GB2438916A

GB2438916A - Digital broadcast receiver and streamer

Info

Publication number: GB2438916A
Application number: GB0611475A
Authority: GB
Inventors: Martin Hall
Original assignee: Individual
Current assignee: Individual
Priority date: 2006-06-09
Filing date: 2006-06-09
Publication date: 2007-12-12
Also published as: GB0611475D0

Abstract

A digital radio receiver for streaming content over a computer network, the receiver receiving a request for a subchannel of a multiplexed radio signal, tuning a tuner to the multiplex carrying the subchannel and then streaming content from the channel over a computer network. Content relating to other subchannels carried by the same multiplex can be streamed concurrently, without the need for additional tuners. For example the digital radio receiver may act as a dedicated receiver for a Local Area Network so that each device in the LAN is not required to have a tuner/receiver themselves connected locally. The digital radio receiver may unicast/multicast different subchannels concurrently to different remote devices such as PCs, media players or network storage.

Description

DIGITAL BROADCAST RECEIVER

FIELD OF THE INVENTION

The present invention relates to a digital radio receiver and method for streaming content over a computer network.

BACKGROUND OF THE iNVENTiON

In recent years digital broadcasting has become popular as a means of delivering audio, video and other content. Compared to conventional analogue AM and FM radio broadcasting, digital broadcasting facilitates the provision of high fidelity content with a greater immunity to noise. In particular, digital broadcasting is well suited to the use of single frequency networks, known for their low multipath interference and fading.

One particular advantage of digital radio broadcasting over conventional analogue radio methods is an improved efficiency in its use of the available frequency spectrum. This is possible since digital broadcasting combines multiple streams of content (radio stations, television channels, programme guide information, etc.) into a single channel, broadcast at a single frequency, that is commonly referred to as simply a "multiplex". Digital radio broadcasting represents a significant increase in efficiency over conventional analogue signals, where each stream of content (each radio station, for example) is assigned an individual carrier frequency at each transmitter. Digital broadcasting allows a far greater number of subchannels to be broadcast in a given frequency band than would conventional analogue techniques, especially when the subchannels are compressed to low bit rates.

There exist a number of devices capable of receiving and rendering digital broadcast content. Examples of such devices are self-contained Digital Audio Broadcasting (DAB) receivers like the PURE (RIM) Tempus (RIM) made by Imagination Technologies, Ltd. and the BRAVIA (RTM) range of television sets made by Sony Corporation, which have built-in Digital Video Broadcasting -Terrestrial (DVB-T) receivers.

Also available are receivers that connect directly to a personal computer to provide content to that computer. This is desirable since it facilitates the storage of content at the computer, for example the recording of audio content to a hard disk for playback at a later date, or of video content to a Digital Versatile Disc (DVD) for playback using a suitable device. Digital broadcasting is well suited to the provision of digital content other than audio or video streams, such as programme scheduling information, headlines, maps and even software applications, content which is readily made available to a user via a computer.

Receivers that connect to a personal computer via a Universal Serial Bus (USB) port or Peripheral Component Interconnect (PCi) card interface are also popular since the computer is able to perform rendering and interface tasks that would otherwise be performed by the receiver. The performance of these tasks at the computer reduces the burden on the receiver and eliminates the need for hardware in the receiver to perform these tasks. Relocating tasks to the computer thereby permits simpler, cheaper and physically smaller receivers with reduced power requirements. An example of a USB-based DVB-T receiver is the WinTV(RTM)NOVA.TStiCk made by Hauppauge Digital, Inc. An example of a USB-based DAB radio receiver is the Wavefinder (RTM) that was made by Psion, PLC.

A user desirous of receiving digital radio content at his personal computer using a prior art receiver must therefore directly coirnect the receiver to his computer, or install it therein. Connecting the receiver to the computer via a connection (perhaps a USB port or PCI slot) results in that connection no longer being available for other uses.

Furthermore it adds weight and bulk to the computer -for example an external USB device connected to a laptop is inconvenient and unsightly. What is more, receivers must be coupled to a suitably positioned aerial for good reception, even though (especially in the case of mobile computers such as laptops) the computer and connected receiver may not always be in a convenient position to do so.

A software application called DAB Bar, written by Alistair MacDonald, permits a computer directly connected to a Psion (RTM) Wavefinder or compatible receiver to receive and decode the content of a subchannel from the receiver and then stream that content to a second computer over a network. However, this arrangement is limited by the receiver hardware: all requests for streamed content must be sent to the computer to which the receivr is connected; this computer must be switched on and must be running &c14) the Windows operating system.

Another means of providing content to computers on a network is so-called internet radio'. In internet radio the content of an audio radio' station is streamed over a TCP/IP connection from a server to a client computer. The streamed content may also be video.

However, internet radio suffers greatly from bandwidth restrictions, connections from a Local Area Network (LAN) to the Internet being a particular bottleneck in many networks. The problems are two- fold: firstly the demand on the server increases in proportion as new clients connect and request simultaneous streaming of content, thus setting a limit on the number of simultaneous receivers of the stream; and secondly the internet radio streams to multiple client computers over the client LAN place a large load on the LAN and particularly on the LAN-Internet gateway. In order to reduce the load on client networks and the bandwidth required by servers, providers of internet radio normally provide content at low bitrates, with 64 kb/s being common. However, audio and video content at low bitrates is of poor quality and a high bandwidth connection to the Internet is therefore required if internet radio is to be received at an acceptable fidelity. Also, content available via digital radio broadcasting is frequently not also available as an equivalent internet radio stream.

It would be desirable to provide digital radio content to personal computers without the disadvantages discussed above.

SUMMARY OF THE INVENTiON

In a first aspect, the present invention provides a digital radio receiver for streaming content over a computer network, said receiver comprising: a first digital radio tuner for receiving digital radio signals, said tuner being configured to generate a first datastream comprising digital content of a first multiplexed digital radio signal received by said first radio tuner; a first demultiplexer configured to receive said first datastream from said first digital radio tuner and isolate packet data corresponding to at least a first requested subchaimcl of said first multiplexed radio signal; a computer network interface for connection to a computer network; and a server configured to stream said isolated packet data to at least one remote device via said computer network interface.

In a second aspect, the present invention provides a method for streaming content over a computer network, said method comprising: using a first digital radio tuner to receive digital radio signals and generate a first datastream comprising digital content of a first multiplexed digital radio signal received by said first digital radio tuner; receiving said first datastream at a first demultiplexer; using said demultiplexer to isolate packet data corresponding to at least a first requested subchannel of said first multiplexed radio signal; connecting to a computer network via a computer network interface; and using a server to stream said isolated packet data to at least one remote device via said computer network interface.

It is highly advantageous to provide digital radio content to clients over a computer network, since it eliminates the need for a receiver to be present at the client's location.

This enables the receiver to be positioned in the best location for reception of broadcasts, and permits the use of aerials that would be inconvenient to locate at the client. For example, a large aerial may offer good reception, but would not be desirable for use in a confined living space. It also eliminates the need to have a receiver present at every client that may wish to receive digital radio, whether or not they are actually doing so.

This is particularly useful for mobile computer systems, where a dedicated local receiver adds weight to the system and draws additional power.

Preferably, the dernultiplexer may be used to isolate packet data corresponding to a second requested subchannel of said first multiplexed radio signal. The isolated packet data corresponding to the first and second requested subchannels may then be streamed to different remote devices. This is particularly advantageous since it eliminates the need for more than one tuner and demultiplexer when streaming multiple subchannels carried by the same multiplex.

The isolated packet data may be streamed using unicasting or multicasting techniques.

Multicasting is especially preferred since it reduces the bandwidth required to stream the same data concurrently to multiple recipients. This avoids the heavy network load that is associated with multiple clients connecting to the same internet radio service.

Optionally, a plurality of digital radio tuners may be present to enable a datastream to be generated for each of a plurality of different multiplexed digital radio signals. A plurality of demultiplexers would then each receive a datastream from a different one of said plurality of digital radio tuners and isolate packet data corresponding to at least one requested subchaimel of said multiplexed radio signals. This enables a receiver to concurrently stream multiple subchannels from different multiplexes. If sufficient tuners are available, the receiver could offer all subchannels on all multiplexes simultaneously.

Optionally, selection of the requested subchannels may be received from a local user interface. Alternatively, and preferably, the selection may be received via the computer network interface.

The remote device to which content is streamed may be a personal computer. It may also be another device capable of rendering the streamed content, or a network storage device. The remote device may be a standalone digital media player capable of receiving internet radio independently of a personal computer. To the digital media player, the stream would appear as that of an internet radio station. One suitable digital media would be the Squeezebox (RTM) made by Slim Devices, Inc. Content corresponding to the isolated packet device may be stored locally at a local storage device. It may also be output locally, via an audio transducer, visual display or output port.

Metadata, preferably in a mark-up fomat to make its content easily accessible and identifiable, can he combined with the isolated packet data.

Optionally, the datastream may be transcoded into an alternative format before it is streamed. This format may be requested from the source of the request for the subchannel. This permits the use of more efficient formats than the native formats used by the subchaimels and also enables compatibility of the receiver with rendering devices that are not able to render those native formats.

The network over which the (lata are streamed may be any suitable computer network.

For example, it may be a wired or wireless Local Area Network (LAN) or Wide Area Network (WAN). The WAN may be the Internet.

The multiplexed digital radio signal can be any suitable signal. It is preferably a Coded Orthogonal Frequency Division Multiplexed (COFDM) radio signal and may conform to any of the Digital Audio Broadcasting (DAB), Digital Video Broadcasting -Terrestrial (DVB-T), Digital Audio Broadcasting -2 (DAB-2) or Digital Multimedia Broadcasting (DMB) formats. It will be appreciated that other formats may also be used.

BRIEF DESCRIPTION OF THE DRAWINGS

Specific embodiments of the present invention will now be described further, by way of example, with reference to the accompanying drawings, in which: Fig. 1 shows a schematic diagram of a digital radio receiver according to the present invention; Fig. 2 shows a schematic diagram of a computer network including the digital radio receiver of Figure 1; and Fig. 3 shows a flow chart of a method according to the present invention.

DETAILED DESCRIPTION OF AN EXEMPLARY EMBODIMENT

Fig. I shows a digital radio receiver in which a tuner (30) is connected to an aerial (20) and a demultiplexer (40). The tuner (30) and demultiplexer (40) together make up a Network Interface Module (NIM) (120). The demultiplexer (40) is in turn connected to a microprocessor (50), as are a user interface (60), a speaker (70), an output port (80), a visual display (90), a storage device (100) and a computer network interface (110). In some embodiments the demultiplexer (40) is a process perfonned by the microprocessor (50).

Fig. 2 shows the digital radio receiver (10) of Fig. I connected to a LAN (200), to which a first personal computer (210) and a first remote storage (220) are also connected. The LAN is connected to the Internet (230), to which a second personal computer (240) and a second remote storage (250) are also connected.

When the receiver is in use, the computer network interface (110) is connected to the LAN (200) and the receiver (10), controlled by the microprocessor (50) establishes the receiver on the LAN (200) using appropriate protocols, for example Dynamic Host Configuration Protocol (DHCP) and Universal Plug and Play.

The aerial (20) receives various multiplexed digital radio signals which are passed to the tuner (30). The tuner (30) is controlled by the microprocessor (50) to scan a predetermined set of frequencies, which may he predefined as a list of frequencies that are known to correspond to digital radio multiplexes. When the tuner (30) detects an available multiplex, information relating to the multiplex is stored in a cache. This cache is preferably non-volatile so that the scanning and storing steps do not need to be repeated each time the receiver (10) is switched on. However, the scanning and storing steps will need to be repeated from time to time, including when the aerial (20) is repositioned, in order to keep the multiplex information up to date.

The receiver (10) exposes an interface on the LAN (200) and via the computer network interface (110) through which it can be controlled and configured. The receiver (10) may then transmit information identifying the available multiplexes and subehannels on the multiplexes over the exposed interface. Such information may be broadcast at predefined times, or may be sent in response to a received request for information. The multiplex and subchanncl information may also be made available locally at the receiver (10), for example on the visual display (90).

Through the exposed interface, the receiver (10) receives a request for the content of a subchannel of one of the available multiplexes. This request is received from the LAN via the computer network interface (110) and may originate from the first personal computer (210), or from the second personal computer (220) over the Internet (230).

Alternatively, the request may be made locally at the receiver, using the user interface (60), which might comprise buttons, a keyboard, a pointing device or a remote control device.

The request for the subchannel is interpreted by the microprocessor (50), which identifies, from the cached multiplex information, which multiplex carries the requested subchannel. The microprocessor (50) then tunes the tuner (30) to the identified multiplex, if it is not already tuned to that multiplex.

In some embodiments the receiver (10) comprises more than one NIM (120) connected to the microprocessor (50), each NIM (120) comprising a tuner (30) and demultiplexer (40). In such embodiments the microprocessor (50) makes a selection between the available NIMs (120) in order to determine which should be tuned to the requested multiplex if none are already so tuned. The skilled person will appreciate that many different procedures are possible for arbitrating the tuning of available NIMs, but in general the processor will in preference select an untuned NIM (120) to tune to the requested multiplex, thereafter selecting a NIM (120) according to predetermined criteria. Such criteria may include the number of requests received for each multiplex, or the order in which requests were received. Preferably, a separate NIM (120) is provided for each multiplex, in order that the receiver can simultaneously receive all subchannels from all multiplexes.

If the requested subehannel is a subchannel of a multiplex to which a NIM (120) is already tuned, there is no need to find another, untuned, NIM (120): the required subchannel datastream can be delivered by the already-tuned N1M (120).

Once tuned to a multiplexed radio signal, the tuner (30) provides a datastream comprising the entire digital content of that signal to the demultiplexer (40). The demultiplexer (40) parses the datastrearn and isolates packet data corresponding to subchannels of the multiplex that have been requested. If only one subchannel has been requested, the demultiplexer (40) need only isolate data corresponding to that subchannel to provide to the microprocessor (50); however, in the case where multiple subehannels have been requested, the data corresponding to each of them will be isolated and provided to the processor (50).

The isolated packet data are streamed from a server implemented by processor (50) to at least one of the first and second personal computers (210, 240), via the computer network interface (110). Alternatively, the data may be sent to other devices on the LAN (200) or Internet (230), such as remote storage devices (220, 250) or standalone media players (260, 270). Normally, the data would be streamed to at least the source of the request for the subchannel, either by unicasting or multicasting. Multicasting is preferred if multiple requests for the same datastream are received.

The isolated packet data may additionally be used to output content locally at the receiver (10). Content may be output as audio through the speaker (70), or another audio transducer. Alternatively content may be output visually using the visual display (90), which may comprise a liquid crystal display (LCD). The content may also be output as a combination of audio and visual data, for example as music through the speaker (70) with metadata identifying the audio track, artist, etc. displayed on the visual display (90).

The isolated packet data may also be used to output content via the output port (80). The skilled person will appreciate that many different standards are suitable for the output port. By way of example, the port may be of a type suitable for outputting rendered content, such as a socket for an audio jack or for composite audio-visual leads. The output port may also be used to output unrendered content via a USB socket, for

example.

The isolated packet data may also be provided to the local storage device (100). The storage device is preferably non-volatile. In a preferred embodiment the storage device (100) accepts removable storage media such as Secure Digital (SD) cards, Compact Flash (CF) cards, or a USB flash drives or writable compact discs (CD-R) or DVDs (DVD-R). However, the local storage device (100) may alternatively comprise a fixed storage device such as a hard drive.

Before it is streamed, the isolated packet data may be transcoded into a different format by the processor (50). For example, DAB radio encodes audio using the MPEG-I Audio Layer II (MP2) format. However, at low bitrates (typically less than 256 kb/s) the MP2 format is less efficient than the MPEG-l Audio Layer III (MP3) format. Since DAB audio is conventionally broadcast at between 64 and 192 kb/s, it is often desirable that the MP2 content be transcoded into MP3 before it is streamed. The transcoded format may be specified in the request for the subchannel.

The processor (50) is optionally configured to add metadata into the streamed content.

This metadata may comprise content that is supplied by the multiplex, or data that is provided at the receiver (10). In particular, such metadata may include data selected from programme information, infonnation concerning signal strength, timing information, advertising and information identifying the receiver (10).

Fig. 3 shows an exemplary method of for streaming content over a computer network.

The method may be implemeiited using the receiver of Fig. 1 and in the network of Fig. 2.

Some prior art digital radio receivers are designed to accommodate multiple tuner modules, each one providing a central processor with a stream that relates to an available subchannel. It is envisaged that a NIM (120) of the present invention could be installed in place of one of said tuner modules. The NIM (120) is able to provide multiple subchannel streams simultaneously and may be physically interfaced to the prior art receiver in a manner than mimics the connectors and electrical signals that would be provided by a plurality of prior art tuner modules. Alternatively, a software layer may be added to the prior art device in order that each subchannel stream provided by the N1M (120) is provided to the processor of the prior art receiver in a form that mimics that of a single prior art tuner module. The prior art device may be further modified to concurrently provide streams corresponding to each of a plurality of received subehannels over a network connection. Such further modification may be effected, for some devices, via a firmware update.

Retrofitting a prior art device with a NIM (120) in the above manner allows a prior art device to be upgraded to receive multiple subchannels of the same multiplex using a single tuner. It is further envisaged that the NIM (120) used with the prior art device may in fact comprise a plurality of NIMs (120), so that the subchannels provided to the processor of the modified prior art device may be subchannels of more than one multiplex.

The method of Fig. 3 commences with the reception (310) of digital radio signals. A datastream comprising digital content of a first multiplexed digital radio signal of the received digital radio signals is then generated (320). The generated datastream includes content from one or more subchannels carried by the multiplexed digital radio signal.

The subsequent step is the isolation (330) of packet data corresponding to a requested one of these subchannels from the datastream. In the event that more than one subchannel is requested, the data corresponding to more than one of the available subchannels may be isolated in this step. A connection is made to a computer network (340) and the isolated data are then streamed (350) to at least one remote device. As described above, the streaming (350) may be by unicast or multicast.

It will be understood that the present invention has been described above purely by way of example and modifications of detail can be made within the scope of the appended claims. In particular, the invention is not limited to a particular broadcast technology.

For example, the format of the multiplexed digital radio signal may be any of Digital Audio Broadcasting (DAB), Digital Video Broadcasting -Terrestrial (DVB-T), Digital Audio Broadcasting 2 (DAB-2), Digital Multimedia Broadcasting (l)MB) or any other

suitable format.

Claims

CLAIMS

1. A digital radio receiver for streaming content over a computer network, said receiver comprising: a first digital radio tuner for receiving digital radio signals, said tuner being configured to generate a first datastream comprising digital content of a first multiplexed digital radio signal received by said first radio tuner; a first demultiplexer configured to receive said first datastream from said first digital radio tuner and isolate packet data corresponding to at least a first requested subchannel of said first multiplexed radio signal; a computer network interface for connection to a computer network; and a server configured to stream said isolated packet data to at least one remote device via said computer network interface.

2. The receiver of claim 1, wherein the demultiplexer is further configured to isolate packet data corresponding to a second requested subchannel of said first multiplexed radio signal.

3. The receiver of claim 2, wherein isolated packet data corresponding to the first and second requested subchannels are streamed to different remote devices.

4. The receiver of any preceding claim, wherein said isolated packet data are multicast to a plurality of remote devices.

5. The receiver of any preceding claim, further comprising: a plurality of digital radio tuners for receiving digital radio signals, each of said tuners being configured to generate a datastream comprising digital content of a different multiplexed digital radio signal; and a plurality of demultiplexers, each demultiplexer configured to receive a datastream from a different one of said plurality of digital radio tuners and isolate packet data corresponding to at least one requested subchannel of said multiplexed radio signals.

6. The receiver of any preceding claim, further comprising a user interface for receiving selection of the requested subchannels.

7. The receiver of any of claims I to 5, wherein requests for subchannels are received via the computer network interface.

8. The receiver of any preceding claim, wherein the remote device is a personal computer.

9. The receiver of any preceding claim, wherein the remote device is a standalone digital media player.

10. The receiver of any of claims 1 to 7, wherein the remote device is a network storage device.

11. The receiver of any preceding claim, further comprising: a local storage device; and logic configured to store content corresponding to the isolated packet data to the local storage device.

12. The receiver of any preceding claim, further comprising: a local output device; and logic configured to output content corresponding to the isolated packet data using the local output device.

13. The receiver of claim 12, wherein the local output device comprises an audio transducer.

14. The receiver of claim 12, wherein the local output device comprises a visual display.

15. The receiver of claim 12, wherein the local output device comprises an output port.

16. The receiver of any preceding claim, further comprising logic configured to combine metadata with the isolated packet data.

17. The receiver of claim 16, wherein the metadata is in a mark-up format.

18. The receiver of any preceding claim, further comprising logic configured to transcode the datastream into a transcoded format.

19. The receiver of claim 18, wherein the transcoded format is requested by the remote device.

20. The receiver of any preceding claim, wherein the server is configured to stream the isolated packet data over a local area network.

21. The receiver of any preceding claim, wherein the server is configured to stream the isolated packet data over a wide area network.

22. The receiver of claim 19, wherein the wide area network is the Internet.

23. The receiver of any preceding claim, wherein the multiplexed digital radio signal is a Coded Orthogonal Frequency Division Multiplexed (COFDM) radio signal.

24. The receiver of claim 23, wherein the multiplexed digital radio signal is a Digital Audio Broadcasting (DAB) signal.

25. The receiver of claim 23, wherein the multiplexed digital radio signal is a Digital Video Broadcasting -Terrestrial (DVB-T) signal.

26. The receiver of claim 23, wherein the multiplexed digital radio signal is a Digital Audio Broadcasting -2 (DAB-2) signal.

27. The receiver of claim 23, wherein the multiplexed digital radio signal is a Digital Multimedia Broadcasting (DMB) signal.

28. A method for streaming content over a computer network, said method comprising: using a first digital radio tuner to receive digital radio signals and generate a first datastrearn comprising digital content of a first multiplexed digital radio signal received by said first digital radio tuner; receiving said first datastream at a first deinultiplexer; using said demultiplexer to isolate packet data corresponding to at least a first requested subehannel of said first multiplexed radio signal; connecting to a computer network via a computer network interface; and using a server to stream said isolated packet data to at least one remote device via said computer network interface.

29. The method of claim 28, further comprising using the dernultiplexer to isolate packet data corresponding to a second requested subchannel of said first multiplexed radio signal.

30. The method of claim 29, wherein using a server to stream said isolated packet data to at least one remote device comprises streaming said isolated packet data corresponding to the first and second requested subchannels to different remote devices.

31. The method of any of claims 28 to 30, wherein using a server to stream said isolated packet data to at least one remote device comprises multicasting said isolated packet data to a plurality of remote devices.

32. The method of any of claims 28 to 31, further comprising: using each of a plurality of digital radio tuners to receive digital radio signals and generate a datastrearn comprising digital content of a different multiplexed digital radio signal; and using each of a plurality of demultiplexers to receive a datastream from a different one of said plurality of digital radio tuners and isolate packet data corresponding to at least one requested subchannel of said multiplexed radio signals.

33. The method of any of claims 28 to 32, further comprising receiving selection of the requested subchannels at a local user interface.

34. The method of any of claims 28 to 32, comprising receiving requests for subchannels via the computer network interface.

35. The method of any of claims 28 to 34, wherein the remote device is a personal computer.

36. The method of any of claims 28 to 34, wherein the remote device is a standalone digital media player.

37. The method of any of claims 28 to 34, wherein the remote device is a network storage device.

38. The method of any of claims 28 to 37, further comprising storing content corresponding to the isolated packet data to a local storage device.

39. The method of any of claims 28 to 38, further comprising outputting content corresponding to the isolated packet data using a local output device.

40. The method of claim 39, wherein the local output device comprises an audio transducer.

41. The method of claim 38, wherein the local output device comprises a visual display.

42. The method of claim 38, wherein the local output device comprises an output port.

43. The method of any of claims 28 to 42, further comprising combining metadata with the isolated packet data.

44. The method of claim 43, wherein the metadata is in a mark-up format.

45. The method of any of claims 28 to 44, further comprising transcoding the datastreani into a transcoded format.

46. The receiver of claim 45, wherein the transcoded format is requested by the remote device.

47. The method of any of claims 28 to 46, wherein using a server to stream said isolated packet data to at least one remote device comprises streaming the isolated packet data over a local area network.

48. The method of any of claims 28 to 47, wherein using a server to stream said isolated packet data to at least one remote device comprises streaming the isolated packet data over a wide area network.

49. The method of claim 48, wherein the wide area network is the internet.

50. The method of' any of claims 28 to 49, wherein the multiplexed digital radio signal is a Coded Orthogonal Frequency Division Multiplexed (COFDM) radio signal.

51. The method of' claim 48, wherein the multiplexed digital radio signal is a Digital Audio Broadcasting (DAB) signal.

52. The method of claim 50, wherein the multiplexed digital radio signal is a Digital Video Broadcasting -Terrestrial (DVB-T) signal.

53. The method of claim 50, wherein the multiplexed digital radio signal is a Digital Audio Broadcasting 2 (DAB-2) signal.

54. The method of claim 50, wherein the multiplexed digital radio signal is a Digital Multimedia Broadcasting (DMB) signal.