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After several years of downturn, the global communications industry is once more growing. As evidence of recovery, it's calculated that sales of communications products have recently risen by 7.9% in a mature market such as North America.

The application of new broadband technologies and services has become a main driving force behind the development of the contemporary communications industry. In response to cutthroat competition, and in an attempt to increase the 'stickiness' of their respective customers, both incumbent operators and cable companies are targeting the provision of high bandwidth-enabled 'triple-play' services and applications.

For would-be triple play incumbent wireline operators, the growing maturity of technologies such as ADSL 2 and 2+ is very good news, as indeed is the availability of increasingly sophisticated, but lower cost home gateways and set top boxes (STBs).

One of the world's major suppliers of ADSL solutions - with well over 12 million DSLAM ports delivered to date – is ZTE, China's largest listed telecommunications supplier. As well as being at the forefront of DSL commercialization, ZTE is a leading organisation in DSL R&D and innovation. As early as the end of 2003, for example, the group had produced an ADSL DSLAM product portfolio that supported ADSL2/2+. Completing its set of DSL competencies ZTE is also a service developer, with triple-play service solutions for data, voice and video.

In advance of FTTx and VDSL being applied on a large scale, ADSL2/2+ can be deployed as an effective means of meeting the demands of high-bandwidth user groups. It can readily support services that require higher bandwidth, such as video, high-speed data interconnection and online gaming, and provide different levels of bandwidth for home users and business users.

Since DSL bandwidth is limited by physical line conditions, a low provisioning rate for long-distance users has traditionally been a challenge for telecom operators. ADSL2 technology is designed to solve this problem, using the pooled principle to adjust the upstream and downstream PSD templates. It shuts down some subchannels in the high band, and increases the transmitting power spectrum density in the low band, without changing the total transmitting power. With READSL technology, higher transmission performance can be achieved in medium and long distances, and long-distance features are greatly improved.

ADSL2 (G.992.3) improves transmission performance by enhancing modulation efficiency and increasing coding gain. The main improvement of bandwidth, however, is achieved through the use of ADSL2+ (G.992.5). ADSL2+ further improves the performance of ADSL2, doubling the downstream spectrum from 1.1 MHz to 2.2 MHz and increasing the number of sub-carriers to 512. In terms of the net data rate it supports, the maximum downstream rate is in excess of 24 Mbps.

An important consideration in the successful provision of triple-play services is that operators need to select the right cooperation partners for the development of services and content. More important for many is that they need network equipment suppliers to provide technical support and expertise.

In terms of broadband access, triple-play services have three important features. The first is that they will bring huge amounts of IP data into access networks. As an illustration, just one home may have multiple STBs and need broadband voice and HDTV, and the peak bandwidth of every home could realistically reach 20 Mbps. The second feature is that IP data streams comprise multiple services, which have different requirements for delay, jitter, packet loss ratio and redundancy. The third characteristic is the 'bursty' nature of services.

These features of triple-play services impose stringent technical requirements on the broadband access network. How well the broadband access network meets these requirements directly determines the quality of service (QoS) of triple-play products. To better support triple-play services, the broadband access network needs to have the following capabilities:

• Support the integrated access of multiple services: providing access for multiple services such as LAN/VDSL/SHDSL/FR/CES.
• Support IP QOS: implementing different QoS assurance policies by marking/identifying different users or service streams of different types.
• Enhanced multicast technology: for example, VLAN, IGMP Proxy, multicast flow control, and multicast service authentication.
• Provide high bandwidth: DSLAM equipment has high requirements for backplane capacity, switching capability, IP upstream forwarding capability and user ports. ADSL2/2+ technology ensures user access bandwidth.

In addition to on-going new broadband service development, integration with the next generation network (NGN) has also become a trend. In this context, the next generation of DSLAM equipment takes the form of a very high bandwidth integrated service access platform (FSAP- service access platform). FSAP adopts IP Gigabit architecture with a backplane capability of 280 G. The bandwidth from the system's core board to user slots is up to 2 G. The system supports over 30 M broadband access for each user, fully ensuring service bandwidth while at the same time providing perfect multicast control technology and a QoS assurance mechanism. The system provides access of broadband and narrowband services, including POTS, TDM, XDSL, LAN and PON, so that operators can build access layer networks that have full-service bearing capability and integrate broadband and narrowband services.

Visit ZTE Corp. online.