Изучение технологий доступа для широкополосной электросвязи (стр. 32 )

–        Outdoor equipment operating temperature: –40°C to +60°C (Single Subs. Unit).

•        Network management:

–        A scalable carrier-class suite of tools that allows operators to easily manage their Fixed Wireless Access network.

II.1.3        SR 500-ip: A Broadband Fixed Wireless Access System for Remote Areas

Brief description of the SR 500-ip system

SR 500-ip is a broadband, high-capacity wireless access system for operators and service providers serving rural and remote areas. It is the first point-to-multipoint (PMP) microwave system to economically combine highly scalable voice capacity with broadband Internet access. With SR 500-ip, service providers can evolve their rural networks to offer leading edge services such as ADSL at 1.5 Mbit/s, while preserving scarce spectrum resources through efficient handling of voice traffic. SR 500-ip makes broadband access in low-teledensity areas a reality and enables service providers to comply with universal access initiatives at the lowest cost. With ADSL capability it is the ideal solution to bring broadband Internet and voice services to rural communities. It can also overlay or replace legacy access networks to add capacity or provide broadband Internet access.

Architecture

As a packet-based PMP microwave access system with network repeater capability, the system can be configured in star, branched or linear network topologies, see Figure 25.

The base station (BS) provides the network interfaces to connect to the core network, and communicates will all remote radio work interfaces are PPP over Ethernet for Internet services and V 5.2 over E1 for voice-band services. The base station can accommodate up to two 4 Mbit/s air links for a total system bandwidth of 8 Mbit/s.

The Network Termination Node (NTN) provides the subscriber interfaces. The NTN is a multi-line, multi-service, outdoor unit that serve a large number of subscribers through copper bscribers connect to the network using a 2-wire equipment, including ADSL modems, standard or payphone sets, as well as V90 modem and bscriber capacity can be increased using an extension cabinet that is cabled directly to the main NTN.

The Network Repeater Node (NRN) is an outdoor unit that is used when line-of-sight between the SR 500‑ip Base Station and NTN is compromised by rough terrain, man-made objects or distance. The NRN can also provide subscriber services using an expansion cabinet.

The system is centrally managed by insight NMS, which handles all operation, ad­min­is­tration, maintenance and provisioning (OAM&P) and support over-the-air software downloads.

Figure 25 – Architecture of SR 500-ip

Main features and benefits

•        Wide Area Coverage

       The system offers log-range microwave links and network repeaters to ensure coverage in difficult to reach areas spread over hundred of kilometres.

•        Broadband IP access

       The system enables service providers to meet universal Internet access mandates and promote development in rural communities.

•        Advance services

       With full CLASS support, transparency to fax and V90 modem traffic and payphone support, the system enables service providers to maximize voice service revenue. Flexible dial-up and ADSL interfaces offer service provider a choice of high-speed Internet solutions.

•        Future proof

       Based on a packet switch architecture, the system is a long-term solution for IP-based services that reduces operators’ technical and financial risk. With such a system, service providers will have access to future IP-based subscriber services while maintaining network stability.

•        Low cost of ownership

       The system offers high capacity and linear scalability, which results in decreased costs on hardware and support. Standard interfaces facilitate network integration, while minimal infra­struc­ture requirements reduce capital costs. In addition, SR 500-ip is centrally managed by insight Network Management System (NMS) to maximize staff productivity and reduce travels to remote locations.

•        High availability and field-proven reliability

       SR 500-ip builds on the technology of SR 500, the most widely deployed rural wireless access system in the world. Reliable in-service performance ensures subscriber satisfaction and preserves revenues streams while minimizing maintenance expenses.

Technical characteristics

•        General

–        Capacity:        up to 2 air links / 8 Mbit/s per base station

–        Frequency bands:        1.5, 2.5, 3.5, 10.5 GHz

–        Access method:        TDMA

–        Duplexing technique:        FDD

–        V5.2 PSTN interface:        Complies with ITU‑T recommendation G.965

–        IP interface:        PPPoE over 10Base-T

•        NTN Services and Capacity

–        Voice:        2-wire VF        48 lines

–        Payphone:        All 2-wire standards and prepay
(12 or 16 KHz) services        48 lines

–        Dial-up Internet:        V.90 modem support (up to 56 kbit/s)        48 lines

–        Broadband Internet:        2-wire ADSL, always-on,
       bandwidth-on-demand        5 lines

•        Power

–        Base station        – 48 VDC

–        Network repeater node:        – 48 VDC

–        Network termination node:        – 48 VDC or 120/240 VAC (+/– 12 VDC optional).

•        Power consumption:

–        Radio Base station:        110 W (average DC per sector 1.5 GHz,
30 dBm, all trunks busy)

–        Network Repeater:        59 W (average DC at 1.5 GHz,
       30 dBm, 25% traffic load)

–        Termination node:        43 W (average DC at 1.5 GHz,
       30 dBm, 10% traffic load)

•        Environmental specifications:

–        Radio Base station (Indoor) operating temperature: 0°C to + 45°C, forced air cooling

–        Repeater and termination nodes (Outdoor) operating temperature: – 40°C to + 55°C

•        Standards Compliance:

–        Ethernet:        IEE 802.3, 10Base-T

–        V 5.2 PSTN:        ITU‑T G.965

–        Voice:        ITU‑T G.711(PCM voice coding),
G.726 ADPCM 32 kbit/s
voice coding A-law and м-law,
G.165 echo cancellation.

–        ADSL:        ITU‑T G.992.2

–        Safety:        IEC 60950

–        EMI/EMC:        ETSI EN 300 385

–        Environment:        ETSI EN 300 01.

Technology Section Conclusion

A similarity of services and applications across different systems is beneficial to users, and this has stimulated the current trend towards convergence. Furthermore, a broadly similar user experience across different systems leads to a large-scale take‑up of products and services, common applications and content and an ease and efficiency of use. However, such convergence should not preclude opportunities for competitive innovation. Access to a service or an application may be performed using one system or may be performed using multiple systems simultaneously (e. g. a digital broadcast channel and a return channel using IMT‑2000).

The increasing prevalence of IP-based applications is a key driver for this convergence and facilitates the establishment of relationships between previously separate platforms. What form these relationships will take depends on market requirements, but they might include, for example, hardware integration within a device, network interworking, common access, authentication, accounting, common man-machine interfaces, portals, roaming and handover between systems.

ANNEX III

Country Experiences

III.1        Africa

III.1.1        Deployment of Broadband Wireless Access in Mali, Africa

Mali is a landlocked country in western sub-Saharan Africa with 80 per cent of the more than 11 million people living in rural areas. The country experiences extreme climate changes, very arid to a heavy rainy season. It also is very hot and humid. The cost of bandwidth in this country is very high and traditional hard-wire solutions for delivering high-speed Internet often leads to higher support costs and disgruntled customers, both of which can affect the bottom line. It also makes the availability of Internet service to residential customers almost non-existent. Afribone Mali began installing Motorola’s Canopy 5.8 GigaHertz radios in 2003 for business and non-government deploying Motorola’s Canopy solution, Afribone Mali SA was able to increase quality of service, keep customers satisfied, and reduce radio frequency cable problems. Afribone is now working on sharing bandwidth with other companies.