The SCTE Spring Lecture Meeting, 2004.

"Converged Networks - The Future of Cable?" The SCTE's seventeenth full day lecture presentation took place on Tuesday 2 March 2004, chaired by Dr. Mark Burns. Graeme Young summarises the days presentations.

Presentations. Slideshows of the papers in zip format can now be downloaded. Right click on the name of the paper and select 'save target as...' When unzipped the presentations are Acrobat files except for the Filtronic presentation which is a Powerpoint slideshow. Please note, these are big files and will take some time to download.

	TV from your Phone Socket: Coming Soon to a Wall Near You David Price, Vice-President of Business Development at Harmonic Inc. As bandwidth requirements diminish because of advances in compression techniques, the availability of bandwidth has increased because of DWDM, DOCSIS and 802.18. Video is driving the advances and is now available throughout the home and in the car and on the mobile 'phone. DSL technology designed for video transport still has a problem of reach in the local loop and of restricted bandwidth. The requirements are for a low bit rate that will deliver broadcast-quality signals in order to be competitive with Terrestrial, CATV and Satellite broadcasting. Advanced services available on DSL must include iTV, VoD, IPPV, and HDTV over simultaneous multi-service streams. DSL is seen as the 'last mile' delivery platform, its various guises being VDSL, ADSL, ADSL2 and ADSL2+. The transport, distribution and access network is ideally IP over ATM as best choice. ADSL2+ qualities include operability over longer local loops to 3kM. MPEG4 provides a real improvement in the SNP required by 4dB with a bit-rate of 2.8Mb/S, 1Mb/S of this is Internet Protocols.

IP Network Enabled Converged Service Gerry White, a Senior Director of Motorola BCS, forecast that the cable infrastructure would build to embrace symmetrical services with Voice over IP, Packet Cable and SIP. The advantage of a converged voice and data-borne range of services will be the convenience of a single bill, Caller Identification delivered to the TV or the PC, Unified Messaging, and a VoD backbone based on IP Gb Ethernet. 20 years ago the challenge was how to put data over voice networks. To-day the challenge is to find the best way to put voice over data networks! Gerry went on to consider the merits of MPLS, L2 Ethernet, RPR/SONET, Point-to-point Optics, HFC Networks and DOCSIS1.1 VN.

	Improving DOCSIS Network Reliability through I Protocol Analysis Brady Volpe, Director of Technical Marketing at Filtronic Sigtek Inc., looked at the working model of a DOCSIS Network. Between three and five percent of DOCSIS modems are offline at any one time. DOCSIS failures may be traceable to RF impairments or may be due to individual modems. Troubleshooting the RF plant is a fairly straightforward matter using traditional test methods and equipment. Problems involving DOCSIS are complicated because normal test methods look at all Cable Modems simultaneously. A DOCSIS Protocol Analyser can address individual Modems.

HFC Broadband Telecommunication Systems - Evolution or Revolution? Oleh Sniezko, CTO of Aurora Networks, asked whether HFC Broadband Telecommunications Systems were in Evolution or Revolution. Certainly converged networks were The Future of Cable. VoIP growth occurs mainly in the business sector. On HFC networks VoIP is showing good signs of growth whereas Broadband is growing only steadily. HFC networks are very successful because of the optical fibre backbones providing high quality signals to short-reach HFC distribution networks. Confusion exists today over the direction they should take next - Digital only, A la carte Services, VoIP, Video Streaming etc. Architectures similarly pose a problem, do we go for HFC, Fibre to the Kerb or Fibre to the Home? Oleh presented Aurora's solution to rapid deployment of robust fibre networks.

	Laser Load Testing Using Analogue Or Digital Carriers Costas Kyriacou, Lab Manager (RF/Optical) at TELEWEST, revealed his work on Laser Load Testing using Digital or Analogue carriers. In a day of interesting papers this technical exposition of the optimum performance of laser transmitters under differing drive conditions was attention-grabbing in the extreme. Costas took us through the entire processes of laser testing to establish optimum output levels beginning with the determination of the correct bias current to ensure high linearity. The effects of over-driving the laser were clearly demonstrated and the sharp rises in CSO and CTB products became absolutely vivid. The calculation of OMI was explained and from the formula the Laser Loading, ideal drive level and maximum possible loading can be calculated. For a 48-channel Analogue loading the ideal laser drive level would be from 21 to 24 dBmV/Carrier, obtained by analysis of the CO, CTB and CNR performance. For a 48-channel digital (64 QAM) loading, analysis of the MER performance the ideal laser drive level would be from 21 to 26 dBmV/Carrier (peak at 24dBmV/Carrier). Figures for a 12 carrier loading for analogue and digital carriers were also shown and the effects of a migration to 256QAM that revealed, surprisingly, little or no change in the optimum drive levels.

The SCTE in Pakistan The final presentation of the day was from Dr Uzair A Khan, Managing Director of Computer Weekly of Pakistan. Dr Khan has been responsible for the establishment of the SCTE in Pakistan, from which starting-point the Society's training courses will be made available. The lack of proper training and instruction has inhibited the success of many of the Cable TV Networks operating in the country. Over 3000 cable operators employ over 100,000 professionals in the cable telecommunication sector and there is an insatiable need for entertainment and information provision in the country. Now there are plans to expose the Pakistani industry to the international market by organising an exhibition at which UK, European and US companies producing and selling CATV hardware will be in attendance. Within this exhibition will be fully working laboratory enabling Industry to experience products hands-on. The involvement of the Pakistan Electronic Media Regulatory Authority, Ministry of Science and Technology and COMSTEC, Cable Companies from the Middle East and Asia is being sought.

	Once again, the SCTE lecture meeting provided a day of interest and stimulation. Our presenters are to be congratulated for the effort they put into the presentations. In addition to the lectures, the day provided an excellent opportunity for informal discussions with old friend and new colleagues.


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