WO2006047064A2

WO2006047064A2 - Method and apparatus for allowing communication over non-licensed spectrum

Info

Publication number: WO2006047064A2
Application number: PCT/US2005/036155
Authority: WO
Inventors: Daniel B. Grossman; Minh N. Hoang
Original assignee: Motorola Inc
Current assignee: Motorola Solutions Inc
Priority date: 2004-10-26
Filing date: 2005-10-05
Publication date: 2006-05-04
Anticipated expiration: 2007-04-26
Also published as: WO2006047064A3

Abstract

A video distribution system is provided that performs the necessary steps to determine an available non-licensed channel for video transmission. Particularly, a video-distribution device (101) checks a centralized database or beacon signal to determine the availability of a non-licensed channel. After the VDD (101) has identified an appropriate non-licensed channel, a television (107) is tuned to that channel so that the VDD (101) can transmit video to the television (107) utilizing the non-licensed channel. This can be accomplished by the VDD (101) notifying a controller (105) of the appropriate channel, and having the controller (105) automatically tune the television (107) to the appropriate channel.

Description

METHOD AND APPARATUS FOR ALLOWING COMMUNICATION OVER NON-LICENSED

SPECTRUM

Field of the Invention

The present invention relates generally to wireless communications, and in particular, to a method and apparatus for allowing communication over non-licensed television spectrum.

Background of the Invention

The Federal Communications Commission (FCC) of the United States of America has proposed allowing limited non-licensed operation in the broadcast television spectrum using channels that are licensed for other users (i.e., television broadcasters and certain public safety agencies). This is detailed in "Unlicensed Operation in the TV Broadcast Bands and Additional Spectrum for Unlicensed Devices Below 900 MHz and in the 3 GHz Band", Notice of Proposed Rulemaking, FCC 04-133, released May 25, 2004. Non-licensed operation under Part 15 of the FCC rules allows devices to be used in certain regions of the electromagnetic spectrum without an FCC license. For the broadcast television spectrum, the FCC has proposed the use of a control signal to allow devices to identify channels that are available for non-licensed operation. The control signal to be specified in the final FCC rules may take the form of a database, or may use channel monitoring or both. Access to the database may be via wired, wireless, or other robust method.

One device that could readily utilize non-licensed operation in the broadcast spectrum is digital television sets, i.e., according to the ATSC standard. A challenge becomes providing a video signal to an existing television set, where the signal utilizes non-licensed operation in the television band subject to a control signal. Therefore a need exists for a method and apparatus for allowing communication over non-licensed spectrum. Brief Description of the Drawings

FIG. 1 is a block diagram of a video distribution system. FIG. 2 is a block diagram of a video distribution device. FIG. 3 is a flow chart showing the operation of the video distribution device of

FIG. 2.

FIG. 4 is a block diagram of a remote control.

FIG. 5 is a flow chart showing operation of the remote control of FIG. 4.

Detailed Description of the Drawings

To address the above-mentioned need a method and apparatus is provided for supplying a television set with a transmission that utilizes non-licensed transmissions in the television band. A video distribution system is provided that performs the necessary steps to determine an available channel for video transmission. Particularly, a video- distribution device checks (e.g., using a centralized database, a beacon signal and/or spectrum sensing) the availability of a channel in the television band for non-licensed operation. The present invention is agnostic as to the means for finding an available non-licensed channel, which will be subject of an FCC rulemaking. After the VDD has identified an appropriate channel, a television is tuned to that channel so that the VDD can transmit video to the television utilizing the non-licensed channel. This can be accomplished by the VDD tuning the television to the appropriate channel by way of a controller, which acts as a proxy for the VDD. The present invention encompasses a Video Distribution Device (VDD) comprising an input receiving video, and control circuitry determining a non-licensed channel for transmission of the received video, wherein the non-licensed channel is a vacant channel in licensed spectrum. The VDD also comprises a first transmitter, transmitting the received video via the non-licensed channel to an external receiver. The present invention additionally encompasses an apparatus comprising a video input receiving video, control circuitry determining a channel for transmission of the received video, a first transmitter transmitting channel information to a remote control device, causing the remote control device to tune a television to the channel, and a second transmitter transmitting the received video via the channel to the television.

The present invention encompasses an apparatus comprising an input device for receiving user commands, a controller for determining a type of user command received, a first transmitter transmitting the command to a first device using a first communication system protocol when the command is from a first set of commands, and a second transmitter transmitting the command to a second device using a second communication system protocol when the command is from a second set of commands.

The present invention additionally encompasses a method comprising the steps of receiving video, determining a non-licensed channel for transmission of the received video, wherein the non-licensed channel is a vacant channel in licensed spectrum, and transmitting the received video via the non-licensed channel to an external receiver.

The present invention additionally encompasses a method comprising the steps of receiving a user command, determining if the command is from a first or a second set of commands, transmitting the command via a first transmitter to a first device using a first communication system protocol when the command is from the first set of commands and transmitting the command via a second transmitter to a second device using a second communication system protocol when the command is from a second set of commands. Turning now to the drawings, wherein like numerals designate like components,

FIG. 1 is a of video distribution system 100. As shown, system 100 comprises video distribution device (VDD) 101, remote control 105, and television 107. Television 107 is a digital television which conforms to the Advanced Television Standards Committee (ATSC) standards and to the FCC rules concerning digital televisions. VDD 101 is a central device in a home providing video content to receivers such as television 107. VDD 101 includes devices such as, but not limited to a "Whole-house Set-Top Box", a "Residential Gateway", . . . , etc. VDD 101 has a plurality of input devices 102 (only one shown in FIG. 1). Such input devices include, but are not limited to video recorders, DVD players, digital terrestrial broadcast television tuners (i.e., utilizing antenna 108), a multi-program video distributor (MPVD) tuner, . . . , etc. (MPVD is a term of art in the FCC rules which broadly encompasses video service providers offering service over any of several different technologies, including cable, direct broadcast satellite, digital subscriber line and optical access networks.) VDD 101 communicates with remote control device 105 via over-the-air link 103 using a wireless local area network (LAN) system protocol (e.g., as defined in IEEE 802.11a, b, or g). VDD 101 transmits video signals via link 104 using an over- the-air ATSC-conforming transmission as a composite multiplex on a broadcast television channel.

Remote control 105 has a user interface (input) such as a multi-button keypad, with which a user interacts with system 100. Remote control 105 communicates with VDD 101 using a wireless LAN protocol. Remote control 105 additionally sends commands to television 107 using standard infrared commands, as is known in the art. As such, a first set of user inputs will be transmitted via link 103 to VDD 101, while a second set of commands will be transmitted yia IR link 106 to television 107. Thus, remote control 105 serves as a proxy for VDD 101, forwarding commands from VDD 101 to television 107.

As discussed above, the FCC has proposed allowing non-licensed operation in the broadcast television spectrum on channels which are not used by licensed users. A non-licensed channel includes any vacant channel in licensed spectrum, wherein a user is not licensed to use the vacant channel. The FCC has proposed the use of a control signal to identify channels which are available for non-licensed operation in a given geographic area. This control signal may take one or more of several forms in the final FCC rules, 47 CFR §15.244. For example, a terrestrial broadcast television station may periodically broadcast a database containing the limits of the so-called Grade B contour for each licensed user in a given area. As another example, spectrum sensing methods may be applied. As a third example, a database may be queried through a communication network such as the internet to return a channel which is not within the Grade B contour of any licensed user. The definition of the control signal will be subject of an FCC rulemaking, and its exact form is not relevant to this discussion.

In order for system 100 to utilize non-licensed operation in the broadcast television spectrum, VDD 101 performs the necessary steps to determine an available channel for non-licensed operation. Particularly, VDD 101 serves as means for performing whatever determination is required by the FCC rules. This may comprise having logic circuitry determine the channel by analyzing a received beacon, or accessing an external database, or determining that no transmissions exist on the non- licensed channel. After VDD 101 has identified an appropriate channel, television 107 needs to be tuned to that channel in order for VDD 101 to transmit audio/video programming to television 107. (In addition, and also to permit more than one television to be utilized, a sub-channel (as defined in the ATSC standards) must be selected by VDD 101 to multiplex the channel among a plurality televisions 107. This is accomplished by VDD 101 notifying remote control 105 of the appropriate channel and selected sub-channel, and having remote control 105 automatically tune television 107 to the appropriate channel and sub-channel).

Once an available channel is determined, and television 107 has been tuned to the channel and a subchannel, all transmissions by VDD 101 to television 107 will take place utilizing non-licensed operation in the television spectrum. Thus, for example, if input device 102 comprises a DVD player, and is playing an MPEG2 program stream to VDD 101, VDD 101 will multiplex the MPEG2 program stream onto a subchannel of an MPEG2 transport stream, and transmit the MPEG2 program stream to television 107 over link 104, utilizing the available non-licensed television channel. FIG. 2 is a block diagram of VDD 101. As shown VDD control circuitry 206 is provided to control the functionality of VDD 101. VDD control circuitry 206 preferably comprises a microprocessor controller, such as, but not limited to a Freescale PowerPC microprocessor.

As discussed above, VDD 101 serves as means for receiving digital video and providing the video to television 107 via non-licensed operation in the television spectrum. While the source of the video received by VDD 101 is irrelevant to this discussion, such sources may include, but are not limited to, an MPVD interface such as a cable television or DBS receiver, an IEEE 1394 (sometimes sold under the trade name "Firewire" or "iLink") interface from an external video recorder or camera, "streaming video" from the Internet, over-the-air television broadcasts received via ATSC transmitter transceiver 211 and an external (e.g., roof mounted) antenna, and internal video storage 209 providing internally-stored content.

As one of ordinary skill in the art will recognize, in order to provide conditional access to services such as premium channels and video-on-demand, MPVDs require a security device (not shown), which is variously known in the art as a "POD" or a "CableCARD". The security device is intended to permit the MPVD to retain ownership of equipment which provides the conditional access function and maintain control over its use and security, while permitting the rest of the customer premises equipment to be owned by consumers. It is designed to be physically inserted into a slot which the selected video flow passes through, so as to decrypt the video flow, as long as the consumer is so entitled.

MPVDs and terrestrial broadcast stations deliver audiovisual programs as MPEG2 transport streams (MPEG2 TS). Additionally, storage 209 typically uses MPEG2 program streams (MPEG2 PS). MPEG2 TS are typically used to multiplex one or more programs, each consisting of several program elementary streams (PES), each of which comprises a video, audio or private data signal. MPEG Processor 208 serves as a video input, taking MPEG2 TS and MPEG2 PS and grooming out the selected programs. Processor 208 may further remove unneeded PES (e.g., eliminating PES containing foreign language audio and/or closed captioning if they are not needed). The ATSC standard provides a mapping between MPEG2 TS program numbers (which relate to PES) and subchannels.

FIG. 3 is a flow chart showing the steps necessary for VDD 101 to transmit video. The logic flow in FIG. 3 assumes that both VDD 101 and television 107 are powered on, and that television 107 is awaiting video transmissions from VDD 101. The logic flow begins at step 301 where VDD control circuitry 206 determines a channel available for non-licensed operation in accordance with the proposed FCC rules specified in 47 CFR §15.244. As discussed, control circuitry determines a vacant channel existing within television spectrum by determining that no transmissions exist on the channel, accessing an external database to determine the availability of the non- licensed channel, or analyzing a received beacon to determine channel availability.

If control circuitry 206 determines that a channel exists (step 303), VDD- 101 selects' a previously unused sub-channel (step 305) and tunes television 107 to the available channel and selected sub-channel, otherwise the logic flow ends at step 309. At step 305, the tuning of television 107 to the available channel and sub-channel is accomplished by relaying a channel tuning command via a first transmitter/receiver (transceiver 210) to remote control 105, which passes the command to television 107. At step 307, the video is broadcast by a second transmitter (ATSC transmitter 211) to an external television receiver (television 107) utilizing the channel and subchannel. The video may be received from any internal or external video source. Preferably, the video is received at the input of an MPEG processor. The digital audio/video streams and associated data received from MPEG processor 208 are marked with an MPEG2 program_id corresponding to the sub-channel as defined in the ATSC standard, and transmitted utilizing the channel via ATSC transmitter 211. Programming navigation pages are additionally sent to television 107 over the sub-channel and channel by ATSC transceiver 211. ATSC transmitter 211 includes a vestigial sideband (VSB) modulator, frequency conversion apparatus, a power amplifier and other components as known in the art.

FIG. 4 is a block diagram of remote control 105. As shown, remote control 105 comprises user interface, or user input 401 comprising a standard keypad. Instructions received via user input 401 are decoded by decoder 405 and input to controller 404. In the preferred embodiment of the present invention, user input 401 is a keypad having a plurality of keys specialized for controlling consumer electronic devices, while decoder 405 comprises a circuit arranged for de-bouncing key presses and mapping them to a digital output. In the preferred embodiment of the present invention controller 404 comprises a standard microprocessor controller such as a 68HC11 processor. Infrared transmitter 402 comprises a standard IR television transmitter, as is known in the art, while wireless LAN transceiver 403 comprises a standard transceiver such as one conforming to the IEEE 802.11 a, b, or g communication system protocol.

During operation, controller 404 receives primitive commands from a human user using user input 401 via input decoder 305. Controller 404 decides whether the particular command is related to obtaining a channel and subchannel, the control of a television, or the control of a VDD. Commands related to obtaining a channel cause controller 404 to initiate a two-way exchange with VDD 101 to obtain a channel in the television band and subchannel, followed by a command to television 107 to tune to that channel and subchannel. Commands related to programming the television cause controller 404 to send a command to television 107 to adjust audio or display parameters (e.g., audio volume or display brightness), in the same fashion as a conventional television remote control. Commands related to controlling the VDD cause controller 404 to initiate a one-way exchange with VDD 101 to cause it to take some action (e.g., to pause while playing a movie). Thus, a first plurality of received commands are transmitted to a first device

(VDD 101) via a first communication system protocol (wireless LAN), using wireless LAN transceiver 403. A second plurality of received commands are transmitted to a second device (television 107) via a second communication system protocol (infrared commands) using infrared transmitter 402. This process is illustrated in FIG. 5.

The logic flow begins at step 501 where controller 404 receives a decoded input command from decoder 405. The input command originated from a user through user interface/user input 401. At step 503, controller 404 determines if the command is from a first set of commands (e.g., digits 0 through 9, "Next Channel", "Fast Forward", "Power ON".). If, at step 503, it is determined that the command is from a first set of commands, then the logic flow continues to step 505, where the command is sent to a first device (VDD 101) via a first communication system protocol (e.g., wireless LAN). The sending of the command to the first device (VDD 101) may cause VDD 101 to return a second command to controller 404 that is received by transceiver 403 (step 507). This second command is interpreted by controller 404 and forwarded on to a second device (e.g., television 107) via infrared transmitter 402 via a second communication system protocol at step 509 (e.g., infrared remote control commands, which are typically specific to particular television manufacturers and known to those skilled in the art.) For example, if a user wishes to watch television, and hits the "ON" button for VDD 101, this causes remote control 105 to forward the instruction via wireless LAN transceiver 403 to VDD 101, causing VDD 101 to return a previously obtained non-licensed channel, select an unused sub-channel and return instructions to remote control 105 to tune television 107 to the appropriate channel and sub-channel. Remote control 105 will then forward the appropriate command (via IR transmitter 402) to television 107, tuning it to the channel and sub-channel.

As discussed, not all commands sent to VDD 101 will cause VDD 101 to return the second command and execute steps 507-509. For example, if the command is to tune, or control video (e.g., digits 0 through 9, "Next Channel", "Fast Forward"), the command sent via the via communication system protocol cause VDD 101 to take the indicated action (e.g., compose a program number to select, change to a next channel in a lineup, fast forward a stored video program) without returning any command that is to be forwarded. Returning to step 503, if it is determined that the command is from a second set of commands, the logic flow continues to step 511 where the command is sent to the second device (television 107) via the second communication system protocol. The command sent via the second communication system protocol are the same as would be sent by a conventional remote control to cause television 107 to take the indicated action (e.g., increase the audio volume or reduce display brightness).

While the invention has been particularly shown and described with reference to a particular embodiment, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention. For example, user input 401 and input decoder 405 in remote control 105 could be replaced by a voice response unit. Additionally, video may be broadcast to any external receiver (e.g., a personal computer), and not simply to existing television sets. It is intended that such changes come within the scope of the following claims.

Claims

1. A Video Distribution Device (VDD) comprising: an input receiving video; control circuitry determining a non-licensed channel for transmission of the received video, wherein the non-licensed channel is a vacant channel in licensed spectrum; and a first transmitter, transmitting the received video via the non-licensed channel to an external receiver.

2. The VDD of claim 1 wherein the control circuitry determines the non-licensed channel by analyzing a received beacon.

3. The VDD of claim 1 wherein the control circuitry determines the non-licensed channel by accessing an external database to determine an availability of the non- licensed channel.

4. The VDD of claim 1 wherein the control circuitry determines the non-licensed channel by determining that no transmissions exist on the non-licensed channel.

5. The VDD of claim 1 wherein the external receiver is an external television receiver.

6. The VDD of claim 1 wherein the non-licensed channel comprises a vacant channel within television spectrum.

7. A method comprising the steps of: receiving a user command; determining if the command is from a first or a second set of commands; transmitting the command via a first transmitter to a first device using a first communication system protocol when the command is from the first set of commands; and transmitting the command via a second transmitter to a second device using a second communication system protocol when the command is from a second set of commands.

8. The method of claim 7 further comprising the steps of: receiving a second command from the first device; and forwarding the second command via the second transmitter to the second device.

9. The method of claim 7 wherein 30 the step of transmitting the command to the first device comprises the step of transmitting the command to a video distribution device (VDD).

10. The method of claim 7 wherein 30 the step of transmitting the command to the second device comprises the step of transmitting the command to a television.