Computing Now Exclusive Content — August 2010

News Archive

July 2012

Gig.U Project Aims for an Ultrafast US Internet

June 2012

Bringing Location and Navigation Technology Indoors

May 2012

Plans Under Way for Roaming between Cellular and Wi-Fi Networks

Encryption System Flaw Threatens Internet Security

April 2012

For Business Intelligence, the Trend Is Location, Location, Location

Corpus Linguistics Keep Up-to-Date with Language

March 2012

Are Tomorrow's Firewalls Finally Here Today?

February 2012

Spatial Humanities Brings History to Life

December 2011

Could Hackers Take Your Car for a Ride?

November 2011

What to Do about Supercookies?

October 2011

Lights, Camera, Virtual Moviemaking

September 2011

Revolutionizing Wall Street with News Analytics

August 2011

Growing Network-Encryption Use Puts Systems at Risk

New Project Could Promote Semantic Web

July 2011

FBI Employs New Botnet Eradication Tactics

Google and Twitter "Like" Social Indexing

June 2011

Computing Commodities Market in the Cloud

May 2011

Intel Chips Step up to 3D

Apple Programming Error Raises Privacy Concerns

Thunderbolt Promises Lightning Speed

April 2011

Industrial Control Systems Face More Security Challenges

Microsoft Effort Takes Down Massive Botnet

March 2011

IP Addresses Getting Security Upgrade

February 2011

Studios Agree on DRM Infrastructure

January 2011

New Web Protocol Promises to Reduce Browser Latency

To Be or NAT to Be?

December 2010

Intel Gets inside the Helmet

Tuning Body-to-Body Networks with RF Modeling

November 2010

New Wi-Fi Spec Simplifies Connectivity

Expanded Top-Level Domains Could Spur Internet Real Estate Boom

October 2010

New Weapon in War on Botnets

September 2010

Content-Centered Internet Architecture Gets a Boost

Gesturing Going Mainstream

August 2010

Is Context-Aware Computing Ready for the Limelight?

Flexible Routing in the Cloud

Signal Congestion Rejuvenates Interest in Cell Paging-Channel Protocol

July 2010

New Protocol Improves Interaction among Networked Devices and Applications

Security for Domain Name System Takes a Big Step Forward

The ROADM to Smarter Optical Networking

Distributed Cache Goes Mainstream

June 2010

New Application Protects Mobile-Phone Passwords

WiGig Alliance Reveals Ultrafast Wireless Specification

Cognitive Radio Adds Intelligence to Wireless Technology

May 2010

New Product Uses Light Connections in Blade Server

April 2010

Browser Fingerprints Threaten Privacy

New Animation Technique Uses Motion Frequencies to Shake Trees

March 2010

Researchers Take Promising Approach to Chemical Computing

Screen-Capture Programming: What You See is What You Script

Research Project Sends Data Wirelessly at High Speeds via Light

February 2010

Faster Testing for Complex Software Systems

IEEE 802.1Qbg/h to Simplify Data Center Virtual LAN Management

Distributed Data-Analysis Approach Gains Popularity

Twitter Tweak Helps Haiti Relief Effort

January 2010

2010 Rings in Some Y2K-like Problems

Infrastructure Sensors Improve Home Monitoring

Internet Search Takes a Semantic Turn

December 2009

Phase-Change Memory Technology Moves toward Mass Production

IBM Crowdsources Translation Software

Digital Ants Promise New Security Paradigm

November 2009

Program Uses Mobile Technology to Help with Crises

More Cores Keep Power Down

White-Space Networking Goes Live

Mobile Web 2.0 Experiences Growing Pains

October 2009

More Spectrum Sought for Body Sensor Networks

Optics for Universal I/O and Speed

High-Performance Computing Adds Virtualization to the Mix

ICANN Accountability Goes Multinational

RFID Tags Chat Their Way to Energy Efficiency

September 2009

Delay-Tolerant Networks in Your Pocket

Flash Cookies Stir Privacy Concerns

Addressing the Challenge of Cloud-Computing Interoperability

Ephemeralizing the Web

August 2009

Bluetooth Speeds Up

Grids Get Closer

DCN Gets Ready for Production

The Sims Meet Science

Sexy Space Threat Comes to Mobile Phones

July 2009

WiGig Alliance Makes Push for HD Specification

New Dilemnas, Same Principles:
Changing Landscape Requires IT Ethics to Go Mainstream

Synthetic DNS Stirs Controversy:
Why Breaking Is a Good Thing

New Approach Fights Microchip Piracy

Technique Makes Strong Encryption Easier to Use

New Adobe Flash Streams Internet Directly to TVs

June 2009

Aging Satellites Spark GPS Concerns

The Changing World of Outsourcing

North American CS Enrollment Rises for First Time in Seven Years

Materials Breakthrough Could Eliminate Bootups

April 2009

Trusted Computing Shapes Self-Encrypting Drives

March 2009

Google, Publishers to Try New Advertising Methods

Siftables Offer New Interaction Model for Serious Games

Hulu Boxed In by Media Conglomerates

February 2009

Chips on Verge of Reaching 32 nm Nodes

Hathaway to Lead Cybersecurity Review

A Match Made in Heaven: Gaming Enters the Cloud

January 2009

Government Support Could Spell Big Year for Open Source

25 Reasons For Better Programming

Web Guide Turns Playstation 3 Consoles into Supercomputing Cluster

Flagbearers for Technology: Contemporary Techniques Showcase US Artifact and European Treasures

December 2008

.Tel TLD Debuts As New Way to Network

Science Exchange

November 2008

The Future is Reconfigurable

Signal Congestion Rejuvenates Interest in Cell Paging-Channel Protocol

by George Lawton

The unexpected signaling demand of smart phones has forced network operators to rethink network engineering and dust off an old protocol to keep networks flowing. Although attention has traditionally focused mostly on payload bandwidth, signaling bandwidth has been growing at a much faster rate. Many experts believe the 3G Partnership Projects (3GPP) cell paging-channel (Cell_PCH) protocol could help solve the problem.

The 3GPP included the protocol with the current mobile-phone specification three years ago, but until recently, carriers and vendors saw little benefit in implementing it. All of that changed with a new technique for conserving smart-phone battery power, which increased the network signaling load by up to five times, noted Phil Twist, head of marketing and communications for Nokia Siemens Networks.

The widespread adoption of Cell_PCH promises to extend battery life, while also keeping the signaling load manageable. In some cases, mobile operators could save 45 million euros by simply turning on Cell_PCH, rather than installing new switching infrastructure, said Twist.

Reports of trouble with the iPhone in New York and San Francisco have highlighted congestion problems. Although neither Apple nor ATT has publicly disclosed the source of these troubles, Michael Thelander, CEO of Signals Research Group, a wireless research consultancy, said the reports match a pattern of signal congestion. A signal congestion problems affects all the traffic in a larger region served by a radio network controller (RNC), whereas a payload-congestion problem would be isolated to data traffic in one small area.

"Part of the problem," Thelander said, "is that people designed networks to scale for data and not signaling."

Understanding Cell Signaling

There are four cell phone signaling states used in a 3G network: idle, forward-access channel (FACH), data channel (DCH), and paging channel (PCH).

In the idle state, which uses the least power, the network knows the phone is on and near a cell tower but doesn't know exactly where. The cell phone can use DCH for transmitting large quantities of data, but it consumes the most power. Cell_PCH can send many short messages efficiently, while keeping battery levels on par with the idle state. It's also far more efficient in terms of the number of signaling messages required to set up and tear down a short data session.

In terms of power usage, Twist said that DCH consumes 200–300 mA of power, compared with 150 mA for FACH, and 5 mA for both idle and PCH. For operators, the main issue is the number of signaling messages to go between different states. Up to 30 messages are required to go from idle to DCH compared to only seven messages between PCH and DCH. Cell_PCH also reduces the time required to set up a call from two seconds for fast dormancy to only a half second.

The Smart Phone "Fix"

When smart phones were first released, Cell_DCH was the only widely available protocol for sending short messages. First-generation iPhones burned through their batteries as they maintained a constant data connection throughout the day.

All this changed in June 2009, when Apple released the iPhone OS 3.0, which supported fast dormancy. The phone could quickly shut down its network connection to significantly increase battery life, but it had the side effect of increasing signaling traffic.

"Usually we had to worry about overall traffic growth," said Woojune Kim, vice president of advanced technology at Airvana. "But we found that the signaling component of traffic was growing the most significantly. As the smart phones became pervasive, they were generating more connections while sending less data."

Cell_PCH promises to help keep battery life down, while reducing signaling load. In one set of tests, Thelander found that it could reduce signaling load by 20 to 40 percent. "With Cell_PCH," he said, "you're reducing signaling rather than adding capacity. It's a more intelligent means of solving the signaling problem."


PCH faces many challenges that will slow its adoption. Steve Kemp, Alcatel-Lucent director of wireless marketing, said many operators haven't adopted it. Reasons include a lack of load-balancing functionality in the Cell_PCH state, the latency to resume transmission, and incompatibility with user equipment. He also noted that many of the fast-dormancy features built into existing smart phones might defeat the benefits of Cell_PCH.

Thelander said the transition can be taxing to mobile operators. They need to test all of the equipment and ensure that it doesn't interfere with normal communications processing. "This could mean that what is 'simple,' actually ends up being quite complex and time consuming," he said.

Despite the challenges, Kemp expects most issues to work themselves out by 2011 with widespread adoption Cell_PCH to follow. In the long run, Cell_PCH will lose importance as 3GPP's Long-Term Evolution (LTE) 4G technology comes to market. LTE is much more efficient at managing signal congestion.

George Lawton is a freelance correspondent in Guerneville, California. You can contact him via his website