Cupria QOS for video over IP


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Whitepaper defining how superior video performance assurance is engineered into the IP protocol stack for Cupria's unique DSL transport chipset

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Cupria QOS for video over IP

  1. 1. Innovation at the network edge APPLICATION NOTEfor enhanced service deliveryand carrier competitiveness . . . QOS & Quality of User Experience for IPTV Services Pure IP Triple Play High-Fidelity IP using Internet Protocol Subscriber Line TM QoS Challenge forThe Cupria Advantage Cable-Competitive Triple-PlayRim Semiconductor - a fabless IC manufacturingfirm – is building “System on a Chip” ICs that QoE – Quality of User Experiencedeliver networking solutions instead of componentdesigns. As such, we are delivering industry-leading innovations in DSP architecture focused © Copyright 2006 (rev1.1b) Rim Semiconductor Companyexplicitly on xDSL applications for the wireline all rights reserved - 503 . 257 . 6700carrier.
  2. 2. xDSL INNOVATION USING CUPRIA Pure IP Triple Play The importance of making a robust, reliable access transport technology available cannot be overstated. The VP in charge of network planning at one of the largest US telcos expressed concern about delivering premium services over xDSL because they were continuously challenged in making their 5Mbps DSL work reliably. Their business plan for 3-tiered DSL service was working fine for the bronze and silver subscribers at 1.5 and 3 Megs respectively, but that service interruptions at 5 Megs was intolerable. So if today’s DSL transport at 5Mbps and higher is not reliable, how could they realistically expect to extend their access network to serve an IPTV strategy? IPTV Work-Arounds Another way to describe our thinking on Cupria is to ask the question, “If you were going to design a new video-over- copper solution for the access network, would it end up looking like toady’s VDSL2?” Repeatedly we have been told by carriers that no, VDSL2 is merely a patched-up VDSL that still cannot deliver the fundamental advances in bandwidth payload, copper reach, and quality of service that a cable-competitive IPTV deployment will require. In 2006, the dominant IPTV installations in actual deployment are using ADSL2+ serving Fig 1 – VDSL2 cobbled as a work-around solution vs. Cupria 18Mbps out to only 3Kfeet and similar numbers are being used for VDSL2 planning. We believe a robust IPTV access network must be planned for 26Mbps serving 6Kfeet. IP-only environment using “Internet Protocol Subscriber Line” One of our objectives in designing a broadband over copper solution form the ground up was to provide an IP-only environment free of the complexities of ATM. We believe that the clearly emerging trend for an all- IP access network makes the most sense for both carriers and equipment makers – and provides the quickest path to making broadband over copper as reliable as POTS. However reliability alone is useless if the payload bandwidth capacity is not large enough to accommodate the multimedia traffic that carriers need to become cable-competitive. Our target service capacity is 26Mbps of Ethernet payload. We believe this is adequate to support the next 20 years of domestic household requirements for voice, video, and data. Rim Semiconductor Company page 2 of 4
  3. 3. xDSL INNOVATION USING CUPRIA Internet Protocol Subscriber Line - IPSL The optimized performance of the Cupria family of transport processors is achieved using a next-generation xDSl protocol we call “Internet Protocol Subscriber Line”, or IPSLTM. The unique qualities of IPSL enhance the ability of the telco to deliver Triple Play Services over existing copper lines by using these features: • Time Division Duplexing - TDD • Rapid Bi-Directional Switching • Adjustable Downstream / Upstream Data Rates • PSD Masks adjustable across the copper spectrum • Adjustable Power Boost within each spectrum band to auto-adapt to NEXT / FEXT • Shorter xDSL frame size • -150 dBm/Hz noise floor (auto-adaptive) • Higher processing efficiency • Reed / Soloman forward error correction • Trellis Coding equalization • Adaptive Equalization • Optimized IP Link & SAR providing four levels of traffic prioritization • Triple-Play grooming of the voice, video, and data streams at the Phy layer The Network QOS Challenge for Triple-Play Originally the copper access network was engineered to support the voice intolerance for audible delay, and to compromise bandwidth requirements with an acceptable level of noise in the circuit. Emerging data requirements flipped this priority in QOS for the copper loop – and ATM provided an ideal method for assuring both data and voice QOS. However today’s emergence of IPTV brings a third – and most demanding – intolerance of both noise and delay. Ethernet data packets will easily re-transmit and re- assemble to make up for noise-induced packet loss. But streaming video cannot tolerate IP delay, which results in picture break-up and/or MPEG artifacts. Delivering a cable-competitive grade of digital video service will mandate that the access loop be engineered to deliver a Bit Error Rate of at least 10 -9 (which delivers an annoying picture artifact every 6 minutes for a 3Mbps SDTV stream). Cupria’s adoption of a Pure-IP transport approach helps bridge the gap Fig 2 – Unique QOS constraints for the video access network in today’s network performance to make cable-competitive IPTV both technically and financially feasible for the copper carrier Rim Semiconductor Company page 3 of 4
  4. 4. xDSL INNOVATION USING CUPRIA QoE – Quality of User Experience The fate of IPTV will hinge on the quality of digital video picture and sound that can be extended across the copper plant. For subscribers to endorse IPTV and switch form cable, the carrier cannot afford to invest in a less than cable-competitive level of image quality. For HDTV, the MPEG4 payload must be 8 to 10 Mbps per channel Fig 3 – MPEG artifacts resulting from packet-loss – with up to three can jeopardize carriers’ ability to effectively compete channels simul- with cable television service taneously served per home, each with a bit-error rate lower than 10 -9. And this performance must be maintained when two VoIP lines are in use and the kids are also downloading music at 1.5Mbps via the internet. Once MPEG artifacts – induced by jitter, latency, and packet errors – are introduced at the Phy layer of the protocol stack, they are uncorrectable Fig 4 - IP Artifacts Irretrievably all the way up the stack. Thus the impact of the xDSL transport device is Embedded in the Protocol Stack of utmost importance in delivering cable-competitive services. Dynamic Bandwidth Management (DBM) Essential to preserving image quality is the adaptive DBM built into Cupria’s DSP. We achieve this by integrating routing functionality to groom the voice, video, and data streams. Rather than leave the control of these streams to the random intelligence of the modem or STB maker, the Cupria phy will assure preservation of video integrity with a minimum Bit Error Rate, accommodate VoIP traffic accordingly, and prioritize internet traffic to not interfere with either the voice or video streams. The QOS functionality provided by IPSL at the CPE within the DSP Fig 5 – “System-on-a-Chip” feature integration consists of: • DiffServ tagging • Dynamic Bandwidth Management for each voice, video, and data channel • Outbound grooming of each discrete channel using an integral routing capability • Optimized IP SAR for reduced latency and jitter to minimize BER in the video stream Meeting the Challenge The access network engineer has never faced such daunting performance requirements. ADSL is at best, a best-effort service while T1 is a constant struggle to preserve with 30% of T1 lines requiring a truck-roll every year. Cupria is anticipating and solving the video access challenge to make IPTV a quality user experience for both the subscriber and the wireline network engineer. Rim Semiconductor Company page 4 of 4