Multiple subscriber interface and simplified provisioning...

Details Multiple subscriber interface and simplified provisioning... Multiple subscriber interface and simplified provisioning...

1999-12-08

2003-06-24

Maung, Nay (Department: 2681)

Telecommunications

Transmitter and receiver at same station

Radiotelephone equipment detail

C455S557000, C455S550100

Reexamination Certificate

active

06584326

ABSTRACT:

FIELD OF THE INVENTION
Mobile cellular to satellite telecommunication systems, and in particular the installation, programming and accessing of subscriber interface modules thereof.
BACKGROUND OF THE INVENTION
Mobile cellular to satellite communication, or SatCom, system radio transceivers having multiple voice and data input/output channels are known. Such mobile cellular to SatCom systems accept data and voice from various sources onboard a host aircraft or other vehicle, encode and modulate this information to appropriate Radio Frequency (RF) carrier frequencies, and transmit these carriers to a satellite constellation for relay to the ground. Mobile cellular to SatCom systems also receive RF signals from the satellite constellation, demodulate these signals, perform the necessary decoding of the encoded messages, and output data or voice for use onboard the aircraft by crew members and passengers. One example of such a mobile cellular to SatCom system is the AIRSAT® Multi-Channel Satellite Communication System, described in a brochure published October 1997 by AlliedSignal Incorporated, entitled “AIRSAT MULTI-CHANNEL SATELLITE COMMUNICATION SYSTEM for IRIDIUM®,” which provides worldwide continuous multichannel voice and data communications for commercial air transport aircraft.
While the number of communication channels provided depends upon the manufacturer's implementation, a typical mobile cellular to SatCom system unit supports multiple communication channels. One specific implementation currently provides 30 voice channels and 30 data channels. Specific proprietary implementations of the mobile cellular to SatCom system unit support multiple external interfaces, including, for example, up to 30 digitized voice channels interfacing with user terminals. Onboard a host aircraft the user terminals are the cabin and passenger telecommunication equipment, such as seatback telephone handsets. The user terminals interface with the mobile cellular unit control system through Subscriber Interface Modules, or SIM cards, that hold the user's identification for billing and other purposes. The SIM cards also each convert analog voice input into a digitized serial data stream. Multiple SIM cards are associated with each channel of the mobile cellular unit. The SIM cards, sometimes referred to as microprocessor cards, include an eight-bit microprocessor that ensures the safety of the data and allows multiple use of a single user terminal.
All mobile cellular units use a micro-controller, or microprocessor, to interface between the main system central processing unit, or CPU, and the SIM cards. The micro-controller is part of a SIM card reader, which also includes several interface circuits, one for each SIM card. The main CPU lacks the processing time available to handle the actual serial data. The SIM card reader off-loads processing overhead from the main system CPU and relays information from the SIM cards. Although all known SIM card readers include a micro-controller interface between the main system CPU and the SIM interface circuits, the SIM card reader generally allows the micro-controller access to only one or at most two SIM cards.
One known implementation includes multiple conventional universal asynchronous receiver-transmitters, or UARTs, each interfacing with a each SIM card to convert the SIM card serial output to parallel data so that it can be received by the CPU. Another known implementation includes a conventional UART and a micro-controller to interface between the SIM cards and the CPU, but fails to allow access to more than one SIM card. Still another known implementation includes a conventional universal asynchronous receiver-transmitter, or UART, to manage the serial output of the micro-controller for the CPU. Although this combination of micro-controller and UART in the SIM card reader allows the main system CPU to access up to six to nine SIM cards, even this level of access is insufficient in mobile cellular units providing as many as 30 or more voice channels. A mobile cellular unit would require several of any of the prior art SIM card readers to support such a large number of channels, thus resulting in multiples of the SIM card reader functionality. Furthermore, the additional micro-controllers reduce overall system reliability.
FIG. 1
is a block diagram of one prior art mobile cellular unit
5
transmitting and receiving signals between multiple user terminals, such as cabin and passenger telecommunication equipment onboard a host aircraft or other vehicle, for example, seatback telephone handsets, and a satellite constellation for relay to ground stations. The mobile cellular unit must access each of the user terminals to provide this user terminal-to-satellite interface. As shown in
FIG. 1
, the mobile cellular unit of the prior art includes a control system
100
having a main system central processing unit, or CPU,
110
performing the actual receive and transmit functions between mobile cellular unit
10
and the satellite constellation. CPU
110
interfaces with multiple user terminals through a SIM card reader
112
.
The SIM card reader illustrated in
FIG. 1
is the only known prior art device that permits the main system CPU to access more than one or two SIM cards. Other mobile cellular units require a different SIM card reader to access each SIM card. In
FIG. 1
, prior art SIM card reader
112
includes a built-in microprocessor, or micro-controller,
114
coupled via common serial I/O chip select. The chip select is a common control line available on each discrete SIM interface module or circuit
116
. An active SIM interface circuit
116
has sole ownership of the common serial I/O line. Multiple lines CS
1
, CS
2
through CS
N
couple to up to nine separate and independent interface circuits
116
to common serial I/O of micro-controller
114
. Thus, each interface circuit
116
allows micro-controller
114
to access one Subscriber Interface Module, or SIM card,
118
. SIM cards
118
interface with the user terminals to convert analog voice input into a digitized serial data stream for transmission over the serial interface to micro-controller
114
. Micro-controller
114
off-loads control of individual SIM cards
118
from main system CPU
110
, thereby reducing demands on the processing time required to handle the actual serial data. Micro-controller
114
incorporates an address register that it decodes to obtain chip selects for SIM cards
118
. These chip selects are used by SIM card interface circuits
116
to access individual SIM cards
118
.
Micro-controller
114
relays information from SIM cards
118
to CPU
110
over a standard RS232 interface. SIM card reader
112
also. includes a universal asynchronous receiver-transmitter, or UART,
120
at each end of the RS232 interface to manage the serial output of micro-controller
114
for CPU
110
by converting the serial data to parallel data so that it can be received by CPU
110
. Still, mobile cellular unit requires multiple SIM card readers
112
to an nine SIM cards, such as is presented by one or more current mobile cellular-to-SatCom implemetations. Thus, as shown, the prior art device requires a complexity and redundancy of circuitry that increases the device cost while reducing reliability.
Accurate mapping of SIM cards to their associated terminals in the mobile cellular unit is critical to functionally enabling a system for operation on the mobile cellular to SatCom network. In a typical installation, the SIM cards are installed in the field. The field installer is required to accurately record each SIM card identification number and note the installation slot to which the SIM card applies. For aircraft installations which incorporate multiple SIM cards for handling multiple user terminals, the field installation process provides numerous opportunities for documenting and recording errors. For example, SIM card identification number transposing, mis-entering and/or mis-recording during installation of the physical slot location in which each individual

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