Posts Tagged ‘Fiber optic’

Huawei sends 400Gbps over next-generation optical network

Thursday, December 26th, 2013

Huawei Technologies and Polish operator Exatel have tested a next-generation optical network based on WDM (Wavelength Division Multiplexing) technology and capable of 400Gbps throughput.

More data traffic and the need for greater transmission speed in both fixed and wireless networks have consequences for all parts of operator networks. While faster versions of technologies such as LTE are being rolled out at the edge of networks, vendors are working on improving WDM (Wavelength-Division Multiplexing) to help them keep up at the core.

WDM sends large amounts of data using a number different wavelengths or channels over a single optical fiber.

However, the test conducted by Huawei and Exatel only used one channel to send the data, which has its advantages, according to Huawei. It means the system only needs one optical transceiver, which is used to both send and receive data. That, in turn, results in lower power consumption and a smaller chance that something may go wrong, it said.

Huawei didn’t say when it expects to include the technology in commercial products.

Currently operators are upgrading their networks to include 100Gbps links. That increased third quarter spending on optical networks in North America by 13.4 percent year-over-year, following an 11.1 percent increase in the previous quarter, according to Infonetics Research. Huawei, Ciena, and Alcatel-Lucent were the WDM market share leaders, it said.

Source:  networkworld.com

Corning taps into optical fiber for better indoor wireless

Monday, May 20th, 2013

Bringing wireless indoors, which was once just a matter of antennas carrying a few cellular bands so people could get phone calls, has grown far more complex and demanding in the age of Wi-Fi, multiple radio bands and more powerful antennas.

DAS (distributed antenna systems) using coaxial cable have been the main solution to the problem, but they now face some limitations. To address them, Corning will introduce a DAS at this week’s CTIA Wireless trade show in Las Vegas that uses fiber instead of coax all the way from the remote cell antennas to the base station in the heart of a building.

Cable-based DAS hasn’t kept up with the new world, according to the optical networking vendor. Though Corning is associated more often with clear glass than with thin air, it entered the indoor wireless business in 2011 by buying DAS maker MobileAccess. That’s because Corning thinks optical fiber is the key to bringing more mobile capacity and coverage inside.

The system, called Corning Optical Network Evolution (ONE) Wireless Platform, can take the place of a DAS based fully or partly on coaxial cable, according to Bill Cune, vice president of strategy for Corning MobileAccess. Corning ONE will let mobile carriers, enterprises or building owners set up a neutral-host DAS for multiple carriers using many different frequencies.

Though small cells are starting to take its place in some buildings, DAS still has advantages over the newer technology, according to analyst Peter Jarich of Current Analysis. It can be easier to upgrade because only the antennas are distributed, so more of the changes can be carried out on centralized gear. Also, small cells are typically deployed by one mobile operator, and serving customers of other carriers has to be done through roaming agreements, he said.

However, some DAS products based on coaxial cable are limited in how they can handle high frequencies and MIMO (multiple-in, multiple-out) antennas, Jarich said. Some vendors are already promoting fiber for greater flexibility and capacity, he said.

Going all fiber — up to the wireless edge, at least — will make it easier and cheaper for indoor network operators to roll out systems that can deliver all the performance users have come to expect from wireless networks, according to Corning. That includes more easily adding coverage for more carriers, as well as feeding power and data to powerful Wi-Fi systems that can supplement cellular data service, the company says.

Wireless signals don’t travel the same way inside buildings as they do outdoors, so one antenna can’t always cover the interior, regardless of whether it’s mounted in the building or on a nearby tower. A DAS consists of many antennas spaced throughout a structure, all linked to a base station in a central location. Most types of DAS use coaxial cable to carry radio signals in from the distributed antennas.

However, those copper cables get more “lossy” as the frequencies they have to carry get higher, meaning they lose a lot of their signal on the way to the base station, Corning’s Cune said. That has left coax behind as new frequencies are adopted, he said. For example, coax isn’t good at carrying the 5GHz band, which is crucial in newer Wi-Fi equipment, Cune said.

MIMO, a technology that uses multiple antennas in one unit to carry separate “streams” over the same frequency, is another big limitation of DAS, according to Corning. MIMO antennas for better performance can be found in newer Wi-Fi gear based on IEEE 802.11n and 802.11ac, as well as in LTE. A coax-based DAS with MIMO antennas needs to have a separate half-inch-wide cable for every stream, which is a major cabling challenge, Cune said.

Corning ONE links each antenna to the base station over optical fiber, converting the radio signals to optical wavelengths until they reach the base station. Fiber has more capacity than coax, can handle higher frequencies, and requires just one cable from a MIMO antenna, Cune said. Because of fiber’s high capacity, it’s relatively easy to bring other mobile operators onto the DAS.

The system is based on optical fiber, but it can be extended over standard Ethernet wiring to provide backhaul for Wi-Fi access points. Each Corning ONE remote antenna unit that’s deployed around a building will have two Ethernet ports to hook up nearby Wi-Fi access points, which can use the fiber infrastructure for data transport to wired LAN equipment, Cune said.

Corning ONE is in beta testing at one enterprise and will have limited availability beginning in late June, after which orders can be placed, Cune said. It is expected to be generally available two to three months later. The company expects its main customers to be mobile operators, though most of those operators will arrange multi-carrier services, he said. Enterprises and large building owners increasingly will step in to buy and deploy the DAS, Cune said.

Source:  networkworld.com

AT&T Labs pumps 495Gbps of data over 7,400 miles

Thursday, March 14th, 2013

It’s a new record for long-distance network speeds.

AT&T Labs researchers are set to present data from a recent test that set a record for long-distance network speeds at the Optical Fiber Communication and National Fiber Optics Engineers Conference (OFC/NFOEC) on March 19.

The researchers, led by AT&T researcher Xiang Zhou, have perfected a technology that allows existing 100 gigabit-per-second fiber connections to be used to transmit over four times as much data. When used with a new low-loss optical fiber, they can sustain that data rate at distances over 7,500 miles. The new technology could dramatically increase the amount of bandwidth on the Internet’s backbone, especially over submarine cables that connect the continents.

The transmission system developed by Xiang Zhou’s team uses a new modulation technique that allows for the tuning of the signal to get the most out of available bandwidth. In the test data being presented next week, the researchers used a recirculating transmission test platform using 100-kilometer fiber cable segments to demonstrate that they could multiplex eight 495Gbps wave-division multiplexed signals with 100GHz of space between them over a distance over 12,000km (7,456.45 miles).

In a statement published by the organizers of OFC/NFOEC, Xiang Zhou said, “This result not only represents a reach increase by a factor of 2.5 for 100 GHz-spaced 400 G-class WDM systems, it also sets a new record for the product of spectral efficiency and distance.” A previous test by Zhou’s team, using 50GHz spacing, was the previous record-holder for 400-gigabit transmission distance—at 3,000 kilometers.

Source:  arstechnica.com

Microwave vies with fiber for high-frequency trading

Tuesday, December 11th, 2012

Stock traders turning to legacy microwave technologies for faster communications

In the world of high-frequency trading, where being ahead of the competition by a few milliseconds can mean profits worth millions of dollars, finance firms are increasingly looking to decades-old microwave technologies for a competitive edge.

Such firms are finding that wireless microwave technology, despite being in use for more than half a century, can deliver data a few milliseconds faster than fiber-optic cable. As a result, the once-stagnant industry of microwave communications is finding itself in an “arms race” among vendors of new competitive offerings, said Mike Persico, CEO of financial exchange service provider Anova Technologies.

“If you want to transport a little bit of data very fast, physics tells you that you have to go through air. Fiber is just not a good idea. It will slow you down,” explained StA(c)phane Ty , co-founder of Quincy Data, which provides microwave services to financial firms.

Ty was one of a number of speakers who discussed the increasing use of microwave technologies at the Quant Invest conference last week in New York.

For financial services firms, getting some piece of competitive intelligence a few milliseconds faster than their competitors can be worth the cost of securing a faster link. Stock trades can take less than a millisecond to execute.

Microwave technologies have been in use for point-to-point connections for decades by the military and by broadcast television stations. Point-to-point wireless microwave transmissions, which operate in the 1.0GHz to 30GHz part of the spectrum, require line of site, though signals can be repeated along the route. A good signal — such as between two mountaintops — can travel as much as 300 kilometers, or around 186 miles.

Microwave use has declined in the past few decades as fiber-optics communications has been able to offer greater bandwidth. These days, the largest microwave link can offer only 150Mbps, though work is being done to develop gigabit microwave technologies.

One advantage microwave still possesses, however, is speed of transmission. Electromagnetic waves travel faster through air than through glass. Light, an electromagnetic wave, can travel at 300,000 kilometers (186,000 miles) per second in a vacuum, and nearly that quickly through air. Light, however, can only travel at about 200,000 kilometers per second in even the clearest glass.

Another speed advantage microwave technologies offer is that their paths tend to be shorter, because signals can be beamed across the most direct path between two points. The length of fiber-optic routes tend to be elongated due to the inability to get right-of-way along the most optimum routes.

One new hot market for microwave providers is between New York and Chicago, both cities with many financial services firms. In 2010, Quincy Data had applied with the U.S. Federal Communications Commission to secure a pathway between Chicago and New York. It found only one other provider that had also submitted a similar request. Since then dozens of other carriers have submitted requests to the agency. Quincy Data has been operational since July selling throughput between the two cities.

Based on the speed of light, the theoretical limit for sending information between New York and Chicago is 7.96 milliseconds. Right now, the state-of-the-art among microwave service providers is about 8.5 milliseconds, Persico said, noting how different providers are trying to secure the fastest rights-of-way and are developing technologies with the lowest latencies, all in an effort to offer the fastest sub-millisecond services for financial firms.

“We’ve been looking at [microwave technologies] for about a year now, in both Europe and the U.S.,” said Ian Jack, head of the U.S. infrastructure business for the New York Stock Exchange, during a panel discussion on the topic. “We’re looking at what the vendor community is doing and trying to leverage that as much as possible.”

Performance is still a big factor, Jack said. Performance “is one of our big challenges as a potential buyer. If you look at the actual uptime for services, it’s not brilliant. Every vendor has a new change, a revelation just around the corner, but we have yet to see that.”

Rain can hamper performance with microwave technologies. So can low-lying clouds. “Interference can bring an entire network down, and you don’t have that with fiber-optic networks,” Persico said. He noted that, eventually, microwave technology vendors will compete more on how robust their networks are, once they offer approximately the same latency times.

Source:  computerworld.com