Abstract: A method of reusing frequency bands between base stations of a terrestrial mobile communications network and a satellite communications network, comprising allocating the frequency bands using integrated resource management and other mitigation techniques in a such a way as to minimise interference between both the systems, thus making optimum usage of valuable frequency spectrum.

Abstract: A satellite communication system (10) includes a satellite (20) which receives first and second data from sources. Each satellite receives control data from a satellite control center (100). An earth processing center (PC) is arranged to process the data received from the satellites, and a wide band network (30) is arranged to transmit the data to the processing center. A receptor terminal (A) is arranged to receive the first data and to place the first data on the network (30) for transmission to the processing center (PC). A second receptor terminal (B) is arranged to receive the second data and to place the second data on the network (30) for transmission to the processing center (PC).

Abstract: A satellite system provides geosynchronous satellites in tundra orbits in respective elliptical orbital planes separated by 120 degrees. The satellites traverse a common figure-eight ground track comprising northern and southern loops. The satellites are controllably switched to operate the satellite currently traversing the northern loop to deliver a selected signal (e.g., a selected frequency signal) to satellite receivers.

Abstract: A method and apparatus for mitigating communications interference between satellite communications systems in different orbits is disclosed. The method comprises the steps of evaluating a geometrical relationship between a second ground station and the satellites in the second satellite constellation, and directing communications between the second ground station and the second satellite according to the evaluated geometrical relationship. In one embodiment communications are handed over from a first satellite to another satellite when the first satellite is no longer at the highest elevation angle of visible satellites. In another embodiment, handover occurs when the first satellite drops below a minimum elevation angle.

Abstract: A wireless communication system includes platforms that generate spot beams and wide-area beams. The system includes a network operations controller that receives signals from user terminals. User terminals determine the signal strengths of the spot beams and the wide-area beams and a ratio may therefore be calculated between the spot beam and the wide-area beams. Based upon the ratio of the spot beam strength and the wide-area beam strength, the network operations controller may adjust the orientation of the platforms relative to the earth to correct for pointing errors and, the network operation controller may compensate as is best possible depending on the type of antenna, a correction for distortion in the antenna.

Abstract: A first transmitting device is used to transmit a first signal on a first carrier frequency to a relay device. The relay device receives the signal by demodulating the first carrier frequency. Subsequently, the relay device retransmits the signal by modulating a second and/or a third carrier frequency. The signal is then recovered at one or more receiving devices by demodulating the second and/or third carrier frequencies. Further, a second transmitting device transmits a second signal on a fourth carrier frequency and the relay device retransmits the signal by modulating a fifth and/or a sixth carrier frequency. The signal is then recovered at one or more receiving devices by demodulating the fifth and/or sixth carrier frequencies. The transmitting and/or receiving devices are preferably voice terminals, such as a wireless telephones or data terminals, such as portable computers.

Abstract: The present non-terrestrial feature transparency system spoofs the Air-to-Ground Network and the ground-based cellular communication network into thinking that the wireless subscriber devices have no special considerations associated with their operation, even though the wireless subscriber devices are located on an aircraft in flight. This architecture requires that the non-terrestrial feature transparency system on board the aircraft replicate the full functionality of a given wireless subscriber device, that has a certain predetermined feature set from a ground-based wireless service provider, at another wireless subscriber device located within the aircraft. This mirroring of wireless subscriber device attributes enables a localized cell for in-cabin communication yet retains the same wireless subscriber device attributes for the air-to-ground link.

Abstract: The invention relates to a security-protected system for positioning by satellites, comprising a constellation of satellites (11) sending out positioning signals under the control of a set of ground stations (14). A user receiver of the said positioning signals comprises means for sending, to a ground station, a request calling for a key which is necessary for interpreting them, advantageously accompanied by a recopy of the positioning signals received. User servicing ground stations comprise means for receiving this request, calculating the position of the user and verifying whether the user possesses a privileged status, and means for addressing the said key to the user receiver, in the event that the verification is positive, this key further comprising means for interpreting the positioning signals with the aid of the key so as to deduce his own position therefrom.

Abstract: A satellite constellation has a plurality of satellites. Each of the satellites has an RF ground link for communicating with a ground station and an optical link for communication with at least one of the plurality of satellites. Each of the satellites has a reconfigurable optical transmitter for sending and receiving data streams. Each reconfigurable optical transmitter has a first optical carrier associated therewith and a reconfigurable optical receiver. The plurality of satellites is arranged to have a first subset of satellites. The first subset of satellites is configured to communicate. The plurality of satellites is reconfigured to have a second subset of satellites having at least one different satellites than that of said first subset. The second subset supercedes the first subset. The second subset of satellites is configured to communicate. Various subset around the globe may form local area networks. The local area networks are preferably optically coupled to form a wide area network.

Abstract: A system and method for informing users of a possible disruption in a communications link established between users traveling on a mobile platform and a fixed base station. In one preferred form, the invention enables a user on a mobile platform to log on to access a web server on the mobile platform and to obtain information on the availability/status of the communications link formed between the mobile platform and the fixed base station. In another preferred embodiment, the user is provided by the web server with a pop-up window which automatically appears on the user's computing device that is periodically updated with useful information concerning the performance of the network on board the mobile platform and/or the status of the communications link linking the mobile platform and a fixed base station, and the possibility of an imminent disruption in the satellite communications link.

Abstract: The present invention uses site diversity reception and RAKE combining reception for the method for a CDMA communication mobile terminal to carry out a cell search to search for a base station with which to communicate. Even if the reception power levels of synchronization acquisition signals sent from a plurality of base stations are lower than a predetermined threshold, in the case where the power level of a signal combining those signals is equal to or greater than the predetermined threshold, the mobile terminal continues processing of requesting position registration to any one of the plurality of base stations and thereby improves communicability.

Abstract: A mobile wireless communications system including a plurality of individual transponding platforms all in communication with a central processing hub. A signal processed by the central processing hub is radiated simultaneously through multiple paths to a plurality of the individual transponding platforms. The signal transmitted to each transponding platform by the hub is appropriately delayed by the hub so as to equalize the differential delay of all such signals from a given receiver location. The radiated signal is then re-radiated by each of the plurality of individual transponding platforms to a mobile satellite terminal that receives the re-radiated signal from the plurality of individual transponding platforms. The signals from the plurality of transponding platforms are all received coherently by the intended user, and incoherently by all other users.

Abstract: A message transmitting method using a short message service (SMS) that can successively transmit messages that a mobile terminal user intends to transmit. According to the long message transmitting method using the SMS, in case that the message to be transmitted exceeds a predetermined length, identifiers representing a boundary of each predetermined unit of the message and an identifier representing that the message is divided and transmitted are inserted into the units of the message, and the message is divided and transmitted according to the inserted identifiers.

Abstract: A sender of a message can transmit a message to an unspecified user merely by specifying a condition of space without specifying a recipient of the message, using an information processing terminal transmitting a message not with a user address to specify a user but with an area address (a condition of space) to specify an area within an electric wave reachable range of a radio base station; and a server converting the area address to a user address which specifies a PHS terminal currently located in the area represented by said area address and transmitting the message with a converted address to a switching equipment.

Abstract: The Inmarsat Capacity Expansion invention, in an embodiment to retrofit a standard Inmarsat-B mobile earth station (MES), combines standard MES equipment and functionality with an assembly containing a diplexer/switch and a digital signal processor, a second SCPC modem that has configurable modulation and error correction capabilities, control signals and paths, and related management and control software and hardware to enable the transmission and reception of standard service types and higher data rate services.

Abstract: A communication system for mobile platforms includes mobile platforms with transceivers identified by Internet Protocol (IP) addresses. A satellite relays a forward link from a ground station to the mobile platforms. The forward link contains IP packet data that is modulated by variable length orthogonal (VLO) spreading codes and that has different information data rates. The VLO spreading code for each IP packet is selected to optimize a desired link margin of the IP packet that is received by the addressed transceiver. The IP packets can also be modulated using a pseudonoise (PN) spreading code. Forward error correction (FEC) may also be applied. The transceivers include a feedback circuit that generates an Eb/No estimate.

Abstract: A system and method for augmenting a wireless communication network to provide at least a portion of digital data to a user is disclosed. The method comprises the steps of receiving the portion of the digital data in a satellite receiver, providing the received portion of the digital data to at least one of a plurality of terrestrial receivers which form the wireless communication network, and transmitting the received portion of the digital data to a user within a service region using the terrestrial transmitter. The apparatus comprises a satellite antenna, for receiving a signal having at least a portion of the data from a satellite, and a satellite receiver, communicatively coupled to the satellite antenna for detecting and demodulating the signal to produce a portion of the digital data, the satellite receiver communicatively coupled to a terrestrial transmitter in a terrestrial wireless communication network.

Abstract: A telephone system for a vehicle comprising: a vehicle transceiver, on board said vehicle, and connectable to a cellular telephone network for bi-directional communication therewith; a server terminal, on board said vehicle, connected to said transceiver and having an identification address; a plurality of user terminals, distributed on board the vehicle, each capable of accepting an identity of a user of the cellular telephone system and each connected to said server terminal whereby a plurality of users may communicate simultaneously with said network via the server terminal; and a location data base for identifying users of the cellular telephone system when their identifies are accepted by respective user terminals and for associating those users with said identification address to permit communication to be established between those users and the cellular telephone system via the server terminal.

Abstract: A state transition diagram is presented for a user's access terminal for a satellite telecommunication system, showing the state of the access terminal's mobility management software layer, in response to various stimuli and conditions as the user enters into and out of various modes of operations, including deactivation, activation and illumination of a dark beam of a spot beam that is a shared resource.

Abstract: A mobile wireless communication system includes information, a portable terminal, a plurality of wireless communication gateway servers, a switching apparatus, and a wireless telephony server. The switching apparatus sets a connection between the portable terminal and a first wireless communication gateway server or another connection between the portable terminal and a second wireless communication gateway server when the first wireless communication gateway server is congested. The wireless telephony server informs a position of the portable terminal to the wireless communication gateway server.

Abstract: A system and method for positioning a dish antenna having a plurality of low noise block converters for the simultaneous reception of signals from a plurality of satellites in a direct broadcast satellite system. An integrated receiver/decoder alternately powers at least two low noise block converters to sample signals for comparison to a threshold value to detect a peak signal for each of the low noise block converters. When the peak signals are detected, they are compared to a master threshold to indicate a master lock for the system.

Abstract: This disclosure describes a method to generate large numbers of spot beams for multiple-beam satellite systems using smaller apertures. This is done by dividing the basic spot beam that has 3 to 4 dB of gain drop within the beam into a number of smaller 1-dB sub-beams. This has the effect of reducing the required peak gain for the antenna by 2–3 dB, thus reducing its size by as much as 50%. The frequency band allocated to the basic beam will be divided among the sub-beams. However, the frequency re-use among the basic beams can be maintained. Frequency allocations have to be coordinated among all beams. This concept is especially applicable to phased arrays using digital beam formers. The DBF complexity is a function of the number of array elements, and is less dependent on the number of beams. Reducing the array size, and consequently reducing the number of elements helps in reducing the complexity, power and mass of the DBF.

Abstract: An uplink power control system and method of the present invention includes a current sensing technique for predicting the P1 db power compression point. A dc current sensor detects the level of dc current transmitted from a control unit to an antenna unit of the system. The current measurements are analyzed to generate a theoretical prediction of amplifier linearity as the power levels are increased. The change in dc current indicates an inflection point where the amplifier no longer behaves linearly to an increase in RF power. Using this inflection point, an accurate assessment of the P1 db compression point of the system can be determined and the signal power levels adjusted accordingly.

Abstract: A multi-beam satellite comprises an input section receiving a plurality of first spot beams and an output section transmitting a plurality of second spot beams. A payload architecture is coupled between the input section and output section. It flexibly and selectively switches and filters the first plurality of spot beams received by the input section and provides signals to the output section to be transmitted as the second plurality of spot beams.

Abstract: A system and method for monitoring the quality of signals transmitted to a remote service area that is located outside of the broadcast area of a main broadcast site. The present invention converts and combines the signals that are to be broadcast from the main broadcast site to a satellite for redistribution to the remote service areas. The converted and combined signals are looped back to a network monitoring operations located at the main broadcast site before being transmitted to the satellite. In another embodiment, the remote broadcast sites send signal strength measurements to the network monitoring operations to provide an indication of satellite transmission problems not related to the quality of the signal being broadcast from the main broadcast site.

Abstract: It is proposed, for better efficacity of the ATN aeronautical telecommunication network, that the requests for logons through the ATN network originating from non-ATC applications be subjected to a validation of the addresses requested by means of two availability tables kept up-to-date and placed in the terminal hosting the applications asking for logons. One of the tables relates to the availability of the local applications and serves to advise the remote terminals. The other table relates to the availability of the remote applications and serves for the validation of the logon requests emanating from the local applications.

Abstract: A communication system has a plurality of high altitude devices that are coupled to user terminals through a plurality of dynamic links. The terminal monitors and changes the multiple dynamic links as the position of the user terminal relative to the high altitude devices changes. The terminal transmits to and receives from the user terminals through the high altitude devices using a plurality of datagrams.

Abstract: A method of reusing frequency bands between base stations of a terrestrial mobile communications network and a satellite communications network, comprising allocating the frequency bands using integrated resource management and other mitigation techniques in a such a way as to minimize interference between both the systems, thus making optimum usage of valuable frequency spectrum.

Abstract: A method up-link fade control for a satellite not having AGC, includes the steps of determining characteristics for correcting channel non-linearity, each characteristic being determined for a different value of up-link fade. A signal representative of up-link fade is determined by a beacon receiver and the signal is associated with a correction characteristic for the up-link fade. The correction characteristic associated with the signal is applied to a corrector of a modulator such that the corrector changes the modulator characteristics to modify constellation parameters at a satellite receiver.

Abstract: This disclosure provides a communications system using a span-loaded flying wing, traveling at relatively slow speeds, that can remain airborne for long periods of time. The communications system uses the airplane as a long term high altitude platform that can serve at lest one of a number of potential functions. One function is to link to a ground station using radio wave signals and a satellite using optical signals. Another function is to serve as a relay station between ground communication nodes and individual end-users. Because the aircraft can tightly hold a station, the end-user's antennas do not need to be continuously adjustable. For such a system, a large number of aircraft can be used, with the end-user antennas being configured for a narrow beamwidth so as to allow frequency reuse for different communication links.

Abstract: The invention relates generally to a method and an arrangement for transferring information in a packet radio service. Especially the invention applies to transferring delay sensitive data, such as speech and video data, in a mobile cellular telecommunications system. It is an object of this invention to provide a solution, in which the physical connection of a packet radio service is kept reserved also during the passive periods of a session but the same physical resource can still be shared between multiple users. In the present solution after the end of an active period of data transmission a predetermined time period is waited until the connection is released. The length of the time period is informed to the mobile station by the network on a dedicated or on a broadcast channel. The length of the time period is preferably made dependent on the required quality of service value of the connection and on the momentary communication activity in the network or cell.

Abstract: A method for communicating between a user terminal and multiple stratospheric transponder platforms includes the steps of positioning a plurality of stratospheric transponder platforms (102, 104, 106, 108) in a substantially fixed position (152) with respect to a user terminal antenna (116) coupled to a user terminal (117) and communicating between the user terminal (117) and at least two of the plurality of stratospheric transponder platforms (102, 104, 106, 108) concurrently.

Abstract: A method and system for controlling a movable appendage on an aerospace vehicle independent from the position of the aerospace vehicle. First and second beacons containing actual position information for the movable appendage are tracked and acquired by first and second beacon tracking sites. The beacon tracking sites report the azimuth and elevation data relating to the position of the movable appendage to a processor where a correction command is determined based on an error calculated from the position data and a desired position. The correction command is communicated to the movable appendage so that appropriate correction to the desired position can be made.

Abstract: This disclosure provides a solar rechargeable aircraft that is inexpensive to produce, is steerable, and can remain airborne almost indefinitely. The preferred aircraft is a span-loaded flying wing, having no fuselage or rudder. Traveling at relatively slow speeds, and having a two-hundred foot wingspan that mounts photovoltaic cells on most all of the wing's top surface, the aircraft uses only differential thrust of its eight propellers to turn. Each of five segments of the wing has one or more motors and photovoltaic arrays, and produces its own lift independent of the other segments, to avoid loading them. Five two-sided photovoltaic arrays, in all, are mounted on the wing, and receive photovoltaic energy both incident on top of the wing, and which is incident also from below, through a bottom, transparent surface. The aircraft includes hinges and actuators capable of providing an adjustable dihedral for the wing. The actuators can be motors or control surfaces.

Abstract: In a satellite communications system, where a user terminal 10, on the surface of the earth 12, can be in diversity communication to an earth station 18 via two orbiting satellites 14, 16 at once, and there is a need, at some time, when one of the two satellites 14, 16 orbits our of range, to engage another satellite 22 in its place, the user terminal 10 is operative to suppress TDMA timeslots in its communications with the two satellites 14, 16 to listen and report on broadcast messages from another satellite 22, the suppressed timeslots being based on an assessment of which of the two satellites has the largest path attenuation.

Abstract: A mobile wireless communications system including a plurality of individual transponding nodes all in communication with a central processing hub. A local user signal is processed by the central processing hub and radiated through multiple paths to a plurality of the plurality of individual transponding platforms simultaneously. The signal is then re-radiated by each of the plurality of the plurality of individual transponding platforms to a mobile terminal associated with a remote user that receives the re-radiated signal from the plurality of the plurality of individual transponding platforms coherently and in phase. The number of transponders and codes used to transmit each user signal can be readily adapted to user requirements. The central hub can determine the position of each of the remote users based on stored information derived from the synchronization of the various signals, and specifically relating to the timing, phase or frequency of the signals in both the forward and return link.

Abstract: Airborne units (2) acquire images as electronic signals either directly or indirectly from first ground based units (2a) and transmit them by broad band radio to second ground based units (3, 4), either directly or indirectly via second airborne units (1), which units (3, 4) record the received image signals for a period of time sufficient to permit a section of the received image to be selected by narrow bandwidth means (5, 6).

Abstract: A communication system having gateway filter and switching networks in forward and return channels of a frequency reuse communication satellite. The system couples subscriber terminals to the Internet or other terrestrial network by way of one or more gateways. The system cross-straps gateway-to-user beam connectivity provided by the communication satellite to allow full coverage of all user beams with a subset of the gateways having reduced frequency reuse. An exemplary system comprises a communication satellite having a return channel and a forward channel. One or more gateways are coupled to the Internet or other terrestrial network and communicate with subscriber terminals by way of the return and forward channels provided by the satellite. The return and forward channels each comprise a filter and switching network that selectively couple signals between the one or more gateways and the subscriber terminals.

Abstract: A system has a stratospheric platform with a payload controller and a phased array antenna having a plurality of elements. A gateway station communicates with the stratospheric platform. The gateway station scales the plurality of elements to form a reconfigurable plurality of beams. The gateway station communicates a control signal to the stratospheric platform to communicate a scaling of the elements. The stratospheric platform configures the elements of the phased array antenna according to the scaling using adaptive interference rejection. The gateway station has an adaptive beam processor coupled to user position files. The adaptive beam processor with the user position data can adaptively cancel interference from other beams.

Abstract: A method for testing upgrades and modifications to a first transmission network by providing a second internet transmission network including components that duplicate or simulate one or more of the components of the first network. The second network duplicates the functionality and configuration of the first network thereby permitting modifications to be installed and tested on the second network prior to installing them on the first transmission network. This in turn allows “bugs” to be found and eliminated before modifications are used on the first network. The invention also allows error signals to be injected to enable operators to compensate for and to avoid these errors before they appear on the first network.

Abstract: The footprint of a first satellite is reconfigurable in orbit by ground control to switch on and off different transponders. Each transponder is connected to a corresponding downlink antenna feed, each of which transmits a downlink beam independent of the others. The satellite can be moved into different orbits or otherwise changed to service new geographic areas by using different combinations of the transponders. In one embodiment, the satellite includes an antenna and components for an uplink beam corresponding to each downlink beam. Various subsets of the downlink antenna feeds are mechanically linked to move in unison using gimbals, each subset using a corresponding gimbal and mechanical driver. The first satellite is sufficiently reconfigurable that it may serve as a back up satellite to a plurality of other satellites in a constellation of satellites.

Abstract: Boeing achieves satellite diversity by having a large discrimination angle for a MEO constellation of communications satellites to limit interference in the Ku-band with GSO communications systems. Each satellite entering an exclusion zone over a GSO ground station terminates all transmissions to provide EPFD within acceptable limits. The Boeing MEO constellation preferably comprises 20 satellites, 5 in each orbit. The four orbits are inclined at about 57° with respect to the equator. Services include an Integrated Digital Service (IDS) and Backhaul Data Service (BDS) to accommodate the needs of different users.

Abstract: A satellite communication system (10) includes apparatus for exchanging communication data between ground-based user sites (21-24, 41-44 and 51-54) and a ground-based wideband network (60). A communication satellite (30) exchanges user communication data with the user sites. Ground-based hub terminals (27, 35, 47 and 57) exchange the user communication data with the satellite (30) and also exchange the data with the network (60). A communication manager (70) determines the communication requirements between the satellite and the network and identifies more than one hub terminal to exchange user communication data with the satellite in the event that one hub terminal is insufficient to meet the communication requirements.

Abstract: A wireless communications system and method provides wireless communications service for user equipment on board an aircraft. The aircraft includes on-board system equipment for supporting the wireless communications service with on-board user equipment. One or more ground stations are used for communicating with the aircraft using a plurality of feeder links for exchanging the wireless communications service's traffic and control information with the on-board system equipment, and for providing interfaces with a terrestrial telecommunications infrastructure. The on-board system equipment transitions connections by the on-board user equipment between the feeder links.

Abstract: An LNB (low noise block down converter) that can have a plurality of receivers connected includes a conversion unit receiving a plurality of types of polarized wave signals transmitted from each of a plurality of satellites to convert the plurality of polarized wave signals into a plurality of intermediate frequency signals, an amplify switch connected to the conversion unit to receive the plurality of intermediate frequency signals as inputs, and having a plurality of outputs connected to a plurality of output ports, respectively, determining a status according to a select signal and providing an amplified intermediate frequency signal, and a first control unit receiving digital serial data to select a satellite from an external source via an output port and providing a select signal according to the digital serial data.

Abstract: A method and system for communicating includes a plurality of cells having base units therein. Each of the base units communicates with a plurality of users within the cells. A communications platform is located in a stratospheric location for transmitting and receiving information with respect to the base units. A gateway station communicates with the communications platform and routes signals to terrestrial networks or other user back through the communications platform. A microcell within at least one of the cells is used to provide coverage in a small geographic area such as within a building. Each of the microcells is also in communication with the gateway station through the platform.

Abstract: A satellite communications system uses multiple ground stations and one or more satellites for communicating between mobile subscribers and a land-based communications network, such as the PSTN or the Internet. Multiple ground stations geographically dispersed minimize toll charges incurred routing calls from a mobile subscriber through the land network by reducing the need for long-distance calling. Further, because each ground station communicates with a given satellite using the same frequency spectrum, the subscriber capacity of the system increases and/or bandwidth requirements for the communications link between ground stations and satellites may be reduced. The present system uses ground-based beamforming techniques enabling each satellite to transmit signals in multiple transmission beams, each beam supporting one or more mobile subscribers. Each beam may reuse the same frequency spectrum, thereby increasing the number of subscribers supported by each satellite.

Abstract: A communication system for a mobile platform satellite service (MPSS) system includes a receiver subsystem (RS) and a transmitter subsystem (TS). A satellite transponder is in communication with the RS and the TS of the mobile platform. A satellite service ground station includes a transmitter subsystem (TS) and a receiver subsystem (RS). A communication link is established between the MPSS system and the ground station, via the satellite transponder. The communications link includes fixed satellite service (FSS) data superimposed on MPSS data in the same frequency band to thereby maximize both satellite transponder utilization and interference budget usage.

Abstract: A method and system for compensating for atmospheric fading is used in a communication system wherein communication signals are exchanged between first and second earth stations via a satellite link, without increasing power of the satellite link. The method includes determining, at one or both of the earth stations, the signal power of a received signal and a signal-to-noise ratio of the received signal; calculating the difference in noise power spectral density in the received signal from that under clear sky conditions; calculating the downlink attenuation; determining the uplink attenuation, and commanding the transmitting earth station to increase its transmit power by an amount to compensate for the uplink attenuation. A corresponding system carries out the method.

Abstract: A satellite system includes a plurality of orbit slots having a first orbital and a second orbital slot. A first satellite occupies a first orbital slot and generates a first set of uniform beams. A second satellite located in a second orbital slot generates a second set of uniform beams. A tiling pattern on the face of the Earth has a plurality of cells, with each of the cells having a defined frequency for communication. The first set of beams and the second set of beams are generated according to parameters to avoid interference between them. The parameters may include satellite orbit separations, beam size, multiplicity of band reuse, and ground station received beamwidth.