THURAYA Innovative Solution for Rural Telephony
By Ahmed Alabd, Senior Engineer Services Development, THURAYA Satellite Telecommuncations Company
Despite the ever expanding and converging digital technologies in the Technical Arena; according to some statistics, there still exist about three billion people living in rural areas without any means of basic communication services. The huge investment required to establish the necessary infrastructure and the low ARPU, drew Telecom Service Providers (TSP) and investors away from these areas; leaving billions of people out of reach. In some countries where Universal Service and other governmental regulations impose the requirement on the TSPs to service these remote areas or be liable for paying huge fines, TSPs often chose to pay the fine, as it is in many cases a small fraction of what they would have paid to invest in furnishing new infrastructure.
Satellite-based Public Telephony Solutions (PTS) provide for a very cost effective and easy deployment of the service. No matter how difficult the terrains are, you can always be in touch with the rest of the world. THURAYA Satellite Telecommunications Company provides two types of PTS; Payphones and Public Calling Offices (PCO). The combination of these two solutions allows customers to benefit from cost-effective telephony services and the operators to avoid the heavy penalties.
After a successful launch of the pilot payphone and PCO projects in different countries with various climatic conditions under the vast coverage of the THURAYA service area, THURAYA was fully geared toward commercial deployment of its innovative and cost-effective PTS whereby THURAYA taps a huge market of remote and rural areas that are of lower population densities, highly scattered settlements and mostly with no means of communications.
Thuraya PTS, with its three different flavors; Indoor, outdoor and PCO, are designed around the concept of Black Box (BB) know generically as Communications Interface Module (CIM).
The purpose of this case study is to show the benefits of the innovative PTS of THURAYA, exemplified by the Payphone solution, in extending the reach to remote areas.
Thuraya PTS Business is highly driven by the huge number of scattered unconnected villages under the Thuraya service footprint. In areas where basic telephony services are non-existent and people cannot afford to buy Satellite Phones, options to connect these areas to the rest of the world are very limited. As it did in other services, Thuraya is pioneering the work in the field of PTS to draw rather more smiles on more faces. The Indian subcontinents and Africa are among the highest areas that would benefit from the Thuraya PTS.
As stated in the Introduction, Thuraya PTS are established around the “Black-Box” (BB) concept. The BB arrangement virtually allows any COTS payphone or PCO to become a THURAYA enabled solution. The BB provides the payphones from one side with the necessary power, dial tone and signaling to start the billing cycle and access to Thuraya network over the satellite from the other side. The BB consists of Thuraya HHT with some other circuitry that provides the necessary power and dial tone requirements. The BB becomes independently operational by inserting a valid SIM card (prepaid or postpaid), connecting the Antennas (Satellite and GPS antennas) and powering it up. For any standard COTS payphone or PCO to work as Thuraya payphones, all you need to do is to connect the BB to the payphone via the standard RJ-11 Interface as depicted in Figure-1 below.
Interfaces between the BB and the Payphone
Upon powering up the BB with the proper configuration and connectivity (e.g. with an active SIM, antennas installed, etc), the Payphone should, in principle, be ready for operation. There are two physical interfaces that exist between the payphone and the BB, these interfaces are:
1. RJ-11 Interface:
This interface between the BB and the Payphone provides the payphone with the necessary power to operate, the polarity reversal to indicate that the call is connected to trigger the charging mechanism and finally, it serves as the voice communication path between the Payphone and the BB.
2. RS-232 Interface:
The Payphone is also connected to the BB via a standard RS-232 interface to handle the security and authentication between the two units. Additionally, All the data calls, from and to, the Payphone Management System (PMS) will be carried over this interface.
The Payphone shall be capable of originating and receiving voice and data calls. The voice calls will be originated by dialling the called number (destination number) using the payphone keypad. Upon call initiation, the Payphone will send a pre-defined PIN code using the RS-232 interface for authentication purposes proceeded with the dialled digits to the BB, which will in turn establish the call to the desired destination. Incoming voice calls are passed over the RJ-11 interface to the Payphone. The Payphone is also capable of originating and receiving data calls using the RS-232 Interface. Data calls are originated by the mean of sending AT commands to the BB. The same interface will be used to receive data calls. The Payphone supports Call Back feature by receiving data call, terminates it, and call the PMS back. While voice calls are servicing the end customer, the Payphone owner uses the data calls for Payphone management purposes that are desirable to monitor the health and administer the system.
The BB expects standard dialled digits with no specific termination key. However, considering the security implementation, the BB establishes calls only if the PIN code sent by the Payphone is correct.
There are three levels of security implemented in the THURAYA Payphone Solutions; these are:
1. Security between the BB and the Payphone:
In addition to securing the BB inside the casing of the Payphone, an authentication process is implemented between the Payphone and the BB. This authentication prevents the misuse of the BB by individual that might be able to have an access to the inside of the Payphone.
2. Security of Chip Cards
THURAYA offers its Payphone solutions with the new generation of Chip Cards (EUROCHIP/T2G) that are designed with the ability to be actively authenticated by an external Module, called Security Access Module (SAM). The SAM is installed in the payphone card reader and is able to authenticate the card by the method of challenge and response.
3. Security of Accessing the Payphone Menu.
The security scheme of the Payphone Menu also limits the access to the Payphone menu to the authorized personnel that have the correct Service Mode passwords. Service mode is a special operating mode pertaining to the payphone maintenance and troubleshooting. There are two methods to enter service mode:
The payphone has two password protected service modes described as:
- Use of Service Card
- Opening of the door
a. Technician Service Mode with restricted accessibility and
b. Master Service Mode with full accessibility.
THURAYA Payphone solution can be powered using the mains or conveniently via the solar power. There is no need to power the two units (BB and Payphone) separately, the Payphone derive its power from the BB directly over the RJ-11 Interface; making the solar solution very convenient and desirable for remote areas and in places were the electricity is discontinuous.
Thuraya PTS offers lost of benefits to both, the Telecom Service Providers (TSPs) or Operators and the end user. Following are some of the benefits to the two segments:
- Benefits to TSPs/Operators
- No need to invest in any infrastructure: This has been the biggest obstacle for Telecom Operators in connecting rural areas.
- Adding new revenue stream: The operators will enjoy their share out of the generated Airtime.
- Fulfilling regional obligations and avoiding heavy fines.
- Expanding their Services’ portfolio and customer base.
- Benefits to the End Users
- No longer out of reach.
- Affordable call charges.
- No subscription or monthly fees.
- Enhanced services during emergency situations.
- Technical Benefits of the Solution
- "Plug-n-Play" solution. With the solar panel option, you can virtually install the payphone and operate it in desirable areas without doing lots of preparatory work.
- Black-Box Concept. Enables almost any standard COTS payphone to become a Satellite-Based Payphone.
- Enhanced security. With the implemented security mechanism, fraud risk is not of an issue.
- Remote access to the Payphone via the PMS. Although this is a standard payphone feature, implementing the "call back" technique over the satellite link adds additional security layer to prevent an unauthorized access to the Payphone.
In summary, Thuraya PTS is a vital service to many parts of globe that reside under Thuraya footprint. The solution offers a very cost effective, efficient, affordable and reliable solution. The innovative technical concept and design of the solution provides Thuraya with a leading edge over other service providers of similar interests, as any COTS payphone could be enabled to provide Thuraya services. This brings the total cost of the solution down and allows operators to reduce their Time-to-Market by deploying the solutions in relatively short time. The high available of the satellite systems in general adds yet another dimension to the precious, diamond like, telephony services.
For more information, please contact:
Ahmed Alabd: email@example.com