MXPA97009984A - Control of closed circuit power for satellite communications system in the terrestrial orbit b - Google Patents

Abstract

The present invention relates to a satellite communications system that includes at least one satellite communication signal repeater, at least one ground station for transmitting a feeder link composed of a plurality of communication signals to at least one a satellite communication signal repeater, and a plurality of user terminals each receiving one of the communication signals on a user link from a satellite communication signal repeater; the satellite communication system further includes a system Closed loop power control having a plurality of internal circuits, individual circuits operating to compensate for one of the user links for communications signal disturbances occurring at least between the user terminal and the satellite communications repeater , and an external circuit that operates to compensate all user links for feeder link alterations that occur between at least one ground station and at least one satellite communication signal repeater

Description

CLOSED CIRCUIT POWER CONTROL FOR SATELLITE COMMUNICATIONS SYSTEM IN LOW LOW LOW ORBIT FIELD OF THE INVENTION The invention relates in general to communication systems based on repeaters and in particular to satellite-based communication systems which, in particular. lene two-way communication signal links between one and rnas sa + elites and at least one ground station.

BACKGROUND OF THE INVENTION Satellite-based communication systems are well represented in the prior art. For example, reference is made to the patent of E.U.A. No. 5,303,286, which was issued on April 12, 1994 to one of the inventors of the present application, and which is entitled "li reis Telephone / Sa + ellite Roami ng System". Reference is also made to the numerous patents of E.U.A., pa + foreign entities and other publications that are registered in the U.S. Patent. 5,303,286. The satellite + e systems of the orbit + networks have been proposed worldwide for mobile communications. These systems provide a capy to use manual communication devices at low cost or terminals. user to communicate via satellite to deliveries in remote, rural, suburban and other-type environments. As an example, user links to and from one or more satellites can operate at a relatively low frequency, such as a UHF signal. The user links are connected by one or more satellites to links from the originator originating in the ground station operating at higher frequency, eg, 3 GHz at 40 GHz or more. The feeder links are connected to a terrestrial gate that allows the user to have access to the teief-om network of public conminator (PSTN), a private network or some other terrestrial communications installation. In general, if the frequency of the elevator link is below 7 GHz, there is a small potential for serial alteration. However, for frequencies above 7 GHz, the effect of rain on the links to and from a satellite becomes increasingly significant. The research carried out by NASA and other quantifics that this rain effect had found the most severe alteration in what are called "rain cells" that are distributed around a site of the satellite link transmitter operating above 7 GHz. An additional consideration in a wireless communication system is the transmission power control. For example, the individual links of the user may be controlled in terms of power by a central site, such as a base station, after which the link alteration information between the user terminal and the exchange station was exchanged. base. This general technique is not known as terminal power control. One function of this power control is to mitigate the fading caused by trees, buildings and other factors that alter RF within the user's link. These alterations have the characteristic of reducing the level of signal power to a low level. To compensate for the reduction in the signal level, the user terminal can be instructed to increase its transmitted power. Correspondingly, the user terminal may be capable of requiring the central station to transmit at a higher power level. However, and in a satellite-based communication system that uses satellites as repeaters, an increase in power transmitted from the user terminal or from the ground station, such as a gate, can result in increased power that is required for the satellite repeater. In that satellite, power is a main resource that must be provided to and divided among many users, any increase in the power consumption of satellite is undesirable, in addition, and for user terminals powered by power, an increase in transmission energy can have a detrimental impact on the number and duration of the cells that can be made before the battery is required to be recharged1. This problem is combined if the link of the same linker is increased, in that the effect will be a reduction in signal strength in all associated user links. To compensate for the reduction in signal strength, all user terminals may require the -terrestrial station to increase its output power, thus significantly increasing the power consumption of satellite. Therefore, it is desirable to provide a power control function for a satellite-based communications system that overcomes these and other problems.

BRIEF DESCRIPTION OF THE INVENTION This invention is directed to a satellite communication system, and to a method implemented by it, to provide adaptive closed circuit power control. According to a method of this invention for operating a satellite communication system having at least one satellite and at least one ground station, the following steps are executed. A first step transmits a reference reference signal with a first frequency from the ground station to the satellite. The link reference signal experiences an attenuation between the ground station and the satellite due, for example, to a rain cell. A next step receives the reference signal with the satellite and repeats the reference signal with a second frequency as a low link reference signal that is transmitted from the satellite. The second frequency is less than the first frequency and not significantly altered or attenuated by the rain cell. The internal link reference signal is transmitted with a power that is a function of the power of the received upper link reference signal. A next step receives the lower link reference signal and determines from the lower link reference signal an amount of attenuation that was experienced by at least the upper link reference signal between the -ground station and the satellite. A next step adjusts a transmitted power of the upper link reference signal according to the determined amount of attenuation to substantially compensate the attenuation. In a further aspect, this invention teaches methods and apparatus that use a broad-aspect lower link power monitor to mitigate the loss of rain in a satellite communication system in low Earth orbit. In addition, according to this invention, a satellite communication system is provided which at least includes a satellite communication signal repeater; at least one terrestrial station for transmitting an ali-linker link composed of a plurality of communication signals to at least one satellite communication signal repeater; and a plurality of user terminals each receiving one of the communication signals on a user link two at least one repetition of a satellite communication signal. According to this invention, the satellite communication system also includes a closed circuit power control system comprising a plurality of internal circuits, individual circuits that operate to compensate one of the user's links for alterations in the signal of communication occurring at least between the user terminal and at least one satellite communication repeater, and an external circuit operating to compensate for all user links for alternating link disturbances occurring between at least one station terrestrial and at least one satellite communication signal repeater.

BRIEF DESCRIPTION OF THE DRAWINGS The aforementioned aspects and other aspects of the invention are more evident in the detailed description of the invention which comes to mind when read in conjunction with the accompanying drawings, in which: Figure 1 is a diagram of blocks of a communication system by elite that is constructed and operated in accordance with a currently preferred embodiment of this frame. Figure 2 is a block diagram of one of the gates of Figure 1; Figure 3 is a block diagram of the communications instrument of one of the satellites of Figure 1. Figure 3 illustrates a portion of a lightning pattern < This is associated with one of the satellites of Figure 1. Figure 4 is a block diagram illustrating ground equipment support, satellite telemetry and control functions. Fig. 5 is a block diagram of the DOMA subsystem of Fig. 2. Fig. 6 is a block diagram illus. the satellite communication system having an adaptive power control function in accordance with this invention; Figure 7 is a block diagram illustrating in more detail the components of the adaptive power control function; Figure 8 is a logic flow diagram illustrating a power control method of this invention; and Figure 9 illustrates a two-level adaptive power control circuit of this invention having a link power control circuit of the outer global linker to compensate for changes in voluminous power and a plurality of power control links of link of the internal user to compensate the enl ce power settings of the user i di idu les.

DETAILED DESCRIPTION OF THE INVENTION Figure 1 illustrates a currently preferred mode of a satellite communication system 10 that is suitable for use with the currently preferred mode of adaptive power control function. In this invention, in order to describe the invention in detail, a description of the communication system 10 will first be made, so that a complete understanding of the power control function can be obtained. The communication system 10 can be subdivided conceptually into a plurality of segments L, 2, 3 and 4. The segment 1 is here called a spatial segment; Segment 2, a user segment; segment 3, a segment of land (land), and segment 4, a segment of the telephone system infrastructure. In the presently preferred embodiment of this invention there are a total of 48 satellites, for example, in a low Earth orbit (LEO, acronym for its English designation: Low Earth Orbit) of 1414 Irn. The satellites 12 are distributed in eight orbital planes, with six satellites equispaced per plane (Ualker constellation). The orbital planes are inclined at 52 degrees with respect to the equator, and each satellite completes an orbit once every 114 minutes. The approach provides almost complete ground coverage, and preferably at least two satellites are visible at any given time from a particular user's use, between about 70 degrees south latitude and about 70 degrees south latitude. the north. In such a way, a user is able to communicate with or from any point on the surface of the earth within an area of gate 18 (GU) 18 oa or from other points on the surface of the earth (through the PSTN), through one or more gates 18 and one or more satellites 12, possibly also using a portion of the segment 4 of i nfrees uctura t the efornea. It should be noted at this point that the foregoing and following description of the system 10 represents only a suitable modality of a communication system within which the teaching of this invention may have use. That is, the specific details of the communication system should not be read or considered in a limiting sense when this invention is put into practice. Continuing now with a description of system 10, a smooth transfer process (delivery) between satellites 12, and also in re The individual beams of 16 point beams transmitted by each satellite (Figure 3B) provides interrupted communications with a technique Multiple Access Code Division (DCMA), Amplitude Spectrum (SS-Spread Spectrum). The SS-CDMA technique is usually similar to the TTA / EIA transient standard "Station Compatibility Standard Moved Base Station, for Broadband Amplitude Spectrum Cellular System, Dual Mode" TIA / EIfi / IS-95, July 1993, although other techniques and other amplitude and CDMA spectrum protocols can be used. Low terrestrial orbits allow fixed or mobile, low power user terminals 13 to communicate via satellites 12, each of which operates, in a preferred embodiment of this invention, only as a "bent tube" repeater. to receive a communications traffic signal (such as voice and / or data) from a user terminal 13 or a gate 18, converts the received communication traffic signal to another frequency band and then retransmits the converted signal. That is, no signal processing occurs on board a received communications traffic signal, and satellite 12 is not aware of any intelligence that may be transporting a received or transmitted communications traffic signal. In addition, one or more direct communication links between the satellites 12 are not necessary. In other words, each of the satellites 12 receives a signal only from a transmitter located in user segment 2, or from a network. transmitter located in the terrestrial segment 3, and transmits a signal only to a receiver located in the user segment 2 or to a receiver-located in the ground segment 3. The user segment 2 may include a plurality of user terminal types 13, which are adapted for communication with satellites 12. User terminals 13 include, for example, a plurality of different types of fixed and mobile user terminals, including, but not limited to: mobile radiotelephones 14, port tiles, mobile radiotelephones 15, mounted on vehicle, from shipments 16 of the type of location / delivery of messages and fixed radio telephones 14a. The user terminals 13 are preferably provided with recirculating ornmdi antennas 13a for bidirectional communication through one or more of the satellites 12. It should be noted that the fixed radiotelephones 14a may employ a directional antenna. This is advantageous in that it allows a reduction in the interference, with a consequent increase in the number of users that can be served simultaneously with one or more of the satellites 12. It should also be noted that the user terminals 13 can be dual use, which include pair circuits also communicate in a conventional manner with a terrestrial cellular system. Referring also to Figure 3A, the user terminals 13 may be capable of operating in a full duplex mode and communicating, for example, by means of RF links in band l_ (lift link or return link 17b) and RF links in S band (downlink or send link 17a), through satellite transponders of sends 12a and 12b, respectively. The return RF band links 17b can operate * within a frequency range of 1.61 GHz to 1625 GHz, a bandwidth of 16.5 MHz < and are digital signals in voice packets and / or data signals, according to the preferred amplitude spectrum technique. The S-band RF links of shipments can operate between a frequency scale of 2.485 GHz to 2.5 GHz, a bandwidth of 16.5 MH. The sending RF links 17a are also modulated in a gate 18, with digital signals in packet of voices and / or signals of ciatos, according to the amplitude spectrum technique. The 16.5 MHz bandwidth of the send link is divided into 13 channels with up to, for example, 128 users assigned per-channel. The return link can have different bandwidths and a given user terminal 13 may or may not have a different channel assigned to it than the channel allocated in the send link. However, when operating in the diversity reception mode on the return link (which receives from two or more satellites 12), the user is assigned the same RF channel for sending and return mail, for each of them. the satellites The ground segment 3 includes at least one, L but generally a plurality of stations 18, which communicate with the satellites 12 by means, for example, of a complete, full-duplex C-band RF link 19 (sending link 19a (to the satellite), radio link 19). - environment 19b (from the satellite)) operating within a frequency range generally above 3 GHz and, preferably, in the C band. The C-band RF links carry bi-directionally the communication linker links and also transport satellite commands to satellites and telemetry information from satellites. The link 19a of the sending linker can operate in the 5 GHz to 5.25 GHz band, while the return link 19b link can operate in the band from 6,875 GHz to 7,075 GHz. The 12 g and 12 h link antenna of the alunentator of Satellite preferably are broad coverage antennas, which subtend a maximum terrestrial coverage area, as seen from the LEO 12 satellite. In the currently preferred mode for the communication system 10, the angle subtended from a given LEO 12 satellite (assuming elevation angles of 10 ° from the surface of the earth) is approximately 110 °. This produces an area of coverage that has around 5,760 km of diameter. The L-band and S-band antennas are multi-beam antennas that provide coverage within an associated terrestrial service region. The L-band and S-band antennas 12d and 12c, respectively, are preferably congruent to each other, as shown in Figure 3B. That is to say, the transmission and reception beams from the spacecraft cover the same area on the surface of the earth, although this aspect is not critical for the operation of the system 10. As an example, several thousand full duplex communications through a given satellite 12. In accordance with one aspect of the system 10, two or more satellite channels 12 can each carry the same communication between a given user terminal and one of the IR gates. This mode of operation, which is described more fully below, thus provides the combination of diversity in the respective receivers, which leads to an increased resistance to weakening and facilitates the maintenance of a smooth delivery procedure. It is noted that all frequencies, bandwidths and the like, which are described herein, are representative of only one particular system. Other frequencies and frequency bands can be used, without changing the principles that are being discussed. As just one example, the feeder links between gates and satellites can use frequencies in a band other than the C band (approximately 3 GHz to 7 GHz, for example, the Ku band (approximately 10 GHz to 15 Hz). or the Ka band (above 15 GHz above). Gate 18 functions to couple the communication instruments or transponders 12a and 12b (Figure 3A) from satellites 12 to infrastructure segment 4. The transponders 12a and 12b include an L-band receiving antenna 12c, an S-band transmitting antenna 12d, a C-band power amplifier 12e, a low-band C-band I2f amplifier, antennas for a C-band 12g, and 12h, section 12? Of conversion of the band frequency L to band C and section 12j of conversion of the frequency of band C to band S. The satellite 12 also includes a master frequency generator 12k and command and telemetry equipment 121 It can also be referred to in this sense, to US Patent No., by E. Hirshfield and 0. A. Tsao, entitled "Mobile Communications Satellite Payload" ("Instrument for Mobile Communications Satellite") (Serial No. 08 / 060,207). Telephone infrastructure segment 4 consists of existing telephone systems and includes floodgates 20 of public land mobile network (PLMN = Public Land Mobile Network), local telephone exchanges, such as regional public telephone networks 22 (RPTN - Regional Public Telephone Networks) or other providers of local telephone services, long distance domestic networks 24, international networks 26, private networks 28 and other RPTN 30. The communication system 10 functions to provide voice communication and / or. bidirectional data between the user segment 2 and the 32 telephones of the public switched telephone r-ed (PSTN) and the non-PSTN 32 telephone of the telephone infrastructure segment 4, or other user terminals of various types, which can be private networks. Also shown in FIG. 1 (and also in FIG. 4), such as a portion of the ground segment 3, a satellite operations control center (SOCC = Satelite Operations Control Center) 36 and an operations control center. on ground (GOCC = Ground Operations Control Center-) 38. A communication path, including a terrestrial data network (GDN) 39 (see Figure 2) is provided for interconnecting gates 18 and TCU 18a, SOCC 36 and GOCC 38 of the ground segment 3. This portion of the communication system 10 provides general control functions of the sterna. Figure 2 shows one of the gates 18 in greater detail. Each gate 18 includes up to four dual-polarization RF-band subsystems C, each of which comprises a dish antenna 40, the antenna actuator 42 and the pedestal 42a, low noise receivers 44 and high power amplifiers. 46. All these components can be located inside a dome structure to provide environmental protection. The gate 18 further includes down converters 48 and up converters 50 for processing the received RF carrier signals and transmitters, respectively. The down converters 48 and the upconverters 50 are connected to a CDMA subsystem 52 which, in turn, is coupled to the public switched telephone r-ed (PSTN) by means of a PSTN method 54. As an option, the PSTN could be bypassed using sattelite satellite links. The CDMA subsystem 52 includes a signal adding / commutating unit 52a, a gate transponder (GTS) subsystem 52b, a GTS 52c controller, a CDMA (GIS) 52d interconnection subsystem, and a bank subsystem selector (SB5) 52e. The CDMA subsystem 52 is controlled by a base station manager (BSM) 52f and operates in a manner similar to a base station compatible with CDMA (eg, a compatible 15-95). The CDMA subsystem 52 also includes the required frequency synthesizer 52g and a 52h receiver of the global positioning system (GPS - Global Positioning Systern). The interstage PSTN 54 includes a service switching point PSTN (SSP) 54a, a call control processor (CCP) 54b, a visitor location register (VLR) 54c, and a protocol interface 54d, for a Base location record (HLR - Horne Location Register). The HLR may be located in the cellular gate 20 (Fig. 1) or, optionally, in the PSTN line 54. The gate 18 is connected to the telecommunication r-edes by means of a normal channel, formed by tr-plows of the SSP 54a. Gate 18 provides an interface and connects to the PSTN by means of the first primary rate phase (PRT = Primary Rate Interface). Gate 18 is also capable of providing a direct connection to a mobile switching center (MSC = Mobile Switching Center). Gate 18 provides fixed signaling of 55-7 ISDN to CCP 54b. On the gate side of this interface, the CCP 54b forms an interface with the CIS 52d and, therefore, with the subsystem 52 of CDMA. The CCP 54b provides protocol translation functions for the system's air interface (AI), which may be similar to transient standard 15-95 for CDMA communications. Blocks 54c and 54d generally provide an interface between gate 18 and the external cellular telephone network, which is compatible, for example, with cellular systems TS-41 (North American standard, AMPS) or with GSM cellular systems (standard European, MAP) and, in particular, with the specified methods to handle rovers, that is, users who make calls outside their base system. Gate 18 supports terminal authentication for the 10 / AMPS system telephones and for the 10 / GSM system telephones. In the service areas where there is no electronic infrastructure, a HI.R can be added to gate 18 and inter-phase with the inter-signal phase 5-7.

A user making a call outside the user's normal service area (erran e-roarner) is accommodated by subject 10, if authorized. Since that errant can be found in any environment, a user can use the same terminal equipment to make a call from any part of the world, and the necessary protocol conversions are made transparently by the gate 18. Protocol protocol 54d it is ignored when it is not necessary to convert, for example, GSM to AMPS. It is within the scope of the teachings of this invention to provide a dedicated universal interface in the cellular gates, in addition to or instead of the conventional "A" method specified for the GSM mobile switching centers and the vendor-owner inter-phases. for mobile switching centers 15-41. It is also within the scope of this invention to provide an interface directly to the PSTN, as indicated in Figure 1, as the signal path designated PSTN-INT. Full gate control is provided by gate controller 56 which includes a route 56a for the ground data network (GDN) 39 mentioned above, and a route 56b for a service control center 60 (SPCC) . The gate controller 56 is generally interconnected with the controller 18, by means of the BSM 52 and by means of the RF encoders 43, associated with each of the antennas 40. The gate controller 56 is coupled to each other. Lonally to a database 62, such as a database of users, satellite ephemeris data, etc., and with an input / output unit (T / 0) 65, which enables service personnel to have access to gate controller-56. The GÜN 39 is also provided with bi-directional interfaces to the telemetry and command unit 66 (TSC) (Fig. 1 and 4). Referring now to Figure 4, the function of the GOCC 38 is to plan and control the use of the satellite by the gates 18 and coordinate that use with the SOCC 36. In general, the trends of the GOCC 38 analyzes generate traffic plans, assign satellite 12 and system resources (such as, but not limited to, power and channel assignments), monitor the operation of global system 10 and issue usage instructions, through GDN 39, to gates 18 , in real time or with Lazio. The SOCC 36 operates to maintain and monitor the orbits, in order to monitor the satellite use information to the gateway to enter the GOCC 38 through the GDN 39, to monitor the general operation of each satellite 12, including the state of the satellite batteries, to establish the gain for the RF serial trajectories within the satellite 12, to guarantee the optimal orientation of the satellite with respect to the surface of the earth, in addition to other functions. As described above, each gate 18 functions to connect a given user to the PSTN for both signal, voice and / or data communications, as well as to generate data, through the database 62 ( figure 2), for billing purposes. The selected gates 18 include a telemetry and command unit (TCU) 18a for receiving telemetry data that is transmitted by the satellites 12 via the back-off link 19b and transmit-commands to the satellites 12, by rails. of the shipping link 19a. The GDN 39 works to connect the gates 18, the GODD 38 and the SOCC 36. In general, each satellite 12 of the LEO constellation operates to relay information from the gates 18 to the users (sending link in C band 19a to send link in band 5 17a), and to r-raise information from users to gates 18 (return link in L band 17b to return link in C band 19b). This information includes SS-CDM and location synchronization channels, in addition to signals to control the power. You can also use various CUMA pilot channels to monitor the interference in the send link. The satellite ephemeris update data is also communicated to each of the user terminals 13, from the gate 18, by means of the satellites 12. The satellites 12 also function to relieve the signal information from the user terminals 13 to gate 18, including access requests, the. > ? power change requests and registration requests. The satellites 12 also display communication signals between the users and the gates 18 and can apply security to mitigate their unauthorized use. In functions, the satellites 12 transmit spatial artifact telemetry data, which include measurements of the satellite functional state. The telemetry current of the satellites, the commands from the SOCC 36 and the communications receiver links 19, all share the antennas 12g and 12h in band (.. Par-to those gates 18 that include a TCU 18a, the data of Received satellite telemetry may be sent immediately to SOCC 36 or the telemetry data may be stored and subsequently sent to SOCC 36 at a later time, typically at the request of the SOCC.The telemetry data, either transmitted immediately or those stored and subsequently sent, are sent by the GDN 39 as packaged messages, each message in packet containing a single frame of smaller telemetry, in case more than one SOCC 36 is providing satellite support, the telemetry data to all SOCCs The SOCC 36 has several interoperable functions with the GOCC 38. One function of metaphase is the information of the orbital position, where the SOCC 36 provides orbital information to the GOCC 38, such that each gate 18 can accurately track the four satellites that may be in view in the gate. This data includes data tables that are sufficient to allow the gates 18 to develop their own contact lists with the satellite, using known algorithms. The SOCC 36 does not need to know the compuer tracking programs. The TCU 1 Ra searches for the downlink telemetry band and identifies in a way the satellite that is being followed by each antenna, before the propagation of the controls, Another function of the metaphase is the information of the state of the satellite that is informed from the SOCC 36 to the GOCC 38. The satellite status information includes both the availability of the satellite / transponder, as well as the state of the battery and the orbital information; and incorporates, in general, any limitations related to the satellite, which would prevent the use of all or a portion of a satellite 12 for communications purposes. An important aspect of the system 10 is the use of SS-CDMA in conjunction with the diversity combination in the gate receivers and in the user terminal receivers. The combination of diversity is used to mitigate weakening effects when the signals reach the user terminals 13 or the gate 18 from multiple satellites, by multiple and different path lengths. The incidence angle receivers in the user terminals 13 and in the gates 18 are used to receive- and combine the signals coming from multiple sources .. Like a? ? example, a user terminal 13 or gate 18 provides diversity combining for the forward link signals or for the return link signals that are simultaneously received from, and simul- taneously transmitted to, tr-birds, multiple beams of the satellites 12. In this sense, the entire description of U.S. Patent No. 5,233,626, issued August 3, 1993 to Stephen fl., is hereby incorporated by reference. Arn s and entitled "Repeater-Diversity Spread Spectrum Co rnunicat ion System" ("Amplitude spectrum communication system, with repeater diversity"). The operation in the continuous diversity reception mode is superior to that of receiving a signal through a satellite repeater and, additionally, there is no interruption in communications in the event that a link is lost due to weakening or blocking by trees or other obstructions that have an adverse impact on the signal received. The multiple direction antennas ies .0 of one of the gates 18 are capable of transmitting the send link signal (gate to the user terminal) through different beams of one or more satellites 12, to support the combination of diversity in the user terminals 13. Ornnidirectional antennas 13a of user terminals 13 transmit through all satellite beams that can be "viewed" from user terminal 13.

Each gate 18 supports a transmitter power control function to address slower weakenings and also supports block interleaving to direct medium to fast weakenings. The power control is implemented both in the sending link and in the reverse link. The response time of the power control function is adjusted to accommodate, in the worst cases, a delay in round trip of the satellite of 30 rni 1 s. The block interleavers (53d, 53e, 53f, FIG. 5) operate in a block branch that is related to 53g encoder packet frames. An optimized inter-tranche segment negotiates a larger tranche and, consequently, an improved error correction at the expense of increasing the overall end-to-end delay. A maximum end-to-end delay is 150 msec or less »This delay includes all delays that include those due to the alignment of the received serial, performed by the diversity combiners, the delays in the encoder processing of voice 53g, the delays of the block interleaver 53d-53f, and the delays of the Viterbí decoders (not shown) forming a portion of the CDMA subsystem 52. Fig. 5 is a block diagram of the send link modulation portion of the CDMA subsystem 52 of Fig. 2. An output of an adder block 53a feeds an agile upstream frequency converter 53b, which, in turn, feeds to the adder and the switch block 52a. The telemetry and control information (TSC) also entered the block '> 2a. A direct-sequence, unmodulated SS-pilot channel generates a Ualsh code of all zeros, at a desired bit rate. This data stream is combined with a short PN code, which is used to separate signals from different gates 18 and different satellites 12. If used, the pilot channel is added in module 2 to the short code and then extended to OPSK or BPSK through the bandwidth of the ADMA RF channel. The different displacement of the psudo-noise code (PN) is provided: (a) a PN code offset to allow a user terminal 13 uniquely identifies a gate 18; (b) a PN code deployment to allow the user terminal 13 to identify (singulate a satellite 12; and (c) a PN code offset to allow a user terminal 13 to identify a given beam of the 16 beams that are transmitted from the satellite 12. The pilot PN codes of the different satellites 12 are assigned different time / ase offsets with respect to the same pilot seeding PN code.If used, each pilot channel which is transmitted by the receiver 18 can be transmitted at a higher or lower power level than the other signals.A pilot channel allows a user terminal 13 to acquire the time control of the sending CDMA channel, provides a reference of phase for coherent demodulation and provides a mechanism to perform comparisons on the strength of the signal, to determine when to initiate the task, however, the use of the pilot channel is not mandatory, and can be To implement other techniques for that purpose. The Sync channel generates a stream of data that includes the following information: (a) time of day; (b) identification of the transmit gate; (c) ephemeris of the satellite; and (d) assigned location channel. The Sync data is applied to a 53h convolution encoder, where the data is convolutionally coded and blocks are subsequently inserted to combat the rapid weakening. The resulting data stream is added in module two to the synchronous Ualsh code and is extended to OPSK or BPSK by means of the bandwidth of the RF channel "CDMA FD." In general, the location channel carries various types of messages that include: (a) a parameter or system message; (b) an access parameter message; and (c) a CDMA channel list message. The system parameter message iCludes the configuration of the locator channel, the registration parameters and the parameters to aid in the acquisition. The message axis access parameters includes the configuration of the access channel and the data rate of the access channel. The CDMA channel list message carries, if used, an associated pilot identi ication and an R code assignment.

Ualsh The voice encoder 53 b3k encodes the voice to a stream of send traffic data in PCM. The send traffic data stream is applied to a ccvcvvc encoder 531, where it is coded cunvoltically and then interspersed with blocks in block 53f. The resulting data stream is combined with the output of a long user code block 53k. The long code is used to separate different susep tor channels. The resulting data stream is then controlled at its power in the multiplexer (MUX) 53rn, module two is added to the Ualsh code and then opened to QPSK or BPSK through the bandwidth of the RF communication channel CDMA FD . Gate 18 functions to demodulate the CDMA return link (s). There are two different codes for the return link: (a) the zero offset code and (b) the long code. These are used by the two different types of return link CDMA channels, i.e., the access channel and the return traffic channel. For the access channel, the gate 18 receives and decodes a download on the access channel that requests access. The access channel message is incorporated into a long preamble, followed by a relatively small amount of data. The preamble is the long PN code of the user's terminal. Each user terminal 13 has a unique, long PN code generated by a unique time shifter to the PN cornun generator polynomial. After receiving the access request the gate 18 sends a message on the send link locator channel (blocks 53e, 531, 53j) recognizing the receipt of the access request and assigning a Walsh code to the user terminal 13 to establish a traffic channel. The gate 18 also allocates a frequency channel to the user terminal 13. Both the user terminal 13 and the gate 18 switch to the assigned channel element and duplex communications begin using the asso- ciated Walsh code (s) (which are extended). The return traffic channel is generated in the user terminal 13 by coded the digital data circumferentially from the local data source or voice coder of the user terminal. The data is then interleaved in blocks at predetermined intervals and applied to a 128-Ary modulator and with a data downloading device, it will reduce confusion, then the data is added to the PM code. zero and are transmitted through one or more of the satellites 12 to gate 18. Gate 18 processes the return link using, for example, a fast Hadamard transformer (FHT = Fast Hadarnard Transform) to demodulate the Walsh code 128-Ary and provide the demodulated information to the diversity combiner. The foregoing has been a description of a currently preferred mode of communication system 10. Se 10 will now give a description of the presently preferred embodiments of the present invention. The sending link is considered as the link from the IR gate to the terminals of the user 13 through at least one satellite 12. The link of the sender 19 is considered to be that portion of the sending link that connects the satellite 12 to and from gate 18, while the user links 17 are considered that portion of the send link from which the satellite 1.2 is connected to and from the terminals of the user 13. Referring to FIG. 6, the link of the host to one or more satellites 12 from gate 18 provides the driving power for the user's links. The user's links The user's links consume a considerable amount of power from satellite 12. There is no alteration of the feeder link, as between gate 18 and satellite 12 ', the satellite power is maximally increased to its links. associated users, thereby increasing the efficiency and capacity of the total system. Nevertheless, if the feeder link itself is altered, such as by a rain cell located between gate 18 and satellite 12", the user's link power control circuit will be previously activated whether or not the The terminal of the particular user 13 is altered, that is, a user terminal 13 which detects a decrease in the received signal strength of satellite 12"will send a message on the reverse link which requires that the power of the sending link be increased. It can be seen that due to attenuation on the link signal of the driver due to a rain drop that all user terminals 13 receiving communication signals from satellite 12"will simultaneously experience a decrease in received power, and Simultaneously, it will require that the link power of the elevator be increased, and the resulting link power of the sudden installer will result in a corresponding significant increase in power consumption in the satellite L2", which operates to repeat the link signals of the alirnent. - to the user terminals 13 with a power corresponding substantially substantially linearly to the power supply of the receiver-received. That is, satellite systems in low-Earth orbit and other satellite systems generally track a satellite as it passes over the ground station, in this case gate 18. This results in the antenna 40 of gate 18 being flipped in such a way that it may be transmitting the link signal of the Fl receiver through the rain cell. As a result, the signal level of the binding portion of the feeder F2 is reduced as compared to Fl. The binding portion of the feeder-F2 experiences additional path loss until it reaches satellite 12. As a result of these losses all the user terminals 13 will demand more I) satellite strengths In accordance with this invention, an external power control circuit is provided at the link of the reactor in gate 18. The power control circuit The external one operates to increase the power transmitted from the antenna 40 of the gate 18 in proportion to the attenuation caused by an alteration of the link of the receiver, in this case a rain cell.This external power control circuit maintains the densi power flow received by the satellite 12"at an almost constant level and, as a result, the terminals of the user 13 do not experience a significant decrease in power received from satellite 12". In accordance with this invention, the outdoor power control circuit includes a reference signal receiver 70 and a reference signal tracking processor 72, as shown in FIGS. 6 and 7. The reference signal receiver 70 and the reference signal tracking processor 72 operates in conjunction with the RF system controllers 43 and RF links of the feeder links! - 46, 50 (as shown in the gate block diagram 18 of Fig. 2). The reference signal receiver 70 monitors a lower link reference signal (R) from the satellites 12 at a specified frequency. This frequency is selected so that it is sufficiently low so that it is not significantly altered by the rain cell (for example a frequency in the F band), and therefore remains essentially at the same level in the R2 ratio as in the proportion Rl. The reference signal receiver 70 demodulates the received SS-CDMA signal and outputs a data stream 70a to an indication of signal strength received by reference signal to the reference signal tracking processor 72 in the comptroller 18. The reference signal tracking processor 72 processes the data stream 70 a and outputs error signals or commands to one or more RF system controllers 43, which in turn controls the gain of the linkage Rf system of the air conditioner 46, 50 on the link 1 to the link N of the gate 18. In this way, the link power of the transmitted air receiver is increased in proportion to the amount of attenuation experienced by the feeder link between gate 18 and a satellite 12. In greater detail, and also referring to the logic flow diagram of Figure 8, in block A the feeder link propagates the spectrum reference signal to the receiver 70 receiving and decoding each of the R reference signals. Since the reference signal link sequence is significantly smaller than the link frequency of the upper link feeder, most of the rain loss ( if there is one) it is incurred by the link signal of the upper link feeder.

Consequently, in block B the received signal power indication signal is compared to a reference predetermined by the reference signal tracking processor 72, and on block C an error signal E proportional to the link loss of the signal. to the speaker caused by a channel alteration, such as rain, is derived and sent to the RF 43 system controllers. That is, one would be! Error (Ei to EN) is derived for each of the feeder relays 1-N. The error signal in turn is used by each controller of the RF system 43 to control, in the block, the power of the combined power link that is composed of the reference signal R and all the terminal communication signals. of individual user 13 to compensate for rain loss. That is, the reference signal R is transmitted over the link of the upper linker with a predetermined PN code and a first frequency of the gate 18, is attenuated by RF alterations, such as rain cell, between the satellite 12"and gate 28, is received, and repeated by satellite 12" at a second lower frequency on the lower link and is received, propagated, desrunulated and processed by the reference signal receiver 70 and the processor- reference signal trace 72. An error signal- is immediately developed which indicates a quantity of RF alteration that is occurring on the feeder link of the upper link, being reminded that the upper link frequency band makes the link The signal of the error is then used to vary the transmission power of the transmitter. Higher link feeder link-to make the power level of each of the signals received by each of the user terminals 13 to remain substantially the same. It should be understood that an error signal may be provided for each of the RF system controllers 43, whereafter each RF system controller 43 derives a change in its associated power link power; or a change in power supply link can be derived in the reference signal tracking processor 72 from the error signal-, for each RF system controller 43 and can be transmitted as a control command. of adequate power to the RF system controllers. Since the ability of a propagation spectrum receiver to separate multiple reference reference signals from a plurality of satellite by the use of a unique PN code for each reference signal, an individual reference signal receiver 70 is they can use- to independently control upper link powers of the power link to each of the satellites 12 within the view of a particular gate 18. In other words, a different PN code is assigned to each reference signal. In this regard, the reference signal receiver 70 can employ a well-known RAKE receiver having a plurality of projections to simultaneously propagate and track a plurality of the reference signals. Alternatively, the reference signal receiver 70 may instead employ a single projection which is subjected to multiple time action between the repeating reference signals by a plurality of satellites 12 which are in view of the reference signal receiver 70. In any case, the link strength of the upper link provider increases only as necessary, allowing more efficient use of satellite capacity and minimizing coordination difficulties with other satellites 12 in similar orbits and sharing the same band. of frequency. This technique also minimizes the link power effect of the above mentioned for ground coordination. For systems that use ba or multiple link beams, a plurality of reference signal receivers 70 (designated 70 'in Figure 7) can be placed at suitable points on the gate cover area and the reference signal data stream is transported to the tracking processor of reference signal 72 on terrestrial data lines, or as a data stream through satellites 12. In the latter case, the data stream can also be received by the receiver of <; reference signal 70 in gate 10 and then input to the reference signal tracking processor 72. As used herein, a power or quality of received signal that is reported back to gate 18 in data stream 70A it may be, for example, a received signal strength indicator (RSSI) measurement, or a signal quality measurement (v. gr-., bit error index measurement (BER) or an error rate measurement of frame derived from the Viterbi decoder measurement The indication of power or signal quality is compared by the reference signal tracking processor 72 with a predetermined value such as a reference signal resistance or signal quality value , and the error signal- is developed in such a way as to represent a deviation between the two compared values.A goal of the external power control circuit is to reduce to a minimum the link power of the alirnentad or in a way that is consistent with the desired link quality. The minimum reduction of the power of link of the alirnentador, although simultaneously provides communications of satisfactory users, conserves thus main power of satellite. The reference value at which the received signal power indication is compared is determined according to the desired power level at which the user terminals 13 are to receive the communication signals that are repeated by the satellites 12 from the alunentator link The reference value does not need to be a fixed value, but 0 it may vary - depending, for example, on the load or total user demand, time of day, or level of (desired 1.F total luxury on land within a given satellite point beam (v. gr .., approximately 154 dBU /? n2 / 4 kHz, as a function of elevation angle), for the case in which a plurality of reference signal receivers 70 are located in the area of life by the gate 18, the gate 18 can process the inputs providing the plurality of reference signal receiver 70 and 70 'by combining them in a predetermined manner, such as by an average or weighted average technique. Reference serial power received from the reference signal receivers 70 'are associated with a region having a high user density (ie urban areas) can be weighted more heavily than the signal power indications received from the regions with a density d e low user The power control technique of this invention compensates for disturbances in the feed links (v.gr-., Rainfall antennum for KA or KU band feeder links, alterations due to a satellite of elevation angle ba or which receives a C-band feeder link, alterations due to signals received from altered beams, etc.), and may also compensate for a degradation in the satellite's operating capacity over time. Referring to Figure 9, the closed circuit power control technique of this invention can be visualized as a two-wave adaptive power control circuit 80 with a global power link control power circuit 82 to co-consider power alterations in volume (eg, those due to rain cells) and a plurality of user link power control circuits 84 to compensate for individual user link disturbances (such as those that r- esultan of the foliage). A time constant of the control circuit 02 for the power of the external feeder link is preferably longer (for example, 5 to 10 times longer) than that of the internal user link power control circuit 04. As a example of the closed circuit power control technique of this invention, it is assumed that the user terminal dynamic power control scale is 10 dB, and if a rain cell introduces a loss of 8 dB to the band send links S received by user terminals from a satellite 12, then an alteration of 6dT) in a user link caused by fade may not be correctable. If instead gate 18 compensates all user links for the 8dB rain cell loss by increasing the link power in a proportional manner, then the dynamic scale of the user terminal power control function is not adversely affected by the loss induced by rain cells.

Although the invention has been particularly described and described with respect to preferred embodiments thereof, those skilled in the art will understand that changes in form and detail may be made therein without departing from the spirit and scope of the invention. .

Claims (29)

.1 NOVELTY OF THE INVENTION CLAIMS

1. - A method for operating a satellite communication system having at least one satellite and therefore a ground station, the satellite communication system also having a plurality of terrestrial receivers, comprising the following steps: - a plurality of upper link signals from the terr-estre station, at least one of the upper link sera being designated as a higher link reference signal, said plurality of upper link signals being transmitted with a first frequency from the terrestrial station to the satellite and experiencing a first amount of attenuation between the terrestrial station and the satellite; receiving the plurality of upper link signals with the satellite and repeating the plurality of upper link signals with a second frequency as a plurality of lower link signals that are transmitted from the satellite to the plurality of terrestrial receivers, the second frequency being less than the first frequency such that the plurality of lower link signals undergo a second amount of attenuation between the satellite and the plurality of terrestrial receivers, the second amount of attenuation being less than the first attenuation amount, the plurality of signals lower link being transmitted with a power that is a function of the power of the received plurality of higher link sera; receiving at least the reference signal of the plurality of lower link signals with at least one of the terrestrial receivers, the received reference signal being designated as a received lower link reference signal, and determining par of the lower link reference signal received the first amount of attenuation that was at least experienced by the upper link reference signal ent-e the ground station and the satellite; and adjusting a transmitted power of the plurality of upper link signals from the ground station according to the determined amount of attenuation to substantially compensate the first amount of attenuation.

2. A method according to claim 1, further characterized by the fact that at least one of the plurality of terrestrial receivers are a plurality of user terminals, and wherein the step of transmitting the plurality of serles of The upper link includes a step of transmitting a link of the upper link feeder from the ground station to the satellite, the link of the higher link feeder comprising a plurality of communication signals for the plurality of user terminals; and wherein the steps of receiving the plurality of upper link signals with the satellite and repeating the plurality of upper link signals includes the steps of receiving the link from the satellite.

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upper link feeder with the satellite and repeating the upper link feed link by transmitting the plurality of satellite communication signals to the plurality of user terminals.

3. A method in accordance with claim 2, further characterized in that the step of adjusting a transmitted power of the plurality of upper link signals includes a step of adjusting power transmitted from the upper link feeder link to compensate for substantial The attenuation in communication signals received from satellite to the plurality of user terminals.

4. A method according to claim 1, further characterized in that the step of transmitting a plurality of upper link signals includes a step of transmitting at least the upper link reference signal with a code of pseudo-noise determined.

5. A step in accordance with claim 1, further characterized in that the step of receiving the lower link reference signal receives the lower link reference signal with a single receiver.

6. A method according to claim 5, further characterized in that the step of transmitting a plurality of upper link signals includes a step of transmitting at least one upper link reference signal with a determined pseudo-noise propagation code, and because the individual receiver responds to pseudo-noise propagation code predefined pair-to propagate the same after leoilpr the lower link reference signal.

7. A method in accordance with claim 1, further characterized in that the step of receiving the lower link reference signal receives the lower link leferon signal with a plurality of receivers (thou are disposed within an area of terrestrial station coverage 8. A method according to claim 5, further characterized in that the step of transmitting a plurality of upper link signals includes a step of transmitting at least one reference signal of upper link with a determined pseudo-noise propagation code, and because each of a plurality of receivers responds to the propagation code of the predetermined pseudo-noise pair to propagate the same after receiving the reference signal of the lower link 9.- A method for operating- a satellite communication system having at least one satellite and at least one ground station, comprising the steps of: If a higher reference reference signal with a first frequency from the earth station to the satellite is used, the upper link reference signal will experience an attenuation between the earth station and the satellite.; receive reference signal with the satellite and repeat the signal

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reference with a second frequency as a lower link reference signal that is transmitted from the satellite, the second frequency being smaller than the first frequency, the lower link reference signal being transmitted with a power (thu is a function of the power of the received upper link reference signal, receive the lower link reference signal and determine from the received lower link reference signal an amount of attenuation that was at least felt by the link reference signal between the terrestrial station and the satellite, and adjust a transmitted power of the upper link reference signal * in accordance with the determined amount of attenuation to substantially compensate the attenuation, wherein the step of receiving the reference signal of lower link receives the lower link reference signal with a plurality of receivers (thou placed within an area of a terr-estr-e station coverage; wherein the step of transmitting a higher link reference signal includes a step of transmitting the upper link reference signal with a predetermined pseudo-radio propagation code, and wherein each of a plurality of receivers responds to the predetermined pseudo-noise propagation code to propagate the same; and wherein the step of adjusting includes a step of combining output signals from each of a plurality of receivers.

10. - A satellite communication system composed of at least one satellite, at least one terrestrial station and at least one receiver, said satellite communication system also comprising: means for transmitting a reference signal of at least one link together with a plurality of upper link user communication signal, the upper link reference signal and the plurality of upper link user communication signals - being transmitted with a first frequency from the ground station to said satellite, the upper link reference signal experiencing an attenuation between the earth station and the satellite; said satellite comprising a receiver- for receiving the upper link reference signal and the plurality of upper link user communication signals, and further comprising a transmitter pair-to transmit the received link reference signal and the plurality of signals ( The upper link user communication received with a second frequency as a repeated lower link reference signal and as a plurality of repeated lower link user communication signals, the second frequency being lower than the first frequency, the reference signal of the lower link and the plurality of repeated lower link user communication signals being transmitted with a power that is a function of the power of the received upper link signals, at least one reference signal receiver comprising an input for receive the lower link reference signal and which also comprises a to output to send the received lower link reference signal; means having an input coupled to the output of at least one reference signal receiver, to determine from the received lower link reference signal an amount of attenuation that was experienced by at least the upper link reference signal input e the ground station and the satellite; and means for adjusting the transmitted power of the upper link reference signal according to the determined amount of attenuation to compensate for the attenuation.

11. A satellite communication system according to claim 10, further characterized in that said terrestrial station includes means for transmitting an upper link feeder link to said satellite, the link of the upper link feeder comprising said plurality of communication signals from top link users - for a range of user terminals; and wherein said satellite includes means for receiving the link from the upper link feeder and for repeating the link of the upper link feeder by transmitting the plurality of satellite user communication signals to the plurality of user terminals.

12. A satellite communication system according to claim 11, further characterized in that said adjustment means adjusts a power transmitted from the link of the upper link alirnentador to compensate-substance lrnent the determined amount of attenuation in the signals of user communication that are received in said plurality of user terminals.

13. A satellite communication system according to claim 10, further characterized in that at least the upper link reference signal is transmitted with a predetermined pseudo-noise code.

14. A satellite communication system according to claim 10, character- ized in addition because there is a plurality of reference signal receivers disposed within a region served by said ground station.

15. A satellite communication system composed of at least one satellite and at least one terrestrial station, said satellite communication system further comprising: means for transmitting a superior link reference signal with a first frequency from the ground station to the satellite, the link reference signal experiencing an attenuation between said ground station and the satellite; said satellite comprising a receiver for receiving the reference signal and further comprising a transmitter for transmitting the reference signal with a second frequency as a repeated lower link reference signal, the second frequency being less than the first frequency, the reference signal lower link-being transmitted with a power (thu is a function of the power of the received upper link reference signal, at least one reference signal receiver comprising an even input to receive the link reference signal lower and further comprises an output for sending the received lower link reference signal, means having an input coupled to the output of at least one reference signal receiver, to be determined from the lower link reference signal received an amount of attenuation that was experienced by at least the upper link reference signal between The land station and the satellite; and means for adjusting a transmitted power of the upper link reference signal in accordance with the determined amount of attenuation to substantially compensate the attenuation; wherein there is a plurality of reference signal receivers disposed within a region served by said ground station; and wherein said determining means combine the output signals of each of the plurality of reference signal receivers.

16. A satellite communication system composed of at least one satellite in the low Earth orbit and at least one ground station, said satellite communication system further comprising: a plurality of terrestrial user terminals; means for bidirectional coupling of said ground station (at least one) to a terrestrial communications r-ed; means for transmitting a link link of higher link with a first frequency from the ground station (at least one) to the satellite, said first frequency being within one of a band Ka, a band Ku and a band C, the upper link feeder link by providing a plurality of propagation spectrum communication signals for said plurality of user terminals and also comprising at least one upper link reference signal, the link of the upper link feeder an attenuation between the earth station and the satellite; said satellite comprising a receiver to receive the link of the upper linker - and which further comprises a transmitter for transmitting the plurality of propagation spectra communication signals as a plurality (ie, spectrum communication signals). lower link propagation to said plurality of user terminals and also for transmitting at least one reference signal co or at least one lower link reference signal, the lower link propagation spectrum communication signals and at least one internal link reference signal being transmitted with a second frequency that is less than the first frequency, the lower link propagation spectrum communication signals and at least one lower link reference signal being transmitted with a power which is a function of the link power of the upper link feeder received, at least a bl

reference signal receiver- composed of an input to receive at least a lower link reference signal and (JU also comprises an output to send the lower link reference signal received; means having an input coupled to the output of at least one reference signal receiver, to determine from the received lower link reference signal an amount of attenuation that was experienced at least by the upper link feeder link between said ground station and said satellite, and means for adjusting a desired power of the link of the upper linker according to the determined amount of attenuation (such that a received signal strength in said plurality of user signals is not substantially reduced). due to an attenuation of the upper link feeder link 17.- A satellite communication system comprising: at least one repe tidora satellite communication signal; at least one ground station for transmitting a link to the linker composed of a plurality of communication signals to at least one satellite communication signal repeater; a plurality of user terminals receiving each of said communication signals on a user link from at least one satellite communication signal repeater; and closed circuit power control means comprising a plurality of individual closed circuits of which! .. >

oper-an to compensate one of said user links for communication signal alterations that occur at least between the user terminal and at least one satellite communication repeater, said circuit power control means The closed loop also comprises a closed circuit which operates to compensate for all user links for link disturbances occurring between at least one ground station and at least one satellite communication signal repeater. 18.- A communication system by satellite in accordance with claim 17, further characterized in that at least one ground station comprises means for transmitting said link of the elevator with a first frequency, the link of the the monitor comprising a plurality of propagation spectrum communication signals for said plurality of user terminals and further comprising at least one propagation spectrum reference signal. 19. A satellite communication system according to claim 18, further characterized in that at least one satellite communication signal repeater is composed of a receiver to receive the link of the antenna and a transmitter to transmit the plurality of signals communication spectrum propagation link to said plurality of user terminals, said satellite signal repeater (at least one) further transmitting the propagation spectrum reference signal as an internal link propagation spectrum reference signal The communication signals of the user link propagation spectrum and the reference signal of the lower link propagation spectrum being transmitted with a second frequency that is lower than the first frequency, the communication signals of the propagation spectrum of the user. user link and the propagation spectrum reference signal n of lower link being ransmitters with a power that is a function of the link power of the upper link feeder; and wherein said outer circuit of said closed circuit power control means is composed of: at least one reference signal receiver composed of an input for receiving and propagating the lower link propagation spectrum reference signal and it further comprises an output to send the reference signal of lower link propagation spectrum-received and propagated; means having an input coupled to the output of at least one reference signal receiver, to determine from the received and de-propagated lower link spread spectrum reference signal an amount of attenuation that was experienced at least by the feeder link between the land station and the satellite; and means for adjusting a power transmitted to the feeder link in accordance with the determined amount of attenuation such that a signal power received at said plurality of user terminals is not substantially reduced due to attenuation of the link to the host. I link higher mentor. 20. An operational satellite communication system with at least one terrestrial communication system, comprising: at least one satellite in terrestrial orbit, said satellite projecting a pattern on the surface of the earth, the pattern being composed of a plurality of beams; at least one terrestrial gate that is bidirectionally coupled to the terrestrial communications system (at least one), said terrestrial gate (at least one) being bidirectionally coupled through the first RF links to said satellite (per or one or more), to transmit communications traffic to and to receive communications traffic from at least said satellite; a plurality of t receivers associated with users of the satellite communications system, each of said plurality of transceivers being bidirectionally coupled through second RF links to at least one satellite to transmit communications traffic to and receive communications traffic from said satellite (at least one), each of the plurality of tranceptors being located in at least one of said plurality of beams; wherein said first RF links use frequencies within a first radiofrequency band, and wherein the second RF links use frequencies within a second radio frequency band that differs from the first radio frequency band and experiences substantially less fading than the frequencies in the first radio frequency band; at least one reference receiver located in at least one of said beams to receive a reference signal from one of the second radiofrequency links, means reliable to receive an output from at least one reference receiver and to determine a quantity of fading experienced by the first RF links between at least one terrestrial gate and at least one satellite, and means for adjusting a transmitted power of the upper links of said first RF links to compensate for the lower links of the second RF links, in said plurality of transducers to determine the amount of fading 21. A satellite communication system according to claim 20, characterized in that said ground gate is located within the first beam and wherein said reference receiver is located within the second beam 22.- A satellite communication system in accordance with n claim 20, characterized in that said satellite is one of a plurality of satellites forming a constellation of satellites in the non-geosineric Earth orbit. 23. A satellite communication system according to claim 20, characterized in that said communications traffic is transported by the first RF links and the second RF links using a spectrum access division multiple access technique. of dissemination. 24. A satellite communication subject according to claim 20, characterized in that at least one satellite is composed of a communication channel of a double tube repeater. 25. A satellite communication system in accordance with claim 20, characterized in that said first radio frequency band is greater than about 10 GHz, and wherein the second radio frequency band is less than about 3 GHz. A satellite communication system according to claim 20, characterized in that there is a plurality of reference receivers arranged in different terrestrial locations, and wherein said determining means combine output signals from at least two of said reference receivers. 27. A satellite communications system of a type that includes at least one satellite in terrestrial orbit, at least one terrestrial station that is coupled through an upper link feeder link to said satellite to transmit signals from user communication to said satellite, and a plurality of receivers associated with users of said satellite communication system, each of the plurality of receivers being coupled to a lower link signal transmitted at least by one satellite, wherein said upper link feeder link employs a frequency within a first radio frequency band and wherein said lower link signal employs a frequency within a second radio frequency band which differs from the first radio frequency band and which experiences substially less fading that the first radio frequency band, said system also comprising at least a fading compensation receiver located within a coverage area of at least one terrestrial station to receive a signal from the satellite, said signal being originally transmitted over the link of the top link resolver at least one ground station, said system further comprising means for controlling upper link feeder link transmission power having an input for receiving an output from at least one fading compensation receiver and for determining a quantity of fading experienced by the feeder link. link between the ground station and at least one satellite, said upper link feeder link power control means-further having an output coupled to the ground station feeder link transmitter to control the transmitted power of the link of top link alirnentador for 5R

compensate- the determined amount of fading. 28. A satellite communications system according to claim 27, further characterized in that said first band of radio frequencies is greater than about 10 GHz, and because said second band of radio frequencies is less than about 3 GHz. - A satellite communication system according to claim 27, further characterized in that there is a plurality of fading compensation receivers arranged at different locations within the coverage area of the ground station, and wherein the control means of Transmission power from the upper link linker combines output signals from at least two of the fade compensation receivers.