The need for Edge QAM

The "Edge QAM" came to existence with Switched Digital Video (SDV). Prior to SDV, QAM modulation was used in cable plants to carry all digital cable services. It sits in hub and is used to move video, voice and data from headends to homes. Each QAM, in a rack-mounted metal box, is capable of carrying 38.8 Mbps of downstream data which is equivalent to one analog channel, 2-3 High-Definition (HD) streams, or 10-12 Standard-Definition (SD) digital video streams.

Even though all QAM use the same architecture, each QAM is dedicated to a specific service. For example, one QAM is used to move Web pages to your cable modem, while another one is assigned to move the digital video channels to your HDTV. Likewise, a QAM dedicated to video on demand (VOD) could not be used for Switched Digital Video (SDV). Hence, the cable operators had to purchase QAM based on services they wanted to provide.

This fundamental issue, created the need for building "Edge QAM", which by definition is capable of carrying both VOD and SDV streams. The next generation Edge QAM will be able to carry IP related services, such as data (Internet service) and voice (VoIP service) in addition to VOD and SDV.

The Players

Some of major vendors of Edge QAM are, Scientific Atlanta/Cisco, RGB Spectrum, Arris, BigBand Networks, Harmonic, Motorola.

The cable operator evaluate the Edge QAM based on three objectives, Price, Density and Openness. With respect to price, currently the QAM are in range on $250. The goal is to reduce to price to $25 range. With respect to density, currently one rack-mounted unit can take between 8-24 QAMs. The cable operators expecting new innovation will increase the density which will ultimately bring the price down. With respect to openness, the cable operator are looking for vendors that eventually can adopt standards protocols.

Functionality

In order Edge QAM move VOD and SDV streams to homes, it needs to communicate with two other device in the network. The "Session Manager", which sets up the linkage between VOD/SDV server and Set-Top-Box and acts upon selecting a channel by viewer. The "Resource Manager", which determines which QAMs are supposed to be moving what stuff and to where. Also see SDV Architecture and IPTV - The software behind SDV for more information.

Currently, the devices are tightly coupled, meaning that they work on propriety protocols. Each manufacturer has developed it's own protocol which makes cable operators bound to purchase set of devices from same vendor. New standard is underway to make the communication protocols between devices consistent. This will create competition among vendors to cut the prices, since cable operators will be able to purchase their devices from multiple vendors. A switch from vendor, a resource manager from another and a session manager from yet a different vendor.

About me:
bruce atlasi is a professional computer engineer, skilled in telecomm and datacomm technologies and architecture. He has diverse working experience with many telecomm start-ups and fortune 100 companies, including Cisco Systems, IBM, and Siemens. He regularly blogs on About Hi-Tech site.

Launching and maintaining successful IPTV services

IPTV operation is booming worldwide at a rapid pace. In Europe alone the IPTV subscribers is more than 1.535 millions. Ever since YouTube began demonstrating the potential of the Internet medium, everyone is racing to launch IPTV, which will eventually replace traditional television broadcasting.

Following some fundamental guideline can help launching and maintaining successful IPTV services. The following outlines some of these guidelines:

• Simplicity. Make the services very simple and easy to use. Providing innovative services, but as simple as possible will appeal to a wider audiences covering youngest, Internet savvy generation through oldest grandpa and grandma generations.

• Packaged Services. Triple-Play package provides TV, Internet and voice all in one deal. The triple-play can also bolsters operational continuity.

• Content delivery Services.

1. Content delivery to TV, PC and Mobile devices
   
2. Exclusive content and features for certain viewers with common interest, such as major/minor league football games
   
3. Interactive options to access real-line match stats, such as goal count, attempts, and cards
4. On-demand titles
5. International television programs
   
6. Ability to transfer downloaded content to mobile device
   
7. Hybrid IPTV/Satellite service
   

• Quality of Services. Quality of Service is one of the most important reason for successful IPTV operation. People will not tolerate poor quality of service or any quality inferior to other pay-TV services such as satellite.
  

• Super fast broadband network. FTTH (Fiber-To-The-Home) provides much more bandwidth and enabling ability to offer high-definition, added-value services and whole home distribution. ATT recently introduced Total Home DVR, which allows delivery of five simultaneous high-definition MPEG-4 video streams around the home - two live and three recorded from DVR, for it's IPTV service via copper VDSL network.

About me:
bruce atlasi is a professional computer engineer, skilled in telecomm and datacomm technologies and architecture. He has diverse working experience with many telecomm start-ups and fortune 100 companies, including Cisco Systems, IBM, and Siemens. He regularly blogs on About Hi-Tech site.

Attacking IPTV QoE issue

One of the most critical challenges of IPTV cable operators is to provide quality of service to their viewers. Since IPTV uses IP networking mechanism to reach the subscribers, many artifacts of Internet can cause poor Quality of Experience (QoE) to viewers, which leads decreased customer satisfaction and increased customer complains through call centers. It is very essential for IPTV operators to resolve QoE issues, in order to increase customer satisfaction and be able to maintain customers for long run.

A recent study shows that QoE accounts for more than 25% of IPTV adaptation obstacles. The other obstacles include, high subscriber fee - equipment (19%), lack of completing programs (15%), satisfied with existing programs (12%), compelling offers from competitions (11%), high subscriber fee - content (11%), poor customer service and support (6%), others (2%).

One of the most common culprit of poor QoE is packet loss, a normal occurrence in any IP network. packet loss happens for many reasons in variety of different locations. There is no way for an IPTV operator to protect the network against all possible causes and different location of packet losses. many packet losses occur in last mile which makes it even more difficult for IPTV operator to detect and address the problem. The following outlines some of common reasons for packet loss:

• Environmental effect, such as home appliances and electrical public transportation systems
• Congestion which normally happens on prime time viewing time
• Bad wiring at customers premises
  
• Heterogeneous network equipment
• Out of sequence packets
• Duplicate packets
• Core network issues, such as lost network links and route convergence
  

Some other reasons which can impact QoE follows:

• Mismatch TSID to service group configuration
• RF interference on specific frequency/QAM channels
• Reed-Solomon error correction efficiency
• Over-subscription/blocking of SDV QAM channels
• Mini-carousel distribution and configuration
• Grooming/muxing issues at the edge QAM device

Solving packet loss issue

One of the simplest, most effective, and least expensive way of correcting packet loss issue is to deploy a layer of software that detects and corrects the packet losses on the fly from the video stream that is being received by customer. The software recovers the packet losses using an algorithm that generates the missing packets and sends them along with the original video content to customer set-top-box which in turn repairs the video before showing it on the customer's monitor.

The followings outlines some of the benefits this software solution that can bring to IPTV operators:

• Scalability - once installed on the headend, it supports an unlimited number of set-top-boxes
  
• Fixes all loss types, regardless of single or multiple events or where it comes from
• Configurable network overhead, with granularity of one packet
• Configurable latency
  

About me:
bruce atlasi is a professional computer engineer, skilled in telecomm and datacomm technologies and architecture. He has diverse working experience with many telecomm start-ups and fortune 100 companies, including Cisco Systems, IBM, and Siemens. He regularly blogs on About Hi-Tech site.