Method and apparatus for providing wireless digital television service

A system that incorporates teachings of the present disclosure may include, for example, a method for receiving one or more wireless digital television signals, wherein each of the one or more wireless digital television signals comprise a plurality of data segments for presenting media content, buffering the plurality of data segments of each of the one or more wireless digital television signals to generate one or more buffered data segments to cause a presentation delay of the media content, and detecting a missing data segment in the one or more buffered data segments. The method can further include transmitting a first request to a cellular communication system to provide the missing data segment, and receiving from the cellular communication system the missing data segment prior to an expiration of the presentation delay to continue a presentation of the media content without interruption. Other embodiments are disclosed.

FIELD OF THE DISCLOSURE

The present disclosure relates generally to a method and apparatus for providing wireless digital television service.

BACKGROUND

The signal quality of wireless broadcast of digital television signals can degrade in vehicular or other non-stationary applications due to fading, multipath and travel between broadcast stations. As is the case with most broadcast technologies, a wireless broadcast of digital television has no feedback mechanism or means to replace video packets or frames lost at the receiving end. Past attempts to solve this problem have proven expensive and non-sustainable.

Third generation Smartphones and other connected devices may receive unicast streamed content on-demand. This content is relatively reliable, as it is sent by cellular radio networks which enable retransmission, error correction and handover mobile applications. On the other hand, a digital television stream may occupy a significant portion of the cell site capacity, and is therefore delivered at an unsustainable cost. The required bandwidth may also lead to congestion situations in venues where multiple users demand (but are unable to receive) the same content.

A standard promulgated by the Advanced Television Systems Committee for mobile and handheld devices, also referred to as mobile digital television, allows television broadcasters to send mobile-optimized content to handheld devices. This new technology requires specialized transmitters and receivers, which both bring additional costs. Lacking a means to provide feedback and receive commands from the network, it is questionable whether this protocol will be as reliable as streaming content received over dedicated cellular connections.

DETAILED DESCRIPTION

The present disclosure describes, among other things, illustrative embodiments of a system for mitigating communication interruptions experienced by user equipment receiving signals from wireless digital television broadcasters.

One embodiment of the present disclosure includes a device comprising a first mobile television receiver, a second mobile television receiver, a cellular transceiver, a memory, and a processor coupled to the first and second mobile television receivers, the cellular transceiver, and the memory. The processor can be operable to receive from the first mobile television receiver a first wireless digital television signal comprising a first plurality of data segments for presenting a television program, receive from the second mobile television receiver a second wireless digital television signal comprising a second plurality of data segments for presenting a copy of the television program, and buffer via the memory the first and the second plurality of data segments to generate a first and a second buffered plurality of data segments to cause a presentation delay of the television program. The processor can be further operable to periodically select data segments from one of the first or the second buffered plurality of data segments, and present the television program according to the periodically selected data segments. Upon detecting a missing data segment in the first and the second buffered plurality of data segments, the processor can also be operable to transmit via the cellular transceiver a request to a network element to provide the missing data segment, and receive via the cellular transceiver the missing data segment prior to an expiration of the presentation delay to continue the presentation of the television program without interruption.

One embodiment of the present disclosure includes a wireless base station, comprising a first television receiver, a second television receiver, cellular transceiver, a memory, and a processor coupled to the first and second television receivers, the cellular transceiver, and the memory. The processor can be operable to receive from the first television receiver a first wireless digital television signal comprising a first plurality of data segments for presenting a media program, receive from the second television receiver a second wireless digital television signal comprising a second plurality of data segments for presenting a copy of the media program, and buffer via the memory the first and the second plurality of data segments to generate first and second buffered plurality of data segments to cause a delay of the media program. The processor can be further operable to receive a request from a mobile device for a missing data segment, detect a copy of the missing data segment in at least one of the first or the second buffered plurality of data segments, and transmit the copy of the missing data segment to the mobile device prior to an expiration of the delay to continue a presentation of the media program at the mobile device without interruption.

One embodiment of the present disclosure includes a method for receiving one or more wireless digital television signals, wherein each of the one or more wireless digital television signals comprise a plurality of data segments for presenting media content, buffering the plurality of data segments of each of the one or more wireless digital television signals to generate one or more buffered data segments to cause a presentation delay of the media content, and detecting a missing data segment in the one or more buffered data segments. The method can further include transmitting a first request to a cellular communication system to provide the missing data segment, and receiving from the cellular communication system the missing data segment prior to an expiration of the presentation delay to continue a presentation of the media content without interruption.

FIGS. 1-2depict communication systems in which a vehicular system can communicate with digital television broadcast stations and a cellular communication system.FIG. 1depicts a vehicle102comprising a communication device104coupled to two digital television antennas106,108. Although the antennas106,108are labeled as high definition digital television antennas, the antennas106,108can receive digital broadcast content such as standard definition television content, high definition television content, and/or digital audio content such as digital radio. The antennas106,108receive wireless digital broadcast signals from broadcast stations202,204such as shown inFIG. 2.

The communication device104can comprise demodulation and signal processing technology which can take advantage of diversity technology principles by receiving identical content from each antenna106,108to improve reception. The communication device104can comprise processing technology such as a microprocessor, a digital signal processor (DSP), and/or a video processor with associated storage memory such as Flash, ROM, RAM, SRAM, DRAM or other storage technologies.

The communication device104can further comprise a display (not shown) such as a monochrome or color LCD (Liquid Crystal Display), OLED (Organic Light Emitting Diode) or other suitable display technology for conveying images to an end user of the communication device104. The communication device104can provide an input interface by way of the display if the display supports touch-screen technology. In another embodiment, the communication device104can be coupled to a key pad for manual control and navigation of a graphical user interface. The communication device104can also comprise an audio system (not shown) to enable a user to listen to audio content supplied by the broadcast stations202,204.

In one embodiment, the communication device104can be coupled to a cellular communication device110that supports third generation (e.g., Universal Mobile Telecommunications or UMTS), fourth generation (e.g., Long Term Evolution or LTE), or other future cellular communication protocols. In the present illustration, the cellular communication device110operates according to an LTE communication protocol. The communication device104can cause the cellular communication device110to exchange messages with a cellular base station120such as shown inFIG. 1.

In one embodiment, the communication device104can be coupled to a short range communication device112for engaging in short range communications with access points operating according to communication protocols such as WiFi (also known as Wireless Fidelity), Bluetooth, Zigbee, or other short range communication protocols. The communication device104can cause the short range communication device112to exchange messages with a network element such as a server operating in a communication system.

In one embodiment, the communication device104can be coupled to a location receiver114(such as a global position system or GPS receiver). The location receiver114can provide the communication device104coordinate information to locate the position of the vehicle102as well as trajectory information indicative of the orientation and direction of travel of the vehicle102, speed, and other relevant factors which can be used to estimate an arrival time at one or more destinations.

The cellular base station120can comprise an eNodeB compliant controller128for supporting LTE communications with mobile devices such as the cellular communication device110. The cellular base station120can also be coupled to a digital television communication device126functionally similar to the communication device104. The digital television communication device126can be coupled to two digital television antennas122,124for diversity reception of communication signals transmitted by the digital television broadcast stations202,204ofFIG. 2.

The digital television communication device126can receive broadcast digital television signals by way of antennas122,124, which it can demodulate into baseband signals to produce data segments as depicted in table130. The sequence of data segments can represent media content such as digital television program or digital radio program. When the digital television communication device126is unable to receive a data segment (indicated by “blank” slots) from one of the antennas122or124, the digital television communication device126resorts to using the data segment received by the other antenna.

For example, in the illustration ofFIG. 1the digital television communication device126is unable to receive data segment 1 from antenna124—see table130. In this instance, the digital television communication device126can resort to using data segment 1 received from antenna122. In the same illustration, the digital television communication device126is unable to receive data segment 5 from antenna122. For this case, the digital television communication device126can resort to using data segment 5 received from antenna124. Diversity reception techniques improves the ability of the digital television communication device126to receive broadcast signals transmitted by broadcast stations202,204(FIG. 2) that do not support retransmission requests. The aforementioned approach for recovery of data segments is also used by the communication device104as depicted by table206ofFIG. 2.

It should be noted that since the cellular base station120is a terrestrial stationary base station, the antennas122and124can be configured to optimize reception of signals transmitted by the digital television broadcast stations202and204—which are themselves also terrestrial stationary stations. Consequently, the cellular base station120has a much higher likelihood of receiving high quality reception of broadcast signals than the communication device104would while the vehicle102is in transit.

FIG. 2illustrates circumstances where the communication device104of vehicle102can receive digital television signals201from broadcast station204with the ability to recover from lost data segments without assistance from other sources. When the communication device104is unable to receive data segments from both antennas106,108, and the data segments are co-aligned (e.g., cannot receive data segment 5 from either antenna), the communication device104will be unable to recover the lost segments, and a presentation fault may occur, which may be perceptible to the user visually and/or audibly.

FIG. 3depicts an illustrative of a method300that can resolve such faults and can provide mobile communication devices such as communication device104a means for reliable communications. Method300can begin with steps302and304in which user equipment such as the communication device104of vehicle102receives wireless digital television signals401as depicted inFIG. 4from broadcast station204. For illustration purposes, the user equipment referred to in the flowchart ofFIG. 3will be referred to herein as communication device104. It is further noted that in the present illustration, the vehicle102is assumed to be in transit. Thus, the communication device104can experience multipath fading (e.g., Rayleigh fading) or other forms of signal degradation.

To mitigate losses of co-aligned data segments, the communication device104can be configured in step306to buffer the data segments extracted from each antenna signal with the memory component of the communication device104. The buffered data segments can be used to cause a presentation delay of media content represented by the data segments. Media content in the present context can represent still image content, moving image content, audio content, or combinations thereof. The communication device104can be configured to cause a presentation delay (e.g., 5-10 seconds) sufficient to allow the communication device104to perform mitigation of data segment losses. In step308, the communication device104can periodically select data segments from either of the buffered data segment streams for presenting media content by way of a presentation interface (display/audio components) of the communication device104as described earlier.

In step312, the communication device104can be configured to detect co-aligned data segments losses due to a degraded signal received by both antennas106,108, which the communication device104is unable to correct by error correction or other mitigation techniques. In the illustration ofFIG. 4, the communication device104is unable to receive co-aligned data segments 0, 4, 5, 8 and 9 as depicted in table402for reasons such as poor signal integrity from either antenna106,108causing an excessively high bit error rate that cannot be corrected with error correction techniques. Since a broadcast transmission is unidirectional, and retransmissions cannot be requested from the broadcast stations202,204, the communication device104proceeds to step314where it submits a request to a cellular communication system for the missing data segments. In the present illustration, the cellular communication system is an LTE base station120ofFIG. 4, which is assumed to represent one of several base stations120accessible to the communication device104as the vehicle travels between base station120cell sites.

As was noted earlier, the base station120ofFIG. 4is stationary and the digital television antennas122,124shown inFIG. 1can be optimally aligned to maintain consistent reception with the broadcast stations202,204. Accordingly, the base station120is not susceptible to the signal degradation experienced by the communication device104due the transit nature of the vehicle102. There is therefore a high likelihood that the base station120can assist the communication device104in recovering any data segment losses experienced by the communication device104. Upon receiving in step314the request submitted by the communication device104, which can include identifying information of the missing data segments (e.g., header information), the base station120can retrieve a copy of the missing data segment from its own buffers, and transmit the missing data segment to the communication device104in step316.

Since the base station120and the communication device104have both buffered the data segments, it is likely that the communication device104will be able communicate the base station120in time to receive the data segment before the expiration of the presentation delay discussed in step306. If the communication device104detects that the presentation delay has not expired in step318, the communication device104proceeds to step322where it inserts the received missing data segment in the data stream and presents the media content (e.g., television program, radio program, etc.) without interruption.

If, on the other hand, the data segment is received by the communication device104after the expiration of the presentation delay, the communication device104can then proceed to step320and present interim content (e.g., advertisement content, or pausing a frame of the media content presentation with music in the background, etc.), while data segments are being recovered. Once the data segments have been recovered, the communication device104can resume presentation of the media content in step322.

Steps318and320can arise in situations where the communication device104experiences a large volume of data segment losses due to a burst error, or other interference factors that can cause an excessive loss of data segments. The base station120can be equipped with substantially more memory than the communication device104. Accordingly, the base station120can buffer substantially more data segments than the communication device104is able to. Under such conditions, the base station120can provide a recovery mechanism that exceeds the buffer capacity of the communication device.

It should be noted that the base station120can also record an entire program (much like a digital video record). In this embodiment, if the user initiates a presentation of a media program after a start time of the broadcast, the user can submit a request to the communication device104to request a unicast retransmission of the missing portion. The communication device104can be configured with a non-volatile memory such as a hard drive or Flash memory to record the live broadcast while presenting the missing portion received from the base station120.

Referring now to step324, the communication device104can also be configured to detect a transition between broadcast stations. This situation is depicted inFIG. 5. In the illustration, the vehicle102has transitioned to a location where the communication device104can sense signals from broadcast stations202and204. In one embodiment, the communication device104can be configured to anticipate transitioning between broadcast stations by utilizing a look-up table stored in the memory of the communication device104that lists broadcast stations and their corresponding transmission frequencies and terrestrial locations. The communication device104can use this look-up table and compare it to its location (determined with the GPS receiver114ofFIG. 1) to anticipate when it will be in communication range of another broadcast station. The list of broadcast stations can be transmitted to the communication device104responsive to the cellular base station120receiving a request from the communication device104.

Alternatively, or in combination, the communication device104can determine its location and inform a base station120in its proximity of the location of the vehicle102, and request updates to the look-up table so that the communication device104can be aware of broadcast stations that it is approaching as the vehicle102continues to change location. The communication device104can determine its location and trajectory and thereby anticipate a transition from broadcast station204to broadcast station202as depicted inFIG. 4. In another embodiment, the communication device104can detect that the diversity signals received from broadcast station204are fading thereby prompting the communication device104to submit a request to the base station120to identify the location of the next broadcast station (in this illustration broadcast station202), and a base station120that serves the new broadcast station if the same base station120is unable to provide such services.

In one embodiment, it is possible that the program channels of broadcast station202are organized differently than the program channels of broadcast station204. To continue a presentation of the same media content without interruption, the communication device104can request a program guide of the broadcast station202on or before it begins receiving digital television signals. With the program guide, the communication device104is able to selectively switch program channels at an opportune time when data segments from the new broadcast station202can be received reliably. By previously buffering the data segments of broadcast station204, the communication device104is able to transition to another channel of broadcast station202for presenting the same content without interrupting the ongoing presentation. Thus to the user, the presentation continues while traveling without an understanding that the communication device104has transitioned to a new broadcast station.

During the transition from broadcast station204to broadcast station202, however, the communication device104can be in the fringes of receiving reliable signals from the broadcast stations202and204. This situation is depicted by table504as shown inFIG. 5. Under this condition, the communication device104can submit a request to the same cellular base station120serving broadcast station204if it is still in communication range, or the communication device104can submit the request to another base station120serving broadcast station202. To selectively choose between base stations120, a cross-reference can be added to the look-up table described earlier to identify which base stations120(identified by base station ID) support which broadcast stations. This information can be provided by any of the base stations120supplying a look-up table update.

Once the communication device104identifies a base station120, it can submit a request for the missing data segments while transitioning to the broadcast station202. As described before, the base station120is stationary and its digital television antennas122,124can be optimally aligned to reliably receive broadcast signals from broadcast station202. Accordingly, it is very likely that the base station120will provide all the missing data segments requested by the communication device104during the transition without interrupting the presentation. If, however, the losses are severe and cannot be mitigated, then the communication device104can transition to step320and present interim content. The communication device104can continue to collect data segments from the base station120until such time that communications with the broadcast station202become reliable as shown in table602ofFIG. 6. That is, when the communication device104detects that there are no longer co-aligned data segment losses, the communication device104can inform the base station120that reception is stable and transmission of data segments can cease.

Method300as just described provides mobile devices configured to receive digital television broadcast signals a means to substantially improve reception by mitigating anomalies such as multipath fading, and other possible interference factors.

Upon reviewing the aforementioned embodiments, it would be evident to an artisan with ordinary skill in the art that said embodiments can be modified, reduced, or enhanced without departing from the scope and spirit of the claims described below. For example, method300can be adapted so that when the vehicle102is in proximity of a WiFi access point, the communication device104can revert to requesting data segments by way of WiFi communications. The communication device104can for instance submit requests over the Internet to a network element that can provide backup support services as described above. The network element can be a communication device126shown inFIG. 1located at a base station120in proximity to the broadcast station in use by the communication device104. Alternatively, the network element can be a content server that stores copies of the media program and can retrieve any data segments identified by the communication device104.

Method300can also be applied to handheld devices such as Smartphones capable of receiving digital television signals and/or digital radio, and enabled with cellular data communication resources (e.g., LTE, etc.) to replace lost segments as described above. Method300can also be applied to satellite receivers that can receive digital television signals and/or digital radio, and which are equipped with cellular data resources to replace portions of lost satellite broadcasts. The satellite receivers can be stationary devices such as set-top boxes which can be enhanced by back-up cellular resources (e.g., LTE via a femtocell) to protect against temporary data losses due to weather conditions. Method300can also be applied to high definition radio receivers enabled with cellular resources (e.g., LTE). A device can receive missing segments from a cellular base station that buffers data segments as they are broadcast. In another embodiment, the base station can request missing segments from a central data center (e.g., a network element server) and then transmit the data segments requested to the device. Other embodiments are contemplated by the present disclosure.

FIG. 7depicts an exemplary diagrammatic representation of a machine in the form of a computer system700within which a set of instructions, when executed, may cause the machine to perform any one or more of the methods discussed above. One or more instances of the machine can operate, for example, as the communication device104, the cellular base station120, the broadcast stations120or combinations thereof. In some embodiments, the machine may be connected (e.g., using a network) to other machines. In a networked deployment, the machine may operate in the capacity of a server or a client user machine in server-client user network environment, or as a peer machine in a peer-to-peer (or distributed) network environment.

The computer system700may include a processor702(e.g., a central processing unit (CPU), a graphics processing unit (GPU, or both), a main memory704and a static memory706, which communicate with each other via a bus708. The computer system700may further include a video display unit710(e.g., a liquid crystal display (LCD), a flat panel, or a solid state display. The computer system700may include an input device712(e.g., a keyboard), a cursor control device714(e.g., a mouse), a disk drive unit716, a signal generation device718(e.g., a speaker or remote control) and a network interface device720.

The disk drive unit716may include a tangible computer-readable storage medium722on which is stored one or more sets of instructions (e.g., software724) embodying any one or more of the methods or functions described herein, including those methods illustrated above. The instructions724may also reside, completely or at least partially, within the main memory704, the static memory706, and/or within the processor702during execution thereof by the computer system700. The main memory704and the processor702also may constitute tangible computer-readable storage media.