multi imsi roaming hub

Technology Within the Multi-IMSI Roaming Hub

SIM Card Technology

Key to the Multi-IMSI Roaming Hub is sophisticated software with heuristic technology running on JAVA-capable SIM cards. This technology allows the SIM card to select the appropriate IMSI to use in each country in order to minimize the outbound roaming costs for subscribers, all without a subscriber’s intervention. The IMSI selection algorithms, which evolve over time and according to customer usage patterns, are managed remotely by Telna. There is no complexity for the buying member who is simply charged according to a binding worldwide IOT list known in advance. Additional IMSIs can be uploaded to SIM cards in the field via OTA as new selling members join the hub, so that SIM cards do not need to be updated manually over time. It is possible to either purchase ready to go Multi-IMSI SIM cards from Telna (on which the member’s existing IMSI range will have been preloaded), or to work with the member’s existing SIM card manufacturer, as long as it supports standard JAVA card technology. It is often less expensive to procure SIM cards from Telna, due to economies of scale that are achieved by aggregating all members’ SIM card purchases.

Core Network Technology

The intelligent Multi-IMSI SIM cards communicate with the redundant, patented Roaming Hub platform located in the Telna core network. This is the business engine of the Multi-IMSI Roaming Hub solution, where all signaling comes together and is routed between buying and selling members. The service is provided to each member on a hosted basis, so that no costly infrastructure is required in the member’s network, which greatly reduces setup times and costs, and makes the solution profitable even with low volumes of outbound roaming traffic. The subscriber is controlled by the home HLR and other network nodes (for example IN) in the usual fashion, so that all home services are available to the subscriber, and realtime billing and fraud control stays in place. There is no new or additional MSISDN assigned to the subscriber, unless this is specifically requested as part of multi-MSISDN services.

Additional Core Network Features

Several innovative add-on services are available to members, in order to customize the customer experience as required by each business case:

Camel Home Routing

The cost of outbound calls can be further reduced by automatically rerouting international calls through the Multi-IMSI Roaming Hub platform according to sophisticated business rules which take into account the specific commercial agreement with each visited network. This service ensures that even calls to non-mainstream countries can be made at a low price.


For particularly frugal subscribers, callback can be enabled to reduce the cost of calls even further. The sophisticated callback mechanism works even on non-USSD capable networks, and real-time billing capabilities are maintained at all times. Subscriber bases can be segmented, and callback can be enabled only on specific groups of subscribers within a buying member’s network.

Multi-MSISDN Technology

For subscribers who travel frequently, buying members can chose to provide multiple MSISDNs to their subscribers, on a single SIM card. This allows subscribers to be reachable at local costs from multiple countries, and is beneficial for multi-national corporate subscribers. All MSISDNs are full mobile numbers capable of receiving both voice, and SMS. At the moment, MSISDNs in USA (3000 cities), Canada (32 cities), United Kingdom, Poland, Australia and Latvia can be provided.

Automatic APN Provisioning

Automatic APN provisioning via over-the-air OMA technology can be provided for popular handsets, to enhance the subscriber’s customer experience and increase usage of data services.

Interstandard Conversion GSM<->ANSI-41 For CDMA Operators

Thanks to the interstandard conversion capabilities of the Multi-IMSI Roaming Hub, it is possible for CDMA operators to enjoy the entire footprint of the hub and gain nearly worldwide coverage, as long as their subscribers can carry dual-mode CDMA-GSM handsets containing a SIM card (or a separate GSM handset). The subscribers remains entirely controlled by the HLR in the CDMA home network, and keep the same phone number when traveling as when they are at home on the CDMA network.


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FR2923128 – General packet radio service personalization profile managing system for mobile telephone, has server for updating profiles, where sending of profiles is repeated with periodicity depending on frequency of arrival of new phones in network
FR2911239 – Call terminating system for e.g. global system for mobile communication network, has voice over Internet protocol platform implementing internet protocol by Internet protocol address, and protocol program transmitting and receiving calls

All patents are fully licensed to Telna by the respective patent holders.