ADSL technology and application prospects

ADSL based on the development of new technology, ADSL2/2 + ADSL has many advantages, operators can help solve a series of problems met in ADSL network operators, especially ADSL2/2 + in the transmission code modulation, using a lot of new technology. This has made ADSL2/2 + has a broad application prospects in the future market.

(1)The transmission performance is significantly improved

The comparison ADSL8Mbit/s the highest rate, the highest rate of ADSL2 up to 12Mbit/s. The first generation of ADSL downstream rate of at least 6Mb/s uplink rate is at least 640kb/s; while G. The 992.3 standard ADSL2 rate of more stringent requirements, should at least support the downstream 8Mb/s, upstream of 800kb/s rate. ADSL2 ability to adapt to poor line environment has been improved to a certain extent, particularly in the longer distance, bridge joints, the case of RF interference, the transmission performance has been further improved. Thus, in the past, due to line quality and can not enjoy the ADSL service users can also open ADSL. With respect to the AD  SL, under the same transmission distance can be obtained, ADSL2 50kbps rate of increase;, ADSL2 can extend the transmission distance of 183 m under the same transmission rate. Transmission performance improvement is mainly due to the following core technologies.

(2)Dynamically adjust the power saving mode

The first generation ADSL transceiver whether in the data transfer state, the power is always the same, the ADSL2 standard is introduced in the two power management mode, saving the power consumption in the while maintaining ADSLalwayson characteristics. L2 low power mode according to Internet traffic, quickly back or leave L0 full-power mode, reducing the overall power loss. L3 low-power mode when a certain period of time there is no flow, ATU-C and ATU-R can be entered into the sleep mode L3. ADSL2 + the introduction of two new state (L2 low power mode, L3 low-power mode), the transceiver in low data rate or data transfer into hibernation, and can greatly reduce the power consumption for central office equipment, also reduce the cooling requirements for solving the monthly subscription system is now widely used in long line or central office equipment power consumption has been online cause too large of great significance. For example, when the user to download a large file, ADSL2 work in L0 full power mode, in order to achieve the highest download speeds; when Internet traffic is reduced, as in reading a long page of text, then download rate reduce, ADSL2 system into L2 low power mode. According to the changes in the flow rate, in L2 ADSL2 system can quickly return to the L0 mode, or within a certain time, if there is no flow, then the system will enter the L3 sleep mode. When the user re-online, the system takes about 3s time to re-initialize, enter a stable state of communication.

(3)Segmentation of the channel management

ADSL2 support bandwidth is divided into different channels, to enable them to adapt to different applications have different characteristics, such as ADSL2 support voice applications so that it has the characteristics of low-latency, high fault tolerance, while supporting the other a data application of a channel, so that it can tolerate a relatively large delay, and the error rate is very low. This letter Tao of the management of the properties to ADSL2 can support CVoDSL (Channelized Voice over DSL) TDM-based 64kbit/s of digitized voice letter Road for the user, and the do not have the voice carrying to the ATM or IP and other high-level protocols and applications. Meanwhile, ADSL2 enhanced online re-configuration functions, support of different channels of dynamic rate allocation, seamless rate adaptation; enhanced spectrum control function, support for single-carrier template; enhanced power control function, central office and remote support power down; optional initialization sequence, supporting rapid error recovery, makes the initialization time reduced from 10s to 3s.

In addition to the above features, ADSL2 also has real-time performance monitoring, modem initialization process standardization, interoperability ability, quick start feature. Fiberstore offers many kinds of Fiber Optic Tester and ADSL Tester is one of them. The common used ADSL Tester is ADSL2+ Tester. It is an easy-to-use, hand-held advanced telecommunication tester that used for the installation, maintenance and measurement of ADSL2+ service. It supports the testing function such as parameter, error, DMM, PING that related to ADSL2+ service, user register authentication on the ADSL2+ user line side. It also directly enables the engineers to verify, troubleshoot and evaluate the ADSL2+ service. It is the right tool for the network test job. Fiberstore supplies a range of ADSL2+ Tester.