JP2006522535A - Transmitter and receiver to determine location - Google Patents

Abstract

A transmitter (110) that transmits a signal (120) for reception by the receiving device (130). The transmitter is configured to insert into the signal an indication of a geographical area where the signal can be physically received. The geographic area is preferably indicated in the signal using geometric figures. The receiving device receives one or more signals, each of which is configured to carry an indication of the geographic area in which each signal is physically receivable and to determine its location from the indication. The receiver can calculate the intersection of the set of geographic areas carried by the various received signals as the geographic area in which it resides. Based on the determined location, the receiver can restrict access to the content when the content is restricted to a specific area.

Description

  Copy protection protects the owner of copyrighted material, such as entertainment material, from unauthorized distribution of the material. However, purchasers of copyrighted materials expect to be able to copy purchased materials for their convenience and enjoyment. Standardization and technology continue to evolve to provide copy protection systems that allow purchasers of protected materials to copy materials freely, but from a broad range of distribution to protected material owners. It still provides some protection.

  One solution to this problem may be to limit the distribution of content to a specific geographic region (eg, one country). For example, a DVD disc purchased in the United States cannot generally be played back by a DVD player purchased in Europe. A similar situation occurs for broadcast content.

  The restriction of the area in broadcasting can be realized by restricting to an area where a broadcast signal can be received. A signal can be received when the antenna is in the correct geographic area. This method is used by terrestrial and satellite broadcasting.

  Other approaches depend on the availability of devices such as set-top boxes (STB). Devices or services required to access content can only be purchased in certain areas. This method is used in Canal + to limit Deutsche TV reception to the Netherlands (a STB must be purchased in the Netherlands and a non-international telephone call must be used to activate the subscription).

  The equipment needed to access the content can be purchased anywhere, but it would be desirable if the content could only be received in the correct geographic area. To tackle it, the device must know its location. The options to achieve this vary widely because the user configures each device to implement a GPS receiver. However, it is not secure enough to allow the user to manually enter the position, and GPS receivers are too expensive.

  It is an object of the present invention to provide a way for the receiver to determine its location with reduced user intervention.

  This object is achieved according to the invention in a transmitter for transmitting a signal for reception by a receiving device, the transmitter being configured to insert an indication of the geographical area in which the signal can be physically received. The

  The purpose is a receiving device that receives one or more signals, each signal carrying a representation of each geographical area in which each signal can be physically received, said device deriving its location from the representation. In a receiving device configured to determine is implemented according to the present invention.

  Geographic regions can be encoded in a variety of ways. A preferred measure is to use the power level used for the transmission of the signal or to display a geographical area using geometric figures (eg one or more rectangles). At the transmitting side, it is possible to determine in advance quite accurately in which geographical region the transmission is physically receivable. This regional representation can be inserted into the signal (eg, metadata such as MPEG transport stream table descriptors), but many other options are also available, such as watermarks.

  The receiver extracts the indication carried in the signal and then determines its location. The indication indicates the geographical area where the signal can be physically received and the receiver is actually receiving the signal, resulting in the receiver having to be in this geographical area.

  The receiver may be coupled to one or more other devices (eg, via a home network). In that case, the receiver sends the determined location to other devices, thereby knowing in which region the other devices are located.

  As multiple signals are received, each may carry its own indication. For example, if the receiver is at the border, or if one display is a subset of the other, these displays may be different. In that case, the receiver needs to use some protocol and estimate the display to determine its location. Some embodiments of the present invention provide such a suitable protocol.

  The representation of the geographical area is preferably a set of geometric figures such as rectangles, circles or ellipses. The receiver can calculate the set of intersections carried in the various signals received as the geographical region in which it is present. This location may be stored in the receiver along with one or more geometric figures.

  The content can carry an indication of the geographic region where the content is allowed to be played, recorded, retransmitted, etc. Based on the determined location, the receiver can restrict access to such content. Next, the receiver compares the displayed area with the location, and if the two do not match, the receiver refuses to play, record, or retransmit the content. If the display is a set of geometric figures, a rejection occurs if the intersection of the set is an empty set.

  Mobile phone positioning systems are known that send the mast ID of the transmitter detected by the mobile phone (along with the associated power level) to the server. The server replies to the phone location using an SMS message. Because this information is kept secret to maintain a competitive advantage, this message does not include the position of the mast. For more information, see the Internet addresses at www.infosyncworld.com/news/n/1999.html and www.infosyncworld.com/news/n/2990.html.

  Advantageous embodiments are given in the dependent claims.

  These and other aspects of the invention will be apparent from and elucidated with reference to the embodiments shown in the drawings.

  Throughout the drawings, the same reference numerals indicate similar or corresponding functions. Some of the functions shown in the drawings are typically implemented in software and therefore represent software entities such as software modules or objects.

  FIG. 1 shows a transmitter 110 that transmits a signal 120 (preferably a broadcast signal) for reception by a receiving device 130. In accordance with the present invention, the transmitter 110 is configured to insert into the signal 120 an indication of the geographical area in which the signal 120 can be physically received.

  In this document, the term “transmitter” is widely used as any device or system capable of transmitting a signal to a receiver. Possible examples include analog or digital television broadcast systems or cable networks.

  Determining where the signal 120 is physically receivable can be done in a variety of ways. A simple method is to use a receiver that moves in the area around the transmitter and record where the receiver can still receive the signal and where it can no longer receive the signal. It is also possible to calculate the area covered by the transmitter based on data such as antenna altitude, transmitter output level and terrain data. For more information, see RECollin's Antennas and radio wave propagation, McGraw-Hill Higher Education, 4th edition, February 1985, MPMHall's Propagation of radiowaves, IEEE Publishing, November 1996, and CHPapas's Theory. Handbooks such as of electromagnetic wave propagation, Dover Pubns, October 1988 and DSJones' Methods in EM wave propagation, Clarendon Publishing, September 1995 are presented to the reader.

  A receiver compliant with the DVB standard may be provided with regional information as part of the DVB signal. The signal on which it depends is only available in a very specific area (DVB-C: City, DVB-IPI: Address). This information can be provided to the device. This information can be provided using service provider specific protocols or by embedding location information in streams received by the receiver in the same way as satellite and terrestrial receivers.

  The location of the device connected to the non-IPI network can be determined by providing information on the signal being received. For DVB-C devices, this is the location of the cable network (always one area). For DVB-T receivers, the position can be determined from receivable signals (generally multiple regions). It becomes more difficult for a DVB-S device that has an enormous area for receiving signals. However, estimation can still be made.

  The BBC provides an overview of the main transmitters used in the UK DVB-T system on the website www.bbc.co.uk/reception/tv_transmitters/index.shtml. Using the information on the website, it is possible to determine a position within about 150 km. When relay stations are used, for example, an accuracy of 40 km can be achieved.

  Reaching the Audience: An Analysis of Digital Broadcast, a report by Mark R. Fratrik, prepared for the October 2003 Association of Maximum Service Television, Inc. and available online at www.mstv.org/docs/DTVRptFinal.pdf Power and Coverage provides similar information for transmitters in the USA, which allows calculations similar to the previously mentioned DVB-T system in the UK.

  FIG. 2 illustrates another embodiment in which transmitter 110 receives signal 120 from another transmitter 210. For example, the transmitter 110 may retransmit the satellite signal over a cable network. The original signal 220 has an indication of the geographical area it can physically receive. The transmitter 110 should replace this original indication in the signal 220 with an indication of the geographical area where the retransmission signal 120 can be received.

  This embodiment is useful when the transmitter is a headend, for example as used when a DVB based method is used. Before the headend transmitter receives the original signal 220 from the other transmitter 210 and retransmits it as signal 120, it must update the regional representation of signal 220. More specifically, the headend replaces the “wide” regional designation (“European Union” or “United Kingdom”) with the narrower region it specifically covers (eg, “London” or “Wales”). May be.

  An indication that the signal 120 can be physically received may be present in content using watermarks or in a side channel, for example. If an MPEG transport stream is used, the display may be inserted into a table (existing table or newly added table). For example, Transport Stream Description Table (TSDT) or Network Information Table (NIT) may be used.

The location can be encoded in a variety of ways. It may be done in a coordinate system or using a human readable variant such as:
・ EU, NL, Eindhoven, Prof. Holstlaan, WY
・ EU, FR, Tarn, Albi, Carmaux, Pampelonne, Lunaget, LeLabot
・ EU, NL, Lopik
The advantage of such a system is that it can communicate with the user (even if input by the user). The disadvantage of such a system is that more detailed information rapidly increases when it is necessary to indicate where the signal can be received in sufficient detail.

  The location may be encoded as a single region representation or a set of region representations (eg, “England, Wales”).

  Another approach is to use coordinates. However, it has the disadvantage that it is difficult to describe irregular shapes. Basic figures such as a circle / rectangle / trapezoid / ellipse can be described relatively easily. For example, describing the coordinates of a region covered by France is quite complicated. The position can only be determined with a certain accuracy.

  Regions where signals can be received can also be determined using the location of the receiver, the output of the transmitter, and the received output. Based on this information, the distance of the receiver to the antenna can be estimated according to the following equation:

この式では、R_iは送信機iの周辺の地理的地域を示し、P_br,iは送信機iの放送出力であり、P_rev,iは送信機iの受信出力である。このような計算はアンテナの形状にかなり依存するため、間違いが多いと予想される。より少ないリソースを必要とする更に簡単な方法は、受信機130の計算に依存する代わりに、信号が特定の出力閾値の上で受信可能な領域として送信機110の受信領域を示すことである。

In this equation, R _i represents the geographical area around transmitter i, P _{br, i} is the broadcast output of transmitter i, and _{Prev, i} is the received output of transmitter i. Since such calculations are highly dependent on the shape of the antenna, many mistakes are expected. A simpler method that requires less resources is to indicate the reception area of the transmitter 110 as an area where the signal can be received above a certain output threshold instead of relying on the calculation of the receiver 130.

  In such an embodiment, transmitter 110 inserts the broadcast power level used for transmission of signal 120 into the signal, along with an indication of its location. The receiver 130 can read this information from the signal 120 and apply the above equation to estimate the distance between the transmitter 110 and the receiver 130. The distance and the location of the transmitter 110 provide the receiver 130 with an estimate of the location. In this embodiment, the receiver 130 must have a means for determining the received output of the transmitter 110.

  Of mathematical figures, a figure using a straight line enables the simplest calculation. The circle shape best fits the area covered by the radio signal. Due to the curvature of the earth, trapezoids are better than rectangles, especially in large areas. It gives a reasonable approximation of the area covered between two longitudes and two latitudes.

  Another discussion to be made is whether the antenna is described using a shape or set of shapes. For transmitters, the circle is an excellent first-order technique for the reception area. For transmitters with directional antennas, a set of ellipses is a better approximation.

  For the country, this is the preferred implementation because a set of rectangles would be a good approximation. An example is shown in FIG. FIG. 3 shows a set of rectangles representing the geographic regions of the Netherlands (NL), Belgium (BE), Denmark (DK) and Germany (DE).

  Given such a set of rectangles as an indication of the signal 120, the receiver 130 can determine its location by simply storing the set of rectangles in local memory. If the receiver 130 is connected to another device, the receiver 130 may transmit the set to the other device. Thus, for example, a residential gateway can notify all devices in the home at that location.

  Thereafter, the receiver 130 may receive content carrying an indication of the geographic region where the content can be accessed. For example, a movie may be broadcast only for reception in the Netherlands. The receiver 130 may access the content only if the location determined to be and the geographical area indicated in the content overlap.

  The representation of the area where the content can be accessed is also preferably provided as a set of geometric figures approximating the area. If the location is determined as a set of rectangles or other geometric shapes as described above, the overlap is determined by simply calculating the intersection of the stored set of shapes and the set of shapes carried in the content. Also good.

  The display may be present in the content, for example using a watermark or side channel. If an MPEG transport stream is used, the display may be inserted into a table (existing table or newly added table). These options are described below.

Receiver 130 may receive multiple signals from multiple different transmitters. As a result, the receiver 130 is also expected to receive a plurality of different indications of different geographical regions. For example, the receiver 130 may be at the German / Belgian border and may receive signals from a German transmitter and a Belgian transmitter that indicate the respective border. Another possibility is that one signal is received, for example indicating the entire United Kingdom, and the other signal is indicative of the principality of Wales. The receiver 130 needs to derive its actual location from these multiple displays. Some options for dealing with this situation include:
-Select a location from the most frequently occurring indication (ie the maximum number of receptions from a particular antenna).
-Select a location from the display carried by the signal with the relatively highest received signal strength. This indicates that the receiver is closest to the transmitter of the signal.
-Select a location from the display carried by the signal with the relatively lowest transmitted signal strength. This indicates that the receiver may be in the area covered by the transmitter of the signal.
Calculate the overlap of various display regions, for example by calculating the intersection of all received geometric figures.
-All options using signal output require that the output of the transmission is included in the metadata and the receiver needs to measure the output of the received signal. The maximum number of channels depends on the homogenous distribution of channels in specific areas that are not accurate. A preferred measure is to determine overlapping regions for different signals. This is easy if the area where the signal can be received is coded with a rectangle. Also, when a circle is used to estimate the reception area, the rectangular countermeasure provides a reasonable countermeasure.

FIG. 4 shows the calculation of the overlap region. The receiver 130 receives a plurality of displays that are graphically displayed as circles in FIG. All circle intersections are illustrated in black. Overlapping areas have been calculated and are indicated by hashing. This overlap region is calculated as a rectangle with the upper left corner (x _left , y _up ) and the lower right corner (x _right , y _down ), but it should be understood that there are several other ways to represent the rectangle. Is also possible. To calculate these coordinates, the following equation is used:

x _left = max (x _i -R _i )
x _right = min (x _i + R _i )
y _up = min (y _i + R _i )
y _down = max (y _i -R _i )
Here, x _i and y _i are the X coordinate and Y coordinate of the circle i, and R _i is the radius of the circle i.

  This leaves the question of what to do if there is a mismatch or what to do if the overlap cannot be calculated. In principle, the receiving area of the transmitter should be chosen so that this cannot occur. If this happens, there are several ways that this problem can be addressed. For example, the user may be prompted to make a selection, and certain portions of the area (eg, from the transmitter with the lowest signal strength) may be excluded from the calculation.

  A number of options are available as described above to insert an indication of the region of the signal 120. The preferred embodiment focuses on signals in the form of MPEG-2 transport streams (especially DVB signals). Information may be encoded into the stream as a descriptor of a new table or an existing table.

  In particular, the new table for position information has advantages and disadvantages. Special tables are useful to manage the overhead inherent in this information and / or for easy remultiplexing when the amount of information carried is large. If the information is embedded in an existing table, NIT or TSDT is the best candidate. The location information is very stable and rarely changes. The same applies to NIT and TSDT information. Therefore, it makes sense to add location information to the NIT information table and / or TSDT table, thereby adding to the other table too often and sending location information too often by adding to the repeating table. Avoid the need to do.

  Since table information is carried using descriptors, location information is encoded in the descriptor format. As a result of this approach, the length of the information will not be greater than 255 bytes.

  In this preferred embodiment, the reception area is best described according to the following table.

任意選択で、信号120は、他の送信機により送信される信号が物理的に受信可能な地理的地域を表す更なる情報を有してもよい。この場合の受信機130は、これらの他の送信機からの信号を受信することができるか否かを決定するべきである。そうでない場合、これらの地理的領域は、受信機130が決定した場所に含まれるべきではない。これらの信号が受信できない場合、明らかに受信機130はこのような信号が受信可能な地域に存在しない。

Optionally, signal 120 may have further information that represents a geographical area where signals transmitted by other transmitters can be physically received. The receiver 130 in this case should determine whether it can receive signals from these other transmitters. Otherwise, these geographic areas should not be included in the locations determined by the receiver 130. Obviously, if these signals cannot be received, the receiver 130 is not in an area where such signals can be received.

  However, due to transmission errors or other problems, there is a risk that these signals may not be received even if the receiver 130 is actually in the correct area. In order to mitigate this risk, it is recommended that these geographical regions are considered only temporarily, or that the decision procedure is repeated if these other signals are received later in time.

  For example, the geometrical figures representing these geographic regions may be subtracted from the geometrical figure in a signal 120 representing an area where the signal 120 transmitted by the transmitter 110 is physically receivable.

  In any device claim enumerating several means, several of these means may be embodied by one and the same item of hardware. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measured cannot be used to advantage.

  It should be noted that the foregoing embodiments are illustrative of the invention rather than limiting and that those skilled in the art can design numerous alternative embodiments without departing from the scope of the invention. is there.

  For the purposes of the present invention, the term “access” includes any and all processes that access and process content material, including but not limited to copying, playing, displaying, and the like. Similarly, the term “copy” includes any and all processes that make a copy of any of the various forms of content material, storing material, providing material to removable storage, remote devices Including, but not limited to, sending material to

  In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word “comprising” does not exclude the presence of elements or steps other than those listed in a claim. An antecedent of an element does not exclude the presence of multiple such elements. The present invention may be implemented using hardware having a number of distinct elements and using a suitably programmed computer.

Schematic display of a transmitter that transmits a signal for reception by a receiving device Other embodiments in which a transmitter receives signals from other transmitters A set of rectangles that represent the geographic regions of the Netherlands (NL), Belgium (BE), Denmark (DK), and Germany (DE) Overlap area calculation

Claims (14)

A transmitter for transmitting a signal for reception by a receiving device,
A transmitter configured to insert into the signal an indication of a geographical area where the signal can be physically received. The transmitter of claim 1, comprising:
A transmitter configured to transmit the signal over a broadcast channel. The transmitter of claim 1, comprising:
Receiving the signal from another transmitter and exchanging in the signal a representation of the geographical region present in the signal with a representation of the geographical region in which the signal transmitted by the transmitter is physically receivable Transmitter configured as follows. The transmitter of claim 1, comprising:
A transmitter configured to insert an output level used to transmit the signal as the display along with an indication of the position of the transmitter. The transmitter of claim 1, comprising:
The transmitter wherein the geographical area is indicated in the signal using geometric figures. A receiving device for receiving one or more signals,
Each signal carries an indication of each geographical area where each signal can be physically received,
A receiving device configured to determine the location from the display. The receiving device according to claim 6,
A receiving device configured to determine its location from the display that occurs most frequently in the display. The receiving device according to claim 6,
A receiver configured to determine its location from an indication carried in one of each received signal received at a relatively highest signal strength. The receiving device according to claim 6,
A receiver configured to determine its location from an indication present in one of each received signal received with a relatively low signal strength. The receiving device according to claim 6,
A receiver configured to determine its location as an intersection of each geographic region. The receiving device according to claim 6,
The display represents the power level used by the transmitter;
The receiver is configured to measure a received power level of a received signal;
The determination is performed on the basis of the display and the reception output level. The receiving device according to claim 6,
The receiving device where the geographical area is indicated in the signal using geometric figures. The receiving device according to claim 6,
A receiving device configured to send an indication of the determined location to another device. The receiving device according to claim 6,
Configured to receive content carrying an indication of a geographic region where the content may be accessed;
A receiving device configured to access the content when a geographical area indicated by the content overlaps with the determined location.

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