Patent Description:
A satellite broadcast signal receiver is connected in use to a LNB of a satellite dish in order to receive signals broadcast by a satellite, typically for receiving television and/or radio channels. The receiver sends control signals to the LNB as required in order to reconfigure the LNB to select a desired channel that can be received by the satellite dish.

So-called "single cable distribution" (sometimes known by the name "unicable") is known which enables the simultaneous delivery of channels from a single satellite dish to multiple receivers (typically for multiple users) over a single coaxial cable. In known single cable distribution, each receiver is allocated a "user band" having a different centre frequency (an "intermediate frequency") for the signals that carry the channel signal (i.e. the broadcast programme) and that are passed from the satellite dish to the receiver.

<CIT> discloses satellite distribution apparatus for distributing digital broadcast signals in a predetermined locality or building. A number of known systems for distributing signals around a multiple dwelling building are described.

<CIT> discloses a satellite receiving system in which program channels are selected from one or more broadband signals and combined with other selected channels and transmitted from a first unit, for example an outdoor unit, to a second unit, for example a gateway, server, or set-top box, using a single cable.

According to a first aspect disclosed herein, there is provided a method of operating a low-noise block downconverter LNB of a satellite dish which is operating according to single cable distribution in which a first user band frequency is allocated for a first satellite broadcast signal receiver to receive signals from the LNB and a second user band frequency different from the first user band frequency is allocated for a second satellite broadcast signal receiver to receive signals from the LNB, the method comprising:.

In this way, power consumption at the LNB may be reduced in the case that plural satellite broadcast signal receivers are being used to watch or listen to the same channel because the LNB only needs to provide one signal at one frequency for those plural satellite broadcast signal receivers. In the case that several (e.g. up to the usual maximum of <NUM>) satellite broadcast signal receivers are connected to the LNB and are all being used to watch or listen to the same channel, this can present a relatively large saving. Further, given that this may be applied across thousands or even millions of deployed single cable distribution systems, the overall power saving across a population can be large.

The signals, which contain the television or radio or the like channels, are transmitted over a cable to the satellite broadcast signal receiver. In a single cable distribution, there is a single cable which passes from the LNB to all of the satellite broadcast signal receivers that are intended to receive channels from the LNB (or, at least, there is a single cable from the LNB into the dwelling or other building in which the satellite broadcast signal receivers are located, even if ultimately there may be separate cables which split off from that single cable and which provide the final connection to the individual satellite broadcast signal receivers).

In an example, the LNB comprises at least a first local oscillator for generating an intermediate frequency signal at the first user band frequency and a second local oscillator for generating an intermediate frequency signal at the second user band frequency, wherein the signal for a broadcast programme channel that is sent by the LNB to a satellite broadcast signal receiver is formed by mixing a radio signal for the broadcast programme channel received at the satellite dish with the intermediate frequency signal for that satellite broadcast signal receiver, wherein if the broadcast programme channel requested by the second satellite broadcast signal receiver is the same as the broadcast programme channel requested by the first satellite broadcast signal receiver, the second local oscillator is not operated or is switched off or is used to provide a different broadcast programme channel to another satellite broadcast signal receiver.

According to a second aspect disclosed herein, there is provided a LNB for a satellite dish which is operable according to single cable distribution in which a first user band frequency is allocated for a first satellite broadcast signal receiver to receive signals from the LNB and a second user band frequency different from the first user band frequency is allocated for a second satellite broadcast signal receiver to receive signals from the LNB, the LNB being arranged to:.

In an example, the LNB comprises at least a first local oscillator for generating an intermediate frequency signal at the first user band frequency and a second local oscillator for generating an intermediate frequency signal at the second user band frequency, the LNB being arranged such that the signal for a broadcast programme channel that is sent by the LNB to a satellite broadcast signal receiver is formed by mixing a radio signal for the broadcast programme channel received at the satellite dish with the intermediate frequency signal for that satellite broadcast signal receiver, wherein if the broadcast programme channel requested by a said second satellite broadcast signal receiver is the same as the broadcast programme channel requested by a said first satellite broadcast signal receiver, the second local oscillator is not operated or is switched off or is used to provide a different broadcast programme channel to another satellite broadcast signal receiver.

According to a third aspect disclosed herein, there is provided a computer program comprising instructions such that when the computer program is executed on a LNB of a satellite dish which is operating according to single cable distribution, the LNB is arranged to carry out a method comprising:.

There may be provided a non-transitory computer-readable storage medium storing a computer program as described above.

In an example, the computer program comprises instructions such that, where the LNB comprises at least a first local oscillator for generating an intermediate frequency signal at the first user band frequency and a second local oscillator for generating an intermediate frequency signal at the second user band frequency, and the signal for a broadcast programme channel that is sent by the LNB to a satellite broadcast signal receiver is formed by mixing a radio signal for the broadcast programme channel received at the satellite dish with the intermediate frequency signal for that satellite broadcast signal receiver:
if the broadcast programme channel requested by the second satellite broadcast signal receiver is the same as the broadcast programme channel requested by the first satellite broadcast signal receiver, the second local oscillator is not operated or is switched off or is used to provide a different broadcast programme channel to another satellite broadcast signal receiver.

According to a fourth aspect disclosed herein, there is provided a method of operating a satellite broadcast signal receiver for receiving signals from a LNB of a satellite dish which is operating according to single cable distribution in which a first user band frequency is allocated for a first satellite broadcast signal receiver to receive signals from the LNB and a second user band frequency different from the first user band frequency is allocated for a second satellite broadcast signal receiver to receive signals from the LNB, the method comprising:.

In an example, the satellite broadcast signal receiver retunes to a user band frequency that is being used by the LNB to provide a signal to said other satellite broadcast signal receiver in response to the satellite broadcast signal receiver receiving from the LNB an instruction to retune to said user band frequency.

According to a fifth aspect disclosed herein, there is provided a satellite broadcast signal receiver for receiving signals from a LNB of a satellite dish which is operating according to single cable distribution in which a first user band frequency is allocated for a first satellite broadcast signal receiver to receive signals from the LNB and a second user band frequency different from the first user band frequency is allocated for a second satellite broadcast signal receiver to receive signals from the LNB, the satellite broadcast signal receiver being arranged to:.

In an example, the satellite broadcast signal receiver is arranged to retune to a user band frequency that is being used by a said LNB to provide a signal to a said other satellite broadcast signal receiver in response to the satellite broadcast signal receiver receiving from a said LNB an instruction to retune to said user band frequency.

As mentioned, a satellite broadcast signal receiver is connected in use to a LNB of a satellite dish in order to receive signals broadcast by a satellite, typically for receiving television and/or radio channels. The receiver sends control signals to the LNB as required in order to reconfigure the LNB to select a desired channel that can be received by the satellite dish.

So-called "single cable distribution" (sometimes known by the name "unicable") enables the simultaneous delivery of channels from a single satellite dish to multiple receivers (typically for multiple users) over a single coaxial cable. In known single cable distribution, each receiver is allocated a "user band" having a different centre intermediate frequency for the signals that carry the channel signal (i.e. the broadcast programme) and that are passed from the satellite dish to the receiver. This enables multiple receivers to use the same satellite dish, which is useful when for example the multiple receivers are all located in the same building as a single satellite dish provided on the building can provide services for the multiple receivers. Moreover, a single cable can connect the satellite dish to all of the multiple receivers, which is convenient for users or installers of the system. (Again, for completeness, it is mentioned that in a typical installation there is a single cable from the LNB into the dwelling or other building in which the satellite broadcast signal receivers are located, even if ultimately there may be separate cables which split off from that single cable and which provide the final connection to the individual satellite broadcast signal receivers.

Referring now to <FIG>, this shows schematically an example of plural satellite broadcast signal receivers <NUM> connected to a satellite dish <NUM>. The satellite broadcast signal receivers <NUM> may be for example television sets, set-top boxes, PVR (personal video recorder, also known as a DVR or digital video recorder), an expansion card for a computer, etc., and may in general be the same type of device or different devices. The satellite broadcast signal receivers <NUM> have one or more processors <NUM>, non-volatile data storage <NUM> for storing data, etc. The satellite dish <NUM> equipment is sometimes referred to as an outdoor unit (ODU), whether actually located outdoors or not. The satellite broadcast signal receivers <NUM> are sometimes referred to as integrated receiver/decoders (IRDs).

Each satellite broadcast signal receiver <NUM> is connected to the satellite dish <NUM> by a wired connection <NUM>. The system shown is a single cable distribution system. Accordingly, there is a single wired connection <NUM> out of the satellite dish <NUM> to the different satellite broadcast signal receivers <NUM> (though there are also individual final wired connections <NUM> to the different satellite broadcast signal receivers <NUM>). In the example shown, there are eight satellite broadcast signal receivers <NUM> (some being indicated by the ellipsis. ), which is a typical maximum for single cable distribution systems. The wired connection <NUM> is typically a coaxial cable, though a plastics optical fibre or other connection may be used.

As is well known per se, the satellite dish <NUM> has a parabolic reflector <NUM> which focusses signals received from a broadcasting satellite (not shown) to a so-called LNB (low-noise block downconverter) <NUM>. The LNB <NUM> is located at the focal point of the parabolic reflector <NUM>, or at least as close to the focal point as is practical. An LNB <NUM> is typically in effect a combination of a low-noise amplifier, a frequency mixer, a local oscillator and an intermediate frequency (IF) amplifier. In general, some of these components, including for example the mixer, may be provided as separate components or modules or may all be included in a single LNB block or module. The LNB may be implemented by or use one or more special semiconductor chips often referred to as "satellite channel routers".

The LNB <NUM> receives the (microwave) signal transmitted by the broadcasting satellite and collected by the parabolic reflector <NUM>, amplifies it, and down converts the block of frequencies to a lower block of intermediate frequencies (IF). The down conversion at the LNB <NUM> permits the use of relatively inexpensive coaxial cable <NUM> to connect the LNB <NUM> to the satellite broadcast signal receivers <NUM>. The cable <NUM> is connected to the LNB <NUM>.

As is known, the broadcast signals transmitted by the satellite for receipt by satellite dishes <NUM> are typically in one or more specific frequency bands and may use a specific polarisation. For example, in Europe, the frequencies currently used by digital video broadcast satellite services DVB-S/DVB-S2 are <NUM>-<NUM> on two polarisations H (Horizontal) and V (Vertical). (In the US, left and right circular polarisation is used rather than horizontal and vertical polarisation as used in Europe and at least most other countries. ) This range is divided into a "low band" with <NUM>-<NUM> and a "high band" with <NUM>-<NUM>. This results in two frequency bands, each with a bandwidth of about <NUM>, each with two possible polarisations. In the LNB <NUM>, these bands are down converted to a frequency in the range <NUM>-<NUM>, which is the frequency range allocated for the satellite service on the coaxial cable between LNB <NUM> and the receivers <NUM>. Numerous individual channels (i.e. television and/or radio channels) are transmitted within each band and having one polarisation or the other.

As mentioned and as illustrated schematically in <FIG>, in known single cable distribution, each receiver <NUM> is allocated a "user band" UB1, UB2,. having a different centre intermediate frequency for the signals that carry the channel signal (i.e. the broadcast programme) and that are passed from the LNB <NUM> of the satellite dish <NUM> to the receiver <NUM>. The different intermediate frequencies can be allocated to the receivers <NUM> in a number of ways. For example, in accordance with the CENELEC (European Committee for Electrotechnical Standardization) EN <NUM> Standard entitled "SATELLITE SIGNAL DISTRIBUTION OVER A SINGLE COAXIAL CABLE IN SINGLE DWELLING INSTALLATIONS", a receiver <NUM> transmits a command to the LNB <NUM> for the LNB <NUM> to generate a number of signals at the available intermediate frequencies, and the receiver <NUM> adopts the first frequency that it encounters when scanning across the band of signals. Alternatively or additionally, the LNB <NUM> can instruct the receivers <NUM> as to which intermediate frequency to use. The LNB <NUM> has plural local oscillators, each for generating a different one of the plural intermediate frequencies which are used for providing signals to the individual receivers <NUM> over the cable <NUM>.

In order to be able to receive and demodulate a particular channel as selected by a user, the receiver <NUM> associated with the user transmits a control signal to the LNB <NUM> to cause the LNB <NUM> to receive and process the correct corresponding signal that is broadcast by the satellite. For example, the control signal may cause the LNB <NUM> to receive and process the corresponding band (high or low) having the corresponding polarisation (horizontal or vertical) that is broadcast by the satellite. As a specific example to illustrate this, the United Kingdom television channel BBC One HD is (currently) broadcast with a frequency of <NUM>,<NUM> and vertical polarisation. Accordingly, to enable the user to watch BBC One HD, a control signal is sent by the receiver <NUM> to the LNB <NUM> to instruct the LNB <NUM> to tune to the low frequency band with vertical polarisation.

A number of different arrangements and standards for such control signals are possible and are used. As a specific example to illustrate this, a voltage of 13V may be transmitted to select a vertical polarisation and a voltage of 18V may be transmitted to select a horizontal polarisation; and a "tone signal" of <NUM> may be transmitted to select the high frequency band, the absence of a tone signal being taken by the LNB <NUM> as selection of the low frequency band.

In operation in known single cable distribution systems, the effect of this is as follows. Assume that a first user, user #<NUM>, with a first satellite broadcast signal receiver #<NUM>, wants to watch channel A. A first local oscillator of the LNB <NUM> therefore sets its frequency as UB <NUM>, which is the user band having the centre intermediate frequency allocated to the first satellite broadcast signal receiver #<NUM>, and provides the channel A on the cable <NUM> as UB <NUM> frequency + Channel A frequency. Assume then that a second user, user <NUM>, also wants to watch channel A. A second local oscillator of the LNB <NUM> therefore sets its frequency as UB2, which is the user band having the centre intermediate frequency allocated to the second satellite broadcast signal receiver #<NUM>, and provides the channel A on the cable <NUM> as UB2 frequency + Channel A frequency. This means that two local oscillators of the LNB <NUM> are operating, even though only a single channel is being watched via the two satellite broadcast signal receivers <NUM> of user <NUM> and user <NUM>. Likewise, if further users want to watch the same channel A, a corresponding number of further local oscillators of the LNB <NUM> are operating in order to provide the respective satellite broadcast signal receivers <NUM> of the further users with the requested channel A at the respective user band frequencies. Given that the same channel A is being transmitted, this effectively results in an unnecessarily high power consumption by the LNB <NUM>.

To address this, in examples described herein, if the channel requested by the second satellite broadcast signal receiver #<NUM> is different from the channel requested by the first satellite broadcast signal receiver #<NUM>, the LNB <NUM> (or, more specifically, the mixer of or associated with the LNB <NUM>) in response provides a signal for the channel requested by the second satellite broadcast signal receiver #<NUM> at the second frequency UB2 which is (normally) allocated to the second satellite broadcast signal receiver #<NUM>. This is in effect the normal operation in a single cable distribution system. On the other hand, if the channel requested by the second satellite broadcast signal receiver #<NUM> is the same as the channel requested by the first satellite broadcast signal receiver #<NUM>, the LNB <NUM> in response to receiving that request provides an instruction to the second satellite broadcast signal receiver #<NUM> for the second satellite broadcast signal receiver #<NUM> to retune to the first frequency UB <NUM> which is allocated to the first satellite broadcast signal receiver #<NUM>. In response to receiving that instruction, the second satellite broadcast signal receiver #<NUM> retunes to that first frequency UB <NUM>. In that way, the second satellite broadcast signal receiver #<NUM> receives the signal for the requested channel which is already being provided by the LNB <NUM> at the first frequency UB <NUM>. This means that the second local oscillator of the LNB <NUM>, which normally generates a signal with the second frequency UB2 for the second satellite broadcast signal receiver #<NUM>, does not need to be operated or can be switched off. This immediately presents a power saving compared to a conventional single cable distribution system. Moreover, the power saving increases for each additional user who is watching the same channel on their own satellite broadcast signal receiver, as each of those satellite broadcast signal receivers can be instructed to retune to receive the requested channel which is already being provided by the LNB <NUM> at the first frequency UB1. Furthermore, in other arrangements, additional satellite broadcast signal receivers <NUM> may be connected to the LNB <NUM> and can make use of the local oscillator of the LNB <NUM> that is not being used at a particular time to provide signals for the other satellite broadcast signal receivers <NUM>. This enables more efficient use of the single cable distribution system as it allows additional satellite broadcast signal receivers <NUM> to be connected. That is, for example the local oscillator of the LNB <NUM> that is not being used at a particular time to provide signals for the other satellite broadcast signal receivers <NUM> can be used to provide a different channel to another satellite broadcast signal receiver.

This is illustrated schematically in <FIG>. At <NUM>, a satellite broadcast signal receiver (in the above, satellite broadcast signal receiver #<NUM>) sends a channel request to the LNB <NUM>. At <NUM>, the LNB <NUM> checks whether the requested channel is already being provided at another UB frequency, for another satellite broadcast signal receiver (in the above, satellite broadcast signal receiver #<NUM>). If yes, then at <NUM> the LNB <NUM> sends a message to the requesting satellite broadcast signal receiver (here, satellite broadcast signal receiver #<NUM>) to retune to the other UB frequency, which is being used for sending the requested channel to the other satellite broadcast signal receiver (here, satellite broadcast signal receiver #<NUM>). In addition, the LNB <NUM> stops operation of the local oscillator for the requesting satellite broadcast signal receiver (here, satellite broadcast signal receiver #<NUM>) if that local oscillator is operating. On the other hand, if at the check at <NUM> it is determined that the requested channel is not being provided at another UB frequency, then at <NUM> the LNB <NUM> sets the local oscillator for the requesting satellite broadcast signal receiver (here, satellite broadcast signal receiver #<NUM>) to operate at the UB frequency for the requesting satellite broadcast signal receiver.

The various commands, requests and instructions, etc. between the LNB <NUM> and the satellite broadcast signal receivers <NUM> may be in accordance with the CENELEC EN <NUM> Standard, which prescribes a Digital Satellite Equipment Communications (DiSEqC <NUM>. x) protocol for the signalling between the LNB <NUM> and the satellite broadcast signal receivers <NUM>.

It will be understood that the processor or processing system or circuitry referred to herein may in practice be provided by a single chip or integrated circuit or plural chips or integrated circuits, optionally provided as a chipset, an application-specific integrated circuit (ASIC), field-programmable gate array (FPGA), digital signal processor (DSP), graphics processing units (GPUs), etc. The chip or chips may comprise circuitry (as well as possibly firmware) for embodying at least one or more of a data processor or processors, a digital signal processor or processors, baseband circuitry and radio frequency circuitry, which are configurable so as to operate in accordance with the exemplary embodiments. In this regard, the exemplary embodiments may be implemented at least in part by computer software stored in (non-transitory) memory and executable by the processor, or by hardware, or by a combination of tangibly stored software and hardware (and tangibly stored firmware).

Reference is made herein to data storage for storing data. This may be provided by a single device or by plural devices. Suitable devices include for example a hard disk and non-volatile semiconductor memory.

Although at least some aspects of the embodiments described herein with reference to the drawings comprise computer processes performed in processing systems or processors, the invention also extends to computer programs, particularly computer programs on or in a carrier, adapted for putting the invention into practice. The program may be in the form of non-transitory source code, object code, a code intermediate source and object code such as in partially compiled form, or in any other non-transitory form suitable for use in the implementation of processes according to the invention. The carrier may be any entity or device capable of carrying the program. For example, the carrier may comprise a storage medium, such as a solid-state drive (SSD) or other semiconductor-based RAM; a ROM, for example a CD ROM or a semiconductor ROM; a magnetic recording medium, for example a floppy disk or hard disk; optical memory devices in general; etc..

Claim 1:
A method of operating a low-noise block downconverter, LNB, (<NUM>) of a satellite dish (<NUM>) which is operating according to single cable distribution in which a first user band frequency is allocated for a first satellite broadcast signal receiver (<NUM>) to receive signals from the LNB (<NUM>) and a second user band frequency different from the first user band frequency is allocated for a second satellite broadcast signal receiver (<NUM>) to receive signals from the LNB (<NUM>), the method comprising:
the LNB (<NUM>) receiving a request from the first satellite broadcast signal receiver (<NUM>) to transmit a signal for a broadcast programme channel to the first satellite broadcast signal receiver (<NUM>), the LNB (<NUM>) in response providing a signal for said broadcast programme channel at the first user band frequency which is allocated to the first satellite broadcast signal receiver (<NUM>);
the LNB (<NUM>) receiving a request from the second satellite broadcast signal receiver (<NUM>) to transmit a signal for a broadcast programme channel to the second satellite broadcast signal receiver (<NUM>);
wherein:
if the broadcast programme channel requested by the second satellite broadcast signal receiver (<NUM>) is different from the broadcast programme channel requested by the first satellite broadcast signal receiver (<NUM>), the LNB (<NUM>) in response provides a signal for the broadcast programme channel requested by the second satellite broadcast signal receiver (<NUM>) at the second user band frequency which is allocated to the second satellite broadcast signal receiver (<NUM>), and
if the broadcast programme channel requested by the second satellite broadcast signal receiver (<NUM>) is the same as the broadcast programme channel requested by the first satellite broadcast signal receiver (<NUM>), the LNB (<NUM>) in response provides an instruction to the second satellite broadcast signal receiver (<NUM>) for the second satellite broadcast signal receiver (<NUM>) to retune to the first user band frequency such that the second satellite broadcast signal receiver (<NUM>) receives the signal for said broadcast programme channel which is being provided by the LNB (<NUM>) at the first user band frequency.