Wireless Local Loop

Throughout the world, local exchange carriers must deliver telephone service to remote areas where wireline facilities are unavailable or too expensive.

Using GSM or S-CDMA standards, GNS designs wireless local loops that solve this problem with cost-effective wireless links between the telecom service provider and its subscribers.


Global Network Solutions' Wireless Local Loop is a radio based, DMA Digital Loop Carrier, that provides a cost effective wireless link between the telecom service provider and subscribers. The system can operate with GSM Handsets/Mobile Units, as well as with GSM compatible Subscriber Units. The system is transparent to the Central Office and subscribers, and interfaces with the most standard Central Office Switches and subscriber telephone equipment.

GSM Wireless Local Loop Architecture


  • Wireless telecommunications services within a 35 Km radius
  • Wireless extension of existing wire services
  • Economical rollout for low and high population density areas
  • Temporary, seasonal, and emergency telecommunications services
  • Adaptable for regional PCS
  • Regular 2-wire linesas well as 4-wire lines/E&M, pay-phone services, mobile phones, fax, and modems
  • Inexpensive alternative to mobile cellular service (without handover)
  • Fixed cellular and mobile cellular services
The system uses the robust GSM technology to deliver high quality voice, privacy and spectrum efficiency.

Each 200 kHz radio channel provides up to 16 simultaneous voice/data connections (future expansion to 32). Optimal network design provided by GNS insures economical service of subscribers, from several hundred up to hundreds of thousands.

Frequency agility allows each radio channel to be placed anywhere in the GSM bands (900 MHz, 1800 MHz or 1900 MHz)

The Service Area (Cell) can be any distance from the Central Office as defined by the location of the Base Radio Station and Tower.


To cover a larger area, a "fixed-cellular" approach with frequency reuse can be employed.

  • Central office site - network access subsystem (NAS) controller

  • CO/Remote sites - base transceiver station (BTS)
  • Subscriber site - single line subscriber unit, pay-phone subscriber unit, GSM

Network Access
The network access subsystem (NAS) ensures system compatibility with the most standard central office switches or could act like a fully functional class 5 switch itself.

  • NAS can also be configured as a tandem switch or long distance switch.
  • Multiple NAS can be interconnected to increase capacity to 100,000 customers.
  • Multiple interface capability include POTS, AMPS, GSM, TDMA, CDMA.
  • Controller supports up to 132 cells (sites) with up to 2,500 simultaneous voice connections.
  • The unit has embedded hot billing and prepaid service package.

Radio Link
The base radio station is a trunked digital radio which may be co-located with the central office or located at a remote site. Signals received from the central office over T1/E1 trunks are compressed and multiplexed into smaller number of radio channels and then broadcast to subscribers. Each 200 kHz RF channel carries 8/16 digital voice/data transmissions. A base transmission station cabinet accommodates up to 24 frequency-agile radio channels (TRXs), allowing up to 195 simultaneous voice/data connections per BTS. The radio link supports GSM bands (900 MHz, 1800 MHz, 1900 MHz) and future dual-band in a single cabinet.

Subscriber Unit
The subscriber unit is a full duplex radio transceiver that contains digital radio and telephone interface circuitry. The subscriber unit provides a standard two-wire loop-start/ ground-start for customer premise equipment and optional payphone interface. Each subscriber line can serve up to 5 telephone sets, including standard telephone devices e.g. speaker phones, answering and facsimile machines, modems, etc. An optional back-up battery provides uninterrupted service in case of a power failures for several hours.

GSM Handset
A GSM hanset can also be used as an enduser device. The solution provides access to any telecom medium. Connection of the system (through NAS) to the public switched telephone network may be done through copper wire, coaxial cable, fiber optic cable, or microwave link. This enables the system to interface to any type of telephone service infrastructure.


The (NAS) system can also be configured to interface with a low earth orbit (LEO) or geostationary (GEO) satellite system, terrestrial cellular, or personal communication service (PCS). This makes the system particularly attractive in areas where the satellite or cellular service provider is the only practical access to the public telephone network.

Areas of applications of the sytem include, but not limited to:

  • Wireless extenion to PSTN
  • Local access system for long distance operators
  • Private networks (oil co., railroad co., etc.)
  • Combination of wireline, fixed access, roaming/mobile services
  • Conventional phones, pay phones, cellular handsets
  • Emergency communications networks
  • Satellite network local distribution system
  • Internet service provision

CDMA - PrimeWave 2000TM
GNS, a world leader in military communications for nearly forty years, uses a revolutionary technology created specifically for wireless local loops - Prime Wave 2000TM - to design CDMA-based wireless local loop solutions. Prime Wave 2000TM is a synchronous code division multiple access (S-DCMA) system based on communications technology developed for international military applications. GNS, a world leader in military communications for nearly forty years, built this leading edge technology on its historical foundations with such companies as Lockheed Martin, Loral, and Unisys.

S-CDMA systems have a large network capacity (1:1 frequency reuse), low transmission power requirements (1Wt), a high data transmission rate (from 64 kbec to 256 kbsec), and secure channels. Because of S-CDMA spectral efficiency, systems using this technology have three times the capacity of such conventional CDMA systems as W-CDMA, B-CDMA, or IS-95, so you get maximum return on your limited network resources.

By combining the antenna and customer premises equipment (CPE) in one unit, the system eliminates cable loss, which can be very high on a GHz frequency band, and therefore increases coverage and reduces bit error rate. Because the network interface unit can interface with the telephone network as a class 5 switch, the system is a very powerful and cost-effective solution.

Spectral Efficiency - S-CDMA is currently the most efficient spread spectrum transmission method. It has capabilities 3-5 times greater than conventional CDMA. In addition, with the inherent 1:1 frequency reuse, operators can easily introduce new cells as subscriber density requirements increase.

Central Office Capability - The system interfaces with the PSTN through a fully functional class 5 switch, with such protocols as R2, CCS, and CAS. In the future, the system will support V5.2. In addition, such features as call forwarding, conferencing, and call waiting are available. The system also has billing and tolling capabilities. Enhanced functions multilevel priority calling is available for emergency applications to support hospitals, fire, police, VIP services, and any application requiring priority treatment.

Security - The system provides a high degree of security against carrier traffic interception for data or voice.

Services - The system supports facsimile machines, modems, computers, pay phones, and standard telephone equipment. Data rates as high as 64kbs provide business and residential internet access features and other applications. ISDN support is planned for the future.

Value - With Prime Wave 2000TM's efficiency and concentration, the operator can deploy cost effective, wireline quality services for high data rates, fax traffic, leased-line services, ISDN, and internet access.

Prime Wave 2000
Radio Base Unit (RBU) - The central radio equipment that can service as many as 2500 subscribers while maintaining up to 100 simultaneous user connections.

Network Interface Unit (NIU) - The interface between the radio elements of Prime Wave 2000TM and the PSTN.

CPE - Customer Premises Equipment
Element Management System (EMS) - A PC- or workstation-based operation, administration, maintenance, and provisioning (OAM & P) terminal.

Subscriber Unit (SU) - The subscriber's link to Prime Wave 2000TM. A wall or pole mounted antenna with integrated radio electronics that serves one, two, four, or eight independent telephone subscribers. Advanced network services that use the ISDN subscriber unit and the X.21 subscriber unit.

Network Termination Unit (NTU) - Small, wall mounted unit that is the connection point for subscriber telephone wiring.

Uninterruptible Power Supply (UPS) - A small uninterruptible power supply that interfaces with the primary power from the customer premises and contains the voltage regulators and emergency backup battery. It features SU backup power approximately six hours talk time and microprocessor controlled charging. It reports battery status and AC line power status back to the EMS of the RBU.

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