AU2017251719B2 - A frequency translation method, device and set top box for a satellite communication system - Google Patents

Abstract

Abstract A FREQUENCY TRANSLATION METHOD, DEVICE AND SET TOP BOX FOR A SATELLITE COMMUNICATION SYSTEM A method, device and set top box arranged to translate input centre frequency values to output centre frequency values based on in-band parameters transmitted utilising the ETSI 300 468 DVB Standard. For any frequency list plan number values, a translation is carried out to determine the input ports, output centre frequency and filter pass bandwidth values based on the determined input centre frequency and values found in the NIT and FLD information in the ETSI 300 468 DVB Standard. Input Signal 135 output Signal Video GUOutpul TurDmdo OTftae Decrptor/ Dcde f DeReulceiv-utplxer Des~crambler - Audio Aud o Decoder Prossor Microprocessor bF Local Meory Infra-red receiver Figure 3

Description

A FREQUENCY TRANSLATION METHOD, DEVICE AND SET TOP BOX FOR A SATELLITE

COMMUNICATION SYSTEM

Technical Field [0001] The present invention relates generally to a frequency translation method, device and set top box for a satellite communication system.

Background [0002] In satellite communication systems, it is known to translate the incoming large bandwidth signals into a desired spectrum of frequencies for use by set top boxes (STBs). However, in known systems, the frequency translation table that is used is a fixed table that is stored in the hardware of a frequency translating device and/or STB.

[0003] As the table is fixed, when it is desired for a different frequency spectrum or plan to be used by a STB, the hardware in the frequency translating device and/or STB must be physically updated by way of an in-field manual update. As the frequency translating devices may be located in difficult to access locations, such as in roof top spaces of multi dwelling units (MDUs) this can be problematic. Further, due to the large number of STBs that may be provided to a service provider’s customers and the large geographical area over which the STBs and frequency translating devices may be installed, the in-field manual updating of the frequency translation table can become a large logistical problem.

Summary [0004] It is an object of the present invention to substantially overcome, or at least ameliorate, one or more disadvantages of existing arrangements.

[0005] Disclosed are arrangements which seek to address the above problems by providing a device and method that enables the frequency translation to occur using available in-band data.

[0005a] According to a first aspect of the present invention, there is provided a method for a satellite communication system comprising the steps of translating at least one input centre frequency value to an output centre frequency value based on, at least, in-band parameters transmitted via the satellite communication system; and utilising one or more frequency list plan number values to perform the step of translating, where the one or more frequency list plan numbers are used to determine at least one of: one or more input ports, output centre frequency and filter pass bandwidth values, based on, at least, a determined input centre frequency and one or more values found in a network information table and frequency list descriptor information within the in-band parameters.

[0005b] According to a second aspect of the present invention, there is provided a device for use in a satellite communication system that is arranged to translate at least one input centre frequency value to an output centre frequency value based on, at least, in-band parameters transmitted via the satellite communication system, wherein the device utilises one or more frequency list plan number values to perform the translation, where the one or more frequency list plan numbers are used to determine at least one of: one or more input ports, output centre frequency and filter pass bandwidth values, based on, at least, a determined input centre frequency and one or more values found in a network information table and frequency list descriptor information within the in-band parameters.

[0005c] According to a third aspect of the present invention, there is provided a set top box for use in a satellite communication system that is arranged to determine at least one output centre frequency value to tune to based on, at least, in-band parameters received via the satellite communication system; wherein the set top box utilises one or more frequency list plan numbers, an LNB offset frequency value and a centre frequency value to determine the frequencies to which it should tune.

[0006] According to a first aspect of the present disclosure, there is provided a method for a satellite communication system comprising the steps of translating at least one input centre frequency value to an output centre frequency value based on, at least, in-band parameters transmitted via the satellite communication system.

[0007] The in-band parameters may be defined in the service information utilising the ETSI 300 468 DVB Standard.

[0008] The method may further comprise the steps of utilising one or more frequency list plan number values to perform the step of translating, where the one or more frequency list plan numbers are used to determine at least one of: one or more input ports, output centre frequency and filter pass bandwidth values, based on, at least, a determined input centre frequency and one or more values found in the network information table and frequency list descriptor information within the in-band parameters.

[0009] The one or more values found in the network information table may be selected from a group of data comprising at least: an orbital position of a satellite; an indication of a position of the satellite in a western or eastern part of the orbit; a centre frequency of an input carrier to be translated for a particular transport stream; a symbol rate of a transponder; a roll off of the transponder.

[0010] The one or more values found in the frequency list descriptor information may comprise a centre frequency value.

[0011] According to a second aspect of the present disclosure, there is provided a device for use in a satellite communication system that is arranged to translate at least one input centre frequency value to an output centre frequency value based on, at least, in-band parameters transmitted via the satellite communication system.

[0012] The in-band parameters may be defined in the service information utilising the ETSI 300 468 DVB Standard.

[0013] The device may utilise one or more frequency list plan number values to perform the translation, where the one or more frequency list plan numbers are used to determine at least one of: one or more input ports, output centre frequency and filter pass bandwidth values, based on, at least, a determined input centre frequency and one or more values found in the network information table and frequency list descriptor information within the in-band parameters.

[0014] The one or more values found in the network information table may be selected from a group of data comprising at least: an orbital position of a satellite; an indication of a position of the satellite in a western or eastern part of the orbit; a centre frequency of an input carrier to be translated for a particular transport stream; a symbol rate of a transponder; a roll off of the transponder.

[0015] The one or more values found in the frequency list descriptor information may comprise a centre frequency value.

[0016] According to a third aspect of the present disclosure, there is provided a set top box for use in a satellite communication system that is arranged to determine at least one output centre frequency value to tune to based on, at least, in-band parameters received via the satellite communication system.

[0017] The in-band parameters may be defined in the service information utilising the ETSI 300 468 DVB Standard.

[0018] The set top box may utilise one or more frequency list plan numbers, an LNB offset frequency value and a centre frequency value to determine the frequencies to which it should tune.

[0019] Other aspects are also disclosed.

Brief Description of the Drawings [0020] At least one embodiment of the present invention will now be described with reference to the drawings and appendices, in which: [0021] Fig. 1 shows a satellite network system using a device in accordance with the present disclosure; [0022] Fig. 2 shows a frequency translation device in accordance with the present disclosure; [0023] Fig. 3 shows a set top box in accordance with the present disclosure.

Detailed Description including Best Mode [0024] Where reference is made in any one or more of the accompanying drawings to steps and/or features, which have the same reference numerals, those steps and/or features have for the purposes of this description the same function(s) or operation(s), unless the contrary intention appears.

[0025] Fig. 1 shows a satellite network system 101 using a device in accordance with the present disclosure.

[0026] The satellite network system 101 includes the head end 103 of a satellite broadcast service provider, e.g. Foxtel. Signals are transmitted from the headend via a satellite transmitter 105 to a satellite 107 that is in a geo-stationary orbit. In this example, there are two differently polarised signals that are transmitted (i.e. uploaded) by the satellite transmitter to the satellite 107, a horizontally-polarised (H) signal and a vertically-polarised (V).

[0027] The H and V signals are transmitted from the satellite 107 back to earth for receipt by any satellite dishes that have been set up to receive these particular signals. For example, a satellite dish 109 located on a multi dwelling unit (MDU) 110 may be configured to receive the H and V signals from the satellite 107. The signals pass through a low noise blocker (LNB) 111 of the satellite dish 109. An H signal output connection 113 is connected to a first input 115 on a frequency translation device 117 and a V signal output connection 119 is connected to a second (different) input 121 on the frequency translation device 117. It will be understood that different polarisation techniques may be used, such as “circular right” and “circular left”.

[0028] It will be understood that the device 117 may have more than two inputs for receiving further satellite signals. For example, the device may have two pairs of input ports, where a first pair of input ports receive the H and V signals from a first satellite and a second pair of input ports that receive the H and V signals from a second (different) satellite.

[0029] The device 117 (see Fig. 3) translates the multiple incoming frequency signals of multiple polarisations such that the signals can be output from a single port 123 that is associated with the two inputs (115,121) and transmitted down a single cable 125. In one example, the device 117 dynamically multiplexes the multiple satellite signals for transmission down the single cable 125, as explained in more detail below.

[0030] TheMDU 110hasa number of different apartments (127,129,131, 133) where each apartment has one or more set top boxes (STBs). A first apartment 127 has two STBs (135A, 135B). A second apartment 129 has a single STB 135C. A third apartment 131 has a single STB 135D. A fourth apartment 133 has a single STB 135E.

[0031] Each of the STBs (135A-E) can receive all the signals transmitted down the single cable simultaneously 125 via a single input port arranged to receive incoming satellite signals and the processor in each STB is arranged to dynamically select the multiplexed signal transmitted down the single cable 125, as explained in more detail below.

[0032] The ability to receive all signals simultaneously in the single cable 125, means that the STBs (135A-E) can be of both basic capability (1 DVB tuner) or advanced capability (many DVB tuners) and all functionality is available to the end customers residing in apartments 127,129, 131, 133.

[0033] Fig. 2 shows an example frequency translation device 117. A first pair 201 of input ports (115, 121) is configured to receive the incoming H and V satellite signals from the satellite dish 109. A processor 203 is configured to operate according to software instructions that are stored in a memory device 205. A power supply 207 provides regulated power to the components within the device 117. A single output port 123 outputs the signals that have been frequency converted, frequency translated from the device 117 for receipt by the connected STBs. The device 117, as explained above, may also have a second pair 209 of input ports (211,213) for use with a second set of H and V satellite signals.

[0034] The processor 203 of the device 117 utilises items of information that are transmitted within the in-band signalling received at the device in order to frequency division multiplex the H and V incoming signals onto the single output port 123. The service information used by the processor to do this is transmitted as part of the ETSI 300 468 DVB Standard (468 Standard). This service information includes information from within the Network Information Table (NIT) and information from within the Frequency List Descriptor (FLD). A network identification number is identified from data within the NIT, where, in accordance with the 468 Standard, networks are assigned individual networkjd values, which serve as unique identification codes for networks. For example, the network identification number (networkjd value) uniquely identifies the network service provider (e.g. 4096 for Foxtel).

[0035] There are four main parameters that are needed by the device 117 in order to translate the incoming frequency bandwidth into the output frequency signals required by the STB 135.

[0036] The first parameter is an indication of which input port of the device is to be used for receiving the incoming signal. This needs to be determined where the device 117 has more than one input port as discussed above.

[0037] This first parameter is determined based on the orbital_position and west_east_flag values in the satellite_delivery_system_descriptor which is transmitted as part of the NIT described in the 468 Standard.

[0038] For example, If the orbitaljposition has a value of 156,0° and west_east_flag has a value of 1 (east) then input ports (or “nozzles") 1 or 2 shall be used depending on the polarisation of the signal. For example, input port 1 could be used when polarisation is 00 (linear - horizontal).

[0039] As another example, if the orbitaljposition is any other value or west_east_flag has a value of 0 (west) then input ports (or “nozzles”) 3 or 4 shall be used depending on the polarisation of the signal. For example, input port 4 could be used when polarisation is 01 (linear - vertical).

[0040] As a further example, the following table may be used by the device 117 to determine which input ports (nozzles) to use based on the orbitaljposition and west_east_flag values:

[0041] The device 117 effectively converts the input signals (from any input port) to be provided as unpolarised output signals along that defined output medium (cable) towards the STB.

[0042] The second parameter required is the input centre frequency. This is the centre frequency of the input carrier to be translated for a particular transport stream. The input centre frequency for each service that will be translated to a new frequency is determined from the satellite_delivery_system_descriptor which is transmitted as part of the NIT described in the 468 Standard. That is, the value “frequency” transmitted as part of the satellite_delivery_system_descriptor is the input centre frequency. This is determined based on a specific network provider determined by the networkjd which is transmitted in the NIT.

[0043] The third parameter is the output centre frequency. This is the centre frequency of the output carrier after it has been translated for a particular transport stream. This value is based on the centre_frequency value in the frequencyJistjdescriptor which is transmitted as part of the NIT described in the 468 Standard.

[0044] The output centre frequency value is also dependent on a frequencyjist_plan_number value, which is stored in the device 117. The frequencyjist_plan_numbervalue determines the channels that are transmitted in a defined area or location, for example. The frequencyJist_plan_number value may be, for example, an integer value between 1 and 32.

[0045] Further, the output centre frequency value is dependent on a fixed local oscillator LO_offsetJrequency value that is also stored in the device 117. The LO_offsetJrequency value is dependent on the specification of the LNB. The LO_offsetJrequency value may be, for example, a value between 9.75 GHz and 11.3 GHz. This value is subtracted from the centre frequency values that are calculated (see below) in order to determine the L-band values of the signals provided to the STB.

[0046] Where there are multiple centre frequency values listed in the frequencyJistjdescriptor the device can determine which centre frequency value to use based on the stored frequencyjist_plan_number. That is, each frequencyjist_plan_number has an associated centre frequency. The output centre frequency is then determined by subtracting the LO_offsetJrequency value from the centre frequency value. As an example, the following table shows example centre frequency values in the frequencyJist descriptor available via the 468 Standard for different frequencyjist_plan_number values.

[0047] For example, where the frequency_list_plan_number = 4, and the LO_offset_frequency = 10.7GHz, the output centre frequency = 1311 MHz, i.e. 12.011 GHz - 10.7GHz.

[0048] A fourth parameter used by the device 117 is the filter pass bandwidth. This is the width of the band pass filter that allows the satellite carrier through, i.e. the OdB attenuation bandwidth. The filter pass bandwidth (FB) is calculated by the device 117 according to the following equation. FB = ROUND (S x (1 + R) + L), where [0049] FB = the bandwidth of the filter to the nearest integer (in MHz). It will be understood that the term “filter” here means that the device is sampling an input at specific frequencies and producing a defined output.

[0050] ROUND is a function to round the resultant number either up or down to the nearest integer. For example, ROUND (36.53) = 37 MHz.

[0051] S = Symbol Rate (in Mega Symbols) of the Transponder. This is obtained from the satellite_system_delivery_descriptor, which is transmitted as part of the NIT described in the 468 Standard. For example, a valid range could be between: 0.05 <= MS <= 45.

[0052] R = Roll off of the transponder. Valid values are defined by Table 38 in the 468 Standard and the satellite_system_delivery_descriptor, which is transmitted as part of the NIT described in the 468 Standard. This effectively enables a wider bandwidth to be produced on the output.

[0053] L= Correction (or offset) value based on the LNB and is a fixed value stored in the device. For example this value may be -1.25Mhz (minus 1.25).

[0054] Therefore, for any of the frequency list plan number values, a translation is carried out to determine the input ports, output centre frequency and filter pass bandwidth values based on the determined input centre frequency and values found in service information transmitted within the in-band data, such as the NIT and FLD information as defined in the 468 Standard.

[0055] An example STB 135 may be any of the STBs 135A-E shown in Fig. 1. The STB 135 receives the incoming satellite signals via a single input port 201. Fig. 3 shows an example STB 135.

[0056] Tuner receiver: The tuner receiver receives and down-converts the input signal from the up-converted broadcaster transmitted signal to a baseband signal.

[0057] Demodulator: The demodulator converts the baseband signal to a digital stream.

[0058] De-multiplexer: A de-multiplexer selects digital streams (e.g. open TV programs, EPG data, closed caption data) within the demodulated digital streams.

[0059] Decryptor/Descrambler: STBs include a decryptor to decrypt those parts of the digital stream that are permitted by the Subscription Management System (SMS). Descramblers are used in DVB systems to unscramble selected scrambled digital streams using a standardised descrambling method that requires a decrypted de-scrambling key. The output of this component is encoded digital video and/or audio streams.

[0060] Video Decoder: The video decoder transforms the encoded digital video signal into a basic picture format suitable for interfacing with a television set.

[0061] Audio Decoder: The audio decoder transforms the encoded digital audio stream into a basic sound format suitable for interfacing with a television set.

[0062] GPU: The GPU is a graphics processor that assembles video frames and stores them in a local memory or a video RAM (not shown). The video frames consist of bitmap graphics (such as the EPG), MPEG graphics and moving video generated by the microprocessor.

[0063] Output Interface: A digital output interface for interfacing with a television (for example). Suitable formats include a high definition multimedia interface (HDMI), a digital visual interface (DVI), a component interface with separate audio, a composite interface with separate audio and a demodulated output with embedded audio.

[0064] Media storage device: This is typically a hard disk used to store selected demultiplexed content (video, audio and/or program data) for later use and/or viewing. If an encrypted or scrambled program is to be recorded, output from the de-multiplexer is typically transmitted to the media storage device. This allows the program to be stored in its scrambled and encoded format, therefore requiring the use of the decryptor/descrambler to decrypt descrambling keys and unscramble the recorded content.

[0065] Local memory: The local memory comprises Random Access Memory (RAM) and Read-Only Memory (ROM). Typically, the RAM is used for the purpose of content buffering and microprocessor use. The ROM is typically used for fixed long-term data and program information. Video frames may be stored in the RAM after they have been assembled by the GPU.

[0066] Audio processor: The audio processor can typically process either audio from content streams or from other data sources specified by (and under control of) the microprocessor, such as from local memory.

[0067] Microprocessor: The microprocessor is used for user interface generation, control of the above components and user interaction. Differing rates of inputs (e.g. digital broadcast stream) and outputs (e.g. storage on the hard disk) can be managed by the microprocessor implementing queues. It should be noted that all connections between the microprocessor and each of the components are not shown for clarity purposes.

[0068] The microprocessor of STB controls the decoding of the service information (SI) transmitted as part of the 468 Standard in order to correctly tune (i.e. switch) to a translated frequency.

[0069] The STB has the frequency_list_plan_number value stored in memory. This value corresponds with the value stored in the device 117.

[0070] In this example, the STB 135 always uses its first input port, which is the designated horizontally polarised signal input port. It will be understood that another of the input ports may be the designated input port.

[0071] The STB 135 utilises the frequencyjist plan number, the LO_offset_frequency value and the centre_frequency values in the FLD to determine the frequencies to which it should tune. This is done in the same way as the device 117 used these values to calculate the output centre frequency.

Industrial Applicability [0072] The arrangements described are applicable to the satellite data transmission industries.

[0073] The foregoing describes only some embodiments of the present invention, and modifications and/or changes can be made thereto without departing from the scope and spirit of the invention, the embodiments being illustrative and not restrictive.

[0074] in the context of this specification, the word “comprising” means “including principally but not necessarily solely” or “having” or “including", and not “consisting only of. Variations of the word "comprising", such as “comprise” and “comprises” have correspondingly varied meanings.

Claims (10)

1. A method for a satellite communication system comprising the steps of translating at least one input centre frequency value to an output centre frequency value based on, at least, in-band parameters transmitted via the satellite communication system; and utilising one or more frequency list plan number values to perform the step of translating, where the one or more frequency list plan numbers are used to determine at least one of: one or more input ports, output centre frequency and filter pass bandwidth values, based on, at least, a determined input centre frequency and one or more values found in a network information table and frequency list descriptor information within the in-band parameters.

2. The method of claim 1, wherein the in-band parameters are defined in service information utilising the ETSI 300 468 DVB Standard.

3. The method of claim 1, where the one or more values found in the network information table are selected from a group of data comprising at least: an orbital position of a satellite; an indication of a position of the satellite in a western or eastern part of the orbit; a centre frequency of an input carrier to be translated for a particular transport stream; a symbol rate of a transponder; a roll off of the transponder.

4. The method of claim 1, where the one or more values found in the frequency list descriptor information comprise a centre frequency value.

5. A device for use in a satellite communication system that is arranged to translate at least one input centre frequency value to an output centre frequency value based on, at least, inband parameters transmitted via the satellite communication system, wherein the device utilises one or more frequency list plan number values to perform the translation, where the one or more frequency list plan numbers are used to determine at least one of: one or more input ports, output centre frequency and filter pass bandwidth values, based on, at least, a determined input centre frequency and one or more values found in a network information table and frequency list descriptor information within the in-band parameters.

6. The device of claim 5, wherein the in-band parameters are defined in service information utilising the ETSI 300 468 DVB Standard.

7. The device of claim 5, where the one or more values found in the network information table are selected from a group of data comprising at least: an orbital position of a satellite; an indication of a position of the satellite in a western or eastern part of the orbit; a centre frequency of an input carrier to be translated for a particular transport stream; a symbol rate of a transponder; a roll off of the transponder.

8. The device of claim 5, where the one or more values found in the frequency list descriptor information comprise a centre frequency value.

9. A set top box for use in a satellite communication system that is arranged to determine at least one output centre frequency value to tune to based on, at least, in-band parameters received via the satellite communication system; wherein the set top box utilises one or more frequency list plan numbers, an LNB offset frequency value and a centre frequency value to determine the frequencies to which it should tune.

10. The set top box of claim 9, wherein the in-band parameters are defined in service information utilising the ETSI 300 468 DVB Standard.