Telecommunications – Transmitter and receiver at separate stations – Plural transmitters or receivers
Reexamination Certificate
1999-12-08
2003-09-02
Bost, Dwayne (Department: 2681)
Telecommunications
Transmitter and receiver at separate stations
Plural transmitters or receivers
C455S013400
Reexamination Certificate
active
06615052
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to radio transceivers having multiple voice and data input/output channels, and in particular to radio frequency power control algorithm for dynamically sharing among the channel transmitters of the available output power.
BACKGROUND OF THE INVENTION
Mobile cellular to satellite communication system radio transceivers having multiple voice and data input/output channels are known. One example of such a mobile cellular to satellite communication 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. Such mobile cellular to satellite communication systems accept data and voice from various sources onboard the aircraft, encode and modulate this information to appropriate Radio Frequency (RF) carrier frequencies, and transmit these carriers to the satellite constellation for relay to the ground. Mobile cellular to satellite communication 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.
FIG. 1
illustrates a block diagram of the avionics forming a specific implementation of the airborne mobile cellular to satellite communication (SatCom) systems equipment
100
of a satellite communication system, which provides worldwide continuous multi-channel voice and data communications for commercial air transport aircraft. Airborne SatCom equipment
100
accepts data and voice input from various sources onboard the aircraft, encodes and modulates this information to appropriate radio frequency (RF) carrier frequencies, and transmits these carriers to the satellite constellation for relay to the ground. The avionics also receives RF signals from the satellite constellation, demodulates these RF signals, performs the necessary decoding of the encoded messages, and outputs data or voice for use on-board the aircraft by crew members and passengers.
The avionics forming one typical implementation of mobile cellular to SatCom equipment
100
for commercial air transport aircraft include, for example, a satellite terminal or telecommunications unit (STU)
102
; cavity filter/low noise amplifier (CF/LNA) package
104
; a high power amplifier (HPA)
106
; and a low gain antenna (ANT)
108
. According to at least one implementation of mobile cellular to SatCom equipment
100
for commercial air transport aircraft, each of the avionics are fully compliant with ARINC Characteristic
761
, Second Generation Aviation Satellite Communication System, and ARINC Characteristic
746
, Cabin Communications System.
In
FIG. 1
, mobile cellular to SatCom equipment
100
resident on multiple aircraft includes, for example, satellite terminal or telecommunications unit
102
, which is essentially a mobile switch, allowing several users, including passengers, flight crew and automated avionics systems, to share the radio channel units (RCUs)
110
contained within satellite telecommunications unit
102
. Radio channel units
110
are modular radio units which typically support both voice and data transmissions on the L-Band radio frequency link, including such standard mobile cellular telephone capabilities as voice mail, call forwarding and worldwide messaging, PC data, packet data, and facsimile transmissions, as defined by GSM, the mobile cellular network found throughout Europe, Africa, Asia, and Australia defining the standards governing wireless networks in those territories. A typical satellite telecommunications unit
102
also supports multiple ARINC
429
interface channels. One specific implementation currently provides 7 communication channels: 3 voice channels and 4 data channels. Specific proprietary implementations of satellite telecommunications unit
102
support multiple external interfaces, including, for example, Conference Europeene des Postes et Telecommunications (CEPT-E1) interface to cabin telecommunications unit (CTU)
112
communicating using ARINC Characteristic
746
protocol over a over a high speed serial bus pair interface, which can accommodate multiple digitized voice channels along with status and control information.
Cabin telecommunications unit
112
interfaces with the cabin/passenger telecommunication equipment
114
, such as telephone handsets
116
and data ports
118
via in integrated services digital network (ISDN). Cabin telecommunications unit
112
supplies the traditional private branch exchange (PBX) features for the cabin/passenger telecommunication equipment. Cabin telecommunications unit
112
also functions to provide signal processing, i.e., analog-to-digital and digital-to-analog conversion; dial tone generation; call queuing; and providing status messages, such as, “Please hold; your call is being processed.”
Cavity filter/low noise amplifier (CF/LNA) package
104
includes cavity filter (CF)
120
and either a low noise amplifier (LNA) or a diplexer low noise amplifier (DLNA)
122
, depending upon the specific embodiment. Cavity filter (CF)
120
and low noise amplifier
104
switch the transmit (TX) and receive (RX) paths to low gain antenna
108
from satellite telecommunications unit
102
. Low gain antenna
108
also amplifies the receive signal to the level required by satellite telecommunications unit
102
. Cavity filter/low noise amplifier circuit
104
insures that the transmit path is isolated from the receive path during the transmit mode to prevent damage to sensitive low noise amplifier
122
. High power amplifier
106
receives and amplifies the combined transmitter output power of all active radio channel units
110
and transmits the amplified signals to antenna
108
for transmission to a satellite network for communication. High power amplifier
106
preferably provides an sufficient RF power level to antenna
108
to maintain the aircraft Effective Isolation Radiated Power (EIRP) within specified limits. The design of high power amplifier
106
generally accounts for varying cable losses and avoid excessive thermal dissipation. Antenna
108
is preferably a weight, size and cost-conscious low profile, low gain antenna that provides adequate link margins from all reasonable aircraft orientations and satellite orbits.
The total fixed power level capability of high power amplifier
106
is divided into multiple radio channel units
110
. Each radio channel unit
110
includes a transmitter (not shown) that transmits at a fixed power level depending upon the type of communication, voice or data, assigned to an individual radio channel unit
110
.
FIG. 1
shows a typical division of radio channel units
110
into four voice channels and three data channels. A processor portion of satellite telecommunication unit
102
directs the various voice communications on handsets
116
to one of the four voice radio channel units and directs data communications on data ports
118
to one of the three data radio channel units. As mentioned above, radio channel units
110
are each permanently assigned as either voice or data channels and preset to appropriate output power levels. Both voice and data channels are preset to an appropriate initial output power level, where this initial output power level is determined according to the system requirements necessary to maintain a particular minimum bit error rate (BER) in the specific voice or data link. Voice data can typically tolerate an overall higher BER than can an equivalent data link and remain useful, i.e. intelligible. The overall BER is a function of the power in the channel. Therefore, the initial power level on the data channels is typically higher than on the voice channels to maintain an acceptable BER. Output power is fixed for each voice and data channel and cannot be shared amo
Bost Dwayne
Honeywell International , Inc.
Ramos-Feliciano Eliseo
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