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  • Sistemas Inalámbricos "Triple Play"

Sistemas Inalámbricos de "Triple-Play" (Video, Datos y Telefonía)

Sistema Inalámbrico “Triple Play” Instalado en Japón

Transceptor y Antena Sectorial en la estación base del sistema “Triple Play”.

Un sistema inalámbrico punto-multipunto de “triple play” (con capacidad para servicio simultáneo de TV digital, datos de alta velocidad y telefonía) ha sido  instalado en la ciudad de Izuka, prefectura de Fukuoka, Japón.

El sistema opera bajo la dirección de V-Network Systems proporcionando  servicios de “triple play” a estaciones remotas a distancias de hasta 5 Kms. de la estación base.

Según un artículo aparecido el 14 de mayo de 2007 en el periódico local Denpa Shinbun, la instalación y operación del sistema es el resultado de una colaboración entre la empresa NetOne, el Instituto de Tecnología de Kyushu, la Universidad de Kinki, Nitsuki, HTK y V-Network Systems.

El sistema esta en pruebas con tres tipos de servicio:

  • Retransmisión de TDT (Televisión Digital Terrestre), con señales de RKB/Fukuoka.
  • Transmisión de canales de video independientes.
  • Servicios de comunicación de datos y acceso a Internet.

La estación base del sistema está instalada en el instituto de Tecnología de Kyushu. Cinco estaciones remotas están a lo largo y ancho de la ciudad.

Después de concluir pruebas operacionales, el sistema tendrá la funcionalidad de un sistema “FTTH inalámbrico” (Fiber to the Home o fibra hasta la casa) para zonas sin recepción de Televisión Digital Terrestre, proporcionando  simultáneamente acceso a Internet de banda ancha de alta velocidad.

La instalación del sistema fue bien recibida por el Sr. Saito, alcalde de la ciudad de Izuka, quien dijo: “Esta ciudad necesita la creación de nueva industria. Estamos muy contentos de que las pruebas de este sistema hayan  comenzado en esta ciudad. Espero con interés el despliegue completo del sistema”.

Después de las pruebas en Izuka se están planeando otras instalaciones pilotos en diversas áreas de Japón tales como Tohoku y Hokkaido.
Takashi EIfuku, de V-Network Systems, ajusta
una de las antenas de la terminal remota.		 Unidad remota del sistema “Triple Play”.

Repetidoras de Doble Vía (TV y Datos) A 28 GHz

Cable AML ha diseñado y fabricado una repetidora bidireccional de cuarta generación que opera en la banda de 28 GHz.

La repetidora fue diseñada para extender el alcance de los transceptores existentes en las Estaciones Base a zonas con un radio de mas del kilómetro y medio que están fuera del área de cobertura de la Estación Base debido a obstrucciones en la línea de vista.

Los repetidores bidireccionales consisten en un módulo de entrada y un módulo de salida (módulos A y B, respectivamente), conectados por cables para poder instalarlos lejos uno del otro, por ejemplo, en lados opuestos de un edificio. Con esto se facilita la instalación en edificios ordinarios reduciendo el problema de la retroalimentación entre las antenas de entrada y de salida.

Cada uno de los módulos consiste en un transmisor y receptor con circuitos separados para las señales de bajada y retorno. En las aplicaciones típicas las señales de bajada son para TV digital y datos mientras que las de subida son exclusivamente para portadoras de datos.


Nuevo Sistema de 28 GHz Transmite Televisión Digital y Datos de Alta Velocidad

Cable AML ha entregado a Terminales de Telecomunicaciones Terrestres en España dos transceptores de estación base (modelo TRX28-130) y dos repetidores de banda ancha (modelo OAR28-001). Estas unidades de alta potencia se usarán en una nueva red que empezará a funcionar en Lisboa ( Portugal) y que se extenderá gradualmente a lo largo del país.

La red avanzada de banda ancha usa el estándar de codificación de vídeo digital terrestre (conocido como DVB-T por sus siglas en inglés) para transmitir vídeo multicanal y servicios de Internet de próxima generación, TV interactiva, telefonía y videoconferencia residencial.

La estación base, utiliza tecnología de alta potencia de TWT (Travelling Wave Tube, por sus siglas en inglés), la cual es utilizada generalmente en satélites debido a su fiabilidad y alta eficacia. Los repetidores de bajo costo permiten extender el rango de la estación base, haciendo posible configurar una necesidad de línea de vista que pueda alcanzar hasta un 90 por ciento de clientes urbanos potenciales a un costo económicamente viable.

El transceptor de estación base de alta potencia acepta 14 portadoras con modulación digital. Cada una de ellas tiene una capacidad de datos de 30 Mbps para una capacidad total en transmisión que excede los 500 Mbps. 

El sistema incorpora varios perfeccionamientos, incluyendo enganche de frecuencia al Satélite de Posicionamiento Global (GPS) para sincronización remota. Éste es un requisito impuesto por la modulación OFDM (Ortogonal Frequency Division Multiplexing), que es el tipo de modulación usada por los porta-dores de la TV digital en el sistema.

Los repetidores bidireccionales de estado sólido no requieren regeneración de frecuencias, que resultaría en un alto costo. Un diseño flexible permite que las secciones de entrada y salida puedan ser instalados a distancias variables.


Two-Way Repeater for LMDS Application

Cable AML has delivered a two-way Repeater to increase the coverage area of a Broadband Wireless System operating at 28 GHz.

Two-way Repeaters can expand coverage of point-to-multipoint fixed wireless systems at lower cost than installing new base stations.

Repeaters are particularly cost effective in cellular systems with a line-of-sight requirement, because they provide extended system range without having to install additional backhaul capacity.

Cable AML has successfully delivered and installed two-way repeaters for fixed wireless systems operating from 2.5 to 28 GHz. The repeater is now part of a system providing multi-carrier digital television, high-speed Internet access, and VoIP capability.


New 28 GHz Broadband Multimedia System Installed

Cable AML recently delivered High-Power base station Transceivers and several subscriber CPE (Customer Premises Equipment) Transceivers for a broadband LMDS system operating in the 28 GHz band. The high-power, broadband base station Transceivers are key components of a multi-carrier system. The system is capable of transmitting several dozen high-quality digital TV signals and simultaneously providing two-way, high-speed data services. Two orthogonally polarized high-gain antennas at the base station provide 360 degree azimuth coverage.

The large volume of bandwidth available at LMDS bands around 28 GHz makes it possible to provide wireless services such as multi-channel digital TV service and high-speed Internet access, which until recently, were available only by cable.

A state-of-the-art, two-way shared-access IP (Internet Protocol) system provides Enterprise, MDU (Multiple Dwelling Units) and residential High-Speed Internet access as well as other enhanced IP services such as VoIP , VPN (Virtual Private Network) services, and high-quality video conferencing. High-capacity dedicated access links can also be implemented for backhaul or high-reliability PTP
(point-to-point) and P-T-MP (point to-multipoint), high-speed connectivity.


Cable AML Delivers IP-Based LMDS System

Cable AML has completed delivery of a state-of-the-art 26 GHz LMDS (Local Multipoint Delivery Service) system designed to provide two-way data services with an IP-based access system.

The BWA-2026 system is the first LMDS system to successfully operate with DOCSIS 1.0 compliant modems at 26 GHz. Significant technical challenges have been overcome by Cable AML's design, which had the primary goal of lowering the per-subscriber cost of 26 GHz Broadband Wireless Access systems.

The system's approach to a lower cost design was based on manufacturing low-cost 26 GHz hardware capable of interfacing with the same low-cost IP-based subscriber modems typically used at lower frequencies (2.5 and 3.5 GHz bands). The system can operate with 64-QAM modulation in the downstream and 16-QAM in the upstream, which makes it possible to offer high data rates to subscribers.

Cable AML developed both the Base Station Transceivers and the CPE (Customer Premises Equipment) Transceivers. Two types of Base Stations were developed, one designed for single-carrier applications and a broadband, high-power unit designed for backbone and macro-cell multi-carrier applications.

Multi-carrier Base Stations can be implemented with a relatively large cell divided into two sectors for small to medium cities or semi-rural areas, whereas single-carrier base stations are desired for multi-sector, high-traffic density cell sites associated with multi-cellular deployments in large cities.


LMDS Transceivers Released

Cable AML has developed a family of state of the art CPE Transceivers (Customer Premises Equipment) designed for use at frequencies from 24 - 31 GHz. The CPE 26TR-001 is designed for operation in the 24 to 27 GHz band. The CPE28TR-001 is designed for operation in the 27 to 31 GHz band. Transceivers are two-way, full duplex (transmit and receive) outdoor RF units designed for digital video and LMDS applications.

The transceiver features a solid state modular design consisting of block down-converter, transmitter and diplexer modules. The receive modules have output IF frequencies compatible with either DOCSIS (VHF and UHF) or DAVIC (L-band) standards. The transmit module input frequency range is in the 45 to 65 MHz band.

A single cable provides the interconnection with the subscriber indoor modem unit, and also provides DC power to the transceiver.

The transceiver outdoor package is mechanically integrated with several different types of antennas depending on the system gain requirements. The integrated design greatly facilitates installation, mounting and alignment (in either horizontal or vertical antenna polarization).


Multimedia LMDS System Installed in Europe

A high frequency 28 GHz Local Multipoint Distribution System (LMDS) has been installed in Lisbon, Portugal. The multi-cell system provides broadband bi-directional multimedia and data services, including Subscription Digital TV, High Speed Internet, Video Conferencing, VoIP and High Speed Data Interconnect.

The system architecture is based on high-capacity macro cells (5-Km radius) interconnected to a central headend and data center by a bi-directional AML link. Smaller data cells within the service area are interconnected by in-band 28 GHz point-to-point links routed through the high-capacity LMDS transceivers in the macro-cells.

The system's cellular structure and the AML backbone for trunking provides the operator with maximum flexibility to optimize coverage in desired target areas regardless of the availability of fiber interconnections between cells.

At the headend, a digital TV satellite reception system provides digital TV multiplexed channels for TV broadcast. MPEG-2 compatible data streams are multiplexed with the video data streams in the downstream direction. The system's upstream data capability makes it feasible to implement true subscriber interactivity.

The customer equipment consists of a 28 GHz CPE (see article on page 4) Transceiver with an integrated 10 inch parabolic antenna. Dual outputs provide separate TV and two-way data capabilities.

Cable AML is proud to have contributed LMDS and AML hardware to what is undoubtedly the most advanced multimedia LMDS system in the world.


Fixed Wireless 26 GHz System Delivered and Installed

Cable AML recently delivered a fixed wireless system operating in the 26 GHz band. The BWA-1026 system is providing high-reliability dedicated access to customers in several locations at data rates of 2,048 Kbps.

The system consists of a base station transmitter integrated with a sectorial 90 degree antenna and CPE (Customer Premises Equipment) units, each consisting of an outdoor unit housing the RF unit (integrated with a directional 12 inch diameter antenna) and an indoor unit.

The high-performance point-to-multipoint system was designed with integrated programmable data rate modulators operating in the QPSK modulation format with a V.35 data interface at both ends.


Point-to Multipoint 28 GHz Broadband Wireless Access Systems Released

Cable AML has just released the BWA-1028 and BWA-4028S Broadband Wireless Access Systems.  These compact fixed-wireless systems are ideally suited to provide "last mile", two-way data service capability to subscribers requiring high-speed connectivity. The BWA-1028 system provides dedicated bandwidth connectivity, whereas the BWA-4028S provides multiple-carrier, multi-service capability well suited for commercial trials. 

The systems operate in the 27.5 to 28.35 GHz or the 28.25 to 28.75 GHz bands for downstream transmission and the 31.0 to 31.3 GHz band for upstream transmission. Range varies between 1 and 4 miles (1.6 and 6.4 Km) depending on climate, capacity utilization and other factors. 

There are multiple-carrier, FDD (Frequency Domain Duplexing) systems capable of supporting multiple carriers with either QPSK, 16-QAM or 64-QAM modulation. The BWA-1028 employs FDM (Frequency Domain Multiplexing) in both downstream and upstream directions, whereas the BWA-4028S is an FDM system with shared-access capability implemented via TDM (Time Domain Multiplexing) for the downstream and TDMA (Time Domain Multiple Access) for the upstream. Either shared-bandwidth or dynamically allocated bandwidth (bandwidth-on-demand) is available for the upstream. 

The BWA-1028 system principal application is for high-capacity private data networks, with data rates ranging from E1/T1 (approximately 2 Mbps) to 10 Mbps per subscriber. 

The BWA-4028S is designed to provide services such as: 

  • IP for fast Internet access (128 Kbps, 256 Kbps and above) 

  • ATM-based, high data rate access systems (E1/T1 and higher) 

  • POTS and Voice over IP (VoIP) telephony 

  • MPEG-2 Digital Video distribution

Like all members of Cable AML's family of Broadband Wireless Access Systems, the BWA-1028 and BWA-4028S systems are deployed in a cellular architecture. The number of subscribers within a given cell is determined by many factors. The most important factor are the number of sectors within the cell, the access system employed, and the modulation format associated with each access system. Frequency re-use plans are required for multiple cell operation. 

The systems are inherently scalable in terms of the number of sectors per cell as well as the number of carriers per sector. A four-sector RF Hub implementation consists of four transceivers and four 90-degree sector antennas. 

At the subscriber's site, a single dish serves as both receive and transmit antenna. The CPE (Customer Premises Equipment) Transceiver consists of an outdoor transceiver integrated with a 35 cm. diameter antenna. The Transceiver is connected to an indoor modem or NIU (Network Interface Unit), which provides the interface to the subscriber equipment (10BaseT, T1/E1, POTS, etc, depending on the requirements). 


Madrid Multi-Access LMDS Commercial Trial A Success

A commercial trial of the world's first 28 to 31 GHz multi-access LMDS system has been implemented in Madrid (Spain) under the auspices of the Madrid Polytechnic University and the Spanish company TTT. The system utilizes base station transceivers, a broadband two-way STL and Customer Premises Equipment (CPE) transceivers provided by Cable AML. 

The goals of the trial were to evaluate fixed-wireless access technologies and services capable of providing advanced high-speed connectivity in a typical European city environment. This was the first trial of its type in Europe. 

The system incorporates high-powermulti-carrier base station transceivers (TRX28-130D models supplied by Cable AML) which enable large cell radius, high data density, and spectral efficiency in a 500 MHz bandwidth (downstream) and 300 MHz (upstream). 

Multi-access capability is provided by multiple access systems integrated into a single RF platform. At least four access systems are being evaluated: 

  • A dedicated bandwidth system for high-value CBR (constant bit rate) service at E1 and higher data rates (up to 10 Mbps/user). 

  • A shared-bandwidth access systems to provide IP connectivity at low cost. 

  • A high-performance, bandwidth-on-demand ATM system to provide high-data rate connectivity to multiple users simultaneously with maximum spectral efficiency achieved through dynamic bandwidth allocation. 

  • Digital TV video broadcast in QPSK and QAM formats. 

Additional system details appear in an article published in the Spanish Journal of Communications Engineering (BIT number 115). A printed copy can be obtained by contacting Cable AML at sales@cableaml.com.