio transmitter of claim 4 , wherein the second group of partitions includes four partitions.

6. The radio transmitter of claim 1 , wherein the service mode includes an MP 1 service mode; and
wherein, when received by a legacy MP 1 service mode receiver, the legacy MP 1 service mode receiver:
interprets the FM radio channel as being in the MP 1 service mode;
interprets encoded bits that are present in the first group of partitions of the FM radio channel; and
does not interpret encoded bits that are present in the second group of partitions of the FM radio channel.

7. The radio transmitter of claim 1 , wherein the service mode includes an MP 1 service mode; and wherein:
the encoded bits in the first and second groups of partitions are encoded at a code rate of 4/7;
the encoded bits in the first and second groups of partitions, together, have a data rate of 96 kbps.

8. The radio transmitter of claim 1 , wherein the service mode includes an MP 3 service mode.

9. The radio transmitter of claim 8 , wherein the desynchronization provides a time diversity to the data in the sideband.

10. The radio transmitter of claim 8 , wherein the plurality of partitions broadcast at the specified frequencies within the sideband provides a frequency diversity to the data in the sideband.

11. The radio transmitter of claim 8 , wherein the first group of partitions of the sideband extends from 115 kHz away from the center frequency to 200 kHz away from the center frequency.

12. The radio transmitter of claim 11 , wherein the first group of partitions includes twelve and two-thirds partitions.

13. The radio transmitter of claim 8 , wherein the second group of partitions of the sideband extends from 100 kHz away from the center frequency to 115 kHz away from the center frequency.

14. The radio transmitter of claim 13 , wherein the second group of partitions includes one and one-third partitions.

15. The radio transmitter of claim 8 , wherein, when received by a legacy MP 3 service mode receiver, the legacy MP 3 service mode receiver:
interprets the FM radio channel as being in the MP 3 service mode;
interprets encoded bits that are present in the first group of partitions of the FM radio channel; and
does not interpret encoded bits that are present in the second group of partitions of the FM radio channel.

16. The radio transmitter of claim 8 , wherein:
the encoded bits for ten of the twelve partitions of the first group of partitions and one and one-third partitions of the second groups of partitions are encoded at a combined code rate of 12/17 and have a service data rate of 96 kbps;
the encoded bits for two of the twelve partitions of the first group of partitions and two-thirds partition of the second groups of partitions are encoded at a combined code rate of ¾ and have a service data rate of 24 kbps; and
the encoded bits in the first and second groups of partitions, together, have a service data rate of 120 kbps.

17. A method for transmitting data over a frequency modulation (FM) radio channel, the FM radio channel having a center frequency and a sideband, the FM radio channel including digital data in a plurality of partitions, each partition being broadcast at a specified frequency within the sideband, the method comprising:
receiving, with processing circuitry, input bits for transmitting;
encoding, with the processing circuitry, the input bits using forward error correction encoding to form encoded bits;
distributing, with the processing circuitry, the encoded bits between an in-band encoded component and a cross-band encoded component, the encoded bits in the in-band encoded component being desynchronized by a specified duration with respect to the encoded bits in the cross-band encoded component;
allocating, with the processing circuitry, the encoded bits of the in-band encoded component into a first group of partitions of the sideband, the first group corresponding to partitions in a sideband of a legacy service mode;
allocating, with the processing circuitry, the encoded bits of the cross-band encoded component into a second group of partitions of the sideband, the second group corresponding to partitions that are absent from the legacy service mode;
modulating, with the processing circuitry, the encoded bits for transmitting; and
directing, with the processing circuitry, the modulated encoded bits to transmitting circuitry for broadcasting in the sideband of the FM radio channel.

18. The method of claim 17 , wherein the legacy service mode comprises one of an MP 1 service mode or an MP 3 service mode.

Assignees

• Ibiquity Digital Corp

Inventors

• Milbar Marek

Classifications

• H04H20/423 Primary

  Transmitter side · CPC title

• H04H2201/183

  FM digital or hybrid · CPC title

• H04H20/30

  by a single channel · CPC title

• H04H20/71

  Wireless systems · CPC title

• H04H20/48

  for FM stereophonic broadcast systems · CPC title