DSL Prime: Technology Advances

DSL Prime reports that the technology is continuing to improve, but some of the innovators are shedding jobs.

by Dave Burstein DSL Prime [August 20, 2004]

"Bell Labs is like a ghost town. They now have 1,500 people where they once had 8,000, with several hundred more soon to leave."
—a recent visitor. We can't afford to let the research die.

1 in 5 Go at Conexant/Globespan
Happy days not all here
A fast 70 percent drop in stock price gave Armando Geday little choice but to fire much of the team built up over years and hundreds of millions of dollars in acquisitions. CFO Robert McMullan, also "resigned for personal reasons." 300 more will leave shortly, after 200 earlier this year. Conexant maintains a strong position with customers and in technology, with many reasons for optimism.

Lots of encouraging news lately, with job opportunities up, record attendance at trade shows (Pulver is sold out for exhibitors at Fall VON) and even some encouragement in stock prices. Reality, however, is not that attractive. Merrill Lynch predicts global capex spending flat in 2004, and slightly down in 2005 and 2006. DSL will grow in sales and share, most likely, but unless the carriers are spending that will be limited. So I'll keep my employment ads free until the end of the year to encourage folks, and I'm glad I have below open positions at TI and Centillium that might be right for some of the Globespan people.

Power Down, Minimum Rate, Bonding, and Everything VDSL2
Crucial choices presenting in D.C.
Carriers need much higher speeds for video offerings, and they can't afford to fall behind cable going to 30 Mbps and higher. That demand has created an urgency to complete VDSL2. T1E1.4 under Tom Starr has defined the DSL standards since the 1990's and remains a key forum, along with ITU SG15/Q4 and emerging Asian alternatives. Ideas coming to the Washington meeting include:

• Dong Wei's simulation results showing "that the application of advanced coding techniques to VDSL2 leads to considerable improvement in rate-reach performance." One key chip vendor has lately argued that requiring more computing power will add cost and delay, while others believe the improved performance is necessary.
  
  
• Alcatel and ST, responding to the video requirements of several customers, led an effort in ITU for "a fixed rate or minimum rate service. The purpose of this tool is to avoid retrains and excessive errored periods and assure service stability based on anticipated service penetration or noise environment defined by the operator." Whether this is a practical or only theoretical problem is unproven, but faster retrains/recovery is certainly to the point.
  
  
• Rethinking of power-down modes. It seemed a no-brainer to reduce power and interference when the user is not actively sending data, capabilities included in the ADSL2 and VDSL2 standards. Some think it will be difficult to implement, because powering up and down affects the other lines in the binder, and creates problems like video dropouts on retrains. One group is recommending a new L2 power saving mode for VDSL2 that does not require the transmission and storing of long B&G tables. DSL Prime believes these are powerdown issues are problems to solve rather than a reason to abandon the goal. The savings are potentially substantial. A few dollars per year per subscriber for electricity adds up for a bell, and is critical in India and China where the goal is to price DSL below $10/month to reach a larger market.
  
  
• The basic band plan for VDSL2, with major implications for the upstream and downstream rates. Framing and interleaving need to be resolved.
  
  
• Whether the tone spacing should be halved.
  
  
• How to incorporate DSM and MIMO. Both have significant value at the 3,000 to 5,000 feet North American telcos are planning for their networks.
  
  
• Resolving remaining issues in the bonding proposals, critical to extend video reach for HD and multiples TV sets.

Copyright 2004 Dave Burstein.
The DSL Prime Newsletter is reprinted with permission.

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