The SCTE Autumn Lecture Meeting & AGM, 2005.

SCTE Autumn Lecture Meeting & AGM, 2005 The SCTE held its 2005 Autumn Lecture Meeting on Tuesday, 27^th September. As usual, the autumn meeting was followed by the AGM of the society. Graeme Young, CTE Deputy Editor, reports.		SCTE Papers Committee chairman, Mark Burns


Janhein van Brienen, Principal Engineer of Telewest Broadband	Upstream RF Signal Management in HFC Networks Janhein van Brienen, Principal Engineer of Telewest Broadband, was first on the podium to tell us about a Practical Approach to Upstream RF Signal management in HFC Networks. He began by saying that today's Telewest Broadband is a result of a series of mergers with, and acquisitions of, other cable networks. This has brought about a rich variety of architectures, ten different ones can be identified amongst their Broadband HFC Networks. The networks consist of a wide range of equipment that represents most of the equipment vendors operating today, and regional sites often have their own ways of operating their systems. Telewest were first in the use of two-way sweep and network alignment equipment, however, whilst most networks were capable of return path working, some were not maintained or equipment for them, had not been commissioned. Preparation for DOCSIS began in 1999, hubsites and head-ends had a complete re-work of return path combining, testing of non-digital ready passives (mainly splitters and isolators) was undertaken and unsuitable items were removed The upstream networks were then tested to ensure their ability to meet DOCSIS requirements. Measures taken to obtain uniformity of performance included the "noise in the notch" test using a 32MHz wide noise signal with a notch at 22.5MHz that is some 55db deep. The test, repeated at five different temperatures in order to assess the performance over the operational temperature span, is performed at the optical transmitter input. The measurement results, expressed in "Power per Hertz" enable easy calculation for signals of different bandwidths. Upstream network gain from the input of the distribution node to the input of a fibre node is normally zero, and NRG is documented for all operational nodes in use in Telewest in the RPM calculator. The RPM calculator tool permits independent calculation of DOCSIS data carriers and CW alignment carriers so that long-established practises can stay in place. Upgrading 3.2 QPSK to 16QAM gave problems with the DOCSIS specification. The CPE upstream transmit power degrades by 3dB to +55dBmV for 16QAM and though most legacy Cable Modems follow the DOCSIS specification, DHTs generally do not. The theoretical average upstream level is 46.5dBmV, and the Cisco UBR default "continuation" threshold of +/-2dB allows cable modems transmitting at 58dBmV to register. Following type approval of a new fibre optic transmitter that has a minimum of 6dB extra gain, developed by one of Telewest's suppliers as a replacement for the original RDL-2 transmitter, a main obstacle of the upgrade to 16QAM will have been removed.

Sharing and Distributing Content within the Home Mr David Keeley, Chief Technology Officer of Motorola CHS, EMEA. David's subject was "Sharing and Distributing Content within the Home" and he began by enumerating the variety of connections that can exist within the home that include Terrestrial, Broadband Cable and Satellite TV with the attendant hardware. With several TV sets, VCRs, DVD player/recorders, PVRs, Radio Sets, Hi-Fi equipment, Computers, and more, an ideal solution to the interconnection problem is required. This solution would be the possibility of no new wiring, Plug and Play ease, self-installation by the consumer, and low cost and wide availability - possibly via retail outlets. The bandwidth requirement, taking into account SDTV, HDTV, IP Data, IP Telephony, and Audio, would be around 27Mb/S, latency of 50mS maximum and an average of about 20mS, jitter of 40mS maximum peak-to-peak, and a Quality of Service that ensures problem-free Data delivery, 2-way telephony, and error-free Video transport and IP streaming on the "pull" model. Once the interconnection issue is settled, future requirements would be delivery to multiple devices with local storage and playback of Multimedia Content and the ability to share such content between devices and users. Motorola's Ucentric Digital Home is one such offering as a solution.		Mr David Keeley, Chief Technology Officer of Motorola CHS, EMEA


Mr Lennart.J.Broers, Market Manager Solutions EMEA & Pacific, C-Cor Broadband Europe BV	The Role of Performance Metrics in Managing VoIP Service and Call Quality Mr Lennart.J.Broers, Market Manager Solutions EMEA & Pacific, C-Cor Broadband Europe BV, filled the spot before lunch with a paper setting out the tools needed by MSOs to achieve a sustainable VoIP market penetration. Telephony is a market in which the customer has high expectations of call quality and reliability. This is the major challenge facing a VoIP service provider, in the access portion of the network issues such as loss, latency and jitter assume significant importance. In characterising performance for telephony services the most commonly used methods are those designed to reflect the customer's perception of the quality of the service. Techniques are employed that simulate the result of a Mean Opinion Score (MOS) that is arrived at by a survey that included various call degradations such as echo, delay, etc. It is important to provide access to emergency services and this is jeopardised by the end-user re-locating the cable modem, so that from a public safety viewpoint operators should be capable of detecting when the physical location of such a modem is changed. Use of the E-model for planning and the ongoing management of networks is cost-effective, scalable and accurate. Ongoing frequent analysis of network capacity demands is important as the growth of data and VoIP traffic increases.

The Next Generation of EuroDOCSIS Mr Volker Leisse of EuroCableLabs took the assembled members through "The Next Generation of EuroDOCSIS". He began by outlining the activities of EuroCableLabs, a subsidiary, but autonomous organisation, of ECCA. The development of emerging technologies looking often far into the future, technical standardisation, certification, and interoperability testing are numbered amongst such activities. Members include a high proportion of the major European Cable operators spread mainly across Western Europe but with increasing interest now being shown by Eastern European Networks. In this respect EuroCableLabs provides a common communication platform for its members. The success of EuroDOCSIS 2 was the transparency it brought, evolving over time from its predecessor, and enabling new services for triple-play with increased capacity and delivery to a wide range of devices including mobiles. In Europe two elements provide the drive into new developments, firstly the need for lower cost and increased capacity, and second, the inclusion of alternative access networks such as DSL. Operators want to be able to meet competition, add new services and establish their networks as a future-proof solution for the delivery of multimedia content. They also wish to embrace business data services, gaming, betting and VoD etc. The key strategy to this is alignment to DOCSIS 3. Modular CMTSs employ architecture that uses echelon devices to effect cost savings and allow better balance of loading applied to fibre optic modulators. The interfaces provide greater capacity and speed. Another requirement of European operators was for the adjustment range of the average power of a port to remain at 11dB to accommodate multichannel architecture. MER was added to the specification and out-of-band spurious also, the latter to protect analogue services. External timing generation is employed, headend eequipment has a common time and frequency domain, the master clock is used for precise burst alignment, and the time stamp can be used to measure latency across networks. The architecture allows scaling of data stream capacity in the most cost-effective way. The new generation of cable modem devices are future-proofed and ready to establish Cable as a platform for quadruple play. With added security, channel bonding is a main feature. Support of IP v 4 and IP v 6 is possible and management of cable modems will be enabled via IP v 6. EuroCableLabs is working in close co-operation with CableLabs of the USA, currently work is progressing on the defining of European requirements for DOCSIS 3 and the presentation of specifications to Cablelabs working groups. Success comes from the continuous development involved with the goal of totally transparent networks to IP traffic.		Mr Volker Leisse of EuroCableLabs


Mr Gary Ellis of ntl Home	Deploying VOD in Europe - Challenges, Optimisations & Results The Next speaker of the afternoon was Mr Gary Ellis of ntl Home. The launch of Video on Demand (VoD) in January 2005 followed ntl's NVoD service, and useful data from the old service was used to predict buying patterns for the new. With 8 million homes passed, 1.2 million customers with cable modems and another 250,000 on ADSL, ntl is the second largest Pay TV provider and has about 4 million pieces of equipment located in customers' homes. The service offers a Family Pack of 150 channels, a bunch of add-on premium channels, and additional services under the command of the "red button" such as TV-email that are based on the Cable Modem. Fitting VoD into the existing network required some upheaval. A National Head-End supplies the fibre optic ring network of 38 Regional Head-Ends that in turn supply 200 hubs from which the HFC networks fan out to typically 500 to 2000 homes. The National Head-End gathers together content from 18 satellite dishes with the national broadcasters supplying theirs via land-lines. The problem was how to overlay this network with VoD. The content is prepared from videotapes and transferred to disc storage, distributed by dedicated fibre, and unicasted out to Regional Head-End VoD servers. All 38 RHEs will have VoD capability by the end of 2006. Ethernet/DWDM delivery is used to the 200 hubs, each Gigabit Ethernet source delivers 200 streams to local QAM modulators that are located in the hub-sites generating a bunch of unique frequencies close to the customers premises. The advantage is that the set-top box does not have to change. Cost is determined by a mix of contention ratio, set-top box sales, video bit-rate and the bandwidth available at the network edges. These absolutely scale the system, and getting the contention ratio wrong means the customers go away because underestimating the maximum number of simultaneous users will mean the system falls down at peak demand times. Fortunately the NVoD service data could be used to indicate customer viewing habits, 13 months of NvoD purchases were analysed and a model created to determine the daily contention ratio. The old NvoD service used a 3.6Mb/S data rate with full resolution and this quality had to be maintained in the new service. MPEG-2 had to be used because of the 1.6M STBs out there, although MPEG-4 would have meant a 20% saving in bit-rate. Comparison tests using 72 observers were made using video material encoded at varying rates on a new, improved encoder and on the current 3.6Mb/S model. The results showed that the new encoders with their greater computing power could be set to 2.9Mb/S to give a substantial bandwidth saving. Sport items were not to be included in the new VoD service. A "Pick of the Week" service proved to be highly popular. It was free, and provided replays of some of the popular programmes broadcast by the five terrestrial services during the previous seven days. The children's TV programming also proved very popular, some of it was free and the remainder was on a very low charge. Music TV also ranked highly in popularity. The service started in Glasgow in January 2005 and over 400,000 VoD enabled homes were established with a further 80,000 added to date. The service, as a whole, has proved very popular, users soon learn to manage the controls easily, main choices being confirmed by the 'red button'. Interesting viewing patterns have emerged with movies making peak figures during the evening hours from 19:00 to 23:00 and on Sunday afternoons. The childrens' service, encouragingly, is little-used after 21:00, and adult-content material peaks after 23:00, tailing off towards 05:00. The predictions of contention ratio have proved accurate, but continuous monitoring of it is employed o produce an hour-by-hour picture of viewing habits. Of the "Pick of the Week" offerings, Doctor Who outclassed any others by a ratio of 2 to 1!

Standards and the AGM To finish the lecture meeting, SCTE President, Dr. Roger Blakeway, gave a summary of the situation regarding standards in the industry. After an overview of the standards bodies and the standards that affect the industry, he went on to give a view of the work currently being undertaken and its implications for the Society's members. Specific attention was paid to the New EMC Directive and its extension to cover installations as well as components and equipments. After Dr. Mark Burns closed the lecture meeting, the president convened the 60^th AGM of the Society. The minutes of the previous AGM and the Report to Members were accepted together with the Auditors Report and the Annual Accounts. The President made reference to the significant reliance on income from involvement in IBC and exhorted attendees to try to recruit more members to make the Society self reliant. The meeting agreed to re-appoint the existing Auditors. This years AGM saw a contest for vacant places on the Executive Committee, a hopeful sign of renewed interest in the Society. David Keeley, Mark Burns and David Woollard were re-elected and will be joined by new members Jon van Brienen and Costas Kyriacou. Following the formal AGM business an informal discussion of the results, so far, of the member survey and the implications for the future direction of the SCTE took place. The President thank all those who had filled in CTE Survey forms during the day and these would be added to those previously analysed and the full results presented in the December issue of CTE.		SCTE President, Dr. Roger Blakeway



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