As large-scale VDSL2 (Ultra High Speed ​​Digital Subscriber Line 2) vectoring deployments are in use, G.fast technology will upgrade FTTx (Fiber Access) deployments by one level. In 2011, VDSL2 vector technology used "de-copper" next-generation access technology to achieve a downlink rate of 100Mbps. Currently, G.fast can transmit hundreds of megabits per second, and the next rate will reach gigabit.
G.fast allows operators to suspend fiber near end users, borrow the last few meters of telephone lines or building yards, and switch to existing telephone lines to transmit fiber-like speed data. This eliminates the need for technicians to enter the building, which is time consuming and costly for any fiber to the home service.
Accelerate fiber deployment
Contrary to what it sounds, G.fast can actually speed up the deployment of fiber optic cable. National “optical cable†will take years or decades: workers will enter each building to install new fiber optic cables, which means that every street and front yard will be dug. However, most end users are reluctant to wait that long, and decision makers have already set aggressive broadband goals. Operators need to be fast and faster.
Installing new fiber optic cables in some places is wasteful or impossible, and G.fast provides a solution for these situations. For example, older buildings are less likely to be equipped with fiber optic cable troughs, and some owners refuse to drill or install new fiber optic cables. Even in the best design, getting the owner's permission, appointment, and installation is a long process, which is cumbersome, time-consuming and costly.
G.fast avoided these complications by leveraging existing in-building telephone lines. Operators have more choices when they choose to transmit cable rate data to end users. Combining the fiber-to-the-home and fiber access deployment models is the most cost-effective and fastest way to provide ultra-broadband services to end users, and it can also effectively speed up the introduction of fiber-optic cables.
Use fiber optic cable at the most economical point
As far as universal UWB is concerned, there is no single best solution, although FTTH is considered to be the least outdated solution and many operators see it as the ultimate goal. However, because fiber-optic access deployments are less expensive and faster to launch than fiber-to-the-home deployments, they are critical in any carrier's strategy.
In a fiber access deployment, the fiber is terminated near the end user (x can be a node, roadside, building, utility pole, manhole, wall, front door, etc.). Starting from this "distribution point", the combined fiber optic G.fast system (or VDSL2 vector system) transmits ultra-high speed data over the telephone line. The difference between the two is speed and distance: G.fast has a wider bandwidth than VDSL2, so it is faster, but because of its higher attenuation, its longest transmission distance is shorter, generally less than 250 meters.
Obviously, because fiber placement must be closer to the end user, the shorter the distance, the higher the cost. Since there are fewer end users in each distribution point, a G.fast system will serve fewer end users. For example, an FTTN (Fiber to Node or Switch Box) deployment using VDSL2 vector technology can transmit 100 Mbps downstream at 400 meters and serve hundreds of end users. A G.fast deployment can transmit downlink speeds greater than 500 Mbps over a distance of 100 meters, but can only serve dozens of users (fiber to the building) in a building. The results show that FTTB/G.fast is twice as expensive as FTTN/VDSL2 vector technology per user, but still 30% lower than FTTH.
Obviously, operators need to weigh the speed, bandwidth and cost to make choices. It may be difficult to understand and difficult at first, but the toolkits for these deployment models (FTTN, FTTH, and others) allow operators to choose the right tools for their work. For each city, street or building, the operator tests various factors (including expected user absorption, pipeline availability, land type and ease of mining, time to obtain permits, etc.) and selects the appropriate deployment model. To ensure that the end user is approached in the most economical way in the shortest possible time.
G.fast achieves the desired effect
Because G.fast provides a natural complement to fiber deployment, operators are very interested in it. As of the first quarter of 2015, Alcatel-Lucent has completed 30 carrier tests and the results show that G.fast has achieved the expected results.
The total code rate is high and stable. At a distance of 100 meters, a code rate of 600 Mbps and above can be achieved (the ITU-TG.9701 standard initially targets 500 Mbps). At a distance of 200 meters, the test results show that the rate is around 500 Mbps (ITU LTE.9701 standard is 200 Mbps).
Unlike VDSL2, all G.fast rates are the total code rate, which is the combination of uplink and downlink. Operators can choose how to allocate total bandwidth for upstream and downstream, for example through their management software, which is a major advantage.
It is important to note that all tests use the VDSL2 spectrum. In networks where VDSL2 is already deployed in the same connector, G.fast is configured to skip the VDSL2 spectrum (to avoid interference), which will result in a code rate that is 150 Mbps lower than the experimental result. The above results are based on the first phase of the ITU-T G.9701 (G.fast) standard and are applied to the 106 MHz spectrum.
Typical G.fast deployment model
The G.fast deployment model is usually represented by a fiber-to-distribution point (FTTdp). The distribution point can be any point close enough to the end user to accommodate the loop length of a typical G.fast and access to an existing telephone line.
Operators are interested in two G.fast deployment models: single-user and multi-user. In the single-user model, most of the fiber is delivered to the home (eg fiber-to-wall or fiber-to-front), and individual users are served by the G.fast node. In a multi-user model, adjacent lines interfere with each other, causing crosstalk and severe performance degradation (rates are reduced by 50% to 90%). To complement multi-user deployments, the G.fast standard includes advanced vectoring techniques to eliminate crosstalk and optimize transmission performance on each line.
Another factor that needs to be considered when deploying G.fast is the power. Due to the short loop length, it is inevitable to deploy dozens or even hundreds of G.fast systems in the delivery area. These systems require power up, and due to the number of nodes and their location (on the pole, under the manhole or on the wall), it is usually not possible to rely on local AC power. Instead, a typical G.fast system can be powered either remotely (central office or street power distribution cabinet) or nearby (end user home, telephone line). The latter requires special maintenance to ensure that the energy consumption between active users is balanced, even if a user power down system is still available.
G.fast will play a vital role in many operators' UWB network strategies and will soon offer more bandwidth to more users. For operators, G.fast leads to faster time to market and a higher return on investment. For decision makers, it means that broadband targets are easier to implement, helping to bridge the digital drop in higher access rates. For end users, G.fast allows them to enjoy new services or socioeconomic benefits. Finally, G.fast will change the lives of millions of people around the world to better develop.
Ultraviolet Climate Resistance Test Chamber
Ultraviolet Climate Resistance Test Chamber,Uv Intensity Test Chamber,Sun Resistant Test Chamber,Sunlight Exposure Test Chamber
Wuxi Juxingyao Trading Co., Ltd , https://www.juxingyao.com