A Global M odel for the Future of Broadcast TV

FARIA Gerard,GUAN Yunfeng

（1.TeamCast Company,Rennes France;2.National Engineering Research Center,Shanghai China）

A Global M odel for the Future of Broadcast TV

FARIA Gerard1,GUAN Yunfeng2

（1.TeamCast Company,Rennes France;2.National Engineering Research Center,Shanghai China）

The Technical Committee of the Future of Broadcast TV initiative(FOBTV)initiated the Global Model Editorial Group(TC-GMEG)to provide an overview of an end-to-end delivery system allowing the implementation of all the collected use-cases.This TC-GMEG report is accordingly organized into five sections:1)A Starting End-to-End Model for Reasoning, 2)Trends in the Multi-Media Value Chain,3)Contours of a LOCAL End-to-End Model,4)Globalization of the Local Model, 5)Beyond the Global Model.This report also proposed the Smart Broadcast concept which is intended to generalize the usage of hybrid platforms along the Multi-Media Value Chain and moves from“blind”delivery to the“managed”delivery.

FOBTV;global model;broadcast TV;Multi-Media

1 INTRODUCTION

The Future of Broadcast TV initiative(FOBTV)was formed in April 2012 by leading world TV organizations to attempt to bring about a unified next-generation broadcast television system.

The Technical Committee has initiated two working groups to progress the FOBTV objectives:“To produce common requirements for a new terrestrial broadcast stan?dard,applicable to mobile devices and accommodating in?ternet connectivity,Ultra HDTV and new coding schemes like HEVC”.Thus:

1）The Use Case Analysis Group(TC-UCAG)has col?lected use-cases from the FOBTV members,performed their analytical classification,and has started to identify relevant technologies and technology gaps,

2）The Global Model Editorial Group(TC-GMEG)has been assigned to provide an overview of an end-to-end de?livery system allowing the implementation of all the collect?ed use-cases.

The TC-GMEG has adopted for the purpose of this study,a“top-down”methodology and has performed mod?eling of the current platform,observations of the trends in all areas of the digital terrestrial television chain and final?ly has elaborated a Global Model for the Future of Broad?cast TV.

This TC-GMEG report is accordingly organized into five sections:1)A Starting End-to-End Model for Reason?ing；2)Trends in the Multi-Media Value Chain；3)Con?tours of a LOCAL End-to-End Model；4)Globalisation of the Local Model；5)Beyond the Global Model.

2 A STARTING END-TO-END MODEL FOR REASONING

Fig.1 three areas of the Digital TV value chain

For the sake of argument,three areas of the Digital TV value chain have been arbitrarily defined(Production, Distribution and Consumption)and are presented in Fig.1.

For historical reasons,the overall broadcast infrastruc?ture for the delivery of TV services has been organized to disseminate simultaneously as many real-time live-events as possible to a massive amount of users for immediateconsumption.

2.1 TV Programm es&Services Production Area

Analogue TV content was limited to continuous pro?cesses for production,distribution&consumption of video and audio signals.These signals were then fully translated into the digital world as digitally compressed audio-visual streams supplying permanent&branded digital pipes.

However,the appearance of digital TVs and TV set top boxes“connected”to the Internet provided TV studios with the opportunity to extend their services in two direc?tions:

1）To enhance the broadcast TV service with addi?tional content delivered in real-time.

2）Tomake available TV programmes at any time af?ter their prime broadcast delivery.

Accordingly,TV studios(or third-party organisations) are producing complementary streams sustaining live broadcast(enriched service)and/or are delivering“on-de?mand”already broadcast TV programmes(enriched offer), in order to provide to the user a feeling of a“personalised TV service”.

As far as the production area is concerned,the hunt for an extended audience pushes its participants to diversi?fy the means used to deliver TV services beyond the“is?land-based”implementation of a vertically integrated broadcast platform.

2.2 TV Programmes&ServicesDistribution

Analogue TV signals were provided in the vicinity of a TV transmission tower,to give a local TV service.In some countries,this was extended nation-wide by replicat?ing local TV cells.

“Localism”has been one of themajor attributesmain?tained by the TV broadcasters;and this has been fully translated to the digital world and digital broadcast infra?structures,which deliver locally either a unique TV ser?vice or amultiplex of TV services(mainly Europe).The ex?tension of the local area is performed by a multiplication of the transmitter sites,operating either on different fre?quencies(Multi-Frequency Network,MFN)or on a unique frequency(Single Frequency Network,SFN).

In every case,the digital broadcast infrastructure de?livers a basic linear TV service using a self-documented“digital pipe”and the receiving terminals need only to decode the Electronic Programme Guide(EPG)embedded in the broadcast pipe to access anymulti-media content.

But in some countries,in order to provide enhanced &“personalised”TV services(i.e.,HbbTV in Europe,Hy?bridCast in Japan),broadcasters are using a broadband in?frastructure provided by third-party Internet Service Pro?viders.In these cases the Programme Guide(EPG),carried by the broadcast pipe,includes the required URL referenc?es needed to access the complementary multi-media con?tent,made available by the broadcaster,on a server con?nected to the Internet.

As far as distribution to the consumer is concerned, the existence of two infrastructures(broadcast&broad?band)seems to support globalisation,as broadcasters aim at delivering a full range of TV programmes&services to a wide range of terminals,only some having access to both the broadcast (one-to-many) and a broadband (one-to-one)deliverymeans.

2.3 TV Programmes&ServicesConsum ption

Analogue TV programmes were usually consumed on a dedicated terminal:the TV set.This concept has also been fully translated to the digital world and digital decod?er– which embeds a digital(signal)demodulator,a digi?tal(source)decoder&the capacity to decode EPGs–ap?pearing either outside(i.e.set top box)or inside(i.e.inte?grated“digital tuner”)the TV terminals.

In some countries,both traditional&enhanced TV services offerings have been extended to non-stationary TV receivers such as the TV sets installed in vehicles (thanks to the robust performance of digital transmission and to ad-hoc network planning),and to Mobile handheld devices as witnessed by the OneSeg&NotTV services de?ployed in Japan.But these new TV services,like HbbTV in Europe and HybridCast in Japan,are conceptually oper?ating two adjacent screens supplied in parallel by two un?correlated networks,and having only a weak cooperation at the application level.

Connected TVs with access to both broadcast& broadband networks has not only allowed some broadcast?ers to emphasise the personalisation behaviour of linearly programmed TV services but also allowed“Over-the-Top”providers to deliver amimic of TV services to every termi?nal having broadband connection.

For Smart Terminals having access only to the broad?band infrastructure,the TV programmes&services are pro?vided as unicast streamed audio&video.As the storage capacity of the Smart Terminals is not exploited,only live consumption of TV services is performed and neither data push nor datacast deliverymethods are used.

As far as the consumption area is concerned,the het?erogeneous connectivity of the terminals increases the ten?dency to repeat TV services on both the broadcast& broadband platforms:repetitions are performed(during the night for instance)on the broadcast platform without knowl?edge of the consumers,and the unicast delivery of TV ser?vices over broadband network seems to constitute a serious contribution to the exponential growth of data traffic observed on the broadband infrastructures.

3 TRENDS IN THE MULTI-MEDIA VALUE CHAIN

The use-cases studied have revealed the deep expec?tations occurring at both ends of the Multi-Media value chain:on the content providers’side,there is a desire to make Multi-Media content available on a multiplicity of platforms,and on the users’side there are expectations for an ubiquitous consumption of Multi-Media content re?gardless of the location,instant of time and screen type available.

These hopes have implications for all segments of the Multi-Media value chain and reveal major challenges for the infrastructures expecting to connect the studios(provid?ers of content)to the users(consumers of content&servic?es).

3.1 M ulti-M edia Production

Nowadays,almost all TV content is produced digital?ly,but professional content providers tend to enlarge their deliveries in terms of format(i.e.higher video resolution, higher audio channel numbers,etc.)and variety(i.e. multi-view angles,3D complement,facilities for impaired people,emergency warnings,etc.).

The historical concept of using a TV infrastructure to disseminate live-events for immediate consumption in real time has changed,and has evolved to the planning of Multi-Media content production for immediate or later re?lease.

For linearly programmed television to remain centric in TV studios,there is both the need to improve the TV service offering in a way that remains inimitable by the In?ternet players,and the goal to increase the user’s freedom of choices in amimic of an“internet TV”service.

If these trends drive Producers to use two delivery platforms in parallel,it also implies managing two costly workflows in studios.The Production area is accordingly studying the“Create Once,Publish Everywhere”(COPE) paradigm having the ambition to run a unique workflow to produce Multi-Media content suitable for a multiplicity of consumption screens supplied by a variety of delivery plat?forms.

An interesting consequence of the COPE paradigm is the underlying desire to operate a“Smart Delivery Plat?form”facilitating the Publish Everywhere concept,but also providing the insurance that Digital Rights will be secure?lymanaged end-to-end!

3.2 M ulti-M edia Distribution

Almost all TV distribution platforms have achieved theirmigration to digital,but they remain structured to de?liver audio-visual content for immediate consumption:the Branded Digital Pipe supplied 24/7 remains a core feature for broadcast TV services.

The“branded digital pipe”inherited the behaviour of a“voice telecom circuit”from the ISO-MPEG System Lay?er11.ISO/IEC 13818“MPEG-2”(1995)defined a collection of“time-stam ps”(i.e.Presentation,Decoding,Programme Clock Reference)accom panying the com pressed audio&video stream s w ithin the TS packets.Accordingly,any m eans carrying transport stream packets shall be jitter free to maintain the coherency of these tim e-stam ps.specification,which defined“Transport Stream”pack?ets to carry digitally compressed audio-video on any distri?bution means having a constant delay and being packet loss&jitter free.The permanent circuit connection charac?teristic has been inherited from the historic features of the analogue platform delivering live television.

None of these circuit characteristics(i.e.permanent &constant)can be satisfied in an Internet Protocol(IP) context,and specific protocols(and consequent overhead) must be used to compensate for the deficiencies of the“best effort”behaviour of IP networks.

Accordingly,the current digital broadcast platform im?plementations appear to be too specialised to distribute Digital Multi-Media content,anywhere,at any time,to an evergrowing multiplicity of terminals-and this increases the requirement for a digital broadband platform operated in parallel to the broadcast one.

The challenge for a future harmonised Multi-Media distribution platform seems to rely on its capacity to make available a large variety of Multi-Media content(not just access to a branded&permanent digital pipe),within anenlarged area(not only in the vicinity of the TV transmis?sion towers),at a time wished by the consumers(not uniquely at the time programmed by broadcasters),on a personal nomadic terminal(not to a digital TV set“prison?er”of amandatory wall outlet).

3.3 M ulti-M edia Consumption

Users tend to consider smart terminals as a“one-shoe-fits-all”or“all-in-one”device and according?ly expect from them ubiquitous access to any Multi-Media service&content.

At home,when watching the family TV,individual“second screen”terminals are used to consume broadcast?ers’data(complementary to the broadcast programme),to chat with the social network community(about current broadcast delivery),and even to watch“individually”a broadcast TV programme other than the one delivered on the family screen.

On the move,users tend to recover their“TV watch?ing experience”while commuting or traveling in foreign countries with the“one-does-it-all”personal terminal, which permanently accompanies them.

These new habits are emphasised by the Digital TV sets having connection to the Internet,via the proliferation of accessible broadband networks (either“operated”(3GPP) or“not operated” (IEEE)) and by the“Over-The-Top”players providing a TV experience over the Internet.

The challenge for the future Multi-Media terminals seems then to be able to access a multiplicity of distribu?tion platforms providing Multi-Media content&services. As none of the existing distribution platforms is able to provide a“universal”coverage,and because TV services of today cannot yet be ubiquitously distributed on every platform,it suggests that future Consumption terminals must be granted with a series of assets:e.g.a“Hybrid Ac?cess interface”(to surf on every platforms);some storage capacity(to disconnect the acquisition of Multi-Media con?tents from the user’s consumption);and a“Smart TV ap?plication”(to hide but also to perform all the technicalities required to locate,to access and to present the Multi-Me?dia content).

3.4 M ulti-M edia Value Chain Trends:FirstOutcomes

The observed trends highlight that the digitalisation of the broadcast TV platform,which translated the ana?logue value-chain(i.e.studio,infrastructure and terminals) in the digital era,has not sufficiently anticipated the evolu? tions of the terminals capabilities and the new usages they introduced from users.

Nevertheless,TV usage remains popular as witness the surveys revealing that the time spent watching profes?sionally produced linearly programmed TV content tends to increase or at least to be stable.Thus it ismore the de?livery of TV services to nomadic terminals,which must be studied,rather than the TV services themselves.

Nomadic terminals have to be served wirelessly and up to now,only wireless broadband radio technologies are able to do so,resulting in a ever-growing pressure to in?crease the amount of spectrum devoted to Mobile Broad?band services.

But,there is no evidence thatmobile broadband infra?structures will be able to deliver live content on a larger scale to simultaneous users,nor to absorb the data tsunami resulting from the ever-growing consumption of streamed video delivered individually to smart mobile terminals. Even if Content Delivery Networks(CDNs)reduce the traf?fic in the core broadband network(by storing content as close as possible to users),the lastmile radio connection is expected to be seriously overloaded by video streams during the peak hours of broadband traffic.Consequently, the“one-to-many”delivery method(also known as broad?cast or multicast)over the last mile radio seems to be a very sensible&sound solution to optimise the lastmile de?livery.

As TV services can benefit from an additional“one-to-one”broadband connection and as mobile broad?band services benefit from using an additional“one-to-many”broadcast capacity,it seems the“hybrid radio”access or interface will constitute a very promising concept for both infrastructures.

Future global optimisation of the whole Multi-Media value chain drives us therefore to consider evolutions for each of its segments:

1）Production must be done using a unique workflow (i.e.COPE)and Services should be agnostic with regard to the Delivery platform.

2）Distribution must use optimally and indifferently broadcast&broadband means,thus allowing either linear?ly programmed or on-demand services,while optimally us?ing the infrastructure resources.

3）Distribution to nomadic Mobile terminals must be done over a hybrid platform(i.e.BroadCast+BroadBand) and must focus on Universal Coverage:accordingly,cooper?ation between hybrid platforms(i.e.Broad?Cast= Satellite or Terrestrial and Broad?Band=IEEE-WiFi or 3GPP-LTE)must be enabled.

4）Consumption must be achievable on all types of terminal running a“Smart TV Ap?plication”,providing that every terminal has a hybrid access interface.Also,if the storage capacity of the terminals is considered,the platform should manage the transfer of Multi-Media content at any time convenient to any of the players(i.e.Producers,Dis?tributors,Consumers).

In summary,to satisfy the trends in the Production and the Consumption areas,the technical platform must manage the distribution of the Multi-Media content within the infrastructure on a global scale,and take benefit from the cooperation between broadcast&broadband platform technologies to optimise their lastmile delivery-possibly using the terminal storage capacity as the ultimate exten?sion of the Content Delivery Network.

4 CONTOURS OF A LOCAL END-TOEND MODEL

The review of the FOBTV use cases highlighted not only the evolution needs for the last mile of the delivery platform,but also revealed that an end-to-end system must be analyzed in terms of its capacity to connect every type ofmultimedia service with every type of“all-in-one”terminal,everywhere,atany time.

Offering a whole range of Multi-Media services im?plies operating a one-to-one connection with every termi?nal.However,to transfer Multi-Media content optimally to all terminals,implies using a one-to-many delivery meth?od instead of a one-to-one“unicast”one,if at all possible.

The UHF band(300 MHz to 3 GHz),which exhibits a range of wavelength sizes appropriate for antennas embed?ded in smart mobile terminals,is therefore very suitable for wireless delivery of Multi-Media content to these devic?es.But,the scarcity of this spectrum resource requires op?timising the service delivery in terms of effectiveness and efficiency of use,especially if targeting global coverage.

Accordingly,a hybrid radio system appears to be the right solution to provide such multidimensional optimisa?tion,and the updated end-to-end model proposed in the following figure outlines the contours of such a“hybrid”platform.

Fig.2 the updated end-to-endmodel

This updated end-to-end model aims at changing the way that the two individual infrastructures operate in paral?lel(i.e.a one-to-many infrastructure performing linear dis?tribution for immediate consumption,and a one-to-one in?frastructure performing on demand distribution)to a com?bined infrastructure that manages the distribution of all Multi-Media content,either as a linear continuity or an on-demand serviceand takes advantage of both the one-to-many and the one-to-one connections that the us?ers have established with the platform.

“Smart Broadcast”is the main ambition here:to re?spond to the current&future needs of the broadcasters wishing to deliver TV Programmes&Services;to respond to the end-users’demands for TV content professionally produced;and,more importantly,for every type of Multi-Media content“on-the-move”using“all-in-one”Smart terminals.

The“Smart Broadcast Infrastructure”aims at reduc?ing the cost of the“l(fā)astmile”delivery(i.e.the collective distribution to the home)as well as the amount of spec?trum necessary to provide this delivery(i.e.using broad?cast instead of unicast as the unique delivery method),and also optimising globally the economic model while serving stationary&mobile terminals.

4.1 Introduction to the Local End-To-End M odel

Nowadays,as different as they are around the globe, all broadcasters have a role concerning localism.In some countries such localism is restricted to a city,in others it means a state or a whole country–but still,broadcasting preserves local cultures,unites communities and helps to develop local economies.

Whilst they worked in the past with video and audio only,broadcasters are now developing Multi-Media pro?gramming;but their knowledge of“how to program for large audiences”remains based on their expertise in the local social context.

Even though the end-to-end modelmust be scalable in order to address the various topologies of terrestrial net?works operated by broadcasters around the world,the ba?sic configuration of the model must also cater for local broadcasting demands.Fig.3 shows the LOCAL configura?tion of the end-to-endmodel.

In this basic configuration,the Production area is rep?resented by the broadcaster’s studio which delivers con?tent& services over a hybrid platform.The platform makes cooperative usage of a one-to-many“broadcast”and a one-to-one“broadband”component to supply the Consumption area,where two categories of terminals are served:the stationary ones(i.e.TV sets)and the mobile ones(i.e.smartmobiles).

4.2 Behaviour of the Production Area

In the basic configuration,the storage capacity located in the studio is used by a(preferably unique)workflow that producesmulti-media contentas a collection ofaudio-visual sequences stored in a“play-out”server.These audio-visual sequences should include complementary information about the different format types and nature;the resulting Multi-Media packages constitute the items of a branded Electronic Programme Guide(EPG)

The EPG,which governs the continuity of the TV ser?vice programmed by the broadcaster,is delivered to both the“Linear TV”&“On-Demand TV”servers.The“Linear TV”server uses the EPG to stream the audio-visual part of the relevantMulti-Media package onto the one-tomany interface while the“One-demand TV”servermanages to deliver the complementary part of the package through the one-to-one interface in response to user’s requests.

To support this Production area behaviour,some tech?nologies are required.Among others:

1）ISO/MPEG is working on a Modern Media Trans?port(MMT)specification with the goal of providing“the transport of MPEGmedia in an interoperable fashion,espe?cially given the recent increased demand of multi-media delivery in the heterogeneous network environment.”An MMT draft specification is expected in 2013,as a compan?ion to the HEVC(H.265)video compression standard.

2）ISO/MPEG-DASH has demonstrated recently(cf. VRT during London Olympic Games)its ability to stream live TV programmes and to deliver TV services over a non-managed(nonoperated)Internet connection.

Interestingly,both technologies(i.e.MMT&DASH) include a transport layer and a presentation layer,high?lighting the recognition of a“Multi-Media Package”as themanaged quantum of Multi-Media content.

The Multi-Media package seems thus to be the unit which has to be distributed and then delivered to the us?ers;and a common set of protocolsmust be used to enable the delivery of these quanta to be agnostic of the means (one-to-one or one-to-many)used to do so.

4.3 Behaviour of the Distribution Area

In the basic configuration,the Distribution area imple?ments a hybrid infrastructure involving a one-to-many component(broadcast)and a one-to-one component (broadband)to bridge the Production&the Consumption areas.

The broadcast transmitter coverage determines the“l(fā)o?cal”area served.Within this local area,the infrastructure serves both stationary&mobile terminals,in both indoor &outdoor locations.

These requirements have implications on both the one-to-many&the one-to-one components of the infra?structure:

1）The one-to-many component suggests a require?ment for the broadcastwaveform to cope with bothmultipa?th propagation(i.e.frequency selectivity of the channel for stationary reception)and Doppler shifted echoes(i.e.fre?quency selectivity&time-variant channel for mobile re?ception).

2）The payload distributed using these waveforms must be protected with at least two levels of robustness in order to cope with outdoor vs indoor reception situations(i. e.further carrier attenuation resulting from the outdoor to indoor penetration loss,proximity effects,etc.)and this payload must be tailored for different categories of screens.

3）The one-to-one component can use a wired Inter?net connection to reach stationary terminals,but to reach mobile terminals a wireless Internet connection ismandato?ry.Accordingly,the wireless one-to-one component could use either the services of an Internet Service Provider (ISP)or a WiFi infrastructure deployed in the“TV white space”.This last alternative offers the advantage that the Distribution infrastructure will be deployed in a“broad?cast”sub-band(i.e.TV channel AND white space chan?nels)that can be secured by the operator of the hybrid in?frastructure especially in terms of radio interferences.

To support this behaviour in the Distribution area, some technological developments are required,including:

1）One-to-many broadcast systems operate close to the Shannon boundary,so increasing the system through?put requires increasing the RF bandwidth(e.g.using chan?nel bonding for instance),and/or using MIMO techniques22.By re-using the RF channel“several”times,M IMO coding techniques increase the capacity of the channel“sever?al”times-extending the range of trade-off between bitrate&robustness.. Both techniques should be evaluated in the light of the throughput thatwill be required for future TV services de?livered in 4K or 8K HDTV formats.

2）As areas covered by the one-to-many& the one-to-one componentsmay notmatch exactly,only a sub?set of the services will be available when only one compo?nent is available.Since the EPG is broadcast with the Multi-Media packages,this self-documented delivery al?lows linear-TV services to be enjoyed over the whole local zone.The full range of TV services will be provided only in areaswhere the two components are available.

3）A“broadcast”transmission mode(in addition to the native“one-to-one broadband”one)will be needed to optimize the delivery of the whole range of TV services in areas where only the one-to-one component is available. The LTE-eMBMS33.eMBMS(Evolved Multimedia Broadcast/Multicast Service)imp lements two one-to-many delivery methods:“Broad?cast”meaning delivery by the network w ithout management of the term inals;“M ulticast”meaning management of indi?vidual inform ation to the term inals prior delivery,and the inform ed term inals having then to connect to the delivered stream.service mode constitutes an example of such an in-band broadcast mode over a broadband wire?less connection.It could provide a“broadcast”mode to sustain the Broadcast/Multicast protocol on an“IEEE-WiFioperated in TV white space”context.

4）Even though the primary business case of the ter?restrial broadcast platform is the Free-to-Air(FTA)one, technologies must be identified to allow various business models for the Distribution area in order to create a viable economic balance for the operator.Conditional Access System (i.e.CAS)technologiesmustbe evaluated for this purpose.

A common set of protocols must be adopted to make the Service delivery agnostic to the number of components available to stationary&nomadic terminals.Similarly,in order to render a Universal service,the cooperation of sev?eral hybrid platforms(i.e.BroadCast=Satellite or Terres?trial or Cable or IPTV;and BroadBand=IEEE-WiFi or 3GPP-LTE or IPTV),usingsuch common set of protocols, should be considered.

4.4 Behaviour of the Consum ption Area

In the basic configuration,the Consumption area is modelled taking in account two categories of terminals:Sta?tionary(with the possibility of wired connection to the Dis?tribution infrastructure)and Mobile(having only wireless connections to the Distribution infrastructure)with the typical consumption usage being the“indoor”one.

Both stationary&mobile terminals are provided with hybrid platform access to the two components of the infra?structure.This is already the case for the so-called“Con?nected TV,”but not for the traditional TV sets that have access only to a broadcast component,nor for the smart ter?minals that have only access to a broadband component.

Within every terminal,the consumption of TV and Multi-Media services is governed by a“Multi-Media appli?cation”having the capability to use the two components provided by the infrastructure.This Multi-Media applica?tion should not be confused with a cooperative presenta?tion layer(i.e.juxtaposition of contentgoverned by a broad?cast centric application)nor with a cooperative network lay?er(i.e.juxtaposition of screens supplied by two uncorrelat?ed networks),but instead,as a Multi-Media Consumption Application that embraces all upper layers down to the net?work layer.

A“branded TV application”can be located by a search engine and delivered to the terminal from the“on-demand TV server”using a traditional Internet con?nection.Additionally,the“on-demand TV server”pro?vides technical information related to the Distribution infra?structure in the local area and the Electronic Programme Guide,which lists the Multi-Media packages related to the past/present/future broadcast periods.As similar infor?mation is continuously delivered via the one-to-many com?ponent using a data carousel,the terminals with no Inter?net access can discover the infrastructure and update their information using a traditional frequency scanningmethod.

The“branded TV application”using the EPG infor?mation presents the collection of Multi-Media packages available on the platform,and responding to the user’s re?questmanages the required terminal connections to deliver the Multi-Media content for immediate consumption.

In the basic implementation of the model,the storage capacity of the terminals has not been considered in the behaviour of the platform.Nevertheless,the“branded TV application”could benefit from such terminal storage ca?pacity to implement“Personal Video Recorder”(PVR)ser?vices.In this case,the application must have the ability to run in the“background”and to access the infrastructure while the terminal ismoving in the coverage area.

To support the desired behaviour in the Consumption area,some technology developments are required,includ?ing:

1）As far as terminals are concerned,the model im?plies the generalisation of a hybrid access,either wired or wireless,which involves a“MoDem/Demod”device imple?menting the lower-layers(up to the network layer)of re?spectively the one-to-one&one-to-many components.If the physical layers of the two access components are dis?tinct by nature,a harmonisation of the data link&network layers of the existing one-to-one broadband system and the future one-to-many broadcast system must be imple?mented.

2）As far as consumption is concerned,the model im?plies a“branded TV application”able to run in the back?ground,implementing the upper layers and interfacing with the devices that implement the lower-layers.Due to the variety of operating systems used in Smart Multi-Me?dia terminals,a generic APImust be defined in order to guarantee the versatility of the hybrid access amongst ter?minals.

3）As far as TV services are concerned,provisions must bemade to allow themanagement of both Digital con?tent Rights(DRM)and Conditional platform Access(CAS).

A common set of protocols must be adopted to allow future Smart Terminals to access Multi-Media content through any hybrid platform.

4.5 Local End-To-End M odel:Summary

The LOCAL implementation of the end-to-end model has highlighted requirements for evolutions in the three ar?eas of the Multi-Media value chain,with three consequenc? es:

1）A first consequence is that instead of implementing a permanent&branded digital pipe,the end-to-end Infra?structuremustmanage Multi-Media packages(i.e.live vid?eo-clips,already produced audio-visual files,etc.)made of Multi-Media components(i.e.audio,video,complemen?tary data,etc.),each retaining the brand name of its ori?gin.In this context,the lower-layers of the protocol stack will not be considered as having a“constant end-to-end delay&errorless behaviour”(i.e.circuit behaviour im?plied by the ISO/MPEG system layer)and accordingly,the transport layer must incorporate provisions to guarantee a“broadcast” Quality of Service even over an“open_but_best_effort”infrastructure(MMT and/or DASH technologies should tackle this constraint).

2）A second consequence is that in order to facilitate competition,the end-to-end platform must embed provi?sions to guarantee both the Digital(Copy)Rights of the content owners(i.e.DRM)and the business model of the operators by the use of a Conditional Access System(CAS) suitable for any configuration of the platform(i.e.working when either single or dual components are available on the termination side of the platform).

3）A third consequence is that the model fosters the generalisation of a“hybrid access”and of a generic“Multi-Media application”in the terminals.That implies a clear definition of the whole protocol stack and a univer?sal interface(API)between hardware&software devices regardless of the operating system environment.

The described Local end-to-end model should be considered as an aggregation of technological bricks that are already in operation on Free-to-Air,IPTV and OTT platforms,but the ambition of the model is to harmonise the usage of these technologies in order to foster the uni?versality of Smart terminals and open functional interfaces.

5 GLOBALISATION OF THE LOCAL END-TO-END MODEL

Even though the prime application of the end-to-end model is to provide“Smart LOCAL TV services”,the end-to-end model must be scalable in order to address the various topologies of terrestrial networks operated by broadcasters around the world.

The expressed wishes to“Create Once and Publish Everywhere”and to“Consume Everywhere at Any Time”imply extending the platform beyond the primary LOCALTV services area and for the sake of argument,Fig.4 is proposed to represent an up-scaled GLOBAL end-to-end model.

Fig.4 an up-scaled GLOBAL end-to-endmodel

In the GLOBAL architecture,a Distribution infrastruc?ture is established by the aggregation of the previously de?scribed local cells,which become its Delivery nodes.Each of the Delivery nodes is required to delivermultimedia ser?vices and takes benefit of a hybrid one-to-one & one-to-manymeans to serve terminals in a local area.

This global architecture aims to take into account the various topologies of broadcast networks operated world?wide nowadays.For instance:

1）A“global TV”operator supplies affiliated“l(fā)ocal TV”operators with content having countrywide destina?tion.The“l(fā)ocal TV”operator broadcasts the“national”content but part of the time,produces and broadcasts its own“l(fā)ocal”content.In this situation,the“Local TV”op?erator controls the content delivered over the“l(fā)ocal area”while the“Global TV”operator acts as a content provider.

2）A“Broadcast Network”operator collects content from various sources and distributes them over a given ter?ritory.In each region,an aggregation of specific content is performed and addressed to a collection of local areas, which each delivers a“multiplex of TV services”.In this situation,the“Broadcast Network”operator centrally con?trols the content delivered over every passive“l(fā)ocal area.”

Whatever the management of the end-to-end plat?form(i.e.,distributed or centralised),two stages of process?ing are performed:the Distribution of contentwithin the in?frastructure and the Delivery to the users through the means available to serve the“l(fā)astmile.”

5.1 the Hybrid Distribution

In the global implementation of the end-to-end mod?el,the“studio servers”are duplicated in a collection of“Delivery Nodes”interconnected by the Distribution infra? structure.

The Delivery node acting as a“Local Studio”stores Multi-Media packages coming from the Distribution infra?structure,but also generates“Local Content”deliv?ered locally and distributed to the other nodes us?ing the Distribution infrastructure.

The end-to-end global infrastructure manipu?lates the“branded Multi-Media package”as a quantum of management,which open numerous possibilities far beyond today’s manipulations of“branded Digital pipes”(i.e.commutation ofbranded circuits):

1）Multi-Media content– not related to live events-can be distributed over the platform to bring them as close as possible to the location where they will be consumed,thus permitting their delivery to the terminals at the most convenient time for the broadcaster,and/or the platform operator and/or the user.In that sense,the“Multi-Media Distribution”area looks like a broadcaster’s branded Content Delivery Network(CDN)having the par?ticularity to use hybrid technologies,for instance a one-to-many satellite distribution to the local nodes and a one-to-many terrestrial distribution to the terminals.This would bemore efficient(and potentiallymore secure)than the CDNs used by OTT providers,

2）Multi-Media content– not related to live events-are stored in the Delivery node in advance until the instant when they should be delivered to the terminals (i.e.time dictated by the EPG time schedule).But if the Delivery node is able to manage the population of termi?nals it serves,the storage capacities of the terminals can be dynamically managed in order to optimise the“cost”of delivery(i.e.delivery organized as a“push data to many”or Multicast service).In that sense,the“Multi-Media De?livery”to terminals could be perceived by the user as a“broadcaster’s branded Cloud”.

The cooperation of one-to-many(i.e.satellite distribu?tion for instance)and one-to-one(for the control&com?mand of the distribution process)components within the Distribution infrastructure constitutes a major asset of this model.

The Distribution infrastructure could also offermedia?tion capacities with other platforms.Accordingly,its CDN (and possibly Cloud)behaviour could be used to extend the territory on which the branded TV services are native?ly offered:Multi-Media packages could be distributed,bycontractual agreement,to foreign platforms which would serve“l(fā)ocal terminals”abroad;foreign terminals could be hosted&served,providing contractual attachment/roam?ing rules,by a local Delivery infrastructure.

If this openness is strongly desired by the two ends of the end-to-end Multi-Media value chain(NB:Publish Ev?erywhere&Consume Everywhere),it provides an opportu?nity for the broadcasters to differentiate their platforms. The clever end-to-end management of the content’s Copy Rights as well as the clever management of the Access Rights to the Delivery platform make this a clear asset…But the underlying technologies for this scenario must be carefully selected especially if they impact on the compati?bility of legacy versions of the nomadic devices.

5.2 LocalDelivery in a G lobalContext

The GLOBAL end-to-end model aims at establishing a global platform performing the dissemination ofMulti-Media content produced&delivered within the in frastructure by LOCAL delivery nodes.The duality of the Multi-Media De?livery nodes is tentatively pictured in Fig.5.

Fig.5 the duality of the Multi-Media Delivery nodes

At the delivery node,every Multi-Media package ei?ther coming from the distribution platform or produced lo?cally is stored in the Multi-Media database,and thus be?comes available for their delivery as soon as possible for immediate consumption,or for their delivery in advance of the time of their consumption,or for their subsequent deliv?ery with regard to catch-up services.

The two servers,linear-TV&on-demand,cooperate in order to optimise the usage of the transmission resourc?es available on the hybrid local delivery cell.Asmuch as possible,the“one-to-many”deliverymeans is used to de?liver Multi-Media packages to the population of served ter?minals:

1）For linear-TV services,the EPG drives the usage of the resource especially for live-events or for packages delivered for the first time(NB:night repetitions of content can be done without real-time broadcasting usingmanage?ment of the terminals storage capacity).

2）For“predictive datacasting”services,the EPG per?mits anticipating the delivery of Multi-Media packages for storage in the terminals,but authorising consumption only at the time imposed by the EPG.

3）For catch-up TV services,the user demands should be employed to identify popular content and then to manage their“predictive”&simultaneous delivery to multiple terminals available in the local cell.

4）Etc.

The ambition of the managed delivery of Multi-Media packages is to counteract the inefficiency of a collective, but blind,delivery service without knowledge of the audi?ence(i.e broadcast“default”),and that of the multiple in?dividual delivery of given content(i.e.broadband“de?fault”).In this way,the system provides to the broadcast?ers an ultimate optimisation in the usage of the scarce spectrum resource they operate.

The hybrid local delivery cell,as in the previous case,is intended to provide a full coverage of the local cell for both the“one-to-many”&“one-to-one” components. If the“one-to-many”coverage could be eas?ily extended by the use of additional SFN transmitters,the extension of the“one-to-one”spots– permitted by the availability of TV white space spec?trum resources– may have(econom?ic)limitations and might require the cooperation of various broadband infrastructures.

Possibly,some areas covered by the one-to-one com?ponentwill be outside the ones covered by the one-to-many component.Accordingly,the availability of a“broadcast”mode-e.g.LTE-eMBMS like-for the one-to-one component would permit the operation of the delivery node even if only a single componentof the hybrid cellwere available.

Incidentally,the availability of an in-band broadcast mode within a broadband wireless connection should con?stitute a promising characteristic to build up in-home ex?tensions within the infrastructure(e.g.in-home Multi-Me?dia LANs).

The delivery of every kind of TV service(i.e.live,pre?dictive,on-demand)will be possible when stationary termi?nals can receive hybrid coverage,while only a subset of TV services will be possible under partial coverage.The nomadicity of mobile terminals adds a constraint to the coverage:the presence ofmobile terminals in the coverage area must be managed and the delivery of Multi-Media packages should be performed when favourable conditions occur,using the predictive datacasting capabilities of the platform.

The consumption node is intended to be universally implemented across every type of terminal,both stationary and mobile.The consumption node involves hybrid access to the hybrid infrastructure,a storage capacity managed by the infrastructure (i.e.by the delivery node)and a Multi-Media consumption application,which acts as a cli?entof the delivery node servers.

The Multi-Media application plays a crucial role in the performance of the global end-to-end model.It guarantees the efficiency of the DRM&CASmanagement,which form the differentiation asset of the platform;it facilitates the op?timum usage of the transmission resource by supporting the variousmethods of delivery(i.e.live,predictive,on-demand). It contributes to the smartbroadcastbehaviour of the platform by permitting nomadic terminals to locate content,to access delivery nodes and to present content to users.

In summary,the proposed model aim at using coopera?tively broadcast and broadband technologies to permit de?livering traditional&extended TV services,while optimis?ing the costs and the resources implied by the wireless de?livery of contents to nomadic Multi-Media terminals.It aims accordingly not to rethink the Multi-Media services but to invent a new way to deliver them.

6 BEYOND THEGLOBALMODEL

The globalmodel for the Future of Broadcast TV stud?ied in this document highlighted the benefits of a hybrid infrastructure combining one-to-many&one-to-one deliv?ery platforms to manage the delivery of Multi-Media con?tent at any-time,anywhere,to any consumer devices.

As far as stationary terminals are concerned,themod?el could be implemented through wired connections to any broadcast&broadband infrastructure,making it suitable for use with the existing satellite,cable or terrestrial plat?forms.

Regarding mobile terminals(by definition,not wired), broadcast&broadband wireless platforms must be used and accordingly some spectrum resourcesmust be allocat?ed to them.

The UHF band(300 MHz-3 GHz)exhibits a range of wavelengths suitable for antennas embedded in smart mobile terminals,and it is particularly suitable as it allows both indoor&outdoor coverage of large areas with a rela?tively low density of transmission sites.

Terrestrial TV transmitter networks are generally planned to serve users’antennas located at 10 metres above the ground level.Network planning experiences have shown that it is necessary to increase the density of broadcast transmitters by a factor of three to four in order to serve“portable”indoor receivers not benefiting from the gain of an outdoor antenna.Also,experimentations us?ing broadcast transmissions co-located with 3G basesta?tions(i.e.30W radiated at 30 m above ground level)have demonstrated that only onethird or one-fourth of the 3G base-stations have to be equipped with broadcast transmit?ters to replicate the 3G services coverage.

The implementation of“Mobile Broadband”systems in the“Broadcast TV”digital dividend spectrum has re?vealed the requirement for a frequency guard band be?tween infrastructures involving high power/low density transmitters&low power/high density transmitters.This preventsmutual interference and guarantees the Quality of Service over the whole coverage area.

The implication of these elements to the implementa?tion of the globalmodel is that three different densities of transmission sites would be required to cohabit in the UHF band,without mutually interfering.It would thus be necessary to define three spectrum bands– one for each network topology-and two guard bands.Accordingly,in between the existing“Broadcast TV”&“Mobile Broad?band”spectrum bands,the definition of a“Mobile Broad?cast”band would permit the deployment of the globalmod?el.

If the Broadcast TV band continues to host the tradi?tional TV services with their possible extension to 4K& 8K UHD services(which will require large but stationary screens),the Mobile Broadcast band enables the deploy?ment of the denser terrestrial infrastructure required for the one-to-many“broadcast”componentof themodel.

As far as the one-to-one“broadband”component of the model is concerned,it could be based either on 3GPP-LTE or IEEE-WiFi technologies,which both bene?fit already from allocated spectrum.The generalisation ofan in-band MBMSmode within these systems should in?crease the range of the coverage areas;and moreover,the suitability of the operation of IEEE-WiFi within the TV white space could provide an additional(spectrum)degree of flexibility in the implementation of the globalmodel.

In summary,the proposed globalmodel aims at offer?ing an efficient means to deliver every category of Multi-Media service-thus extending the range of TV ser?vices to Mobile terminals and also providing an efficient method to divert part of the traffic overloading broadband networks;traffic essentially related to Multi-Media content individually delivered over a unicastwireless link.

To reach the“Universal Coverage Grail”for every cat?egory of Multi-Media service,the cooperation of coverage is required and the Servicesmust be formatted to be agnos?tic of the lastmile(hybrid)infrastructure used to deliver such services-anytime,anywhere,and on any devices.

From a terminal perspective,a global picture should be represented as Fig.6.

Fig.6 global picture from a terminal perspective

7 CONCLUSIONS

The global model for the Future Of Broadcast TV studied in this documentaims atproposing an overview ofan end-to-end architecture covering the current and future needs of the TV broadcasters.

The Smart Broadcast concept is intended to gener?alise the usage of hybrid platforms(i.e.in one-to-many and one-to-one modes)along the Multi-Media Value Chain.Broadcast&Broadband technologies are used to render a full range of TV services either to stationary TV sets or tomobile smart terminals,and to provide a user ex?perience beyond the quality of service available on the In?ternet.

The Smart Broadcast proposal also moves from“blind”delivery to the“managed”delivery of Multi-Me?dia content,sustained by a cooperative usage of the best wireless technologies available to reach nomadic terminals, and thus justifying the usage of the spectrum presently oc? cupied by the broadcasters.

The model described in this study implies rethinking themethods used to render TV services(not the TV servic?es themselves):the“branded Multi-Media package”must replace the“branded digital pipe”;the one-to-many deliv?ery method must be used as much as possible and even backed up by the one-to-one method;a hybrid radio ac?cess must be generalized in the terminals;and a“multi-media application”must replace the self-discovery of broadcast services.

In summary,the globalmodel proposed for the Future Of Broadcast TV aims to reconcile the COPE44.COPE:Create Once,Publish Everywherestudios with the ATAWAD55.ATAWAD:Any Time,Any W here,Any Deviceusers.Themodel framework introduces some new core concepts and is intended to provide a future-proof response to all the use cases identified by the FOBTV com?munity.

??健男

2014-07-30

【本文獻(xiàn)信息】FARIA Gerard1,GUAN Yunfeng2.A Global Model for the Future of Broadcast TV[J].電視技術(shù)，2014，38（17）.