TIME-MULTIPLEXED SPECTRUM SHARING

Abstract

Systems and methods are provided for providing content to a receiver. A first broadcaster is configured to broadcast a first content on a channel over an associated first region of signal coverage. A second broadcaster is configured to broadcast a second content, different from the first content, on the channel over an associated second region of signal coverage that overlaps the first region of signal coverage to form a region of overlap. A gateway device is configured to schedule transmission times for the first and second broadcasters, such that a receiver tuned to the channel receives the first and second content as a time divisional multiplexed signal.

Description

TECHNICAL FIELD

The present invention relates to RF communication systems and is particularly directed to systems and methods for sharing a broadcast channel among a plurality of broadcasters.

BACKGROUND OF THE INVENTION

Time-division multiplexing (TDM) is a method of transmitting and receiving independent signals over a common signal path by means of synchronized switches at each end of the transmission line so that each signal appears on the line only a fraction of time in an alternating pattern. The time domain is divided into several recurrent time slots of fixed length, one for each subchannel. A sample byte or data block of first subchannel is transmitted during a first time slot, a second subchannel is transmitted during a second time slot, and so forth. One TDM frame consists of one time slot per subchannel plus a synchronization channel and, optionally, an error correction channel. After the all of the subchannels, error correction, and synchronization, the cycle starts all over again with a new frame, starting with a second sample, byte or data block from the first subchannel.

SUMMARY OF THE INVENTION

In accordance with an aspect of the present invention, a system is provided including a first broadcaster configured to broadcast a first content on a channel over an associated first region of signal coverage. A second broadcaster is configured to broadcast a second content, different from the first content, on the channel over an associated second region of signal coverage that overlaps the first region of signal coverage to form a region of overlap. A gateway device is configured to schedule transmission times for the first and second broadcasters, such that a receiver tuned to the channel receives the first and second content as a time divisional multiplexed signal.

In accordance with another aspect of the present invention, a method is provided for providing content to a receiver. A first frame of content is broadcast on a channel over an associated first region of signal coverage from a first location. A second frame of content is broadcast on the channel over an associated second region of signal coverage from a second location. The second region of signal coverage overlaps the first region of signal coverage to form a region of overlap. Transmission times are scheduled for the first and second frames, such that a receiver tuned to the channel receives the first and second frames as a time divisional multiplexed signal.

In accordance with yet another aspect of the present invention, a system is provided for providing content to a receiver. A first broadcaster is configured to broadcast, from a first location, a first frame of content on a channel over an associated first region of signal coverage. A second broadcaster is configured to broadcast, from a second location, a second frame of content, different from the first frame, on the channel over an associated second region of signal coverage that overlaps the first region of signal coverage to form a region of overlap. A gateway device includes multiplexing logic configured to ensure that the first broadcaster and second broadcaster use complimentary parameters for broadcasting their respective content, such the first frame of content does not overlap the second frame of content.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other features of the present invention will become apparent to those skilled in the art to which the present invention relates upon consideration of the following description of the invention with reference to the accompanying drawings, wherein:

FIG. 1 illustrates one example of a spectrum sharing arrangement among a plurality of broadcasters;

FIG. 2 illustrates a simplified example of a frame structure for the transmission in accordance with an aspect of the present invention;

FIG. 3 illustrates a method for providing content to a receiver; and

FIG. 4 is a schematic block diagram illustrating an exemplary system of hardware components capable of implementing examples of the systems and methods disclosed in FIGS. 1-3.

DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1 illustrates one example of a spectrum sharing arrangement among a plurality of broadcasters. FIG. 1 illustrates a situation in which multiple broadcasters are providing signal coverage over respective regions 12 and 14 having a significant region of overlap 16 at a same frequency band. It will be appreciated that, in a standard system, the region of overlap 16 would experience significant interference between the broadcast signals. Accordingly, a receiver 22 located within the region of overlap 16 would be unlikely to receive a usable signal, particularly if the broadcasters were broadcasting different content.

A plurality of broadcasters 32 and 34 share at least an overlap in their respective service regions. It will be appreciated that, by a broadcaster, it is meant a system capable of conditioning and transmitting a signal, carrying content, such as video, audio, and/or data. A given broadcaster can be associated with one or more than one transmitters for carrying the content. Each broadcaster 32 and 34 may be providing a different content to its associated service region 32 and 34, such that the region of overlap can receive multiple, different content signals.

In the spectrum sharing arrangement utilized in the system of FIG. 1, however, the broadcasters 32 and 34 can share the channel via a time multiplexing arrangement, such that they transmit on the same allocated channel, but at different times. Specifically, each broadcaster 32 and 34 can broadcast its associated content within a single allocated time slot, such that within the region of overlap, the content from the various broadcasters is received in a time-multiplexed fashion. It will be appreciated that a receiver 22 located within the region of overlap can include appropriate logic for extracting the time-multiplexed content into the individual content streams, such that all broadcasted content can be available at a device associated with the receiver.

To this end, each individual broadcaster would be assigned a periodic time slot during which they transmit their content. The broadcaster will output no signal during the time slots belonging to other broadcasters. In one implementation, each frame has a coded header which identifies the type of frame. A consumer receiver can tune to content associated with a specific broadcaster by searching for the correct header.

A gateway device 40 can buffer the broadcast content and schedule the frame transmission times for individual transmitters. A user can enter frame durations, percent usage, and other parameters to the gateway device 40 to allocate the time slots among the various broadcasters. The gateway device 40 can include multiplexing logic 42 configured to ensure that gateways used for transmitters sharing an allocated channel use complementary parameters, such that the time slots align. It will be appreciated that, while the above discussion focuses on broadcast, a broadcaster with rights to a spectrum allocation in a region could also use this method to share spectrum with other entities which are not traditional broadcasters. A broadcaster could also broadcast other content in same timeslot in different parts of his coverage area.

To ensure that the content from the individual signals is provided in the appropriate time slot, the gateway device 40 can provide a digital signal, including synchronization data, to the plurality of broadcasters 32 and 34 to allow the transmitters 32 and 34 to operate synchronously. It will be appreciated that the digital signal from the gateway device 40 can also contain content to be broadcast by one or more of the plurality of broadcasters 32 and 34, but, for the purpose of example, it is assumed that at least one broadcaster is broadcasting content that is not provided via the digital signal.

In one example, the synchronization data can include a symbol indicating the beginning of a frame, such as a P1 symbol in the Digital Video Broadcasting—Second Generation Terrestial (DVB-T2) protocol. In one example utilizing MPEG-2 data, the cadence signal can be formed by inverting the value at the MPEG-2 data packet synchronization word at the beginning of every other field (e.g., at the beginning of each frame). This allows the various transmitters to coordinate the beginning of each data frame according to an associated time reference (e.g., a GPS receiver). In an alterative embodiment, the synchronization data can instead utilize a frame-level time stamp, inserted in place of every other MPEG-2 synchronization word that instructs the transmitters 32 and 34 as to when the frame should be transmitted and provides any other operation necessary for synchronization.

In one implementation, respective transmitters associated with each broadcaster can be configured for increased efficiency during intermittent operation. For example, the transmitter can be configured such that one of the optimization states of the amplifier is a no signal state. In one example, the amplifier can utilize a dynamic power source at one or more associated power amplifiers, allowing the system to enter a substantially dormant state when the transmitter is not broadcasting. To this end, the efficiency of the transmitter can be significantly increased.

Pending spectrum repack will incentivize individual broadcasters to share single allocated channels with other broadcasters in a region. While individual broadcasters could combine their content into a single multiplex that is transmitted from a single transmitter, the illustrated system allows the individual broadcasters to keep their own multiplex and transmitter, with the accompanying flexibility this allows in providing content. Accordingly, a more efficient use of the available spectrum can be achieved.

FIG. 2 illustrates a simplified example of a frame structure 100 for the transmission in accordance with an aspect of the present invention. In the illustrated implementation, only two broadcasters are illustrated, although it will be appreciated that the systems and methods described herein can be used with more than two broadcasters. Further, in this example 100, the broadcasters utilize the entirety of a given superframe 110, 120, and 130. It will be appreciated, however, that the broadcasters can instead use a portion of a larger frame, for example, a future extension frame in a hybrid broadcasting arrangement.

In the illustrated implementation, the time slots 111, 112, 121, 122, 131, and 132 within each superframe 110, 120, and 130 are of equal length and maintain a standard order of broadcast within each superframe. While this arrangement of frames is not necessary for the operation of the system, it will be appreciated that by assigning the time slots in this order, it is possible to reduce the necessary frequency of headers or timing information provided to a receiver associated with the system.

In view of the foregoing structural and functional features described above, a methodology in accordance with various aspects of the present invention will be better appreciated with reference to FIG. 3. While, for purposes of simplicity of explanation, the methodology of FIG. 3 is shown and described as executing serially, it is to be understood and appreciated that the present invention is not limited by the illustrated order, as some aspects could, in accordance with the present invention, occur in different orders and/or concurrently with other aspects from that shown and described herein. Moreover, not all illustrated features may be required to implement a methodology in accordance with an aspect the present invention.

FIG. 3 illustrates a method 150 for providing content to a receiver. At 152, a first frame of content is broadcast, from a first location, on a channel over an associated first region of signal coverage. In one example, the first frame includes a coded header that can be used by a receiver to identify content from the first location. Alternatively or additionally, the frame can be located within a future extension frame of a broadcasting standard, such as the digital video broadcasting, terrestrial (DVB-T2) standard.

At 154, a second frame of content is broadcast, from a second location, on the channel over an associated second region of signal coverage that overlaps the first region of signal coverage to form a region of overlap. In one example, the second frame includes a coded header that can be used by a receiver to identify content from the second location. It will be appreciated that, since the two broadcasters will be broadcasting different content, it can be desirable to broadcast over similar areas, such that the first region of signal coverage can be substantially coextensive with the second region of signal coverage.

Further, more than two broadcasters can share the channel, with the total number constrained only by the available bandwidth associated with the channel and the specific application. For example, the method could further include broadcasting, from a third location, a third frame of content, different from each of the first and the second frame, on the channel over an associated third region of signal coverage that overlaps the region of overlap. And to provide diversity of content to the receiver, the first region of signal coverage, the second region of signal coverage, and the third region of signal coverage can be substantially coextensive.

At 156, transmission times for the first and second frames are scheduled within the superframe, such that a receiver tuned to the channel receives the first and second frames as a time divisional multiplexed signal. In one implementation, a user is allowed to configure parameters associated with a superframe containing the two frames of content, and more specifically the scheduled transmission times, via an associated user interface. For example, the user can be allowed to select a length of each of the first frame and the second frame or a percent of the superframe used by each of the first location and the second location.

The illustrated method 150 allows broadcaster to keep control of their content multiplex, modulation and transmission but share a single allocated channel with other broadcasters in same geographic region. Other television systems require cooperation of content providers to combine transport streams into single multiple for broadcast. Further, cellular TDMA systems are lower power and don't cover as large a geographic area per transmitter.

FIG. 4 is a schematic block diagram illustrating an exemplary system 200 of hardware components capable of implementing examples of the systems and methods disclosed in FIGS. 1-3. The system 200 can include various systems and subsystems. The system 200 can be a personal computer, a laptop computer, a workstation, a computer system, an appliance, an application-specific integrated circuit (ASIC), a server, a server blade center, a server farm, etc.

The system 200 can includes a system bus 202, a processing unit 204, a system memory 206, memory devices 208 and 210, a communication interface 212 (e.g., a network interface), a communication link 214, a display 216 (e.g., a video screen), and an input device 218 (e.g., a keyboard and/or a mouse). The system bus 202 can be in communication with the processing unit 204 and the system memory 206. The additional memory devices 208 and 210, such as a hard disk drive, server, stand-alone database, or other non-volatile memory, can also be in communication with the system bus 202. The system bus 202 interconnects the processing unit 204, the memory devices 206-210, the communication interface 212, the display 216, and the input device 218. In some examples, the system bus 202 also interconnects an additional port (not shown), such as a universal serial bus (USB) port.

The processing unit 204 can be a computing device and can include an application-specific integrated circuit (ASIC). The processing unit 204 executes a set of instructions to implement the operations of examples disclosed herein. The processing unit can include a processing core.

The additional memory devices 206, 208 and 210 can store data, programs, instructions, database queries in text or compiled form, and any other information that can be needed to operate a computer. The memories 206, 208 and 210 can be implemented as computer-readable media (integrated or removable) such as a memory card, disk drive, compact disk (CD), or server accessible over a network. In certain examples, the memories 206, 208 and 210 can comprise text, images, video, and/or audio, portions of which can be available in formats comprehensible to human beings. Additionally or alternatively, the system 200 can access an external data source or query source through the communication interface 212, which can communicate with the system bus 202 and the communication link 214.

In operation, the system 200 can be used to implement one or more parts of a broadcast system in accordance with the present invention, such as the multiplexing logic 42. Computer executable logic for implementing the broadcast system resides on one or more of the system memory 206, and the memory devices 208, 210 in accordance with certain examples. The processing unit 204 executes one or more computer executable instructions originating from the system memory 206 and the memory devices 208 and 210. The term “computer readable medium” as used herein refers to a medium that participates in providing instructions to the processing unit 204 for execution, and can, in practice, refer to multiple, operatively connected apparatuses for storing machine executable instructions.

From the above description of the invention, those skilled in the art will perceive improvements, changes and modifications in the invention. Such improvements, changes and modifications within the skill of the art are intended to be covered by the appended claims.

Claims

1. A system comprising: a first broadcaster that broadcasts a first content on a channel over an associated first region of signal coverage;a second broadcaster that broadcasts a second content, different from the first content, on the channel over an associated second region of signal coverage that overlaps the first region of signal coverage to form a region of overlap; anda gateway device that schedules transmission times for the first and second broadcasters, such that a receiver tuned to the channel receives the first and second content as a time divisional multiplexed signal.

2. The system of claim 1, wherein the first and second broadcasters have associated first and second power amplifiers, each of the first and second amplifiers having an optimization state for a condition in which no signal is received.

3. The system of claim 1, the channel comprising a series of superframes, each superframe comprising a first frame broadcast by the first broadcaster with a first coded header and a second frame broadcast by the second broadcaster with a second coded header.

4. The system of claim 1, the gateway device comprising a user interface configured to allow a user to configure parameters associated with the channel.

5. The system of claim 4, the channel comprising a series of superframes, each superframe comprising a first frame broadcast by the first broadcaster and having a first duration and a second frame broadcast by the second broadcaster and having a second duration, the user interface being configured to adjust each of the first duration and the second duration.

6. The system of claim 4, the channel comprising a series of superframes each having a common duration, the user interface being configured to adjust the common duration of the series of superframes.

7. The system of claim 1, the channel comprising a series of superframes, the gateway device comprising multiplexing logic to ensure that the first broadcaster and second broadcaster use complimentary parameters for broadcasting their respective content, such that a given superframe of the series of superframes contains content from each of the first broadcaster and the second broadcaster, and the content from the first broadcaster does not overlap the content from the second broadcaster.

8. The system of claim 1, wherein the region of overlap is a first region of overlap the system further comprising a third broadcaster configured to broadcast a third content, different from each of the first content and the second content, on the channel over an associated third region of signal coverage that overlaps the first region of overlap to form a second region of overlap within which the receiver tuned to the channel receives the first content, the second content, and the third content as the time divisional multiplexed signal.

9. A method for providing content to a receiver comprising: broadcasting, from a first location, a first frame of content on a channel over an associated first region of signal coverage;broadcasting, from a second location, a second frame of content, different from the first frame, on the channel over an associated second region of signal coverage that overlaps the first region of signal coverage to form a region of overlap; andscheduling transmission times for the first and second frames, such that a receiver tuned to the channel receives the first and second frames as a time divisional multiplexed signal.

10. The method of claim 9, wherein broadcasting the first frame comprises broadcasting the first frame with a first coded header and broadcasting the second frame comprises broadcasting the second frame with a second coded header, the method further comprising identifying content from a given location at a receiver within the region from the corresponding coded header.

11. The method of claim 9, further comprising allowing a user to configure parameters associated with s superframe containing the first frame and the second frame via an associated user interface.

12. The method of claim 11, wherein allowing the user to configure parameters associated with the superframe comprises allowing a user to select a length of each of the first frame and the second frame.

13. The method of claim 11, wherein allowing the user to configure parameters associated with the superframe comprises allowing the user to select a percent of the superframe used by each of the first location and the second location.

14. The method of claim 9, further comprising broadcasting, from a third location, a third frame of content, different from each of the first and the second frame, on the channel over an associated third region of signal coverage that overlaps the region of overlap.

15. The method of claim 14, wherein the first region of signal coverage, the second region of signal coverage, and the third region of signal coverage are substantially coextensive.

16. The method of claim 14, wherein broadcasting the first frame comprises broadcasting the first frame within a future extension frame of a transmission standard associated with the channel.

17. A system for providing content to a receiver comprising: a first broadcaster that broadcasts, from a first location, a first frame of content on a channel over an associated first region of signal coverage;a second broadcaster that broadcasts, from a second location, a second frame of content, different from the first frame, on the channel over an associated second region of signal coverage that overlaps the first region of signal coverage to form a region of overlap; anda gateway device comprising multiplexing logic configured to ensure that the first broadcaster and second broadcaster use complimentary parameters for broadcasting their respective content, such the first frame of content does not overlap temporally with the second frame of content.

18. The system of claim 17, the gateway device being configured to schedule transmission times for the first and second frames such that a receiver in the region of overlap that is tuned to the channel receives the first and second frames as a time divisional multiplexed signal.

19. The system of claim 17, wherein the first and second broadcasters have associated first and second power amplifiers, and each of the first and second amplifiers have an optimization state for a condition in which no signal is received.

20. The system of claim 17, the gateway device comprising a user interface configured to allow a user to configure parameters associated with the channel.