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WORLD l'NTEI.LECl'UAI._ PROPERTY ORGANIZATION
`International Bureau
`
`'.'lilfl'r'*
`‘«’r»-1‘
`
`INTERNATIONAL APPLICATION PUBLISHED UNDER THE PATENT COOPERATION TREATY (PCT)
`
`-
`
`(51) International Patent Classification 5 =
`H043 1/034’ 7,26’ “MM 11/00
`
`(11) International Publication Number:
`(43) International Publication Date:
`
`WO 96/31009
`3 October 1996 (03.l0.96)
`
`(21) International Application Number:
`
`PCI‘/US95/03898
`
`(22) International Filing Date:
`
`27 March 1995 (27.03.95)
`
`(81) Designated States: CA. CN. JP. RU. European pawn! (AT,
`BE, CH, DE, DK, ES, FR, GB, GR, IE, n“, LU, MC. NL.
`PT, SE).
`
`(71) Applicant: CELSAT AMERICA, INC. [US/US]; Suite 220, Published
`3460 Torrance Boulevard, Torrance, CA 90503 (US).
`With international search report.
`
`(72) Inventor: OTTEN, David, D.; 532 South Gertruda, Redondo
`Beach, CA 90277 (US).
`
`(74) Agent: DRUMMOND, William, H.; Drummond & Duckworth,
`Suite 500. 4590 MacArthur Boulevard, Newport Beach, CA
`92660 (US).
`
`(54) Title: CELLULAR COMMUNICATIONS POWER CONTROL SYSTEM
`
`(57) Abstract
`
`Two-way adaptive power control and signal quality monitoring and power control responsive thereto are provided for controlling
`the power output levels of transmitters (210) to the minimum necessary for satisfactory communications. Each transmission includes a
`code representative of the transmitter output power level. Receivers (212) compare this code to the received signal strength and ajust
`their associated transmitter power output level accordingly. Bit error rate (218) and SNR (223) are monitored by receivers to develop a
`measure of signal quality (220). A signal quality code is transmitted (250) to remote units and transmission output power level is adjusted
`in response.
`
`Petitioner's Exhibit 1006
`
`Petitioner's Exhibit 1006
`
`

`
`FOR THE PURPOSES OF INFORMATION ONLY
`
`Codes used to identify States party to the PC!‘ on the front pages of pamphlets publishing international
`applications under the PCI‘.
`
`AM
`AT
`AU
`BB
`BE
`BE‘
`BG
`31
`BR
`BY
`CA
`CF
`CG
`CH
`CI
`CM
`CN
`CS
`CZ
`DE
`
`Annenia
`Austria
`Ausmlia
`Barbados
`Belgium
`Burkina Faso
`Bulgaria
`Benin
`Brazil
`Belarus
`Canada
`Central African Republic
`Congo
`Switzerland
`Cote d'Ivoire
`Cameroon
`China
`Czechoslovakia
`Czech Republic
`Gennany
`Denmark
`Estonia
`Spain
`Finland
`France
`Gabon
`
`United Kingdom
`
`Kenya
`Kyrgystan
`Democratic People's Republic
`of Korea
`Republic of Korea
`Kazakhstan
`Liechtenstein
`Sri Lanka
`Liberia
`Lithuania
`Luxembourg
`Latvia
`Monaco
`Republic of Moldova
`Madagascar
`Mali
`Mongolia
`Mauritania
`
`Tajikistan
`Trinidad and Tobago
`Ukraine
`Uganda
`United States of America
`Uzbekistan
`Viet Nam
`
`Petitioner's Exhibit 1006
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`Petitioner's Exhibit 1006
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`CELLULAR COMMUNICATIONS POWER CONTROL SYSTEM
`
`BACKGROUND
`
`The invention relates to communication systems and in particular, to a
`
`cellular mobile communications system having integrated satellite and ground
`
`nodes.
`
`The cellular communications industry has grown at a fast pace in the
`
`United States and even faster in some other countries. It has become an
`
`important service of substantial utility and because of the growth rate,
`
`saturation of the existing service is of concern. High density regions having
`
`high use rates, such as Los Angeles, New York and Chicago are of most
`
`immediate concern. Contributing to this concern is the congestion of the
`
`electromagnetic frequency spectrum which is becoming increasingly severe as
`
`the communication needs of society expand. This congestion is caused not
`
`only by cellular communications systems but also by other communications
`
`systems. However, in the cellular communications industry alone, it is
`
`estimated that the number of mobile subscribers will increase on a world-wide
`
`level by an order of magnitude within the next ten years. The radio frequency
`
`spectrum is limited and in view of this increasing demand for its use, means to
`
`more efficiently use it are continually being explored.
`
`Petitioner's Exhibit 1006
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`Petitioner's Exhibit 1006
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`Existing cellular radio is primarily aimed at providing mobile telephone
`
`service to automotive users in developed metropolitan areas. For remote area
`
`users, airborne users, and marine users, AIRFONE and INMARSAT services
`
`exist but coverage is incomplete and service is relatively expensive. Mobile
`
`radio satellite systems in an advanced planning stage will probably provide
`
`improved direct-broadcast voice channels to mobile subscribers in remote areas
`
`but still at significantly higher cost in comparison to existing ground cellular
`
`service. The ground cellular and planned satellite technologies complement
`
`one another in geographical coverage in that the ground cellular
`
`communications service provides voice telephone service in relatively
`
`developed urban and suburban areas but not in sparsely populated areas, while
`
`the planned earth orbiting satellites will serve the sparsely populated areas.
`
`Cellular communications systems divide the service areas into
`
`geographical cells, each served by a base station or node typically located at its
`
`center. The central node transmits sufficient power to cover its cell area with
`
`adequate field strength.
`
`If a mobile user moves to a new cell, the radio link is
`
`switched to the new node provided there is an available channel. Present land
`
`mobile communication systems typically use a frequency modulation (FM)
`
`approach and because of the limited interference rejection capabilities of FM
`
`modulation, each radio channel may be used only once over a wide
`
`geographical area encompassing many cells. This means that each cell can
`
`use only a small fraction of the total allocated radio frequency band, resulting
`
`in an inefficient use of the available spectrum.
`
`In some cases, the quality of
`
`Petitioner's Exhibit 1006
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`Petitioner's Exhibit 1006
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`speech is poor because of the phenomena affecting FM transmission known as
`
`fading and "dead spots." The subjective effect of fading is repeated
`
`submersion of the voice signal in background noise frequently many times per
`
`second if the mobile unit is in motion. The problem is exacerbated by
`
`interference from co-channel users in distant cells and resultant crosstalk due to
`
`the limited interference rejection capability of FM. Additionally,
`
`communications privacy is relatively poor; the FM signal may be heard by
`
`others who are receiving that frequency.
`
`In the case where one band of frequencies is preferable over others and
`
`that one band alone is to be used for mobile communications, efficient
`
`communications systems are necessary to assure that the number of users
`
`desiring to use the band can be accommodated. For example, there is
`
`presently widespread agreement on the choice of L-band as the technically
`
`preferred frequency band for the satellite-to-mobile link in mobile
`
`communications systems.
`
`In the case where this single band is chosen to
`
`contain all mobile communications users, improvements in spectral utilization
`
`in the area of interference protection and in the ability to function without
`
`imposing intolerable interference on other services will be of paramount
`
`importance in the considerations of optimal use of the scarce spectrum.
`
`Troubling both terrestrial and satellite communication is channel fading,
`
`in which communications channel experiences fading due to numerous factors
`
`such as changes in weather conditions, signal propagation, local terrain etc..
`
`Petitioner's Exhibit 1006
`
`Petitioner's Exhibit 1006
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`Satellite transceivers are generally located in geosynchronous earth orbit,
`
`approximately 22,300 miles from earth, and as such, are approximately the
`
`same distance from mobile units. Accordingly, path loss in the satellite
`
`charmel is relatively minor, on the order of only a few dB. Unfortunately,
`
`satellite transmissions still experience substantial fading due to the direct
`
`component of the satellite signal being summed with multiply reflected
`
`components of the satellite signal, thereby inducing channel fading of several
`
`dB.
`
`In contrast to satellite transmission, the terrestrial to mobile
`
`transmission is substantially effected by the distance between the mobile unit
`
`and the cell site. For example, one mobile unit may be located at a distance
`
`many miles from the cell site, while another may be only yards away.
`
`Accordingly, path loss variations of terrestrial transmissions may be orders of
`
`magnitude greater than experienced by satellite transmissions. Further, the
`
`terrestrial transmissions typically experience substantial fading due to the signal
`
`being reflected from many different features of the physical environment. As a
`
`result, a signal may arrive at a mobile unit from many different directions
`
`causing both constructive and destructive summation of the signals.
`
`Additionally, the transmitted signal may be partially obstructed by buildings,
`
`foliage, and the like to produce additional signal fading.
`
`In order to overcome these constraints, the transceivers of typical
`
`communications systems commonly radiates at a power level which is 30 to 40
`
`Petitioner's Exhibit 1006
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`Petitioner's Exhibit 1006
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`dB greater than is required on the average in order to overcome fading nulls.
`
`This results in greatly increased inter-system interference, reduced battery life
`
`and a reduction of potential users in the communications system.
`
`The severely limited commodity in the satellite links is satellite prime
`
`power, a major component of the weight of a communication satellite and
`
`thereby a major factor in satellite cost. Generally in systems such as this, the
`
`down links to individual users are the largest power consumers and thus for a
`
`limited satellite source power, may provide the limiting factor on the number
`
`of users that can be served. Thus it is important to design the system for
`
`minimum required power per user.
`
`It would be desirable to provide a power control system to compensate
`
`for fading and interference without exceeding the minimum amount of power
`
`necessary to overcome such interference. To this end, numerous designs have
`
`been developed in an attempt to control transmitter power. A transmitter
`
`power control system is disclosed in the patent to Wheatley, III, U.S. Patent
`
`No. 5,267,262. Wheatley, III discloses the cell site measuring the signal
`
`strength and signal quality, i.e. bit error rate, of a signal transmitted by the
`
`mobile unit. The cell site processes the signal strength and signal quality to
`
`determine the desired signal strength for that mobile unit and transmits a power
`
`adjustment command back to the mobile unit. This power adjustment
`
`command is combined with the mobile unit’s one way estimate of received
`
`signal strength to obtain a final value of the mobile unit transmitter power.
`
`Petitioner's Exhibit 1006
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`Petitioner's Exhibit 1006
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`Unfortunately, Wheatley discloses telemetering the transmit power only as a
`
`static parameter at call setup time, not for the purpose, nor at a sample rate
`
`sufficient to support dynamic compensation of the received signal strength for
`
`adaptive power variations in a two-way adaptive power control system where
`
`both transmitters continuously adapt their respective transmit power.
`
`A similar concept to control transmitter power is disclosed in Wilson et
`
`a_1., U.S. Patent No. 5,293,639. Wilson et al. discloses the control of the
`
`output power level of a transmitted signal by the mobile unit transmitting a
`
`first message on a first communications channel to a repeater station. The
`
`repeater station measures the quality of the received first message to produce a
`
`quality metric representative of the quality of the first message. The repeater
`
`station retransmits the first message back to the mobile unit, appending the
`
`quality metric for determination by the mobile unit of its output power.
`
`Unfortunately, the retransmission of the first message is unnecessary in many
`
`system applications thus requiring additional power, and causing unnecessary
`
`signal interference.
`
`It is therefore an object of the present invention to provide an improved
`
`method and apparatus for controlling the transmitter power of a transceiver of
`
`a cellular communications system including an adaptive two-way power control
`
`system which continuously maintains each transmitted signal power at a
`
`minimum necessary level, adapting rapidly to, and accommodating signal fade
`
`dynamically and only as necessary.
`
`Petitioner's Exhibit 1006
`
`Petitioner's Exhibit 1006
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`SUMMARY OF THE INVENTION
`
`Briefly and in general terms, the invention, is directed to a cellular
`
`communications system having an adaptive transmitter power control system
`
`and method compensate for received signal strength variations, such as those
`
`caused by buildings, foliage and other obstructions.
`
`Each receiver determines
`
`the quality of the received signal and provides a local quality signal to its
`
`associated transmitter in the respective transceiver indicative of that received
`
`signal quality. Each transmitter also transmits the local quality signal provided
`
`to it from its associated receiver and the transceiver is additionally responsive
`
`to the quality signal received from the other transceiver with which it is in
`
`communication to control its own output power in the response to that quality
`
`signal.
`
`In yet a further aspect, a path loss measure is derived from the received
`
`signal strength and from data included in each transmitted signal which
`
`indicates that transmitter’s output power level. Based on the derived path loss
`
`and the transmitter’s power level data, the receiver can then adjust the power
`
`output of its own associated transmitter accordingly.
`
`In a more detailed aspect, the error rate of the received signal is
`
`determined in providing the quality signal, and in another aspect, the signal-to-
`
`noise ratio (SNR) is measured to determine quality. The transceiver receiving
`
`Petitioner's Exhibit 1006
`
`Petitioner's Exhibit 1006
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`the error rate signal or the SNR from the other transceiver controls its own
`
`transmitter power output in response.
`
`Other aspects and advantages of the invention will become apparent
`
`from the following detailed description and the accompanying drawings,
`
`illustrating by way of example the features of the invention.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`FIG. 1 is a block diagram showing an overview of the principal
`
`elements of a communications system in accordance with the principles of the
`
`invention;
`
`FIG. 2 is a diagram of the frequency sub-bands of the frequency band
`
`allocation for a cellular system;
`
`FIG. 3 is a overview block diagram of a communications system in
`
`accordance with the principles of the invention without a network control
`
`center;
`
`FIG. 4 is a diagram showing the interrelationship of the cellular
`
`hierarchical structure of the ground and satellite nodes in a typical section and
`
`presents a cluster comprising more than one satellite cell;
`
`Petitioner's Exhibit 1006
`
`Petitioner's Exhibit 1006
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`FIG. 5 is a block diagram of a satellite link system showing the user
`
`unit and satellite node control center;
`
`FIG. 6 is a block diagram of one embodiment of satellite signal
`
`processing in the system of FIG. 5;
`
`FIG. 7 is a functional block diagram of a user transceiver showing an
`
`adaptive power control system;
`
`FIGS. 8a through 8h show timing diagrams of an adaptive, two-way
`
`power control system; and
`
`FIG 9 is a functional diagram of a two-way power control system
`
`incorporating telemetered signal-quality deficiency supervisory control.
`
`FIG 10 is a functional diagram of a power control system combining
`
`adaptive signal quality power control and adaptive path loss power control.
`
`DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
`
`As is shown in the exemplary drawings, the invention, though not
`
`limited to, is preferredly embodied in a cellular communications system
`
`utilizing integrated satellite and ground nodes both of which use the same
`
`modulation, coding, and both responding to an identical user unit.
`
`Petitioner's Exhibit 1006
`
`Petitioner's Exhibit 1006
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`Referring now to FIG. 1, an overview of a preferred communications
`
`system 10 is presented showing the functional inter-relationships of the major
`
`elements. The system network control center 12 directs the top level allocation
`
`of calls to satellite and ground regional resources throughout the system.
`
`It
`
`also is used to coordinate system-wide operations, to keep track of user
`
`locations, to perform optimum allocation of system resources to each call,
`
`dispatch facility command codes, and monitor and supervise overall system
`
`health. The regional node control centers 14, one of which is shown, are
`
`connected to the system network control center 12 and direct the allocation of
`
`calls to ground nodes within a major metropolitan region. The regional node
`
`control center 14 provides access to and from fixed land communication lines,
`
`such as commercial telephone systems known as the public switched telephone
`
`network (PSTN). The ground nodes 16 under direction of the respective
`
`regional node control center 14 receive calls over the fixed land line network
`
`encode them, spread them according to the unique spreading code assigned to
`
`each designated user, combine them into a composite signal, modulate that
`
`composite signal onto the transmission carrier, and broadcast them over the
`
`cellular region covered.
`
`Satellite node control centers 18 are also connected to the system
`
`network control center 12 via status and control land lines and similarly handle
`
`calls designated for satellite links such as from PSTN, encode them, and
`
`multiplex them with other similarly directed calls into an uplink trunk, which
`
`is beamed up to the designated satellite 20. Satellite nodes 20 receive the
`
`Petitioner's Exhibit 1006
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`Petitioner's Exhibit 1006
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`uplink trunks, frequency demultiplex the calls intended for different satellite
`
`cells, frequency translate and direct each to its appropriate cell transmitter and
`
`cell beam, and broadcast the composite of all such similarly directed calls
`
`down to the intended satellite cellular area. As used herein, "backhaul" means
`
`the link between a satellite 20 and a satellite node control center 18.
`
`In one
`
`embodiment, it is a K-band frequency while the link between the satellite 20
`
`and the user unit 22 uses an L-band or an S—band frequency.
`
`As used herein, a "node" is a communication site or a communication
`
`relay site capable of direct one— or two-way radio communication with users.
`
`Nodes may include moving or stationary surface sites or airborne or satellite
`
`sites.
`
`User units 22 respond to signals of either satellite or ground node
`
`origin, receive the outbound composite signal, de-modulate, and decode the
`
`information and deliver the call to the user. Such user units 22 may be mobile
`
`or may be fixed in position. Gateways 24 provide direct trunks, that is,
`
`groups of channels, between satellite and the ground public switched telephone
`
`system or private trunk users. For example, a gateway may comprise a
`
`dedicated satellite terminal for use by a large company or other entity.
`
`In the
`
`embodiment of FIG. 1, the gateway 24 is also connected to that system
`
`network controller 12.
`
`Petitioner's Exhibit 1006
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`Petitioner's Exhibit 1006
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`All of the above-discussed centers, nodes, units and gateways are full
`
`duplex transmit/receive performing the corresponding inbound (user to system)
`
`link functions as well in the inverse manner to the outbound (system to user)
`
`link functions just described.
`
`Referring now to FIG. 2, the allocated frequency band 26 of a
`
`communications system is shown. The allocated frequency band 26 is divided
`
`into 2 main sub-bands, an outgoing sub-band 25 and an incoming sub-band 27.
`
`Additionally the main sub-bands are themselves divided into further sub-bands
`
`which are designated as follows:
`
`Outbound Ground 28 (ground node to user)
`
`Outbound Satellite 30 (satellite node to user)
`
`Outbound Calling and Command 32 (node to user)
`
`Inbound Ground 34 (user to ground node)
`
`Inbound Satellite 36 (user to satellite node)
`
`Inbound Calling and Tracking 38 (user to node)
`
`All users in all cells use the entire designated sub-band for the described
`
`function. Unlike existing ground or satellite mobile systems, there is no
`
`necessity for frequency division by cells; all cells may use these same basic six
`
`sub-bands. This arrangement results in a higher frequency reuse factor as is
`
`discussed in more detail below.
`
`Petitioner's Exhibit 1006
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`Petitioner's Exhibit 1006
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`In one embodiment of the communication system, a mobile user’s unit
`
`22 will send an occasional burst of an identification signal in the IC sub-band
`
`either in response to a poll or autonomously. This may occur when the unit 22
`
`is in standby mode. This identification signal is tracked by the regional node
`
`control center 14 as long as the unit is witl1in that respective region, otherwise
`
`the signal will be tracked by the satellite node or nodes.
`
`In another
`
`embodiment, this identification signal is tracked by all ground and satellite
`
`nodes capable of receiving it. This information is forwarded to the network
`
`control center 12 via status and command lines. By this means, the applicable
`
`regional node control center 14 and the system network control center 12
`
`remain constantly aware of the cellular location and link options for each
`
`active user 22. An intra-regional call to or from a mobile user 22 will
`
`generally be handled solely by the respective regional node control center 14.
`
`Inter-regional calls are assigned to satellite or ground regional system resources
`
`by the system network control center 12 based on the location of the parties to
`
`the call, signal quality on the various link options, resource availability and
`
`best utilization of resources.
`
`A user 22 in standby mode constantly monitors the common outbound
`
`calling frequency sub-band 0C 32 for calling signals addressed to him by
`
`means of his unique spreading code. Such calls may be originated from either
`
`ground or satellite nodes. Recognition of his unique call code initiates the user
`
`unit 22 ring function. When the user goes "off-hook", e.g. by lifting the
`
`handset from its cradle, a return signal is broadcast from the user unit 22 to
`
`Petitioner's Exhibit 1006
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`Petitioner's Exhibit 1006
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`any receiving node in the user calling frequency sub-band IC 38. This initiates
`
`a handshaking sequence between the calling node and the user unit which
`
`instructs the user unit whether to transition to either satellite, or ground
`
`frequency sub-bands, OS 30 and IS 36 or OG 28 and IG 34.
`
`A mobile user wishing to place a call simply takes his unit 22 off hook
`
`and dials the number of the desired party, confirms the number and "sends"
`
`the call. Thereby an incoming call sequence is initiated in the IC sub-band 38.
`
`This call is generally heard by several ground and satellite nodes which
`
`forward call and signal quality reports to the appropriate system network
`
`control center 12 which in turn designates the call handling to a particular
`
`satellite node 20 or regional node control center 14. The call handling element
`
`then initiates a handshaking function with the calling unit over the 0C 32 and
`
`IC 38 sub-bands, leading finally to transition to the appropriate satellite or
`
`ground sub-bands for communication.
`
`Referring now to FIG. 3, a block diagram of a communications system
`
`40 which does not include a system network control center is presented.
`
`In
`
`this system, the satellite node control centers 42 are connected directly into the
`
`land line network as are also the regional node control centers 44. Gateway
`
`systems 46 are also available as in the system of FIG. 1. and connect the
`
`satellite communications to the appropriate land line or other communications
`
`systems. The user unit 22 designates satellite node 48 communication or
`
`ground node 50 communication by sending a predetermined code.
`
`Petitioner's Exhibit 1006
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`Petitioner's Exhibit 1006
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`
`Referring now to FIG. 4, a hierarchical cellular structure is shown. A
`
`pair of clusters 52 of ground cells 54 are shown. Additionally, a plurality of
`
`satellite cells 56 are shown. Although numerals 54 and 56 point only to two
`
`cells each, this has been done to retain clarity in the drawing. Numeral 54 is
`
`meant to indicate all ground cells in the figure and similarly numeral 56 is
`
`meant to indicate all satellite cells. The cells are shown as hexagonal in shape,
`
`however, this is exemplary only. The ground cells may be from 3 to 15 km
`
`across although other sizes are possible depending on user density in the cell.
`
`The satellite cells may be approximately 200-500 km across as an example
`
`depending on the number of beams used to cover a given area. As shown,
`
`some satellite cells may include no ground cells. Such cells may cover
`
`undeveloped areas for which ground nodes are not practical. Part of a satellite
`
`cluster 58 is also shown. The cell members of such a cluster share a common
`
`satellite node control center 60.
`
`Referring again to FIG. 1 as well as to FIG. 4, the satellite nodes 20
`
`make use of large, multiple-feed antennas 62 which in one embodiment provide
`
`separate, relatively narrow beamwidth beams and associated separate
`
`transmitters for each satellite cell 56. For example, the multiple feed antenna
`
`62 may cover an area such as the United States with, typically, about 100
`
`satellite bearns/cells and in one embodiment, with about 200 bearns/cells. As
`
`used herein, "relatively narrow beamwidth" refers to a beamwidth that results
`
`in a cell of 500 km or less across. The combined satellite/ground nodes
`
`system provides a hierarchical geographical cellular structure. Thus within a
`
`Petitioner's Exhibit 1006
`
`Petitioner's Exhibit 1006
`
`

`
`WO 96/31009
`
`PCT/US95/03898
`
`-15-
`
`dense metropolitan area, each satellite cell 56 may further contain as many as
`
`'
`
`100 or more ground cells 54, which ground cells would normally carry the
`
`bulk of the traffic originated therein. The number of users of the ground
`
`nodes 16 is anticipated to exceed the number of users of the satellite nodes 20
`
`where ground cells exist within satellite cells. Because all of these ground
`
`node users would otherwise interfere as background noise with the intended
`
`user—satel1ite links, in one embodiment the frequency band allocation may be
`
`separated into separate segments for the ground element and the space element
`
`as has been discussed in connection with FIG 2. This combined, hybrid
`
`service can be provided in a manner that is smoothly transparent to the user.
`
`Calls will be allocated among all available ground and satellite resources in the
`
`most efficient manner by the system network control center 12.
`
`An important parameter in most considerations of cellular radio
`
`communications systems is the "cluster", defined as the minimal set of cells
`
`such that mutual interference between cells reusing a given frequency sub-band
`
`is tolerable provided that such "co-channel cells" are in different clusters.
`
`Conversely all cells within a cluster must use different frequency sub-bands.
`
`The number of cells in such a cluster is called the "cluster size".
`
`It will be
`
`seen that the "frequency reuse factor", i.e. the number of possible reuses of a
`
`frequency sub-band within the system is thus equal to the number of cells in
`
`the system divided by the cluster size. The total number of channels that can
`
`be supported per cell, and therefore overall bandwidth efficiency of the system
`
`is thus inversely proportional to the cluster size.
`
`Petitioner's Exhibit 1006
`
`Petitioner's Exhibit 1006
`
`

`
`WO 96131009
`
`PCT/US95I03898
`
`-17-
`
`Referring now to FIG. 5, a block diagram is shown of a typical user
`
`unit 22 to satellite 20 to satellite node control 18 communication and the
`
`processing involved in the user unit 22 and the satellite node control 18.
`
`In
`
`placing a call for example, the handset 64 is lifted and the telephone number
`
`entered by the user. After confirming a display of the number dialed, the user
`
`pushes a "send" button, thus initiating a call request signal. This signal is
`
`processed through the transmitter processing circuitry 66 which includes
`
`spreading the signal using a calling spread code. The signal is radiated by the
`
`omni-directional antenna 68 and received by the satellite 20 through its narrow
`
`beamwidth antenna 62. The satellite processes the received signal as will be
`
`described below and sends the backhaul to the satellite node control center 18
`
`by way of its backhaul antenna 70. On receive, the antenna 68 of the user unit
`
`22 receives the signal and the receiver processor 72 processes the signal.
`
`Processing by the user unit 22 will be described in more detail below in
`
`reference to FIG. 7.
`
`The satellite node control center 18 receives the signal at its antenna 71,
`
`applies it to a circulator 73, amplifies 74, frequency demultiplexes 76 the
`
`signal separating off the composite signal which includes the signal from the
`
`user shown in FIG. 5, splits it 78 off to one of a bank of code correlators,
`
`each of which comprises a mixer 80 for removing the spreading and
`
`identification codes, an AGC amplifier 82, the FECC demodulator 84, a
`
`demultiplexer 86 and finally a voice encoder/decoder (CODEC) 88 for
`
`converting digital voice information into an analog voice signal. The voice
`
`Petitioner's Exhibit 1006
`
`Petitioner's Exhibit 1006
`
`

`
`W0 96/31009
`
`PCI‘IUS9Sl03898
`
`-13-
`
`signal is then routed to the appropriate land line, such as a commercial
`
`telephone system. Transmission by the satellite node control center 18 is
`
`essentially the reverse of the above described reception operation.
`
`Referring now to FIG. 6, the satellite transponder 90 of FIG. 5 is
`
`shown in block diagram form. A circulator/diplexer 92 receives the uplink
`
`signal and applies it to an L-band or S-band amplifier 94 as appropriate. The
`
`signals from all the M satellite cells within a "cluster" are frequency
`
`multiplexed 96 into a single composite K-band backhaul signal occupying M
`
`times the bandwidth of an individual L-/S-band mobile link channel. The
`
`composite signal is then split 98 into N parts, separately amplified 100, and
`
`beamed through a second circulator 102 to N separate satellite ground cells.
`
`This general configuration supports a number of particular configurations
`
`various of which may be best adapted to one or another situation depending on
`
`system optimization which for example may include considerations related to
`
`regional land line long distance rate structure, frequency allocation and
`
`subscriber population. Thus, for a low density rural area, one may utilize an
`
`M-to-1 (M > 1, N= 1) cluster configuration of M contiguous cells served by a
`
`single common satellite ground node with M limited by available bandwidth.
`
`In order to provide high-value, long distance service between metropolitan
`
`areas, already or best covered for local calling by ground cellular technology,
`
`an M-to-M configuration would provide an "inter-metropolitan bus" which
`
`would tie together all occupants of such M satellite cells as if in a single local
`
`calling region. To illustrate, the same cells (for example, Seattle, Los
`
`Petitioner's Exhibit 1006
`
`Petitioner's Exhibit 1006
`
`

`
`wo 95/31009
`
`PCT/U S95/03898
`
`-19-
`
`Angeles, Omaha and others) comprising the cluster of M user cells on the left
`
`side of FIG. 6, are each served by corresponding backhaul beams on the right
`
`side of FIG. 6.
`
`Referring now to FIG. 7, a functional block diagram of a typical user
`
`unit 22 is shown. The user unit 22 comprises a small, light-weight, low—cost,
`
`mobile transceiver handset with a small, non-directional antenna 68. The
`
`single antenna 68 provides both transmit and receive functions by the use of a
`
`circulator/diplexer 104 or other means.
`
`It is fully portable and whether
`
`stationary or in motion, permits access to a wide range of communication
`
`services from one telephone with one call number.
`
`It is anticipated that user
`
`units will transmit and receive on frequencies in the 1-3 GHz band but can
`
`operate in other bands as well.
`
`The user unit 22 shown in FIG. 7 comprises a transmitter section 106
`
`and a receiver section 108. For the transmission of voice communication, a
`
`microphone couples

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