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Technical Newsletter

DecLoop 1.42 MB pdf

DECLoop Overview

Internet Connectivity 435 KB pdf

Internet Connectivity

Single Subscrition Unit 248 KB pdf

SSU/Data Modem

Base Station Controller 171KB pdf

Base Station Controller

Subscriber Terminal 176KB pdf

Subscriber Terminal

  1.  Wireless Local Loop (WLL)
       Fact & Fiction

  2.  Can Local Loop Business
       be attractive enough for
       private investors?

  3. An emerging star in WLL market?

DECLoop Wireless Local Loop system is designed to provide simultaneous circuit switched voice and medium-rate connectivity at homes and offices. Based on MC-TDMA standard specifications, DECLoop™ provides a complete wireless access solution for new and expanding telecommunication networks at a cost and service quality comparable to wired networks.

  System Features   Range of Transmission
  System Architecture   Application Diversity
  Key Specifications   Internet Connectivity
  Network Expansion

System Features

•  A telecommunication infrastructure system for wireless local loop application
•  Toll quality voice (32kbps ADPCM)
•  High speed Internet connectivity (sustained 70kbps)
•  Simultaneous voice and data
•  Dynamic Channel Allocation (no frequency planning)
•  Minimal initial infrastructure cost
•  Cost-effective and highly scalable WLL solution
•  Faster financial return

System Architecture

The basic system consists of DECT Interface Unit (DIU), Compact Base station (CBS) and Single Subscriber Unit (SSU).

DIU (DECT Interface Unit)
The DIU is a DECT exchange for wireless subscribers and provides an interface to the Public Switched Telephone Network (PSTN). Functions such as call processing, CBS powering and PCM/ADPCM transcoding are handled by the DIU.

CBS (Compact Base Station) more info...
The CBS is a small, unobtrusive pole or wall mounted unit providing 12 simultaneous speech channels. Each CBS can serve 30-70 subscribers and to cater for high subscriber densities, several CBSs can be co-located.

SSU (Single Subscriber Unit - Data Modem) more info ...
The Single Subscriber Unit - Data Modem is the new generation of fixed subscriber terminal in the DECLoop ™ system. The SSU/Data Modem offers direct Internet connectivity.

MW (Multi-Wallset)
The Multi-Wallset provides simultaneous voice service to four subscribers. It has all the features of the WS, but at a significantly lower per-line cost.

RBS (Relay Base Station)
A Relay Base Station extends the range of the DECLoop™ system by relaying DECT packets between the CBS and subscriber units. The RBS can handle 11 calls simultaneously.

BSD (Base Station Distributor)
The BSD is an optional unit used for the remote deployment of base stations through an E1 link over microwave, fiber or copper links. Each BSD can support upto four base.

NMS (Network Management System)
The DECLoop™ system provides a Network Management System that can be used to manage up to 30 DIU’s & their subscribers.

OMC (Operation and Maintenance Console)
It provides a userfriendly interface to the system administrator/Operator. OMC handles system administration, maintenance, call control, billing, traffic measurement and subscriber functions.

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Key Specifications

Number of Subscribers 1000 (Maximum); per DIU
Number of CBS 20 (Maximum); per DIU
Number of BSDs 5 (Maximum); per DIU
Operating Frequency (Mhz) DB1 1880 – 1900
DB2 1900 – 1920
DB3 1910 – 1930
Redundancy Hot Standby provided for all single point failures, except failure of
interface cards. 
Network Configuration Local Exchange with R2MF signaling on E1 interface. Access unit with V5.2 interface on E1 lines. DID-PBX with R2-MF signaling on E1 lines & Two-wire junction lines. PABX with two wire junction lines.
Busy Hour Call Attempts (BHCA) 20,000
Maximum Traffic
per CBS
5 erlang at 0.5% blocking; supports typically 33 subscribers at 0.15 Erlang/sub. 50 subscribers at 0.1 Erlang/sub. & 70 subscribers at 0.07 Erlang/sub
Voice Coding Toll Quality, 32 kbps ADPCM as per ITU T G. 726
Instruments Supported Standard two wire telephone or payphone with battery reversal & 16/12 KHz (optional) metering pulse. Modems up to 9.6 kbps, G3 Fax. RS 232 Interface to PC for 35 or 70 kbps internet access
Number of Tones Up to 11
Number of 3 party conferences 8
Number of Announcements 10 (2 six-second segments played alternately for each announcement.)
Modulation GFSK, MC-TDMA
Data Transmission Rate Up to 32 kbps (simultaneous voice and data) or up to 64 kbps data only.

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Network Expansion

Since WLL subsystems can be added as and when needed, network planning is simplified and network deployment can be achieved more quickly and at a much lower cost.

1. Initial set up 2. Add SSU/Data Modem

3. Add Base Stations 4. Add DIUs

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Range of Transmission

Some WLL systems use high power transmitters in order to extend their range of transmission. In contrast, in the DECloop™ system, the long range is achieved using cost effective Relay Base Station for up to 25 Km coverage and the Base Station Distributor for even longer distances.

Using an omni-directional antenna, one CBS
can cover an area with up to 4km
The range can be extended to up to 10km LOS, using directional antenna.

The range can beextended to up to 25km LOS, using direction alantenna and RBS.
Note: Transmission between CBS and RBS is the sameDECT standard (i.e. 1880-1900MHz, 250mW)

The range can be even further extended using BSD.

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Application Diversity

Urban Area
50,000 subscriber/km2

Micro-cells of 100m radius
having overlapping coverage.

Multiple CBS on street poles connected to DIU directly or through BSD.
Rural Area
1 subscriber/ km2 or less

Macro-cells of up to 25km radius

Multiple RBS on a single tower can serve desired number of subscribers.

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Internet Connectivity more info ...

With DECLoop™, subscribers can enjoy Internet connectivity at 70 kbps or have simultaneous voice and Internet access at sustained 35 kbps. The ethernet port on the SSU/Data Modem provides a direct connection to a PC.

With the use of a Remote Access Switch, the Internet traffic is separated and diverted to the ISP network, thereby reducing the traffic congestion on the PSTN.

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