WO2019043378A1

WO2019043378A1 - A decoder, encoder, computer program and method

Info

Publication number: WO2019043378A1
Application number: PCT/GB2018/052436
Authority: WO
Inventors: John Nicholas Wilson; Stephen Beck; Nicolas Pierre Rose
Original assignee: Sony Corporation; Sony Europe Limited
Priority date: 2017-08-31
Filing date: 2018-08-29
Publication date: 2019-03-07
Also published as: GB2566440A; GB201713957D0

Abstract

A broadcast decoder operable in a low power mode and a high power mode, comprising circuitry configured to: receive physical layer data in the low power mode; detect a parameter in the physical layer data, and in the event of a positive detection of the parameter, the circuitry is further configured to: determine delay data; switch the broadcast decoder to operate in the high power mode at a specified time after detection of the parameter, the time being defined by the delay data; and trigger an alert.

Description

A DECODER, ENCODER, COMPUTER PROGRAM AND METHOD

BACKGROUND

Field of the Disclosure

The present technique relates to a decoder, encoder, computer program and method.

Description of the Related Art

The "background" description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in the background section, as well as aspects of the description which may not otherwise qualify as prior art at the time of filing, are neither expressly or impliedly admitted as prior art against the present technique.

An Early Warning System has been proposed for inclusion in the Digital Video Broadcasting Service Information (DVB SI). In the proposal, the television receiver monitors the announcement flag in the announcement switching flag field in the Transport Stream Header (HDR). The television receiver will switch to the appropriate audio channel in response to receiving the announcement flag.

However, this arrangement requires not only the tuner and the demodulator within the television to be operational, but also the television to be switched on to switch to the appropriate audio channel. In many cases when emergencies occur, the television will be in a low power or standby mode. Accordingly, the user of the television will not be given warning of an emergency.

In GB1618835.1 filed on 8 November 2016, the contents of which are hereby incorporated by reference, there is described a technique which allows the television receiver to receive an Early Warning System transmission in standby and to switch out of standby and to trigger an alert upon receipt of an Early Warning System flag.

One consequence of such a beneficial system that has been identified by the inventors is the possible impact on the electrical distribution network should all televisions in a location all switch on (out of standby) at the same time. This is particularly relevant in the event of an emergency situation where infrastructure may be fragile or damaged. The consequence described is not limited to the technique described above.

It is an aim of the disclosure to address this issue.

SUMMARY According to the disclosure, there is provided a broadcast decoder operable in a low power mode and a high power mode, comprising circuitry configured to: receive physical layer data in the low power mode; detect a parameter in the physical layer data, and in the event of a positive detection of the parameter, the circuitry is further configured to: determine delay data; switch the broadcast decoder to operate in the high power mode at a specified time after detection of the parameter, the time being defined by the delay data; and trigger an alert.

Other features and embodiments may be generally written as in the following claims appended hereto. The foregoing paragraphs have been provided by way of general introduction, and are not intended to limit the scope of the following claims. The described embodiments, together with further advantages, will be best understood by reference to the following detailed description taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

A more complete appreciation of the disclosure and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:

Figure 1 shows a television receiver 100 according to embodiments of the present disclosure;

Figure 2 shows a television transmission device 200 according to embodiments of the present disclosure; Figure 3 shows a flow chart explaining the set-up process of the television receiver of Figure 1 ;

Figure 4 shows a flow chart explaining an Early Warning Signal process in the television receiver of Figure 1;

Figure 5 shows a flow chart explaining the operation of the television transmission device of Figure 2; Figures 6 and 7 show example embodiment locations of the Early Warning Signal in the physical layer; Figure 8 shows an example embodiment where a single warning message is shown to multiple regions in the event of a static Service Description Table;

Figure 9 shows an example embodiment where an appropriate warning message is shown to a single region in the event of a static Service Description Table;

Figure 10 shows a flow chart similar to Figure 4 explaining the operation of the Early Warning Signal process when the television receiver 100 is switched on;

Figure 11 shows a flow chart similar to Figure 4 explaining the operation of the Early Warning Signal process when the television receiver 100 is in standby (low power) mode;

Figure 12 shows an electrical distribution system;

Figures 13A and 13B show embodiment flow charts implemented in a television receiver according to Figure 1;

Figure 14 shows a flow chart of other embodiments of the disclosure; Figure 15 shows a flow chart implemented in a transmission device 200 according to Figure 2;

Figure 16 shows a television receiver 100 according to embodiments;

Figure 17 shows a flow chart of embodiments implemented in the television receiver of Figure 16; and Figure 18 shows an embodiment of the disclosure including a television receiver of Figure 1 or 16.

DESCRIPTION OF THE EMBODIMENTS

Referring now to the drawings, wherein like reference numerals designate identical or corresponding parts throughout the several views.

Figure 1 shows a television receiver 100 according to embodiments of the present disclosure. The television receiver 100 may be a set-top box receiving terrestrial television, cable television or satellite television, or may be a device receiving television services via a data connection such as broadband

Internet connection, or via a mobile communication network. Of course, although the foregoing mentions a television receiver 100, the disclosure is not so limited. Indeed any kind of broadcast receiver or decoder is envisaged such as digital radio device or the like. Devices may be mains electricity or battery powered. The television receiver 100 may be integrated into a television display device or an optical disc reader such as a Blu-Ray or DVD player. Alternatively, the television receiver may be integrated into a games console, Personal Computer or any kind of suitable device. The television receiver may take the form of a software application that is executed on a hand-held device or on any of the aforementioned device types. An automotive vehicle may comprise a television receiver according to embodiments of the present disclosure. A handheld computing device or mobile telephone may comprise a television receiver according to embodiments of the present disclosure. An electronic device of any sort may comprise a broadcast receiver according to the present disclosure and use the broadcast receiver solely for the purposes of obtaining warnings in case of an emergency.

The operation of the television receiver 100 is controlled by a controller 105. The controller 105 may take the form of a controller circuitry which is typically made of semiconductor material and which runs under the control of computer software embodied as computer readable code. This code may be stored within the controller 105 or may be stored elsewhere within the television receiver 100. In one embodiment example, the computer software is stored within storage medium 125 which is connected to the controller 105. Storage medium 125 may be formed of any kind of suitable media such as solid-state storage or magnetic or optical readable media. Other data such as user profile information, application data, and content may be also stored on storage medium 125.

Also connected to controller 105 is a television decoder 120. The television decoder 120 may take the form of communication circuitry which is configured to receive television signals encoded using the

Digital Video Broadcasting (DVB) set of Standards. In embodiments, the encoded television signals may be broadcast or delivered in a multicast or unicast mode over a terrestrial link, a cable link, satellite link, broadband internet connection or over a cellular (mobile telephone) network. Indeed, although the foregoing describes DVB, the disclosure is not limited and the television decoder 120 may be configured to receive television signals in the Advanced Television Systems Committee (ATSC) format, according to Association of Radio Industries and Businesses (ARIB) standards, DTMB (Digital Terrestrial Multimedia Broadcast) or any other appropriate format.

The television decoder 120 comprises a demodulator 121 and a tuner 122. 121 and 122 may be embodied in a single circuitry package. The television decoder 120 is connected to an antenna 130 which allows these television signals to be received. The antenna 130 may take the form of a Yagi and log-periodic type antenna or a satellite dish, cable head-end or any kind of appropriate reception device. In some television decoder device embodiments, the antenna takes the form of a modem that receives television signals from a cable connection, for example a broadband Internet connection. Indeed it is envisaged that in the television receiver 100 of embodiments may be connected to an antenna 130 to receive broadcast signals and to an internet connection to receive content and data over the internet or a network of some kind, whether wired or wireless. In embodiments, therefore, the television receiver 100 may receive data (such as, but not limited to audio and/or video data) as both broadcast signals and Internet Protocol packets. The controller 105 is also connected to a user input module 135. The user input module 135 may be a remote control or commander, touchscreen, stylus, keyboard, mouse, gesture recognition system, microphone for voice control or any kind of device suitable to allow the user to control the operation of the television receiver 100.

The controller 105 is also connected to a user output module 115. The user output module 115 may be a display (into which the television receiver is integrated or connected), wearable technology such as a smart-watch or goggles, or any kind of device suitable to allow the user to receive the televisual output of the television receiver 100. Network connected systems with displays or audio outputs in general are envisaged, such as utility meters, CCTV displays or intercoms. The alert that is generated by the television receiver 100 according to embodiments could be output to such a device via the user output module 115.

Within the controller 105 is a power control device 110 which may be integrated to, or separate from the controller 105. The operation of the power control device 110 is controlled by controller 105 and its operation will be described later. The power control device 110, like the controller 105 may be embodied as circuitry and may be controlled by software stored on storage medium 125. Figure 2 shows a television transmission device 200 according to embodiments of the present disclosure. The television transmission device 200 may be a delivery system transmitting terrestrial television, cable television or satellite television. Indeed, although the foregoing describes DVB, the disclosure is not limited and the television decoder 120 may be configured to receive television signals in the Advanced Television Systems Committee (ATSC) format or any other appropriate format. The operation of the television transmission device 200 is controlled by a controller 205. The controller 205 may take the form of a controller circuitry which is typically made of semiconductor material and which runs under the control of computer software embodied as computer readable code. This code may be stored within the controller 205 or may be stored elsewhere within the television transmission device 200. In this specific example, the computer software is stored within storage medium 225 which is connected to the controller 205. Storage medium 225 may be formed of any kind of suitable media such as solid-state storage or magnetic or optical readable media. Other data such as user profile information, application data, and content may be also stored on storage medium 225. 225 may be cloud storage. 225 may be a dispersed storage medium comprising multiple storage devices. Also connected to controller 205 is a television encoder 220. The television encoder 220 may take the form of communication circuitry which is configured to transmit television signals encoded using the Digital Video Broadcasting (DVB) Standard. In embodiments, the encoded television signals may be delivered over a terrestrial link, a cable link, satellite link, broadband Internet connection or over a cellular (mobile telephone) network. The television encoder 220 is connected to an antenna 230 which allows these television signals to be transmitted or broadcast. For wireline based delivery systems the antenna is replaced by a modem, switch, server, or Content Delivery Network.

The controller 205 is also connected to a user input module 235. The user input module 235 may be a remote control or commander, touchscreen, stylus, keyboard, mouse, gesture recognition system or any kind of device suitable to allow the user to control the operation of the television transmission device 200.

The controller 205 is also connected to a user output module 215. The user output module 215 may be a display (into which the television receiver is integrated or connected), wearable technology such as a smart-watch or goggles, or any kind of device suitable to allow the user to view the televisual output of the television transmission device 200. Within the controller 205 is an early warning encoder 210 which may be integrated to, or separate from the controller 205. The operation of the early warning encoder 210 is controlled by controller 205 and its operation will be described later. The early warning encoder 210, like the controller 205 may be embodied as circuitry and may be controlled by software stored on storage medium 225.

Early/Emergency Warning System Figure 3 shows a process explaining the set-up process 300 of the television receiver 100 of Figure 1 according to embodiments of the disclosure. The process starts at step 305. The process step 305 may be initiated when the television receiver 100 is first powered on by a user, or under a further set up process initiated by the user. In step 310, the television receiver 100 performs a television tuning process. This may be performed automatically or manually. This tuning process 310 is known and so will not be described any further. However, it is important to note here that during this tuning process 310 at least one broadcast service is tuned and stored within storage 125. In embodiments, this broadcast service is a broadcast service having a dedicated role of providing emergency announcements. In other embodiments the broadcast service may also deliver at least one of audio/video/data content. In some embodiments the broadcast service carrying the data relevant for emergency announcements may be broadcast using transmission parameters to ensure that the broadcast service is more robust than other services broadcast from the same transmitter, i.e. offer a greater likelihood successful decoding at a receiver. Some parts of the emergency announcement transmission data such as EWS flags might be carried in signalling data fields which are more robust than the broadcast content data fields of the transmitted signal. The DVB triplet associated with this emergency announcement broadcast service is stored within a non-volatile area within the storage 125. The term "DVB triplet" is a term known in the art and describes the three identifiers Original Network ID, Transport Stream ID and Service ID which are sent as part of the Service Description Table (SDT). In the event of a static SDT, this triplet allows the television decoder 120 to identify and decode the broadcast service immediately from storage 125. Of course, other broadcast standards use other mechanisms to identify and decode the broadcast services. These are envisaged.

In addition or alternatively to storing the Triplet, the controller 105 may also extract and store the emergency announcement currently being broadcast on the emergency announcement broadcast service. This announcement may be an image, a video and/or audio content indicating the presence of an emergency. Moreover, the storage 125 may have an emergency announcement in the form of an image, video and/or audio factory set and stored within the non-volatile region of storage 125. This is particularly useful in the event that the SDT is dynamic and changes regularly as will become apparent later.

The process moves to step 315 where the user is asked to input their location. In embodiments, location and/or language selection may take place prior to step 310. This location information may indicate the region in which the television receiver 100 is located. This location (region) information may be different to a postal code or zip code. It may be optional for a user to enter a postal code or zip code. The user may be advised that the requested user information is for the purposes of receiving emergency alerts and that this information is securely stored in the device and not disseminated further. Accordingly, it may be allocated for storage in a secure part of memory in the device. In particular, the region information may indicate an approximate geographical region of the television receiver. For example, in the UK, the region information may indicate County, or whether the television is located in the North, South, East or West parts of England, Scotland, Wales or Northern Ireland. Indeed, different granularity may be provided. For example, the user may be presented with a set of drop down menus which provides various levels of granularity. So, for example, the first drop down menu may indicate country, the second drop down menu may indicate North, South, East and West, and the third drop down menu may indicate towns and cities in the locality. Specifically, as an example, the person may select, Scotland->West->Ayr or England->North->Sheffield. Of course, other mechanisms such as the user selecting a predefined region in a map of the country of interest displayed on the screen. Embodiments may use such hierarchical encoding, or the numeric value could be arbitrary or be aligned to an alphabetically sorted list of the regions or could be aligned to known regional codes such as the numbers assigned to departments in France.

Of course, the region information may be established using automatic positioning such as GPS, using WiFi hotspots, the location of the nearest mobile/cellular infrastructure equipment or the like. This information may be determined from circuitry in the television receiver or from a connected device such as a cellular telephone .

After the region information has been established, a numeric value is attributed to the location. In embodiments, the region information selected by the user is formatted according to the Target Region Signalling in [2] . Specifically, the region information is formatted according to the Target Region Descriptor in section 6.4.11 and the Target Region Name Descriptor in 6.4.12 of [2] . In the first example above, Scotland will be encoded as a 24 bit value in the country_code descriptor, the region_depth will be 2, the primary_region_code will be an 8 bit value representing West and the secondary_region_code will be an 8 bit value representing Ayr. Similarly, in the second example above, England will be encoded as a 24 bit value in the country_code descriptor, the region_depth will be 2, the primary_region_code will be an 8 bit value representing North and the secondary_region_code will be an 8 bit value representing Sheffield.

Of course, in embodiments of the disclosure, other mechanisms of signalling the region information are envisaged. For example, instead of having a country_code_descriptor which is a 24 bit value, the country may be the primary_region_code having 8 bits, the north, South, East and West may be the

secondary_region_code having 8 bits and the City/Town may be tertiary_region_code having 16 bits. Of course any value may be attributed to these codes.

Once the region of the television receiver 100 is set, the user may switch the television receiver into standby mode. This is step 320.

In embodiments of the disclosure, the standby mode is a low power mode. In other words, the power consumption of the device in which the television receiver 100 resides drops below a threshold value. It is desirable to reduce the power consumption to 0.25 or 0.5 Watts. There may be multiple standby modes with different power consumption levels. In embodiments, the standby mode with the lowest level of power consumption is still able to monitor the signalling data for the presence of EWS data. At least part of the tuner/demodulator is powered up for this purpose in standby mode. In order to achieve this, many components within the television receiver 100 are switched off or placed into a low power mode. In one example, the controller 105 is partially powered down so that broadcast services and transport streams are no longer tuned and decoded. However, in the low power mode, physical layer broadcast data is still received by the tuner 122 and demodulated by the demodulator 121 in the television decoder 120. Examples of this type of data is the LI pre, LI post and in-band signalling fields as well as T2 PHY layer and PLPs. This low power operation will be used later during the monitoring of the Early Warning Signal according to embodiments of the disclosure.

After the television is in low power mode, the television receiver 100 according to embodiments of the disclosure will then perform Early Warning Signal monitoring as explained with reference to Figures 4 and 5. The Early Warning Signal monitoring is performed in step 325.

The process ends in step 330.

Referring to Figure 4, the process 325 for performing Early Warning Signal monitoring according to embodiments is shown. The process 325 starts in step 405 after the television receiver 100 is placed in stand-by or in a low power mode. The process moves to step 410 where the television decoder 120, and specifically the demodulator 121 and the tuner 122 receive physical layer broadcast data. It should be noted here that the television decoder 120, the demodulator 121 and the tuner 122 operate in the low power or stand-by mode.

As part of this reception and decoding, the tuner 122 and the demodulator 121 look for an Early Warning Signal monitoring flag located within the physical layer broadcast data. This flag may be a single bit or may be a plurality of bits in length. As the Early Warning Signal monitoring flag is located in physical layer broadcast data, the demodulator 121 and the tuner 122 may detect this flag even when operating in a low power mode.

The Early Warning Signal flag may be located in the RESERVED field of the Ll-pre-signalling; in the RESERVED 2 field of the Ll-Post Config and/or the RESERVED 1 filed of the Ll-Post Dynamic. The Early Warning Signal flag may be located in the RESERVED l field of the padding field mapping of in- band type A (IB-A) and in the RESERVED B field of the padding field mapping of in-band type B (IB- B). This would allow for backwards compatibility with existing receivers. There may be cycling of version of the Early Warning Signal flag on each emergency event occurrence to avoid repeated wake-ups of the same event in the same region. These example locations are shown in Figure 6 and Figure 7 respectively.

These are only example locations, and the Early Warning Signal flag may be located anywhere in the physical layer broadcast data. In the event of detecting the Early Warning Signal monitoring flag in the physical layer broadcast data, the controller 105 switches the television receiver 100 to operate in a high power mode. In other words, the television receiver 100, including the television decoder 120 wakes up and begins to operate in a high power mode. The high power mode is a power mode using at least some more energy than the standby power mode. The high power mode may enable decoding/reproduction of audio only. Any display may or may not be enabled. Energy may be saved by disabling the display or operating the display with reduce brightness or powering up only part of the display or a smaller auxiliary display. It will be appreciated that at times of emergency situation, power supplies may be affected or reduced or limited or otherwise controlled. This means that the television receiver 100 is aware that an Early Warning Signal has been broadcast.

However, the receipt of this Early Warning Signal may be erroneous. This would issue a so-called "false positive" response to the television. Issuing a false positive may cause alarm and may also mean users are likely to disable the Early Warning system. In order to reduce the likelihood of this, a double check is in place in embodiments of the disclosure. Now operating in the high power mode, the television decoder 120 tunes to its last broadcast service and decodes the audio transport stream. In other words, the television decoder 120 tunes to the last broadcast service it decoded prior to standby. It should be noted that although the audio transport stream is described, the disclosure is not so limited and any transport stream, such as video is envisaged. The transport stream may be an IP packets encapsulated as a transport stream. Anyway, in step 415, the television decoder 120 decodes the audio transport stream from its last broadcast service. The controller 105 checks the Adaptation Field data descriptor within the audio transport stream. The Adaptation Field data descriptor is described in section 6.2.1 of [2]. Specifically, the controller 105 checks whether announcement switching data field is set in the

adaptation field data identifier. If the announcement switching data field is also set, then the likelihood of two false positives is unlikely and an Early Warning Signal is deemed to have occurred. An alarm may be triggered at this point. In other words, the process of Figure 4 may jump to step 435 at this point. The details of the alarm will be described later.

In embodiments of the present disclosure, however, the Early Warning Signal will be received by all television receivers receiving broadcast signals from the same transmitter or over the same Single

Frequency Network (SFN). In other words, all television receivers over a large geographical region may issue an alarm. In many instances, the Early Warning Signal may be relevant to only a part of the geographical region and it is a further aim of embodiments of the present disclosure to avoid users in non- affected parts being unnecessarily disturbed. Therefore, rather than jumping to step 435 to trigger an alarm, the process moves to step 420.

In step 420, the television decoder 120 retrieves the Program Map Table (PMT) from the MPEG transport stream. Specifically, the television decoder 120 retrieves the PMT from the currently tuned broadcast service. As noted above, this may be the last tuned broadcast service prior having been placed into standby (by a user).

In the event that the last tuned broadcast service cannot be retrieved (for example if no lock on the signal can be achieved), the television decoder 120 will tune to each or at least one further broadcast service or broadcast multiplex in turn until an MPEG transport stream can be decoded and a PMT retrieved. In the event that the time taken to tune to each broadcast service in turn exceeds a threshold time or in the event that no MPEG transport stream can be decoded, the process may jump to step 430 and an alarm raised.

Anyway, in the event that the PMT can be decoded, an Early Warning Signal (EWS) descriptor within the PMT will be retrieved. It should be noted that the EWS descriptor is a new descriptor which will be part of the PMT. PMT is an example of where such data could be located. More generally such data can be located in SI/PSI tables or as private data such as private data in the PES header of any service component or in the header of a PES, or indeed in the Network Information Table (NIT) or in the EIT Actual present/following. The EWS descriptor will have the form below in table 1 :

Table 1 announcement_type: This is the 4 bit field from the announcement support descriptor in table 19 of section 6.2.3 in [2] - this field may additionally include an additional 4 bits reserved to make a complete 8 bit byte. primary_region: This is the 8 bit field from the target_region_descriptor in table 147 of section 6.4.11 in [2]. This field is set to indicate the primary region for which the EWS signal is intended. secondary_region: This is the 8 bit field from the target_region_descriptor in table 147 of section 6.4.11 in [2]. This field is set to indicate the secondary region for which the EWS signal is intended. tertiary_region: This is the 16 bit field from the target_region_descriptor in table 147 of section 6.4.11 in [2]. This field is set to indicate the tertiary region for which the EWS signal is intended.

As noted above, the new EWS_descriptor will be located in the PMT in embodiments. This is because the PMT in the MPEG transport stream is updated regularly. In particular, the PMT is updated every 25- 500ms, typically 100-200ms. In other words, the time period between successive updates of the PMT is small. This means that, in the case on an emergency, the PMT will be updated very quickly and thus the alarm will be triggered quickly but reliably.

After the EWS_descriptor has been retrieved from the PMT, the process moves to step 425. In step 425, the primary_region field, the secondary_region field and the tertiary_region field retrieved from the EWS_descriptor is compared with the primary_region field, the secondary_region field and the tertiary_region field stored in storage 120. The stored primary_region field, the secondary_region field and the tertiary_region field are derived at set-up as explained with reference to Figure 3.

In the event that none of the fields match, the process ends without triggering the alarm. This is because the television receiver 100 is not located in the region for which the EWS is intended.

However, in the event that the stored primary_region field, the secondary_region field and the tertiary_region field match the the primary_region field, the secondary_region field and the

tertiary_region field retrieved from the EWS_descriptor, the television receiver 100 is deemed to be in the location for which the EWS signal is intended. The "match" path is followed in Figure 4 and the process moves to step 430 where an alarm is triggered.

It should be noted here that although the above triggers the alarm in the event that all region fields match, the disclosure is not limited to this. For example, if the user of the television receiver 100 does not complete all the fields in the set up process of Figure 3, then the alarm will be triggered in the event that the field providing greatest granularity is selected. In other words, if the user only completes the primary_region field and the secondary_region field and does not complete the tertiary_region field, the alarm will be triggered in the event that the only primary_region field and the secondary_region field match. Similarly, in the event that the EWS is meant for a large area (for example, the entire west part of Scotland), the EWS descriptor may include a blank field, or a specific pattern of bits, in the

tertiary_region field which indicates a so-called "don't care state" so that the television receiver 100 should trigger the alarm in the event that only the primary_region field and the secondary_region field match.

In step 430, the alarm is triggered. This alarm is designed to alert the user in the event that the user is asleep or not near the television receiver 100. Therefore, the alarm may be an audio alarm such as a siren or a pulsating bell sound to alert the user. The controller 105 of the television receiver 100 may play the audio alarm at maximum volume, or at a volume level above a threshold value. The volume may be attained instantly or the volume may gradually increase to maximum volume over a short period of time, of say 2 seconds. This would avoid a sudden shock to the user whilst also alerting the user of an emergency quickly. In embodiments of the disclosure, this alarm may be instead or in addition, an image or video for example a red screen to ensure users who have hearing problems are notified of the emergency.

The content of the alarm may be retrieved from the non-volatile part of the storage 125. In particular, as noted above in respect of Figure 3, the content may be retrieved from the emergency broadcast service at the time of set-up and stored within the memory 125. In the event that the Service Description Table (SDT) is static, the content of the alarm may also be retrieved from the emergency broadcast service whose DVB Triplet (or equivalent) is stored in the storage 125 at set-up. In other words, when an alarm is triggered, the television receiver 100 will tune to the emergency broadcast service and will display the content and provide the audio from this service. The volume on the device to which the television receiver 100 is coupled will be set to maximum or above a predefined threshold as explained above. This has the advantage of receiving up to date emergency information identifying the type of emergency and providing instructions to users either via audio, image or both.

However, in the event that SDT is dynamic, then the alarm will be the content (image, video and/or audio) stored in the storage 125 at set-up. The television receiver 100 will then retrieve the DVB Triplet or equivalent of the emergency broadcast service from the received SDT. This will allow the television receiver 100 to tune to the emergency broadcast service. However, there will be an approximate delay of 2 seconds in retrieving the DVB triplet (or equivalent) from the dynamic SDT. Therefore, in order to ensure that user is alerted to the emergency as soon as possible, the stored alarm content will be triggered, and after the DVB Triplet is retrieved, and the emergency broadcast service tuned to, the content from the emergency broadcast service may be displayed and played.

If reception of the emergency broadcast service is lost or disrupted, the alarm from storage may be retrieved. In embodiments an alarm from the emergency broadcast service can be stored and then later retrieved should the reception be lost or disrupted. There may be an additional warning retrieved from memory to indicate that retrieved information may not be up to date. The time of the last known accurate information from the emergency broadcast service may be output to give an indication to the viewer/listener of its likely accuracy.

The above describes the situation where a generic emergency exists. However, in embodiments, the announcement_type field in the EWS_descriptor may trigger different alarms depending upon the type of emergency. For example, the alarm triggered to the user in the event of an earthquake may be different to the alarm in the event of a tsunami. In this instance, the announcement type flag is also read from the EWS descriptor and an appropriate alarm triggered. For example, during set-up, a different "DVB Triplet" or equivalent may be associated with each announcement type and each "triplet" (or content from that emergency service) is stored in the non-volatile part of storage 125. Thus, in the event of an emergency, the appropriate broadcast service is tuned to or the stored content associated with the type of emergency is retrieved from storage 125. This provides the user with a more accurate indication of what actions to take.

The process ends in step 435.

It is envisaged that the alarm will continue for either a predetermined period of time or until the

EWS descriptor in the PMT is given a null value, or the EWS flag in the physical layer broadcast data is not set. Moreover, it is also possible that for a predetermined period after the alarm has been triggered, the controller 105 will stop the television receiver 100 from entering low power mode to ensure that the user is kept informed of emergency instructions.

In some instances, there may be multiple EWS signals for a particular region. For example, in the event of an earthquake in a coastal region, there is the risk of a tsunami. This means an earthquake alarm and a tsunami alarm may be required.

In this case, the PMT may carry a plurality of EWS descriptors. Each one may be uniquely identified in the descriptor tag of the EWS_descriptor. In this instance, each EWS_descriptor would include the announcement type field, primary region field, secondary region field and tertiary region field. In this instance, in the event that the primary_region field, the secondary_region field and the tertiary_region field match the stored primary_region field, the secondary_region field and the tertiary_region, the announcement_type field is extracted. The television receiver 100 then knows the type of the emergency, which, in this case, is an earthquake and a tsunami. The television receiver 100 can then cycle between the alarms stored for an earthquake and a tsunami. For example, the television receiver 100 may display the stored content or the content from the emergency broadcast service whose triplet was stored at set up (for a static SDT) for an earthquake for 10 seconds and then display the stored content or the content from the emergency broadcast service whose triplet was stored at set up (for a static SDT) for the tsunami for 10 seconds. In the event of the same emergency type in both regions, it is envisaged that the television receiver 100 would use the same message for both regions. This generic message may include a message asking the user to tune to a local weather or emergency channel, to check the Internet or some other advice. This is shown in Figure 8. In order to further improve this, in embodiments where the static SDT, the

announcement support descriptor in SDT may be extended to include the target region descriptor shown in [2] . In this example embodiment, the triplet information for the emergency channel configured for a particular region (defined by the target region descriptor) will be included in the SDT

announcement support descriptor. An example is shown in Figure 9. Specifically, the extended SDT announcement support descriptor will include the announcment type, the original network id, the transport stream id and the service id as currently. However, in addition, the announcement support descriptor would also include the target region descriptor from 6.4.11 in [2] . Therefore, in the event that the announcement type field in the announcement support descriptor of the extended SDT announcement support descriptor matches the announcement type field in the

EWS_descriptor mentioned above and the target_region_descriptor in the extended SDT

announcement_support_descriptor matches the target_region_descriptor field in the EWS_descriptor mentioned above, then the appropriate triplet (the original network id, the transport stream id and the service_id will be retrieved from the extended SDT announcement_support_descriptor and the television receiver 100 will tune to the appropriate broadcast service to display the appropriate message or video and/or audio.

Of course, in the event that the SDT is dynamic, the SDT would need to be retrieved. In this case, the television receiver 100 would know from the EWS_descriptor that the receiver was located in a region for which an earthquake warning and a tsunami warning are issued. The television receiver 100 would therefore identify the DVB triplet of emergency broadcast service having an appropriate

announcement type field in the SDT and would tune to that broadcast service.

This cycle may continue until the EWS flag is not set in the physical layer.

Alternatively, a single EWS_descriptor may be issued with an inner loop which identifies the various different announcement_type field, primary_region field, secondary_region field and tertiary_region field. However, the principles set out above for a plurality of EWS descriptors may be followed. Figure 5 shows a flow chart 500 explaining the operation of the television transmission device 200 according to embodiments of the present disclosure. The flow chart 500 process begins at step 505. In the event of an emergency deemed severe enough to notify the public immediately, the television transmission device 200 sets the Early Warning Signal flag in step 510. This is set in the physical layer broadcast data. The adaptation field data descriptor is then set in the audio transport stream for all broadcast services transmitted by the television transmission device 200. Specifically, the announcement switching data field is set in the adaptation_field_data_identifier. This is step 515.

The EWS_descriptor identifying the type of emergency in the announcement_type field is set. The primary_region field, the secondary_region field and the tertiary_region field identifying the location of the emergency is also set. The EWS_descriptor is generated in step 520.

The EWS descriptor is inserted into the Program Map Table (PMT) of the MPEG transport stream in step 525.

The process ends at step 530. This same process is shown in a slightly different manner in Figures 10 and 11.

Although the foregoing describes the alarm being provided by the television receiver 100, the disclosure is not limited. In the event that the television receiver 100 is connect to a wearable device or another connected device (e.g. utility meter, security system or multi-room audio system) , the alarm may be triggered on that device in addition to or instead of on the television receiver 100. Although the foregoing has the emergency information being provided over a broadcast network, the disclosure is not so limited. The DVB triplet (or equivalent) may be replaced or embellished by an IP address to which the television receiver 100 or other device should connect. This means that should the television broadcast infrastructure be incapacitated by the emergency, the information may still be retrieved from another source. Although the foregoing has been described with reference to television, the disclosure is not so limited. Any mechanism where an early warning flag may be received in a low power mode, and where the receiver transitions to a high power mode to receive a transport stream including a double check is envisaged. This may be over a radio or mobile telephone network operating in a broadcast mode.

Also, in embodiments, a broadcast receiver operable in a low power, comprising receiving circuitry configured to demodulate broadcast physical layer data in the low power mode and control circuitry configured to: detect an early warning system flag in the demodulated broadcast physical layer data, and in the event of a positive detection; the control circuitry is configured to trigger an audible alert is envisaged. The audible alert may be output at a volume level above a threshold. The audible alert may persist as an alarm until the broadcast receiver is sufficiently powered up or has decoded sufficient of a received transport stream to decode audio and/or video and/or data content which describes the reason for the alert, providing further information or instructions from the authorities as to what to do or what precautions to take. The level of the audible alert may be maintained when switching to reproducing audio and/or video providing further information. Early warning descriptor and emergency broadcast services may alert users to tsunamis, earthquakes, volcanic eruptions, adverse weather conditions, natural disasters or other natural occurring phenomena causing risk to life, sight or limbs, industrial disasters, such as gas leaks, release of toxic substances, acts of terrorism, risks of firearm attacks, prison breakouts, likely presence of fugitives, threats to water supply, risk of highly infectious disease, swarming insects or the like. The reason for the emergency may or may not be disclosed. There may simply be instructions to stay indoors, close all windows, find high ground, conserve energy, stay off communication channels such as mobile phones, etc. Power Distribution Protection

As noted above, one consequence of a large number of television receivers switching from a low power mode such as standby to a high power mode or a power mode higher than a standby mode but less than a maximum operating power of a receiver such as when triggering the alert is that the electrical distribution network may be overloaded or adversely stressed. So, in general terms the high power mode is a mode of operation consuming more electricity than the low power mode. The term high power mode is used for ease of understanding. Embodiments of the disclosure aim to address this.

Referring to Figure 12, an electrical distribution system 1200 is shown. In this electrical distribution system 1200, a power station 1205 generates electricity. The power station 1205 is connected to a number of electrical substations 1210A-1210D. These electrical substations provide electricity to various dwellings. Within these dwellings, television receivers such as those described in Figure 1 are provided. These are shown in Figure 12 as television receiver 100A-100D. It will be appreciated that the number of television receivers shown in Figure 12 is far less than in reality. As an example, one electrical substation is connected to around 120 homes. Therefore, one electrical substation may supply power to around 500 television receivers. It is appreciated that not all of these may be connected to a broadcast network that delivers EWS.

During an emergency, should all of the television receivers connected to one sub-station switch instantly from a low power mode to a high power mode, stress will be applied to the sub-station. This stress takes the form of the high load and this can cause a surge in demand which can damage the electrical substation.

In addition, if many electrical sub-stations have a surge in demand by many television receivers 100A- 100D instantly switching from the low power stand-by mode to a high power mode, the power station 1205 may be placed under considerable burden and a so-called "brown out" may occur where the demand is so high that the power station cannot supply the required electricity. This may result in one or more of the electrical sub-stations becoming incapacitated or the power station 1205 not having enough capacity to service the requests from the television receivers. Thus, the substation may break or the television receiver 100A-100D may act in an inappropriate or unforeseen manner. This is particularly the case in an emergency situation where infrastructure is placed under considerable strain.

It is an aim of embodiments of the present disclosure to address this problem.

Referring to Figure 13A and Figure 13B, embodiments according to the present disclosure are shown. In particular, flow diagrams 1300A and 1300B performed at the television receiver 100 are shown.

Referring to Figure 13A, a process 1300A starts at 1305A. The process then moves to step 1310A where the controller 105 in the television receiver 100 decodes the physical layer data. This occurs in a low power mode as noted above. Specifically, this decoding step is similar to that performed in Figure 4 where the physical layer data is received and checked for the EWS flag. It is not necessary for the entirety of the physical layer data to be checked. It may be sufficient just to check a preamble part or a part of a preamble, for example ATSC3.0's "bootstrap" signalling described in A/321 :2016 System Discovery and Signalling in which there are Emergency Alert wakeup bits encoded. Therefore, for brevity the decoding of the physical layer data in the low power mode will not be explained any further hereinafter.

The process moves to step 1315A where the process checks whether a parameter has been received in the physical layer data. In embodiments, this parameter may be the EWS flag or the Emergency Alert wakeup bit noted above. Indeed, any parameter of the physical layer data which indicates that an alert must be signalled to the user is envisaged. This is typically in response to an emergency or some other warning required to be indicated to an entirety or part of a population.

If no parameter is received, the process follows the "no" path and returns to step 1310A. On the other hand, if the parameter indicating an emergency is received, the "yes" path is followed to step 1320A.

In step 1320A, in response to receiving the parameter, the controller 105 determines delay data. The delay data is data which indicates to the television receiver 100 the length of time to wait before the television receiver 100 should move from the low power mode to a high power mode and to trigger the alert to the user.

The delay data may be determined in numerous ways. The controller 105 may operate to generate its own delay data in response to receiving the parameter. The delay data may be based upon a characteristic of the receiver. For example, the receiver's serial number may be used as seed into an algorithm running on receiver circuitry. For example other pre-stored values, values retained in memories when the receiver was last in operation or values generated by the circuitry in decoding the physical layer data in low power mode such as bit error rate calculations in may be used as a seed. The algorithm may be a pseudo random number generator or a hash value generator.

Such circuitry may pre-exist in a broadcast receiver but be intended for another purpose. It could be reused without requiring additional circuitry. Examples might be shift registers used for interleaving or for pilot decoding or data unscrambling as long as they do not interfere with the low power mode decoding of the physical layer data.

The algorithm may be the same in each receiver but using for example the serial numbers as the seed will generate entirely different delay values even if serial numbers are nearly the same. Serial numbers may be alphanumeric characters. It is not necessary that they be of a fixed length or format between models or manufacturers. For example, the last 8 characters of the serial number could be used as the seed.

In embodiments the MAC address of a network interface of a receiver could be used as a seed to generate the delay data. Indeed since this should be unique value, a portion of it for example in the three least significant bytes could be used to determine a delay. For example the last hexadecimal character could select a delay from 0-15 seconds in 1 second increments. Increments of course need not be of 1 second.

In embodiments, receivers belonging to owners with particular disabilities could be configured with delay data that guarantees their receivers will power up without delay. This may be by differently configuring the algorithm and/or seed value. It may be by bypass circuitry.

The process then moves to step 1325 A. In step 1325 A, the controller 105 checks whether the time period defined by the delay data has passed. In other words, the controller 105 checks whether the time period has expired. If the time period has not expired, the "no" path is followed and the process returns to step 1325A where the process effectively waits until the time period has expired.

If the time period has expired, the "yes" path is followed and the process moves to step 1330A. In step 1330A, the television receiver 100, under control of the controller 105, switches to the high power mode. The process then moves to step 1335A where an alert in triggered. In embodiments, the alert may be the television switching on maximum volume and playing a noise through the speakers. This noise may be white noise or a particular tone. Other examples of the noise may include sirens. In embodiments, the noise is white noise because this will ensure that should a user be hard of hearing in respect a particular frequency of noise, they will hear at least part of the white noise so as to provide an alert. In addition, or alternatively, the display may also switch on and present either a particular icon to the user or a particular coloured screen as explained above in respect of Figures 1 to 11.

Of course, the alert may take many forms. As another example, the audio alert may sound but the visual alert using the display may not be activated. This is advantageous from an electrical distribution network point of view as the audio provision in a television receiver 100 requires far less power than switching on the back light in a display. Indeed, other combinations of alerts exist. For example, when the television receiver 100 receives the delay data in step 1315, the audio alert may be triggered instantly and the back light may be switched on only after expiration of the time provided in the delay data. Additionally or alternatively, as explained in Figure 17, the alert may be triggered in a different device in communication with the television receiver 100.

Once the alert has been triggered in step 1335 the process then ends in step 1340A. Figure 13B describes a further embodiment for providing delay data. A process 1300B describing the further embodiments start at step 1305B.

The process moves to step 1310B where the physical layer data is decoded. This is similar to step 1310A described in Figure 13 A. However, instead of the parameter being used to trigger the generation of the delay data in the television receiver 100 as in the case of Figure 13 A, in the embodiments of Figure 13B, the delay data is included in the parameter.

For example, the received delay data may be a specific value of time such as 3 seconds. In this instance, the television receiver 100 will switch from the low power mode to the high power mode 3 seconds after receipt of the received delay data. In this instance, the transmitting devices 200 may optionally regionalise the surge in demand. In other words, the received delay data transmitted from transmitting devices 200 geographically close to the emergency may indicate a low time period and transmitting devices 200 geographically further from the emergency may have higher time periods. This ensures that television receivers 100 close to the scene of the emergency will switch on quickly without over burdening the electrical distribution network. The received delay data may be a time range such as 1 to 5 seconds. In this instance, the television receiver 100 will switch from the low power mode to the high power mode sometime within 1 to 5 seconds after receipt of the received delay data. In this same manner as above, the transmitting devices 200 may optionally regionalise the surge in demand so that a range of 1 to 5 seconds is sent to television receivers geographically located near the emergency and a different range of 6 to 10 seconds is sent to television receivers located further from the scene of the emergency. In addition, by providing a time range, the television receivers which receive such a range would switch to a high power mode at different times within that range. The received delay data may be a seed used by the television receiver 100 to generate a time at which the television receiver 100 would switch to the high power mode and trigger the alert. This seed may relate to a serial number or another unique code associated with the television receiver. For example, the seed may trigger any television receivers having a serial number ending in an even number to switch to the high power mode and trigger the alert at a particular first time or within a particular first time range and any television receivers having a serial number ending in an odd number to switch to the high power mode and trigger the alert at a particular second, different, time or within a second, different, time range.

As explained above, in the embodiment of Figure 13B, the received delay data may be any kind of data that informs the television receiver 100 that it needs to move to the high power mode and provides information indicating the time at which the television receiver must switch to the high power mode.

The location of the received delay data within the physical layer data may depend upon the content of the received delay data. For example, if the delay data was a specific time value, the size of the delay data would be less than if the delay data was a range of times.

In embodiments of Figure 13B, the received delay data may be placed in the RESERVED fields of the LI -pre signalling, the RESERVED 2 fields of the LI -post config signalling or the RESERVED l fields of the LI -Post Dynamic signalling of Figure 6. Returning to Figure 13B, the process then moves to step 1315B where the decoded physical layer data is checked to see if delay data has been received. If no delay data has been received, the "no" path is followed back to step 1310B.

Alternatively, if delay data has been received in step 1315B, the "yes" path is followed to step 1320B.

In step 1320B, the time at which the television receiver 100 switches from the low power mode to the high power mode is determined. As noted above, in the description of Figure 13B, this may be determined as a result of the controller 105 applying the seed value received in the delay data to a pre- stored algorithm.

The pre-stored algorithm may vary between the devices to ensure that the same seed received by numerous television receivers do not result in the same delay before the television receiver switches from the low power mode to the high power mode. Of course, all of the mechanisms described above with reference to the various forms of received delay data may be used to determine the time at which the television receiver 100 is to switch to the high power mode. Operation of circuitry to seed an algorithm may increase electricity consumption of the device but this computational usage is small and is still within the scope of the low power mode. The computational usage would be less that powering up a television receiver to be able to output audio only. The computational usage would be less that powering up a television receiver which has a screen and displaying information. The computational usage would be less that powering up a television receiver, which has a screen, and actuating the backlighting circuit. The process then moves to step 1325B.

In step 1325B, the time period determined in step 1320B is compared with the current time. If the time has not been reached, in "no" path is followed and the controller 105 in the television receiver 100 waits until the time period has been reached. Once the time period determined in step 1320B has been reached, the "yes" path is followed to step 1330B. The bypass circuitry mentioned may bypass steps 1315B, 1320B and 1325B.

In step 1330B, the television receiver 100, under control of the controller 105, switches to the high power mode. The process then moves to step 1335B where the alert is triggered. This alert is similar to that alert generated in the embodiments of Figure 13A and so will not be explained hereinafter.

Once the alert has been triggered in step 1335B the process then ends in step 1340B.

In addition to the embodiments described above with reference to Figure 13A and 13B, , a flag, for example 1 bit, in the physical layer data could trigger the receiver to wake up (switch power mode). Data in the payload could be decoded which might be data signalling the location of the emergency or threat. This payload data could be compared with location information stored in the receiver. This further embodiment is described in the flow chart 1700 of Figure 14.

The flow chart 1700 starts at step 1705. The process moves to step 1710 where the location of the television receiver 100 is compared with the location of the emergency or threat. If the controller 105 determines that it is at or within the location signalled or otherwise (step 1715) in the payload, then the delay applied could be within a first time range (step 1720). This first time range may be, for example, 0-10 seconds.

Alternatively, if the controller 105 determines that it is outside of the location of the emergency, but within a first threshold distance of the location signalled or otherwise in the payload (step 1725), then the delay applied could be within a second time range (1730). This second time range may be, for example, 11-20 seconds.

If the television receiver 100 is outside of the first threshold distance, the no path of step 1725 is followed to step 1730 where no alert is triggered. The process ends in step 1740.

Whilst it may not be so critical to avoid a power overload or stress in the location that is within a threshold distance but outside of the location of the emergency situation, there will still be benefits to applying the delay because the effect on the electricity infrastructure of many receivers powering up may affect a larger or overlapping area to the area which to which the parameter indicating the emergency, (such as the EWS flag) is signalled.

As described, a random number or pseudo random number could be used determine which delay to apply in the first time range. Similarly a random number or pseudo random number could be used to select which delay to apply in the second time range. The disclosure is not limited to two time ranges. Three or more time ranges is possible with more threshold distances applied.

The time ranges may be calculated by applying an offset to the first time range. For example the second time range may be 0-10 seconds with an offset of 10 seconds, and a third time range may be 0-10 seconds with an offset of 20 seconds.

It will be appreciated that the television receiver 100 when decoding payload data may increase power consumption to a level that is more than a standby level but less than a high power mode. In an illustrative example only, operating in standby mode may use 0.4 W, decoding the parameter such as the EWS flag in physical layer signalling may be possible in standby mode or use a little more, say 0.5W.

Determining the delay (as described in Figures 13A and 13B) may increase power consumption to 1W. Determining the delay dependent on location for example using the decoded payload data may bring the consumption to 3W. In embodiments this may still be considered low power mode. Triggereing an audio alert may bring the consumption to 10W. Triggering a visual alert may bring the consumption to 80W to, for example, illuminate the backlight. If the backlighting is switched to maximum, consumption increase to 100W. In embodiments, the audio alert and visual alert is provided in high power mode. In embodiments, the controller 105, in the case of triggering an emergency alert, may not illuminate the backlight to its maximum, even if the receiver's menu setting is that the user desires maximum backlight illumination.

In embodiments the alert may be displayed after a first delay time with first backlight brightness (say 50%) and after a second delay time the backlight brightness may be increased to a second backlight brightness. The second delay time may be greater than the range of possible first delay times to allow other receivers to have powered up, to the high power mode and provide the intended alert to their users.

Referring now to Figure 15, a process 1400 carried out on the transmitter device 200 is shown. This process will be carried out in conjunction with the television receiver 100 of the embodiments described with reference to Figure 13B. The process 1400 starts at step 1405. The process then moves to step 1410 where the delay time is set. The transmitter device 200 then produces the corresponding delay data which is sent to the television receivers of Figure 13B and is thus received by the television receiver 100 in step 1315B.

The delay data to be transmitted to the television receiver described in reference to Figure 13B is inserted into the physical layer data in step 1415 and the broadcast physical layer data including the delay data to be transmitted to television receivers operating according to Figure 13B is transmitted in step 1420. This transmission may be made to all television receivers in a particular geographical location.

For example, all television receivers 100 located close to the geographical location where an emergency has taken place may have delay data set which is very short so that the television receiver 100 operating according to embodiments of Figure 13B switches from a low power mode to a high power mode and the alert is triggered very quickly so as to warn people. On the other hand, television receivers operating according to embodiments of Figure 13B that are located further from the emergency may be able to wait for a longer time before the trigger is activated.

The process then moves to step 1425 where the process ends.

In the embodiments of Figures 13A, 13B, 14 and 15 assists in randomising the switch on times for the television receivers in a location to avoid a surge in demand that damages infrastructure. The delay data thus controls the switching time for the television receivers in a broadcast area so that a sub-station or group of sun-stations and a power station within the electrical distribution network are not over burdened by the simultaneous (or substantially simultaneous) switching of a large number of television receivers from a low power mode to a high power mode. The use of delay data (either generated within the television receiver according to Figure 13A or received over a network according to Figure 13B) may assist in staggering the switch on times of receivers or at least reducing the number of receivers that power up simultaneously.

Referring to Figure 16, another embodiment aimed at addressing the same problem of power distribution integrity is described. In the television receiver 100 according to embodiments of Figure 16, the television receiver 100 is connected to a mains power source 1511 and a local power source 1512. Specifically, the mains power source is connected to a mains power source connection 1510 and the local power source is connected to a local power source connection 1505. Both the mains power source connection 1510 and the local power source connection 1505, are connected to the controller 105.

In embodiments, the mains power source 1511 is connected to the electrical power distribution network 1200 explained with reference to Figure 12. In other words, the mains power source 1511 is the source of electrical power sent over on electrical distribution network serving a geographical region.

A local power source may be a battery or solar panels or a battery rack which is located within the dwelling. This local power source may serve one or only a small number of dwellings. Accordingly, only a small number of television receivers 100 according to embodiments are switched from the low power mode to the high power mode and the alert triggered. This ensures that the electrical distribution network 1200 is not overloaded when a large number of television receivers switch between the low power mode and the high power mode and the alert triggered.

Moreover, by switching to the local power source, even if the local power source is overloaded due to the demand placed upon it, the effect of such overloading will only affect a small number of dwellings and will not impact the wider electrical distribution network.

In embodiments, the controller 105 determines whether the television receiver 100 is powered from the mains power source or the local power source. This choice is dependent upon the receipt of an

Early/Emergency Warning Signal. This will be explained with reference to Figure 17.

Referring to Figure 17, a flow chart 1600 showing the operation of the television receiver 100 of Figure 15 is shown. The flow chart 1600 begins at step 1605. The process moves to step 1610 where the controller 105 decodes the physical layer data whilst operating in a low power mode. This has been previously described with reference to Figure 4 and Figure 13A and Figure 13B and so will not be described here and after for brevity. The process then moves to step 1615 where the controller determines if warning data has been detected in the physical data. The warning data is, in embodiments, the early warning data or the emergency warning data described in Figures 1 - 11, although, of course other data is envisaged. For example, if the delay data described in Figure 13B is detected, then this implicitly informs the television receiver 100 of Figure 15 that there is an emergency. The content (i.e. the time information) contained in the delay data of Figure 13B may then be ignored, but the receiver 100 may treat the delay data as a flag that an emergency is taking place. In the event that the warning data or the delay data has not been detected, the "no" path is followed back to step 1610. On the other hand, if the warning data or delay data has been detected, the "yes" path is followed and the process moves to step 1620. In process 1620, the controller 105 switches to operate the television receiver 100 from the local power source. In other words, the controller 105 powers the television receiver 100 from the local power source connection 1505 rather than the mains power source connection 1510. The process then moves to step 1625. In step 1625, the controller 105 switches the television receiver 100 from operating in the low power mode to operating in the high power mode. Optionally, the television receiver 100 may then trigger an alert. The process then moves to step 1630 where the process ends.

By switching the power supply in the television receiver 100 from the mains power source to a local power source, and then switching into the high power mode, the burden on the mains power source can be mitigated. This is because, where available, the television receivers 100 connected to a local power source will draw their power from the local power source thus freeing resource in the mains power source for provision of that electrical power to television receivers 100 requiring it. In the above embodiments, the television receivers 100 have been described as triggering alerts using either audio or displays within the television receiver 100. However, as Figure 17 shows, embodiments are not restricted to this.

In particular, referring to Figure 18, a television receiver 100 according to embodiments is wirelessly connected to a second device 1800. The second device 1800 may be an IOT device or other wireless device which may notify the user of an alert. For example, the second device 1800 may be a smart watch or smart phone to which the television receiver 100 is connected. This allows various other alerts to be triggered upon receipt of the early warning signal to the broadcast receiver 100. In other words, although the aforesaid describes the broadcast receiver switching to a high power mode to then trigger the alert, the disclosure is not so limited. Instead, or alternatively, or even additionally, the broadcast receiver 100 may trigger an alert on a remote device such as a user's smart watch. This second device 1800 would, in embodiments, be battery operated. This removes the need to be powered using a mains power source and therefore reduces the negative impact on the electrical distribution system 1200. The IOT device could be a control which reacts to the nature of the early warning, for example if a chemical leak is signalled and the IOT device is able to control the opening and closing of windows, it may close all windows. Should likely flooding or tsunami be signalled and the IOT device is able actuate flood defences, it may actuate those defences.

As noted above, the embodiments are not limited to a television receiver. For example, a stand-alone device comprising a small display or flashing light to provide a visual alert and an audio device such as a speaker or piezo electric actuator to provide an audio alert are envisaged. Embodiments may relate to audio only receivers. Embodiments may relate to data only receivers, for example with text-to-speech output capabilities. Embodiments may relate to combinations thereof.

Numerous modifications and variations of the present disclosure are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the disclosure may be practiced otherwise than as specifically described herein.

In so far as embodiments of the disclosure have been described as being implemented, at least in part, by software-controlled data processing apparatus, it will be appreciated that a non-transitory machine- readable medium carrying such software, such as an optical disk, a magnetic disk, semiconductor memory or the like, is also considered to represent an embodiment of the present disclosure. It will be appreciated that the above description for clarity has described embodiments with reference to different functional units, circuitry and/or processors. However, it will be apparent that any suitable distribution of functionality between different functional units, circuitry and/or processors may be used without detracting from the embodiments.

Described embodiments may be implemented in any suitable form including hardware, software, firmware or any combination of these. Described embodiments may optionally be implemented at least partly as computer software running on one or more data processors and/or digital signal processors. The elements and components of any embodiment may be physically, functionally and logically implemented in any suitable way. Indeed the functionality may be implemented in a single unit, in a plurality of units or as part of other functional units. As such, the disclosed embodiments may be implemented in a single unit or may be physically and functionally distributed between different units, circuitry and/or processors.

Although the present disclosure has been described in connection with some embodiments, it is not intended to be limited to the specific form set forth herein. Additionally, although a feature may appear to be described in connection with particular embodiments, one skilled in the art would recognize that various features of the described embodiments may be combined in any manner suitable to implement the technique. Embodiments of the present technique can generally described by the following numbered clauses:

1. A broadcast decoder operable in a low power mode and a high power mode, comprising circuitry configured to: receive physical layer data in the low power mode; detect a parameter in the physical layer data, and in the event of a positive detection of the parameter, the circuitry is further configured to:

determine delay data; switch the broadcast decoder to operate in the high power mode at a specified time after detection of the parameter, the time being defined by the delay data; and trigger an alert.

2. A broadcast decoder according to clause 1, wherein the parameter is an Early Warning System flag.

3. A broadcast decoder according to clause 1, wherein the circuitry is configured to determine the delay data based upon a characteristic of the broadcast decoder.

4. A broadcast decoder according to clause 3, wherein the characteristic is a Media Access Control (MAC) address of the broadcast decoder or a serial number of the broadcast decoder.

5. A broadcast decoder according to clause 1, wherein the received parameter includes the delay data. 6. A broadcast decoder according to clause 5, wherein the delay data is a seed value and the circuitry is configured to: determine the specified time using the received delay data.

7. A broadcast decoder according to clause 1, wherein when operating in the high power mode, the circuitry is configured to transmit a wake-up signal to another device.

8. A broadcast decoder according to clause 1, comprising audio driving circuitry and display driving circuitry, wherein in the event of an alert being triggered, the circuitry is configured to: control the audio driving circuitry to switch on an audio emitting device connected thereto. 9. A broadcast decoder according to clause 8, wherein in the event of an alert being triggered the circuitry is configured to control the display driving circuitry to switch on a display device connected thereto at the time determined by the delay data.

10. A broadcast decoder according to clause 8, wherein in the event of an alert being triggered the circuitry is configured to control the audio driving circuitry to produce white noise through the audio emitting device. 11. A broadcast encoder operable to communicate with a broadcast decoder of clause 5, the broadcast encoder comprising circuitry configured to: insert delay data into the broadcast physical layer data; and modulate the broadcast physical layer data for broadcast. 12. A broadcast encoder according to clause 11, wherein the circuitry is configured to insert first delay data into broadcast physical layer data to be broadcast to a first region, and insert second, different, delay data into broadcast physical layer data to be broadcast to a second region.

13. A broadcast decoder operable in a low power mode and a high power mode, the decoder comprising a mains power source connection and a local power source connection and circuitry configured to: receive physical layer data in the low power mode; detect warning data within the physical layer data, and in the event of a positive detection, the circuitry is configured to switch the broadcast decoder to operate in the high power mode, wherein the circuitry is configured to use power from the mains power source connection during the low power mode and use power from the local power source connection during the high power mode.

14. A broadcast decoder according to clause 13, wherein the local power source is a battery.

15. A broadcast decoding method comprising: receiving physical layer data in a low power mode; detect a parameter in the physical layer data, and in the event of a positive detection of the parameter, the method further comprises: determining delay data; switch the broadcast decoder to operate in a high power mode at a specified time after detection of the parameter, the time being defined by the delay data; and triggering an alert. 16. A method according to clause 15, wherein the parameter is an Early Warning System flag.

17. A method according to clause 15, comprising: determining the delay data based upon a characteristic of the broadcast decoder. 18. A method according to clause 17, wherein the characteristic is a Media Access Control (MAC) address of a broadcast decoder or a serial number of a broadcast decoder.

19. A method according to clause 15, wherein the received parameter includes the delay data. 20. A method according to clause 19, wherein the delay data is a seed value and the method comprises: determining the specified time using the received delay data. 21. A method according to clause 15, wherein when operating in the high power mode, the method comprises transmitting a wake-up signal to another device.

22. A method according to clause 15, wherein in the event of an alert being triggered, the method comprises: controlling the audio driving circuitry to switch on an audio emitting device connected thereto.

23. A method according to clause 22, wherein in the event of an alert being triggered the method comprises controlling a display device to be switched on at the time determined by the delay data. 24. A method according to clause 22, wherein in the event of an alert being triggered, the method comprises controlling audio driving circuitry to produce white noise through the audio emitting device.

25. A broadcast encoding method to communicate with a broadcast decoder performing the method of clause 19, the broadcast encoding method comprising: inserting delay data into the broadcast physical layer data; and modulating the broadcast physical layer data for broadcast.

26. A method according to clause 25, comprising: inserting first delay data into broadcast physical layer data to be broadcast to a first region, and inserting second, different, delay data into broadcast physical layer data to be broadcast to a second region.

27. A broadcast decoding method comprising, comprising receiving physical layer data in a low power mode; detect warning data within the physical layer data, and in the event of a positive detection, the method comprises switching to operate in a high power mode, the power being provided by a mains power source connection during the low power mode and a local power source connection during the high power mode.

28. A method according to clause 27, wherein the local power source is a battery.

29. A computer program product comprising computer readable instructions which, when loaded onto a computer, configures the computer to perform a method according to clause 15.

Other embodiments may describe a broadcast decoder operable in a low power mode and a high power mode, comprising circuitry configured to:

-receive physical layer data in the low power mode

-switch the broadcast decoder to operate in the high power mode at a delay time after detection of one or more parameters in the physical layer data, the delay time being generated by the circuitry, and

-to trigger an alert. The delay time may be generated by the circuitry in response to delay data received as a parameter of the physical layer data

Corresponding method steps are envisaged. Further a corresponding encoder and encoding method is also envisaged.

Reference

[1] ETSI TS 101 154 v2.2.1 (2015-06); DVB Digital Video Broadcasting (DVB); Specification for the user of Video and Audio Coding in Broadcasting Applications based on the MPEG.2 Transport Stream.

[2] ETSI EN 300 468 vl .15.1 (2016-03); DVB Digital Video Broadcasting (DVB); Specification for Service Information (SI) in DVB Systems.

Claims

2. A broadcast decoder according to claim 1, wherein the parameter is an Early Warning System flag.

3. A broadcast decoder according to either claim 1 or 2, wherein the circuitry is configured to determine the delay data based upon a characteristic of the broadcast decoder.

4. A broadcast decoder according to claim 3, wherein the characteristic is a Media Access Control (MAC) address of the broadcast decoder or a serial number of the broadcast decoder.

5. A broadcast decoder according to claim 1, wherein the received parameter includes the delay data.

6. A broadcast decoder according to claim 5, wherein the delay data is a seed value and the circuitry is configured to: determine the specified time using the received delay data.

7. A broadcast decoder according to any preceding claim, wherein when operating in the high power mode, the circuitry is configured to transmit a wake-up signal to another device.

8. A broadcast decoder according to any preceding claim, comprising audio driving circuitry and display driving circuitry, wherein in the event of an alert being triggered, the circuitry is configured to: control the audio driving circuitry to switch on an audio emitting device connected thereto.

9. A broadcast decoder according to claim 8, wherein in the event of an alert being triggered the circuitry is configured to control the display driving circuitry to switch on a display device connected thereto at the time determined by the delay data.

10. A broadcast decoder according to claim 8, wherein in the event of an alert being triggered the circuitry is configured to control the audio driving circuitry to produce white noise through the audio emitting device.

11. A broadcast encoder operable to communicate with a broadcast decoder of claim 5, the broadcast encoder comprising circuitry configured to: insert delay data into the broadcast physical layer data; and modulate the broadcast physical layer data for broadcast.

12. A broadcast encoder according to claim 11, wherein the circuitry is configured to insert first delay data into broadcast physical layer data to be broadcast to a first region, and insert second, different, delay data into broadcast physical layer data to be broadcast to a second region.

14. A broadcast decoder according to claim 13, wherein the local power source is a battery.

15. A broadcast decoding method comprising: receiving physical layer data in a low power mode; detect a parameter in the physical layer data, and in the event of a positive detection of the parameter, the method further comprises: determining delay data; switch the broadcast decoder to operate in a high power mode at a specified time after detection of the parameter, the time being defined by the delay data; and triggering an alert.

16. A method according to claim 15, wherein the parameter is an Early Warning System flag.

17. A method according to either claim 15 or 16, comprising: determining the delay data based upon a characteristic of the broadcast decoder.

18. A method according to claim 17, wherein the characteristic is a Media Access Control (MAC) address of a broadcast decoder or a serial number of a broadcast decoder.

19. A method according to claim 15, wherein the received parameter includes the delay data.

20. A method according to claim 19, wherein the delay data is a seed value and the method comprises: determining the specified time using the received delay data.

21. A method according to any one of claims 15 to 20, wherein when operating in the high power mode, the method comprises transmitting a wake-up signal to another device.

22. A method according to any one of claims 15 to 21, wherein in the event of an alert being triggered, the method comprises: controlling the audio driving circuitry to switch on an audio emitting device connected thereto.

23. A method according to claim 22, wherein in the event of an alert being triggered the method comprises controlling a display device to be switched on at the time determined by the delay data.

24. A method according to claim 22, wherein in the event of an alert being triggered, the method comprises controlling audio driving circuitry to produce white noise through the audio emitting device.

25. A broadcast encoding method to communicate with a broadcast decoder performing the method of claim 19, the broadcast encoding method comprising: inserting delay data into the broadcast physical layer data; and modulating the broadcast physical layer data for broadcast.

26. A method according to claim 25, comprising: inserting first delay data into broadcast physical layer data to be broadcast to a first region, and inserting second, different, delay data into broadcast physical layer data to be broadcast to a second region.

28. A method according to claim 27, wherein the local power source is a battery.

29. A computer program product comprising computer readable instructions which, when loaded onto a computer, configures the computer to perform a method according to any one of claims 15 to 28.