Presentation on theme: "Doc.: IEEE 802.11-03/0653r0 Submission July 2003 Andy Gowans - UK RA Update from UK (DVB and DTG) on Wireless Home Networking Projects Andy Gowans Private."— Presentation transcript:
doc.: IEEE /0653r0 Submission July 2003 Andy Gowans - UK RA Update from UK (DVB and DTG) on Wireless Home Networking Projects Andy Gowans Private Business Systems Unit UK Radiocommunications Agency
doc.: IEEE /0653r0 Submission July 2003 Andy Gowans - UK RA STRUCTURE OF THE PRESENTATION Background Digital TV in Europe Update On DVB activities Current DVB position DVB Commercial Requirements DTG Activities in UK Current DTG position Digital Video Sender Work Points to Note Future Liaison
doc.: IEEE /0653r0 Submission July 2003 Andy Gowans - UK RA Background Digital TV Rollout. The UK lead the world in the rollout and take up of digital TV. The UK government have set target to switch off all analogue Terrestrial TV by 2010 provided certain targets are met. UK government encourage any platforms that make digital TV services more accessible. At moment to receive Digital signals subscribers require a set top box or Digital TV at every receiver point. DVB/DTG looking to identify practical ways of distributing digital TV services around the home to help enable take up of digital TV.
doc.: IEEE /0653r0 Submission July 2003 Andy Gowans - UK RA What is the DVB Project? The Digital Video Broadcasting Project (DVB) is an industry-led consortium of over 300 broadcasters, manufacturers, network operators, software developers, regulatory bodies and others in over 35 countries committed to designing global standards for the global delivery of digital television and data services. DVB project office is based in European Broadcasting Union in Geneva.
doc.: IEEE /0653r0 Submission July 2003 Andy Gowans - UK RA Update On DVB Activities Current DVB Position Together DTG & DVB have invested considerable effort into the development of set of commercial for a fully functional Wireless Home Networking (WHN). WHN Commercial requirements intend to allow for anticipated user requirements and compliment existing DVB commercial requirements for wired In-Home Digital Networks (IHDN). Have currently put the work to specify practical implementation on hold because they view that none of the current main standards meet the requirements. Are not looking to endorse manufacturers proprietary solutions only. May be willing to endorse a future standard that meets the requirements.
doc.: IEEE /0653r0 Submission July 2003 Andy Gowans - UK RA Update On DVB Activities Current Wired Architecture
doc.: IEEE /0653r0 Submission July 2003 Andy Gowans - UK RA Update On DVB Activities Home Access Network (HAN) Wired HAN spec based on ATM25 and 100baseT Expect Ethernet to be de-facto for IP based services. HAN should be able to provide intra-home connections to other Ethernet devices. Would not be expected to carry Audio Video traffic that HLN is designed for. Home Local Network (HLN) B ased on IEEE1394 for interconnection of audio/video devices. Includes full protocol stack and a user interface. Initial Wired solution only to allow connection of clusters of equipment in one room. To migrate to interconnect clusters of equipment in different rooms when cost becomes acceptable and interoperability is proven. Current Wired Architecture
doc.: IEEE /0653r0 Submission July 2003 Andy Gowans - UK RA Update On DVB Activities Evolution to DVB(WHN) expected: If low cost solutions available. to enable portable device solutions HAN and HLN to evolve from wired to hybrid wired and/or wireless. Would be necessary to interface with terminals originally intended for both types of wired network and support more than one type of protocol in some cases it will not be necessary to implement two separate wireless networks. WHN should be able to inter-operate with wired network technologies identified in the IHDN specification. Should use Licence Exempt Spectrum to reduce cost. Major requirements to be (a) delivery of multimedia services including video from a home server to one or more television sets in the home. Current systems for standard definition TV may require as much as 32Mbit/s. (b) The wireless network must allow for delivery of both HAN and HLN applications at the same time.
doc.: IEEE /0653r0 Submission July 2003 Andy Gowans - UK RA Update On DVB Activities DVB(WHN) Commercial Requirements (1): 1. The WHN shall be able to carry all DVB services including broadcast TV, broadband interactive video (including control functions), fast Internet and other data plus low latency services including telephony between devices. 2. The WHN shall be able to support the services provided by the DVB In- Home Digital Network specifications. 3. The WHN shall be able to convey at least one DVB compliant standard definition MPEG-2 video service together with associated services (including interaction channels). However, the system must also be scalable to increase the number of services that can be transported or must be defined to carry more services than the above at the base level. 4. The WHN shall be capable of supporting both isochronous and asynchronous applications.
doc.: IEEE /0653r0 Submission July 2003 Andy Gowans - UK RA Update On DVB Activities DVB(WHN) Commercial Requirements (2): 5. A means of signalling or identifying the different types of application and their bandwidth requirements should be specified to enable appropriate network management. 6. There should be mechanisms available to allow network problems and configurations to be identified and resolved. 7. The increase in latency due to the wireless network shall be less than 20ms to ensure that interactive TV and games applications can be supported. 8. At least one quasi error free DVB service channel shall be supported in a typical home where adjacent homes have similar networks deployed. There is an example of a worst case scenario. 9. The WHN shall support multiple devices on the same channel with apparent full-duplex connectivity.
doc.: IEEE /0653r0 Submission July 2003 Andy Gowans - UK RA Update On DVB Activities DVB(WHN) Commercial Requirements (3): 10. The WHN shall degrade gracefully under conditions of channel or capacity congestion. 11. The WHN shall support a configurable priority mechanism to support differentiation of services. 12. The WHN shall be based on recognised international and/or regional standards. 13. The WHN should not expose the user to any greater risk of eavesdropping, tampering or invasion than a DVB wired network. 14. The installation of a WHN shall not require the presence of a trained technician. 15. Where competing technologies meet the requirements, the more cost-effective solution should be selected. 16. It shall be possible to have an heterogeneous wireless/wired home network.
doc.: IEEE /0653r0 Submission July 2003 Andy Gowans - UK RA What is the DTG? The Digital Television Group (DTG) was formed in 1995 to set technical standards for the implementation of digital terrestrial television (DTT) in the UK and now encompasses all digital TV platforms and convergence issues on a world-wide basis. Membership of the DTG is open to all companies involved in digital TV broadcasting on all platforms with a commitment to published standards and open markets. The DTG supports DVB standards and a non-discriminatory approach that will enable an open and competitive market in service provision, receivers and conditional access, which is consistent with the European Union Directive on Television Transmission Standards. For more info see
doc.: IEEE /0653r0 Submission July 2003 Andy Gowans - UK RA Who are the DTG members? A Antenna Technicians Association (World), Asia Pacific Broadcasting Union (Affiliate), ATI Research Inc B BBC, BBC Technology, Beko Elektronik, Boxclever, Broadband Wireless Association (Affiliate), BSkyB, BT exact Technologies, C Cabot Communications, Carlton Television, Channel 4, Channel 5, Comet Group, Commercial Television Australia (World), Conexant Systems, Confederation of Aerial Industries (Affiliate), Consumers Association (Affiliate), Crown Castle International, D DCMS (Affiliate), Daewoo Electronics Sales UK Limited, Deaf Broadcasting Council (Affiliate), Department of Trade and Industry (Affiliate), Dibcom, DigiTAG (Affiliate), Digitenne B.V, Digital Broadcasting Australia (Affiliate), Dixons Stores Group, E Eldon Technology, Ezcom Technology Ltd, F FD Learning Limited,Frontier Silicon, H Hauppauge, Hearing Concern (Affiliate), Hitachi Home Electronics, Hospital Group, Humax Co Ltd, I Imagination Technologies, Intellect (Affiliate), ITC, ITVA, J JVC Europe Ltd, Labgear, LG Electronics, LSI Logic, M Maxview, Micronas Holding GmbH, Moving Image Society, (BKSTS), N NEC Electronics, Netgem SA, Network 10 - Australia (World), Nine Network - Australia (World), Nokia UK, Norkring - Norway (World), NovaPal Ltd, NTL, O OFTEL, onTV Europe Limited, P Pace Micro Technology, Panasonic European Television, Philips Semiconductors, Pioneer Technology UK, Promax - Spain (World), Q QVC R RETRA (Affiliate), RF Magic Inc, RNIB (Affiliate), RNID (Affiliate), Royal Television Society (Affiliate), S S.I.S.V.EL - Italy (World), S4C, SAGEM SA, Samsung Research, Sanyo Industries, SBS Corporation (World) SCM Microsystems, Sharp Laboratories Europe, Snell & Wilcox, Sony UK, STMicroelectronics, Strategy and Technology, Sysmedia, T Tandberg Television, Techsan Electronics, Teldis, Teletext, Televés UK (World), Telewest Communications, TDN (The Digital Network) (Affiliate), Thomson Multimedia, Toshiba Information Systems,TRIAX, W Walt Disney Television International, Z Zarlink Semiconductors
doc.: IEEE /0653r0 Submission July 2003 Andy Gowans - UK RA Update On DTG Activities DTG WHN Study (Digital Video Sender) Recent ITC survey showed 75% UK households had 2 or more analogue TV sets and 90% have VCRs. ITC survey shows 40% take up in UK of Digital TV services. The main aim of DTG WHN group is to identify practical ways of distributing digital TV services to devices around the home to help enable take up of digital TV. Primary requirement is to deliver “free to air” DVB-T signals to 2nd and 3rd TV’s throughout the home without the need of a cable feed to an external aerial or Set Top Box. It is also desirable to enable these terminals to access TV related services from other sources. Looking at a transition through 3 different usage scenarios. Initial usage scenario looking to use 5.8GHz ISM band within existing Short Range Device rules (e.g. 25mW max E.I.R.P).
doc.: IEEE /0653r0 Submission July 2003 Andy Gowans - UK RA DTG WHN Study (Digital Video Sender) Usage Scenarios Scenario 1 - Basic - Aimed at satisfying the basic requirements associated with the turnoff of the analogue TV services. View “free to air” TV services, Local channel selection independent of service being viewed on main TV, tele`text, now and next schedule Scenario 2 - Intermediate - To Allow TV services from other digital and analogue sources to be viewed. Subscription services (no extra channel selection), PDR playback, Analogue playback incl pay TV and VCR’s (see note 1) Scenario 3 - Advanced - Fully functional WHN multiple sources Selection of multiple sources, e.g terrestrial,satellite ect.(see note 2), Simultaneous use of different services in different rooms, Mixed content formats plus non-MPEG sources (see note 2), Full EPG capability, Bi-directional TV based interactive services,Video On Demand, Internet access on TV with implied interactivity (See note 3),CCTV (inc.remote control) Notes 1).The users may not distinguish this from the other intermediate cases even though significant extra complexity is required to allow for analogue inputs. This option does, however, allow for carriage of pay TV signals output from DST STB’s and it may therefore be popular, as for current analogue video senders. 2).Only feasible if the decoder associated with the display device is able to decode the content. This may require different middleware, CA system, etc. 3).Although many users would value inclusion of a LAN capability and some manufacturers may wish to provide it in their products this is considered out of the scope of this document.
doc.: IEEE /0653r0 Submission July 2003 Andy Gowans - UK RA Update On DTG Activities DTG WHN Study (Digital Video Sender) Usage Scenarios DTG views on possible market development in standards options 1.Multiple non-interoperable solutions will be marketed, although each may individually work satisfactorily and satisfy the local requirements. 2.Two (or more) interoperable specifications and solutions may be produced, operating with different levels of functionality, each appropriate to the target market and profile. 3.A single specification will be created which will allow several interoperable options within it, with different levels of functionality. Each profile would be compatible with the simpler profiles. 4.A single specification will be created which will be considered suitable for all applications. Option 1 is clearly not desirable because it would result in a fragmented and confusing market. Option 4 would probably be best if cost was not one of the most significant drivers. However, because the usage scenarios range from a single 2nd TV only through to an extremely complex system the market will probably require either option 2 or 3. Of these, option 3 would be most likely to enable a sustainable market. It is therefore believed that this is what we should aim for and that the resulting specification should be promoted by DTG within DVB and other bodies.
doc.: IEEE /0653r0 Submission July 2003 Andy Gowans - UK RA Update On DTG Activities DTG(WHN) Functional Requirements (1): 1. Forward or Broadcast Channel - The forward channel is based on DVB-T specifications and it is transmitted from the gateway via a 5.8GHz carrier. Signal either selected from off air DTT transmissions using a tuner for scenario 1 or generated locally in the gateway for more advanced profiles. 1.2 Bit Rate - The total bit-rate for the forward channel will be determined by the nature of the nature and bit-rate of the content being carried, and the requirements in terms of the number of simultaneous services to be carried. Where more than one service is to be carried the bit-rate requirement will be the sum of the service bit-rates but the maximum rate will be limited to DVB -T specifications and receiver capabilities Timing - The time delivery of some data (isochronous) is very critical and must match the buffering which has been designed into the receivers using the appropriate guidelines. The order of recovery or the ability to re- order the received data is therefore important. It is assumed that the receivers will be based on current DTG guidelines.
doc.: IEEE /0653r0 Submission July 2003 Andy Gowans - UK RA Update On DTG Activities DTG(WHN) Functional Requirements (2): 1.4. Error Performance - Broadcasting by definition involves transmission of information of one to many basis as a result, as a result individual receivers cannot request retransmission of any part of the data. The amount and type of error protection is limited by the capabilities of existing DVB-T receivers. Tests have shown that it will be necessary to use some form of diversity processing to achieve an acceptable QOS Security - For transmission of free to air services there is no need to add extra security to the signal but Digital pay TV services are encrypted an will only be decoded by equipment with required CA/decryption system. There will be a need for extra security where content is decoded and re- encoded locally in order to achieve copy protection and avoid eavesdropping in more advanced profiles.
doc.: IEEE /0653r0 Submission July 2003 Andy Gowans - UK RA Update On DTG Activities DTG(WHN) Functional Requirements (1): 2.Control Channel - A control channel is required in all cases to allow for content selection and interactive services. This is primarily intended to manage the forward path but it could also be used for some independent applications. It has been agreed that this should be bi-directional in order to allow for security applications in a practical manner and to avoid restricting the applications that can be provided. It is also now recognised that the interface to the node should be wireless to allow for delivery to portable devices. The control channel should ideally operate over the same range/number of obstructions as the forward channel. In the case where a repeater is used for the forward channel, it should be possible to implement a repeater for the control channel also. The control channel should ideally be based on a recognised standard to allow its use anywhere in the world. The system must automatically monitor the available channels in the 5.8GHz SRD band and send information to the gateway via the control channel so that it can select a channel that is either not in use or that will have the least interference. The control channel should also be capable of carrying the information necessary to maintain the optimum performance of the link, for example closing the TPC loop or providing feedback to an intelligent transmit antenna system.
doc.: IEEE /0653r0 Submission July 2003 Andy Gowans - UK RA Update On DTG Activities DTG(WHN) Functional Requirements (2): 2.1. Bit Rate -The bit rate required will depend on the application. A simple extended remote control system will require intermittent transmission at a relatively low bitrate but there could be a significant number of simultaneous users in an urban area due to voting in game shows etc. If some form of CA/authentication is carried back to the gateway the bitrate would probably still be low but much more regular and may have minimum and maximum inter-message intervals. A bit rate of around 60kb/s (after FEC) would be ideal as it would allow for Internet services to the TV at PSTN modem rates. However, this would also imply a 100% duty cycle. Allowing for this application might create considerable interference, restrict the range of frequency bands and increase the cost. This application is therefore not considered essential.
doc.: IEEE /0653r0 Submission July 2003 Andy Gowans - UK RA Update On DTG Activities DTG(WHN) Functional Requirements (2): 2.2Timing Probably the most important aspect of timing in the control channel is low latency where any user interaction is concerned, it has previously been proven in the design of user interfaces that any significant delays in giving user feedback (i.e. >200ms) generally cause serious problems in terms of multi-keying, etc. A maximum round trip delay of 100ms for the control channel is therefore considered necessary. 2.3 Authentication/Privacy It will be necessary to ensure that the gateway is only able to control a restricted set of devices. It is also necessary to provide pairing to prevent a neighbour from eavesdropping on messages delivered via the control channel including those that authorise decoding of the TV services on the forward channel.
doc.: IEEE /0653r0 Submission July 2003 Andy Gowans - UK RA Update On DTG Activities DTG(WHN) Functional Requirements (QOS): 3.1. Delay - The delay parameter defines that end to end delay requirement for an application. Some factors influencing delay are packet size, packet queuing, transmission time, jitter buffering and number of hops for a packet switched network. For digital TV distribution over a home network, distinct parameters can be identified. Start up delay - the delay associated with service establishment including operations such as bandwidth allocation and connection establishment. This delay should not exceed 500ms. The control channel should not increase the latency by greater than 150ms over the performance of the normal Set Top Box.
doc.: IEEE /0653r0 Submission July 2003 Andy Gowans - UK RA Update On DTG Activities DTG(WHN) Commercial Requirements (QOS): 3.2. Jitter - An application will have a finite tolerance to variations in the transmission delay. For digital TV, the presentation of video and audio should not jitter by more than 500ns from the programme clock reference. 3.3 Reliability - The reliability parameter defines how tolerant an application is to data loss. The definition of a quasi error free (QEF) DVB reception is less than one visible error per hour. For a high end DVB service of 32MBps with around 80 x 106 packets/hour this leads to a packet error rate (PER) of 1.25 x 10 ‑ 8 and a resulting worst case bit error rate (BER) of x 10 ‑ 11. The probability that the control channel will be blocked should also be very low - no more than one remote command per hour may be delayed by more than 250ms in the working range of a forward channel.
doc.: IEEE /0653r0 Submission July 2003 Andy Gowans - UK RA Update On DTG Activities For questions on Presentation or for more info on DTG(WHN) Commercial Requirements Group