European Space Agency

AMG4.7, 4.8, 4.9 and LSF2.1 MP1.0


There are separate development efforts for this project which are captured internally within Altobridge as AMG4.7, 4.8, 4.9 and LSF2.1 MP1.0

The goal of the Altobridge solution is to provide GSM services in a number of deployments using efficient use of satellite bandwidth through the AltoBridge patented Call handling Model and Signalling Encoding Scheme. The signalling encoding and handling scheme ensures that the system uses the least possible satellite bandwidth while supporting all necessary signalling for compatibility with PLMN requirements such as mobile authentication.

The call model can make use of raw satellite bandwidth or can piggy-back on top of existing ISDN (Q.931) based systems whichever is most appropriate; this allows existing satellite equipment to be used in a most cost effective method. Data streams carrying voice traffic are compressed to ensure optimal cost to quality ratios.

AMG4.7 Project

AMG4.7: The main objectives of AMG4.7 were to satisfy requirements to put the Remote Gateway software onto a single board computer. Currently at the remote site we need to deploy two pieces of hardware, a Remote Gateway Linux machine and a Pico BTS. The implementation of this feature will remove the necessity for having a RGW unit at the remote location by adding a processing board to the BTS unit and porting the RGW functionality to this unit. This results in reducing the cost of goods for remote deployments.

AMG4.8 Project

AMG4.8: The main objectives of AMG4.8 were to satisfy a number of new requirements such as to introduce handover capability and also the replacement of the current SS7 stack with the R4S. This included the following features:

  • Intra BSC handover,
  • Inter BSC handover,
  • Handover to public BSC,
  • Replace TE SS7 platform by R4S platform.

AMG4.9 Project

AMG4.9: The main objectives of AMG4.9 were to satisfy a number of new requirements. The main new functionality introduced was as follows:

  • UW POD Cluster,
  • Local Switching Area,
  • Cluster and Local switching area,
  • VBSC will local switch all the calls within a Local Switching Area,
  • Paging by UW POD cluster,
  • Paging Optimization,
  • Lawful interception,
  • Filter of the target by IMSI, IMEI, MSISDN.

LSF2.1 Project

LSF 2.1 MP1.0 builds on our release of the Local Switching product by improving its functionality. Specifically this release adds new requirements and also maintenance work. The new features included:

  • BCF expansion to non consecutive spans,
  • AMR 7.4 HR Support,
  • Export of Performance Management stats,
  • Support for a new set of BTS Alarms including AIS, IP, PPP.


For LSF2.1 MP1.0 end to end System Test was only possible in the customer lab environment. As such we had to work very closely with the customer.

The Handover Feature required significant amounts of lab testing and recoding due to the complexity of the feature.


AMG4.7/4.8/4.9:- We have demonstrated our ability to provide both single and multiple TRX remote system which generates a positive Return On Investment for GSM operators and helps them meet their universal Service Obligations for small communities (100 to 200 users) with a relatively high ARPU. In the Aero Market the EXP1 release allows integration with the Panasonic Server which will allow the Aero solution to integrate with the Panasonic In Flight Entertainment Hardware, thus reducing roll out costs and providing a channel to market through Panasonic a world leader in In Flight entertainment systems.

AMG 4.7+ licences have been sold to Stratos to facilitate the roll out of Fleet Broadband (FBB) in the merchant maritime market.

Altobridge will directly target the Remote Community market on land, typically remote communities linked by VSAT to the main switch and therefore with high transmission costs. The developments under AMG4.7+ will allow Altobridge to further enhance its offering in the remote market by reducing site costs through the replacement of the Remote Gateway with a single board computer in the Base Station (BTS), reducing the Ground Gateway (GGW) cost by replacing the TietoEnator SS7 stack. AMG 4.7+ will also introduce necessary features such as Handover between sites, Clustering, Local Switching between clusters, Paging and Lawful Intercept without which MNOs could not lawfully install the Altobridge BSC in some countries.

LSF2.1 MP1.0:- This project built on top of the existing 2.1 release by providing over 40 enhancements for the release.

The LS solution offers a significant reduction in operating expenditure of GSM sites as a percentage of calls are locally switched, reducing satellite and terrestrial bandwidth requirement. This results in extra savings for the operator. Satellite bandwidth requirements are further reduced by optimisation of the Abis over IP.

The following codecs are supported:

  • Full Rate (FR)
  • Half Rate (HR)
  • Enhanced Full Rate (EFR)
  • All AMR codecs

LS supports intra cell handover and Inter cell handover within the RGW. This means that the call remains locally switched after the handover.

If one of the parties on a locally switched call requires handover to a cell outside of the RGW, the call is handed back to the network.


AMG4.9 Project

Architectural Diagram

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BTS: This element of the overall system shall consist of a standard low power pico-cell BTS.
AltoPod: The Altobridge Remote Gateway, in conjunction with the Altobridge Ground Gateway, shall enable the use of minimal bandwidth while providing ubiquitous GSM Voice and SMS services to mobile users. It essentially shall emulate the GSM function of a BSC in conjunction with the Altobridge Ground Gateway.

Remote Gateway Structure

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Satcom Terminal: This aspect of the overall solution provides connectivity between the Remote Gateway and the Ground Gateway.
Ground Earth Station (GES): This entity of the overall solution provides the connectivity between the satellite network and terrestrial telephony and packet data networks. It is the complimentary peer of the satellite terminal equipment.
Ground Gateway: The Ground Gateway shall provide the complementary peer of the Remote Gateway and this system shall provide a standard inter-connect to the Public Land Mobile Network (PLMN) this essential part of the Altobridge product offering shall enable multiple Remote Gateways to interact with standard GSM network through one interface.
MSC: The Mobile Services Switching Centre (MSC) is an integral part of an existing PLMN. It shall provide standard MSC and Visitor Location Register (VLR) functions for the subscribers at remote locations.

LSF2.1 MP1.0 Project

Architectural Diagram

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To integrate Local Switching into the customer product suite, two new network elements are integrated into the current BSS architecture:

  • RGW - remote Abis gateway located with the BTS
  • CGW - central Abis gateway located with the BSC.

The RGW (Remote Gateway) and the CGW (Central Gateway) as seen in the figure above are the base components of Local Switching technology. The RGW is the interface between the remote BTS and the E1 or T1. The CGW is the interface between the BSC and the E1 or T1.

The other components (BSC, MSC etc) are independent of the Altobridge solution and not governed by our architecture in anyway. As such, their function remains the same as described previously in the AMG architectural description.


As this project encompasses separate deliverables, there were different project plans as detailed below.

The implementation and execution of all projects was achieved and all deliverables have been completed.

AMG4.7/4.8/4.9:- The project plans addressed delivering the software features on the AMG releases in line with the planned timeline to exceed customer expectations.

Specifically, the features developed and delivered included:

  • Single Board Computer Porting
  • Intra BSC handover
  • Inter BSC handover
  • Handover to public BSC
  • Replace TE SS7 platform by R4S platform
  • UW POD Cluster
  • Local Switching Area
  • Cluster and Local switching area
  • VBSC will local switch all the calls within a Local Switching Area
  • Paging by UW POD cluster
  • Paging Optimization
  • Lawful interception
  • Filter of the target by IMSI, IMEI, MSISDN

LSF2.1 MP1.0:

This project delivered the following features:

  • BCF expansion to non consecutive spans
  • AMR 7.4 HR Support
  • Export of Performance Management stats
  • Support for a new set of BTS Alarms including AIS, IP, PPP

Current status

Project was successfully completed in November 2011.

Status date

Friday, November 4, 2011 - 13:09