`
`(12)
`
`United States Patent
`Campanella
`
`(0) Patent No.:
`(45) Date of Patent:
`
`US 6,944,139 Bl
`Sep. 13, 2005
`
`(54)
`
`DIGITAL BROADCAST SYSTEM USING
`SATELLITE DIRECT BROADCASTAND
`TERRESTRIAL REPEATER
`
`(75)
`
`Inventor:
`
`§. Joseph Campanella, Gaithersburg,
`MD (US)
`
`(73)
`
`Assignee: WorldSpace Management
`Corporation, Washington, DC (US)
`
`(*")
`
`Notice:
`
`Subject to any disclaimer, the term ofthis
`patent is extended or adjusted under 35
`U.S.C. 154(b) by 0 days.
`
`(21)
`
`Appl. No.
`
`09/647,007
`
`(22
`
`PCTFiled:
`
`Jul. 10, 1998
`
`(86)
`
`PCT No.:
`
`PCT/US98/14280
`
`§ 371 (cX1),
`(2), (4) Date:
`
`Sep. 26, 2000
`
`(87)
`
`PCTPub. No... WO99/49602
`
`PCTPub. Date: Sep. 30, 1999
`
`Related U.S. Application Data
`
`Provisional application No. 60/079,591, filed on Mar.
`27, 1998.
`
`nt)? sescassanciens Spicastabaeie
`. HO4B 7/155
`370/315; 370/480; 455/3.02;
`455/17
`................:0s0000. 370/315, 316,
`Field of Search.
`370/480, 481, 485; 455/3.01, 3.02, 3.06,
`455/11.1, 12.1, 7, 16, 17, 427, 430, 118
`
`References Cited
`
`(60)
`
`(51)
`(52)
`
`(58)
`
`(56)
`
`U.S. PATENT DOCUMENTS
`
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`4,506,383 A *
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`
`S/1983 AIeXIS ......cececens
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`wee 455/17
`
`...... wide BTS/S8
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`
`4,901,307 A
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`
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`............. 370/18
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`............. 370/20
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`.......... 370/50
`3/1994 Hulyalkar et al.
`........... 348/723
`4/1994 Noreen et al.
`............... 455/3.2
`6/1994 Briskman .......
`wee SIDS/1
`9/1995 Sheynblat
`...
`375/346
`9/1995 Mueller ............c. 75/224
`
`
`
`(Continued)
`FOREIGN PATENT DOCUMENTS
`
`CA
`
`2209165
`
`1/1998 woes HOFB 1/69
`
`OTHER PUBLICATIONS
`
`Layer, David H., “Digital Radio Takes to the Road”, JEEE
`Spectrum, Jul. 2001, pp. 40-46.
`
`(Continued)
`
`Primary Examiner—Min Jung
`(74) Attorney, Agent, or Firm—Roylance, Abrams, Berdo &
`Goodman, L.L.P.
`
`(57)
`
`ABSTRACT
`
`A digital broadcast system is provided which usesa satellite
`direct radio broadcast system having different downlink
`modulation options in combination with a terrestrial repeater
`network employing different
`re-broadcasting modulation
`options to achieve high availability reception by mobile
`radios (14), static radios and portable radios (14) in urban
`areas, suburban metropolitan areas, and rural areas, includ-
`ing geographically open areas and geographic areas charac-
`terized by high terrain elevations. Two-arm and three-arm
`receivers are provided which each comprise a combined
`architecture for receiving both satellite and terrestrial sig-
`nals, and for maximum likelihood combining of received
`signals for diversity purposes. A terrestrial repeater is pro-
`vided for reformatting a TDM satellite signal as a multicar-
`rier modulatedterrestrial signal. Configurations for indoor
`and outdoorterrestrial repeaters are also provided.
`
`26 Claims, 10 Drawing Sheets
`
`56
`
`n COEFFICIENTS
`
`
`
`
`PERIODIC INSERTION
`MULTICARRIER
`GUARD INTERVAL
`BIT STREAMS OF
`INSERTION BY
`OF SYMBOL SYNCHRON-
`MODULATED
`
`
`
`INTO n PARALLEL
`INCREASING RATE
`IZATION & SYMBOL
`GAPFILLER
`
`OF SAMPLES
`PHASE REFERENCE
`WAVEFORM
`
`
`
`
`106
`
`108
`
`Petitioner Sirius XM Radio Inc. - Ex. 1005, p. 1
`
`Petitioner Sirius XM Radio Inc. - Ex. 1005, p. 1
`
`
`
`US 6,944,139 B1
`Page 2
`
`U.S, PATENT DOCUMENTS
`
`9/1995 Fruit et al. .......eeeeeee 375/202
`5,454,009 A
`
`........... 375/130
`1/1996 Briskman et al.
`5,485,485 A *
`
`8/1996 Philips .....cccccceeeee STOO
`5,550,812 A
`wee 455/13.1
`11/1996 Linquist et al.
`..
`5,574,970 A
`
`1/1997 Briskman ........
`we 455/523
`5,592,471 A
`
`3/1997 Olds et al. wo...
`we 455/12.1
`5,613,194 A
`we. 375/260
`6/1997 Tzanneset al.
`..
`5,636,246 A
`
`6/1997 Wiedeman .......
`wee 370/320
`5,640,386 A *
`
`oo... 348/21
`8/1997 Kostreski et al.
`5,659,353 A
`3/1998 Rickard .........0...
`wee 370/293
`5,726,980 A
`
`7/1998 Sykes et al.
`..
`we 378347
`5,784,418 A *
`8/1998 Briskman .....
`wee 455/344
`5,794,138 A
`5,848,060 A * 12/1998 Dent
`............
`. 370/281
`5,864,579 A
`1/1999 Briskman .....
`wee 375/200
`
`...
`wee 455/428
`5,930,708 A *
`7/1999 Stewart et al.
`....
`we 370/210
`5,953,311 A
`9/1999 Davieset al.
`
`wee 370/342
`5,970,085 A * LD/1999 Yi occ
`
`cesccssessessessecsesseeseenee 375/142
`6,061,387 A *
` S/2000 Yi
`5/2001 Wiedeman et al. ...... 455/552.1
`6,233,463 BL*
`6,249,514 BL*
`6/2001 Campanella ................ 370/316
`6,404,775 BL*
`6/2002 Leslie et al. 0... 370/466
`
`OTHER PUBLICATIONS
`
`Hoeher, P. et al., “Helicopter Emulation of Archimedes/
`Mediastar Satellite DAB Transmission to Mobile Receiv-
`ers”, International Journal of Satellite Communications,vol.
`15, pp. 35-43 (1997),
`Tuisel, U. et
`al., “Carrier-Recovery for Multicarrier-
`Transmissin Over Mobile Radio Channels”, International
`Conference on Acoustics, Speech and Signal Processing,
`ICASSPGE,San Francisco, 1992, pp. 677-680.
`F.C.C. Application of Satellite CD Radio, Inc. for Private
`CD Quality Satellite Sound Broadcasting System, May 18,
`1990.
`Terrestrial and Satellite Digital Sound Broadcasting to
`Vehicular Portable and Fixed Receivers in the VHF/UHF
`Bands,
`International Telecommunication Union, Radio
`Communication Bureau, Geneva, 1995, pp. 18-34, 48-49,
`87-93, 118, 162, 168-172, 183, Annex C, Table of Contents
`and Description of Digital System B.
`Principles for the Guidance of EBU Members for WARC-92
`Broadcasting-Satellite Service, European Broadcasting
`Union, Feb. 1991 Draft SPB 483-E, pp. 1-75.
`
`Le Floch et al., “Digital Sound Broadcasting to Mobile
`Receivers”, IEEE, Transactions on Consumer Electronics,
`Aug. 1989, vol. 35, No. 3, pp. 493-503.
`“Proceedings from Second International Symposium on
`Digital Audio Broadcasting: The Soundof 2000”, Toronto,
`Canada, Mar. 14-17, 1994, vol. I, pp. 158-181 and vol. II, pp.
`63-108 and pp. 240-248.
`Annex C to ITU-R Special Publication on Terrestrial and
`Satellite Digital Sound Broadcasting to Vehicular Portable
`and Fixed Receivers in the VHF/UHF Bands on “Digital
`System B”, Nov, 1, 1994,
`in Complimentary Terrestrial
`Introduction of Satellite
`Digital Sound Broadcasting in the WARC-92 Frequency
`Allocations, International Telecommunication Union, Docu-
`ment 10/30-E, Feb, 22, 1995, pp. 1-17.
`Advanced Digital Techniques for UHFSatellite Sound
`Broadcasting: Collected Papers on Concepts for Sound
`Broadcasting Into the 21“ Century, European Broadcasting
`Union, Extracted from EBU Document SPB 442,Jan. 1998,
`pp. 11-69.
`“Mixed Satellite/Terrestrial Sound Broadcasting Service:
`Effect of a Co-Channel Satellite Service on a Terrestrial
`DSB Coverage”, International Telecommunications Unit,
`Radio Communications Study Group, Document 1OB-CAN-
`6, Oct. 8, 1993, pp. 1-8.
`The Eurcka
`147 Project, Digital Audio Broadcasting
`System, DAB Project Office, Germany, pp. 1-11.
`De Gaudenzi, R., “Analysis of an AdvancedSatellite Digital
`Audio Broadcasting System and Complementary ‘Terrestrial
`Gap-Filler Single Frequency Network”, IEEE Transactions
`on Vehicular Technology, vol. 43, No. 2, May 1994, pp.
`194-210.
`Linnartz, Jean-Paul M.G. et al., “Wireless Communication”,
`copyrighted 1995,
`Zheng,H. et al., “Subband Coded Image Transmitting Over
`Noisy Channels Using Multicarrier Modulation”, Technical
`Research Report T.R. 98-20, Institute for Systems Research.
`Miller, John E., “Application of Coding and Diversity
`Coding to UHF Satellite Sound Broadcasting Systems”,
`IEEE, pp. 465-475, copyright 1988.
`
`* cited by examiner
`
`Petitioner Sirius XM Radio Inc. - Ex. 1005, p. 2
`
`Petitioner Sirius XM Radio Inc. - Ex. 1005, p. 2
`
`
`
`U.S. Patent
`
`Sep. 13, 2005
`
`Sheet 1 of 10
`
` Nw
`
`US 6,944,139 B1
`
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`
`Petitioner Sirius XM Radio Inc. - Ex. 1005, p. 3
`
`Petitioner Sirius XM Radio Inc. - Ex. 1005, p. 3
`
`
`
`U.S. Patent
`
`Sep. 13, 2005
`
`Sheet 2 of 10
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`US 6,944,139 B1
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`Petitioner Sirius XM Radio Inc. - Ex. 1005, p. 4
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`Petitioner Sirius XM Radio Inc. - Ex. 1005, p. 6
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`Petitioner Sirius XM Radio Inc. - Ex. 1005, p. 11
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`
`US 6,944,139 BI
`
`This application claims benefit of provisional application
`No. 60/079,591 filed Mar. 27, 1998,
`
`FIELD OF INVENTION
`
`10
`
`A digital broadcast system is provided which uses a
`satellite direct
`radio broadcast system having different
`downlink options in combination with a terrestrial repeater
`network employing different
`re-broadcasting options to
`achieve high availability reception by mobile radios, static
`radios and portable radios in urban areas, suburban metro-
`politan areas, rural areas,
`including geographically open
`areas and geographic areas characterized by terrain having
`high elevations.
`BACKGROUNDOFTHE INVENTION
`
`2
`1
`DIGITAL BROADCAST SYSTEM USING
`In accordance with another aspect of the present inven-
`SATELLITE DIRECT BROADCASTAND
`tion, a satellite delivery system andaterrestrial repeater
`TERRESTRIAL REPEATER
`operate using different carrier frequencies. The terrestrial
`repeater employs multipath-tolerant modulation techniques.
`In accordance with yet another aspect of the present
`invention, a satellite delivery system and a terrestrial
`repeater both employ multipath-tolerant modulation tech-
`niques and can be configured to use the same or different
`carrier frequencies, depending on the type of waveform
`used. The satellite delivery system preferably employs a
`TDM or code division multiple access (CDMA)-type wave-
`form. The terrestrial repeater preferably employs a multi-
`path-tolerant waveform such as CDMA,Adaptive Equalized
`TDM (AETDM), Coherent Frequency Hopping Adaptively
`Equalized TDM (CFHATDM) or Multiple Carrier Modula-
`tion (CM).
`In accordance with still another aspect of the present
`invention, a single geostationary satellite transmits downlink
`signals which can be received by radio receivers in the LOS
`ofthe satellite signal, as well as by terrestrial repeaters. Each
`terrestrial repeater is configured to recover the digital base-
`band signal from the satellite signal and modulatethe signal
`using multicarrier modulation (MCM) for retransmission
`toward radio receivers. Radio receivers are configured to
`receive both a quadrature phase shift keyed (QPSK) modu-
`lated TDM bil stream, as well as an MCM stream. Radio
`receivers are programmed to select a broadcast channel
`demodulated from the TDM bit stream and the MCM bit
`stream, andto select the broadcast channel recovered with
`the least errors using a diversity combiner.
`In accordance with still yet another aspect of the present
`invention, a DBSis provided which comprises two geosta-
`tionary satellites in combination with a networkofterrestrial
`repeaters. The terrestrial repeaters are configured to process
`satellite downlink signals to achieve the baseband satellite
`signal and to modulate the signal using MCM. Radio receiv-
`ers are configured to implementa diversity decision logic to
`select from amongthree diversity signals, including the two
`satellite signals and the MCM signal. Each radio receiver
`employs maximum likelihood combining of two LOSsat-
`ellite signals with switch combining between theterrestrial
`re-radiated signal, or MCM signal, and the output of the
`maximum likelihood combiner.
`
`Receivers in existing systems which provide digital audio
`radio service (DARS) have been radically affected by mul-
`tipath effects which create severe degradations in signal
`quality, such as signal fading and inter-symbol interference
`(ISI). Fading effects on broadcast channels to receivers can
`be sensitive to frequency, particularly in an urban environ-
`ment or geographic areas with high elevations where block-
`age of line of sight (LOS) signals from satellites is most
`prevalent. Locations directly beneath a satellite (hereinafter
`referred to as the sub-satellite point) inherently have the
`highestelevation angles, while locations that depart from the
`sub-satellite point
`inherently have decreasing elevation
`angles and, accordingly, an increase of the earth center angle
`subtended between the sub-satellite point and the reception
`location. Locations that are near the sub-satellite point
`typically enjoy virtually unblocked LOSreception. Thus,the
`need for terrestrial reinforcement of potentially blocked
`LOSsignals is minimal. When the LOSelevation angle to
`the satellite becomes less than about 85 degrees, however,
`blockage by tall buildings or geological elevations(i.e., on
`the order of 30 meters) becomes significant. Terrestrial
`re-radiation for gap filling is needed to achieve satisfactory
`coverage for mobile radios, static radios, as well as portable
`radios. In areas where the heights of buildings or geological
`sites are relatively low (i.e., on the order of less than 10
`meters), the blockage is not significant until the LOS eleva-
`tion angle is lower than 75 degrees. Thus,at the mid-latitude
`and high latitude locations within the coverages of one or
`more broadcastsatellites, terrestrial re-radiation is needed to
`achieve suitable radio reception. A need exists for fully
`satisfactory radio reception that combines satellite LOS
`transmission andterrestrial re-radiation ofa satellite down-
`link signal waveform.
`SUMMARY OF THE INVENTION
`
`In accordance with one aspect of the present invention, a
`digital broadcast system (DBS) is provided which over-
`comes a number of disadvantages associated with existing
`broadcast systems and realizes a number of advantages. The
`DBS of the present
`invention comprises a TDM carrier
`satellite delivery system for digital audio broadcasts (DAB)
`and other digital
`information which is combined with a
`networkof terrestrial repeaters for the re-radiation of satel-
`lite downlink signals toward radio receivers. Theterrestrial
`repeaters are configured to employ multipath-tolerant modu-
`lation techniques.
`
`30
`
`35
`
`40
`
`45
`
`50
`
`60
`
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`In accordance with another aspect of the present inven-
`tion, a broadcast channel may be selected from the three
`diversity signals by using maximum likelihood combining
`of all
`three signals,
`that
`is, early and late LOSsatellite
`signals and the MCM signal from the terrestrial repeater.
`
`BRIEF DESCRIPTION OF 'THE DRAWINGS
`
`These and other features and advantages of the present
`invention will be more readily comprehended from the
`following detailed description when read in connection with
`the appended drawings, which form a part of this original
`disclosure, and wherein:
`FIG. 1 depicts a digital broadcast system for transmitting
`satellite signals and terrestrial signals in accordance with an
`embodiment of the present invention;
`FIG, 2 is a diagram of a digital broadcast system com-
`prising a satellite and a terrestrial repeater in accordance
`with an embodimentof the present invention;
`FIG. 3 is a schematic block diagram illustrating a gen-
`eration of a multicarrier modulated (MCM)signal in accor-
`dance with an embodiment of the present invention;
`
`Petitioner Sirius XM Radio Inc. - Ex. 1005, p. 13
`
`Petitioner Sirius XM Radio Inc. - Ex. 1005, p. 13
`
`
`
`US 6,944,139 BI
`
`3
`FIG. 4 is a schematic block diagram depicting a radio
`receiver arm configured to demodulate MCM signals in
`accordance with an embodiment of the present invention;
`FIG. 5 is a block diagram illustrating MCM signal
`demodulation in accordance with an embodiment of the
`
`present invention;
`FIG. 6 is a schematic block diagram depicting a radio
`receiver arm configured to demodulate time division multi-
`plexed (TDM) signals in accordance with an embodiment of
`the present invention;
`FIG, 7 is a block diagram illustrating QPSK TDM signal
`demodulation in accordance with an embodiment of the
`present invention;
`FIGS. 8 and 9 are schematic block diagrams illustrating
`respective embodiments of the present invention for diver-
`sity combining in a radio receiver;
`FIG. 10 illustrates a system of combining three diversity
`signals using a maximum likelihood decision unit in accor-
`dance with an embodiment of the present invention;
`PIG. 11 is a schematic block diagram illustrating TDM
`signal demultiplexing in accordance with an embodiment of
`the present invention;
`FIG. 12 illustrates a system of combining bit streams
`recovered at a radio receiver using a maximum likelihood
`decision unit ona first satellite signal and a delayed second
`satellite signal and then a diversity combinerfor terrestrial
`repeater signal and the output of the maximum likelihood
`decision unit in accordance with an embodiment of the
`
`present invention;
`FIG. 13 illustrates an arrangement for indoor reception of
`a broadcast signal in accordance with an embodimentof the
`present invention; and
`FIG. 14 illustrates an arrangement for terrestrial repeaters
`along a path in accordance with an embodiment of the
`present invention.
`
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`DETAILED DESCRIPTION OF THE
`PREFERRED EMBODIMENTS
`
`40
`
`1 depicts a digital broadcast system (DBS) 10
`FIG.
`comprising at least one geostationary satellite 12 for line of
`sight (LOS) satellite signal
`reception at
`radio receivers
`indicated generally at 14. Another geostationary satellite 16
`ata different orbital position can be provided for time and/or
`spatial diversity purposes as discussed below in connection
`with FIGS. 6 and 7. The system 10 further comprisesat least
`one terrestrial repeater 18 for retransmission of satellite
`signals in geographic areas 20 where LOS reception is
`obscured bytall buildings,hills and other obstructions. The
`radio receiver 14 is preferably configured for dual-mode
`operation to receive both satellite signals and terrestrial
`signals and to select one ofthe signals as the receiver output.
`As stated previously, the present invention relates to a
`DBS 10 for optimized static, portable and mobile radio
`reception. In accordance with the present invention, the DBS 55
`10 combinesline-of-sight (LOS) receptionofsatellite wave-
`forms that are optimized for satellite delivery with re-
`radiation of the LOS signal from the satellite 12 or 16 via
`one or moreterrestrial repeaters 18. The terrestrial repeaters
`18 use other waveforms which are optimized for terrestrial
`delivery where blockage of the satellite LOS signal occurs.
`LOSsignal blockage caused by buildings, bridges, trees and
`other obstructions typically occurs in urban centers and
`suburban areas. Waveforms particularly suitable for LOS
`satellite transmission are Time Division Multiplex (TDM)
`and Code Division Multiple Access (CDMA). Multipath-
`tolerant waveforms particularly suitable for overcoming
`
`45
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`
`4
`terrestrial multipath interference encountered in blocked
`urban
`areas
`are CDMA, Adaptive Equalized TDM
`(AETDM), Coherent Frequency Hopping Adaptively Equal-
`ized TDM (CFHATDM) and Multiple Carrier Modulation
`(MCM).
`Frequency hopping is described in U.S. Pat. No. 5,283,
`780,
`to Schuchman et al, which is hereby incorporated
`herein by reference. When a terrestrial repeater 18 employs
`AETDM, radio receivers 14 are provided with an equalizer
`(not shown). For AETDM, a TDM bit stream is received
`from the satellite 12 or 16. The bit stream is converted into
`a new TDM bit stream into which training sequences are
`inserted by a process called puncturing. Puncturing replaces
`a small fraction of the TDM data bits with the training
`sequences. The numberof bits punctured is so small that the
`errors thereby produced are correctable at the receiver by
`forward error correction. The new TDMbit stream is QPSK-
`modulated by the repeater onto a radio frequency (RF)
`carrier that is transmitted at high power into the multipath
`environment of a central city business district, for example.
`This transmitted signal is received by a receiver 14 equipped
`with an adaptive time domain equalizer. By using the
`training sequences,
`it can adjust
`the taps of an inverse
`multipath processor to cause the various multipath arrival
`components to add constructively. The signal thus recon-
`structed is next processed to recover the bits of the TDM
`stream with high accuracy. The forward error correction
`available in the receiver 14 corrects both the errors intro-
`
`duced by the puncturing and those caused by thermal noise
`and receiver impairments.
`In accordance with another aspect of the present inven-
`tion, the combination ofa satellite-efficient LOS waveform
`and terrestrial multipath interference-tolerant waveform in a
`DBS system is the optimum means for achieving high
`availability reception by mobile radios, static radios and
`portable radios in urban areas, suburban areas and in rural
`areas. For example, in accordance with an embodiment of
`the present
`invention illustrated in FIGS. 2-9, an MCM
`signal
`is sent from a network ofterrestrial repeaters 18
`deployed to cover a blocked area with high reception
`availability. The signaling techniques described in connec-
`tion with the present
`invention are applicable over the
`electromagnetic wave frequency range from 200 to 3000
`MHztofacilitate the combination of LOSsatellite radiation
`with terrestrial re-radiation of the signal received from the
`satellite 12 or 16.
`Optimal satellite waveforms permit very efficient trans-
`formation of solar power, which is collected by the solar
`arrays of the satellites 12 and 16 into radiated radio fre-
`quency power. These waveforms are characterized by a low
`peak-to-average power ralio (i.c., crest factor), thereby per-
`mitting operation of high power amplifiers that feed the
`satellite earth-pointing antennas at or near the maximum
`power output and therefore the most efficient power output.
`A TDM waveform is particularly useful
`for permitting
`operation within a few tenths of a dB of maximum power
`output. A CDMA waveform that uses properly selected
`codes allows operation at approximately 2 to 4 dB below
`maximum power output. Because the MCM waveform is
`composed of the sum of hundreds of phase modulated
`sinusoids, as described below with reference to FIG. 3, the
`MCM waveform inherently possesses a high peak-to-aver-
`age ratio. Consequently, a MCM waveform encounters
`significantly greater amplitude and phase intermodulation
`distortion in the satellite’s high power amplifier. To achieve
`acceptable reception by an LOS satellite receiver, a MCM
`waveform is backed in the high power amplifier and allo-
`
`Petitioner Sirius XM Radio Inc. - Ex. 1005, p. 14
`
`Petitioner Sirius XM Radio Inc. - Ex. 1005, p. 14
`
`
`
`US 6,944,139 BI
`
`5
`cated a receiver implementation impairmentof at least 6 dB
`on the down-link budget, as compared with a quadrature
`phase shift keying (QPSK) TDM waveform. This translates
`to a 4-to-1 reduction in satellite power conversion, rendering
`the MCM waveform an unsuitable choice for satellite LOS
`
`delivery on a DBS 10. Regarding the AETDM and
`CFHATDM waveforms, these waveforms are specifically
`designated to combat
`terrestrial multipath and are not
`intended for, nor are they efficient, for satellite LOS delivery.
`Regardingterrestrial reinforcement by re-radiation of the
`satellite LOS signal from a terrestrial repeater, for example,
`a TDM waveform is not suitable because its reception is
`severely impaired by multipath effects. Furthermore, some
`proposed systems which use CDMA waveformsfor rein-
`forcement repeat the same program signal using one COMA
`channel code for LOS satellite delivery and another CDMA
`channel code for terrestrial re-radiated delivery on carriers
`that occupy the same frequency bandwidth. Reception is
`achieved by means of adaptive rake receivers. These pro-
`posed CDMA systems are disadvantageous because an
`annulus zone occurs in which reception is not possible
`between the region where the reinforcement signal can be
`received and the region where the satellite LOS signal can
`be received. Receivers 14 in the annulus are not able to
`receive the terrestrial re-radiated signal because the signal
`powerlevel falls below a receiver threshold for that signal.
`These receivers 14 are also not able to receive the satellite
`LOS signal because there remains sufficient re-radiated
`signal to jam LOSsatellite reception. Thus, these receivers
`14 in the annulus must move far enough away from the zone
`of re-radiation to decrease the re-radiated signal power to
`below the threshold of jamming; otherwise, LOS satellite
`reception is not possible.
`In accordance with one embodiment of the present inven-
`tion, the CDMA waveform is adapted to make possible its
`use for simultaneous delivery via satellite LOS and via
`terrestrial
`re-radiation, The CDMA channel codes are
`assigned for each delivery to different RF carriers. The
`orthogonality thereby created permits the two signals (1.e.,
`the satellite LOS signal and the terrestrial repeater signal) to
`be separated by RF/IFfiltering in the radio receiver.
`Theidentification of workable and unworkable waveform
`combinations for accomplishingterrestrial reinforcement of
`satellite LOS reception in accordance with the present
`invention are listed in the TABLE 1. More than one type of
`modulation or signal formatting method can be used with the
`satellite signal, as well as with the terrestrial repeater signal.
`
`TABLE 1
`
`Not
`Satellite
`Reinforcement Recom- Recom- RF Carrier Spectra
`Waveform
`Waveform
`mended mended Are:
`
`TDM
`TDM
`Xx
`Same or Different
`TDM
`AETDM
`Same or Different
`TDM
`MCM
`Different
`TDM
`CFHATDM
`Different
`TDM
`CDMA
`Different
`CDMA
`CDMA
`Different
`CDMA
`AETDM
`Different
`CDMA
`CHFATDM
`Different
`CDMA
`MCM
`Different
`x
`CDMA
`ANY
`Same
`x
`AETDM
`ANY
`Same or Different
`X
`CFHATDM
`ANY
`Same of Different
`
`
`ANY xMCM Same or Different
`
`
`x
`Xx
`x
`Xx
`Xx
`Xx
`Xx
`Xx
`
`AETDM waveforms can be satisfactorily implemented
`and operated in multipath environments characterized by
`
`6
`signal propagation delays as long as 20 microseconds (us).
`Care must be exercised to ensure that signal arrivals from
`distant repeaters 18 do not exceed this bound. The adap-
`tively equalized re-radiated waveform can be received by
`radio receivers 14 designed to use the parent non-equalized
`TDM waveform when the former does not exhibit severe
`multipath. This compatibility prevents obsolescence of
`direct LOS non-equalized TDM radios when the AETDM
`re-radiation is turned on.
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`The CFHATDM waveform can be satisfactorily imple-
`mented and operated in multipath environments character-
`ized by delays as long as 65 ws. Care must be exercised to
`ensure that signal arrivals from distant repeaters 18 do not
`exceed this bound. The waveform cannot be received by
`radio receivers 14 designed to use the parent non-equalized
`TDM waveform.
`The MCM waveform can be satisfactorily implemented
`and operated in multipath environments characterized by
`delays as long as 65 ys. The maximum delay is affected by
`the guard lime assignment given to the waveform’s periodic
`symbol period assignment. Care must be exercised to ensure
`that signal arrivals from distant repeaters 18 do not exceed
`this bound. The waveform cannot be received by radio
`receivers 14 designed to use the parent non-equalized TDM
`waveform.
`The CDMA waveform can be satisfactorily implemented
`and operated in multipath environments characterized by
`delays determined by the span of the time delays imple-
`mented in the rake paths at the receivers 14. Care must be
`exercised to ensure that all signal arrivals from distant
`repeaters 18, multipath reflections and different satellites do
`not exceed this bound. The waveform cannotbe received by
`radio receivers 14 designed to use the parent non-equalized
`TDM waveform.
`The satellite signals can be transmitted from one satellite
`12 or 16 or from twosatellites 12 and 16. Use of two
`geostationary satellites 12 and 16 sufficiently separated in
`their orbits creates diversity in the LOS elevation and
`azimuth angles to enhance signal
`reception availability.
`Also, time diversity achieved by repeating a satellite signal
`from a single satellite 12 or 16, or by transmitting a signal
`from twosatellites 12 and 16 with the properly selected time
`difference, further enhances the reception availability.
`In accordance with a preferred embodimentofthe present
`invention, a waveform comprising multiple channel TDM
`with QPSK,Offset QPSK,Differential QPSK, Differentially
`Coded QPSK, or Minimum Shift Keyed (MSK) modulation
`is used for the transmission of signals from a satellite for
`LOSreception by a radio receiver 14. Terrestrial re-radiation
`is preferably implemented using an MCM waveform
`designed to carry a TDM bit stream of a capacity of up to
`3.68 Mbit/s. MCM is preferably implemented which creates
`between 400 and 1200 multiple carriers by means of an
`Inverse Fast Fourier Transform as described below in con-
`wa aT
`5 nection with FIG, 3, resulting in a symbol period between
`200 and 300 ws. A guard interval of between 55 to 65
`microseconds is included in each symbol period. The MCM
`waveform is designed to accommodate Doppler carrier
`frequency shifts among multipath components occurring
`simultaneously. Puncturing is preferably used to eliminate
`bits or pairs of bits from the TDM bit stream to reduce the
`rate to a value of between 70%to 80% of the 3.68 Mbit/s
`rate. Aspecial symbolis inserted between eachofa selected
`number of FFT-generated symbols periods to provide a
`means to recover symbol period timing and carrier fre-
`quency synchronization. In the receiver 14, a Viterbi soft
`decision trellis decoder is preferably implemented to re-
`
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`Petitioner Sirius XM Radio Inc. - Ex. 1005, p. 15
`
`Petitioner Sirius XM Radio Inc. - Ex. 1005, p. 15
`
`
`
`US 6,944,139 BI
`
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`7
`suitable mobile reception. Thus, fully satisfactory mobile
`establish the bits or bit pairs punctured at the repeater 18, as
`reception requires a system that co