US006144711A
`6,144,711
`(11) Patent Number:
`United States Patent 5
`Raleigh et al.
`[45] Date of Patent:
`Nov. 7, 2000
`
`
`[54] SPATIO-TEMPORAL PROCESSING FOR
`5,691,727 11/1997 CyZs ceescesssssssseseseseecneesseceneereene 342/361
`COMMUNICATION
`5,752,173
`5/1998 Tsujimoto ...esccecseccseeesseeeseeees 455/137
`5,809,019 9/1998 Ichihara et al.oeseee 370/334
`
`
`esceccsessssessseecsneeeeee 370/329
`5,886,988
`[75]
`Inventors: Gregory G. Raleigh, El Granada;
`3/1999 Yun et al.
`Vincent K. Jones, IV, Redwood
`5,905,721
`5/1999 Liu et al.
`sseeessesseesseesseessesnees 370/342
`Shores; Michael A. Pollack, Cupertino,
`5,966,094 10/1999 Ward et al.
`eeecccceccceeseeneeeen 342/373
`all of Calif.
`
`[73] Assignee: Cisco Systems, Inc., San Jose, Calif.
`[21] Appl. No.: 08/921,633
`[22]
`Filed:
`Aug. 27, 1997
`
`[60]
`
`Related U.S. Application Data
`Provisional application No. 60/025,227, Aug. 29, 1996, and
`provisional application No. 60/025,228, Aug. 29, 1996.
`[SL] Unt, C07 ee cecccseecsssesssssecessseccessneeeseess HO4L 1/02
`[52] U.S. Ch. eeccecccecsssee 375/347; 375/346; 375/349
`[58] Field of Search 0.0.0...eee 375/219, 260,
`375/316, 346, 347, 348, 285, 349, 350;
`370/342, 203, 210; 455/63, 64, 65; 708/403,
`404, 405
`
`[56]
`
`References Cited
`US. PATENT DOCUMENTS
`6/1982 Gruenberg vessscssssessseuseeeen vo2ER
`4,337,376
`AT1O,O44 12/1987 NOssen srvsrvorcnrnrerrinenie 375/40
`
`ceesssssssssssessenseeste 455/64
`5,134,715
`7/1992 Parl et ale
`5,228,025
`7/1993 Le Floch et al.
`..seecseeceneees 370/20
`5/1994 Savary et al. cessseesscssssseeeeen 370/18
`5,315,584
`
`oeesccccsccssseeseeceeee 455/49.1_
`5,345,599
`9/1994 Paulraj et al.
`5,471,647
`11/1995 Gerlach et al. cece: 455/63
`... 375/231
`5,479,444 12/1995 Malkamakietal.
`
`5,479,447 12/1995 Chow et al. vccccccscessseeeeees 375/260
`5,510,799
`4/1996 Wishart
`......cceccecesseeeceeeseeees 342/373
`ee 5/1996 Roy,Il etal....
`-- 370/95.1
`
`7/1996 Carney a)rr 375/219
`>
`?
`5,548,819
`8/1996 RObBD wvcccccccseseeseeeeseseseesesesees 455/59
`5,566,209
`10/1996 Forssenetal.
`w. 375/262
`
`...cccccesesscssssssseeeees 370/310
`5,592,490
`1/1997 Barratt et al.
`5,634,199
`5/1997 Gerlach et al.
`...eeeeccsseeeeeen 455/63‘
`... 370/329
`5,642,353
`6/1997 Roy,Il etal. ...
`
`7/1997 Forssen et al... sesso 370/312
`5,649,287
`
`FOREIGN PATENT DOCUMENTS
`0253 465 BL
`3/1987 European Pat. Off.
`.
`0253465 Al
`3/1987 European Pat. Off.
`.
`WO 95/22873
`8/1995 WIPO.
`WO 96/30964 10/1996 WIPO .
`WO 98/09381
`3/1998 WIPO.
`WO 98/09395
`3/1998 WIPO .
`OTHER PUBLICATIONS
`J. Hirono, M. Saito and C. Kamise, Digital Terrestrial
`Television Broadcasting with OFDM—AStudy on the Per-
`formance of Single Frequency Networks—International
`Broadcasting Convention, p. 178-183 (Sep., 1996).
`PA. Voois, “Two-dimensional Signal Processing for Mag-
`netic Storage Systems,” Ph.D. Thesis, Stanford University,
`Stanford, CA, pp. 1-136 (Dec. 1993).
`(List continued on next page.)
`Primary Examiner—Stephen Chin
`Assistant Examiner—Chieh M. Fan
`Attorney, Agent, or Firm—Ritter, Van Pelt & Yi LLP
`Sy Sen,
`,
`ABSTRACT
`;
`.
`o,
`Aspace-timesignal processing system with advantageously
`reduced complexity. The system may take advantage of
`multiple transmitter antenna elements and/or multiple
`receiver antenna elements, or multiple polarizations of a
`single transmitter antenna element and/or single receiver
`antenna element. The system is not restricted to wireless
`contexts and may exploit any channel having multiple inputs
`or multiple outputs and certain other characteristics. Multi-
`h fie.
`ourp
`.
`di
`Iti i
`:
`_—~Path elects in a transmission medium cause a multiplicative
`Wicrease 1n capacity.
`
`[57]
`
`32 Claims, 26 Drawing Sheets
`
`po20a |
`
`200
`1
`2]
`RSW1,1) L- ‘yat)
`120
`
`
`
`Pemadutation
`Recener peseval (1,2)
`
`
`AFSystem
`#4
`:
`;
`2 ne
`
`
`GaN
`2 | RSW CoM)
`'
`
`1
`
`x(4M)
`
`a
`
`antenna
`
`
`
`
`
`
`.
`°
`
`
`
`
`Receiver
`Demodulation
`SOP
`.
`> and
`I
`#Mp
`PFsyst
`antennaMp
`
`i
`
`120
`
`200
`
`'
`
`
`
`220d
`°
`.
`: Asin) 1 x,t)
`|
`'
`:
`RSW(N,2}
`! x(N,2)
`pol
`2
`2201
`:
`|
`RSW (N,M)
`1
`1
`boo --------------
`
`' x(N,M)
`1
`1
`
`1
`
`SAMSUNG 1005
`
`1
`
`SAMSUNG 1005
`
`

`

`6,144,711
`
`Page 2
`
`OTHER PUBLICATIONS
`
`Ohkawa, Kouichi, “Performance of Multicarrier Trellis—
`Coded 8PSK Using Frequency Hopping in Rayleigh Fading
`Channels,” National Conference Publication—Institution of
`Engineers, Australia, National Conference, vol.
`1, p.
`145-149, Nov. 20-24, 1994.
`Sourour, Essam A., “Performance of Orthogonal Multicar-
`rier CDMAin a Multipath Fading Channel,” IEEE Trans-
`actions on Communications, vol. 44, No. 3, p. 356-367,
`Mar. 1996.
`
`Ichikawa, Hirofumi, “Frequency Diversity Effects in Mul-
`ticarrier Digital Radio Systems,” Electronics and Commu-
`nications in Japan, Part 1, vol. 74, No. 8, p. 70-77, Aug.
`1991.
`
`Gudmundson, Mikael, “Spectral Efficiency of a Multitone
`Frequency Hopping System for Personal Communication
`Systems,” IEEE Vehicular Technology Conference, Part 3
`(of 3) Stockholm, vol. 3, p. 1650-1654, Jun. 8-10, 1994.
`Gulliver, T. Aaron, “Order Statistics Diversity combining in
`Worst Case Noise and Multitone Jamming,” IEEE Vehicular
`Technology Conference, vol. 2, p. 804-809, Jul. 25-28,
`1995.
`
`Monnier, R., “Digital Television Broadcasting with High
`Spectral Efficiency,” IEEE Conference Publication No. 358,
`p. 380-384, Jul. 1992.
`for
`Del Re, Enrico, “Digital Multicarrier Demodulator
`Regenerative Communication Satellites,” Alta Frequenza,
`vol. 57, No. 10, p. 545-559, Dec. 1988.
`Omori, Youko, “Multicarrier 16QAM System in Land
`Mobile Communications,” IEICE Transactions on Commu-
`nications, vol. E77—B, No. 5, p. 634-640, May 1994.
`Ananasso, Fulvio,
`“Clock Synchronous Multicarrier
`Demodulator for Multi-Frequency TDMA Communications
`Satellites,” IEEE International Conference on Communica-
`tions, vol. 3, p. 1059-1063, 1990.
`Friese, M., “Multicarrier Modulation with Low Peak—
`to—Average Power Ratio,” Electronics Letters, vol. 32, No.
`8, p. 713-714, Apr. 11, 1996.
`Benyassine, Adil, “Optimal Subchannel Structuring and
`Basis Selection for Discrete Multicarrier Modulation,” IEEE
`Communication Theory Muini—Conference, Proceedings,
`CTMG,p. 97-101, 1995.
`Sawahashi, M., “Multicarrier 16QAM Transmission with
`Diversity Reception,” Electronics Letters, vol. 32, No. 6, p.
`522-523, Mar. 14, 1996.
`Daffara, Flavio, “A New Frequency Detector for Orthogonal
`Multicarrier Transmission Techniques,” IEEE 45th Vehicu-
`lar Technology Conference, p. 804-809, Jul. 25-28, 1995.
`C.E. Shannon, “Mathematical Theory of Communications:
`Part 1 and Part II,” The Bell System Technical Journal, pp.
`379-423, 623-656, 1948.
`S.A. Fectel and H. Meyr, “Optional Feedforward Estimation
`of Frequency—Selective Fading Radio Channels using Sta-
`tistical Channel Information,” in Proc. SUPERCOMM/ICC
`°92, vol. 2, (Chicago, IL), pp. 677-681,1 1992.
`L.H. Brandenburg and A.D. Wyner, “Capacity of the Gaus-
`sian channel with Memory: The Multivariate Case, ” Bell
`Syst. Tech. Journ., vol. 53(5), pp. 745-778, May-Jun. 1974.
`R.S. Cheng and S. Verdu, “Gaussian Multiaccess Channels
`with ISI: Capacity Region and Multiuser Water—Filling,”
`IEEE Trans. Inform. Theory, vol. 39(3), pp. 773-785, May
`1993.
`
`J. Salz, Digital Transmission Over Cross—Coupled Linear
`Channels, AT & T Tech. Journ., vol. 64(6), pp. 1147-1159,
`Jul—Aug. 1985.
`
`A. Duel-Hallen, “Equalizers for Multiple Input Multiple
`Output Channels and PAM Systems with Cyclostationary
`Input Sequences,” IEEE Journ. On Sel. Areas in Comm.,
`vol. 10(3), pp. 630-639, Apr. 1992.
`J. Yang and S. Roy, “On Joint Transmitter and Receiver
`Optimization for Multiple—input Multiple—output (MIMO)-
`Transmission Systems,”
`JEEE Trans. Commun, vol.
`42-(12), pp. 3221-3231, Dec. 1994.
`J.Yang and S. Roy, “Joint Transmitter-Receiver Optimiza-
`tion for Multi-Input Multi—Output Systems with Decision
`Feedback,” IEEE Trans. Information Theory, vol. 40(5), pp.
`1334-1347, Sep. 1994.
`D.C. Cox and R.P. Leck, “Distributions of Multipath Delay
`Spread and Average Excess Delay for 910 Mhz Urban
`Mobile Radio Paths,” IEEE Trans. Antennas and Prop., vol.
`AP-23, pp. 206-213, Mar. 1975.
`S.B. Weinstein and P.M. Ebert, “Data Transmission by
`Frequency—Division Multiplexing Using the Discrete Fou-
`rier Transform,” IEEE Transactions on Communications,
`vol. 19(5), pp. 628-634, Oct. 1971.
`A. Ruiz, J.M. Cioffi, and S. Kasturia, “Discrete Multiple
`Tone Modulation with Coset Coding for the Spectrally
`Shaped Channel,” IEEE Trans. Commun, vol. 40(6), pp.
`1012-1029, Jun. 1992.
`R.M. Gray, “On the Asymptotic Eignevalue Distribution of
`Toeplitz Matrices,” IEEE Trans. Information Theory, vol.
`vol. 18, pp. 725-730, Jun. 1972.
`G. Forney, “Maximum-—Likelihood Sequence Estimation of
`Digital Sequences in the Presence of IntersymbolInterfer-
`ence,” IEEE Trans.
`Inform. Theory, vol. IT-18(3), pp.
`363-378, May 1972.
`J.L. Holsinger, “Digital Communications Over Fixed Time—
`Continuous Channels With Memory, with Special Applica-
`tion to Telephone Channels,” M.I.T. Research Labratory
`Electronics Report, vol. 430, 1964.
`T.M. Cover and J.A. Thomas, Elements of Information
`Theory. New York: John Wiley, chapter 2, pp. 12-49,
`chapter 8, pp. 183-223, chapter 10, pp. 239-265 1991.
`R.J. Muirhead, Aspects of Multivariate Statistical Theory,
`New York: John Wiley, chapters 4 and 5, 1982.
`W.C. Jakes, Microwave Mobile Communications. New
`York: John Wiley, chapters 1, 5 and 6, 1974.
`W. R. Braun and U. Dersch, “A Physical Mobile Radio
`Channel Model,” IEEE Trans. Vehicular Technology, vol.
`40, pp. 472-482, May 1991.
`A.E. Bryson and T.C. Ho, Applied Optimal Control, Wash-
`ington D.C. Hemisphere Publishing, pp. 24-29, 1968.
`S. Kasturia, J. Aslanis, and J.M. Cioffi, “Vector Coding for
`Partial-Response Channels,” IEEE Transactions on Infor-
`mation Theory, vol. 36(4), pp. 741-762, Jul. 1990.
`E. Biglieri, D. Divsalar, PJ. Mclane, and M.K. Simon,
`Introduction to Trellis Coded Modulation with Applications.
`New York: Macmillan Publishing, 1991.
`P. Lancaster, Theory of Matrices. New York: Academic
`Press, chapter 2, 1969.
`G.G. Raleigh and J.M. Cioffi, “Spatio-Temporal Coding for
`Wireless Communications.” Submitted to IEEE Transac-
`tions on Communications, Jan. 1996.
`Justin C-I. Chuang, “Burst Coherent Demodulation with
`Combined Symbol Timing, Frequency Offset Estimation,
`and Diversity Selection,” IEEE Transactions on Communi-
`cations, vol. 39, No. 7, pp. 1157-1164, Jul. 1991.
`Leonard J. Cimini, Jr., “Analysis and Simulation of a Digital
`Mobile Channel Using Orthogonal Frequency Division
`Multiplexing,” IEEE Transactions on Communications,ol.
`Co. 33, No. 7, pp. 665-675, Jul. 1985.
`2
`
`2
`
`

`

`U.S. Patent
`
`Nov.7, 2000
`
`Sheet 1 of 26
`
`6,144,711
`
`| J
`
`IS
`
`OV
`
`0€
`
`0¢
`
`Ok
`
`emmmococom oc ts
`
`
`
`AeuyeuuayuyXL
`
`eeoe
`
`“A
`
`'i'i
`
`éOe
`
`walskS4Y8UoNe|NPoyy
`
`‘bai4-a0edsXx]
`
`JOSSE0010-Ad
`
`Buiures|
`
`joquiAs
`
`uonoeluy
`
`Bulaeaajuy9Japoouz
`
`Begjnduy
`
`3
`
`
`
`
`
`
`
`

`

`U.S. Patent
`
`Nov.7, 2000
`
`Sheet 2 of 26
`
`6,144,711
`
`Joyewioeg
`loo[9°
`
`JOAIB00Y
`
`
`
`}#JE}I4SSEqpueg
`
`Joyejodsaquy|.#JOYL4sSegpueg
`
`jomimsuell=loo|
`
`oo[2
`
`Nz
`
`Joyewioeq
`Noo[9-
`
`e
`
`e
`
`JBAIBD9Y
`
`
`
`
`
`N#J0ul4SSBEqPUeg
`
`JoyejodiequyN#Je}I4Ssegpueg
`JOYIWSUEL|Neo|
`
`oo(2
`
`6Old
`
`OZ
`
`No
`
`
`
` 0908NoJOXIN
`
`4
`
`
`
`
`
`

`

`U.S. Patent
`
`Nov.7, 2000
`
`Sheet 3 of 26
`
`6,144,711
`
`O€l
`
`
`
`Q|jeuLeYD
`
`OS}
`
`a
`
`
`
`eByeqIndino
`
` Jap00eq
`
`Buaeaajuleq
`
`JONIBOOY
`
`‘bai4-aoeds
`
`1OSS8001d
`
`JY9uolyeinpowaq
`walsis
`
`Ol}
`
`ertots.ed~~oeeX
`
`ApuBuuajuyXY
`
`€Ola
`
`5
`
`
`
`
`
`

`

`U.S. Patent
`
`Nov.7, 2000
`
`Sheet 4 of 26
`
`6,144,711
`
`qoZ\
`
`yunejoweay
`
`e091
`
`SSO|auIMBUlUedpa}oRJjal10pe}oayjad@uoUeU]GOW9qUDYedHINY\|
`‘uoeZuBjodauoaABYJeu}SJusWajeBUUA}UeYIMjauUeYOUONeBedoud
`
`
`
`
`
`
`gS
`
`oS
`
`aseg
`
`6
`
`
`

`

`U.S. Patent
`
`Nov.7, 2000
`
`Sheet 5 of 26
`
`6,144,711
`
`a}OWsy
`
`<—_———_——
`
`Lo“”oe“~~
`
`yyuolezuejodYIMJUEWa|aBULa]UyLU
`
`guoezUejodYIMJuaWa|aBUUs|UY_A
`
`
`wun)suyedguOleZe|Od
`<+-------\
`
`
`B09}
`
`
`
`
`
`pueyuoeZuBIOdUjIMSuedeOWJoaUOaqUBDYJEdNINY
`
`
`
`JOS]JosOM)BY]“GgUOHEZUE|OdYIMsyyed9JOWWJOBUO
`
`‘reuoBoyyoaqjouAewJoAewsujed
`
`sujedgUOI]EZUB|Od
`
`NNN
`
`Sh
`
`SS
`
`aseg
`
`7
`
`
`

`

`6,144,711
`
`9“Old
`
`U.S. Patent
`
`
`
`\odo1pedAudpukslows!BUsaMjaqsyjedB10oqUBDYedHINy
`
`Nov.7, 2000
`
`Sheet 6 of 26
`
`Bo9| ‘yod
`
`
`
`opedJaujouepuea}OWaBy]UBEMjeqsUuJedS/O40aUOpue
`
`8
`
`

`

`U.S. Patent
`
`Nov.7, 2000
`
`Sheet 7 of 26
`
`6,144,711
`
`180a
`
`FIG.7
`
`9
`
`

`

`U.S. Patent
`
`Nov.7, 2000
`
`Sheet 8 of 26
`
`6,144,711
`
`00¢
`
`Ol
`
`0b061
`
`|ulg
`
`JBAIBIOY
`
`dOs
`
`uoleinpowaq
`
`wayshs44
`
`pue
`
`BAIS9Y
`
`BUUBIUY
`
`BuuaUuy
`
`ywsuel|\ug
`
`10
`
`uoHe|npoyyJoyIusue]|
`Wass4Y408
`puee
`
`|Ulg
`
`9°
`Is
`
`10
`
`
`
`
`

`

`U.S. Patent
`
`Nov. 7, 2000
`
`Sheet 9 of 26
`
`6,144,711
`
`|ulg
`
`pueeJ9AI909}uoyejnpowsgq
`
`00¢Och
`
`|ulg
`
`pueeJBAIB99}uolyejnpowsq
`
`eeeeee
`
`NulgHiyaanaday
`
` BUUDSJUYNulg‘49Nl909Y°Lt
`
`
`
`walshs4Y°dOS
`Uewalsh4Y°dOS
`WWSUBL|LgNe
`ywsued|rNeewarsks44465°pue
`
`uolyejnpoyySse|ulg
`wiaishg4Y“it°pue
`OrO61
`Or061
`
`
`
`002Oct
`
`BUUd]UY
`
`6:
`JIA
`
`euua]Uy
`
`euua]UY
`
`e®eeee
`
`LuoneinpoyyJoyiwsuell,|e@sug
`
`11
`
`11
`
`
`
`

`

`U.S. Patent
`
`Nov.7, 2000
`
`Sheet 10 of 26
`
`6,144,711
`
`|Las
`
`BAOWOY
`
`aIj9AQ
`
`XWJBld
`
`ppy
`
`a1j9AQ
`
`Xd
`
`|L44l
`
`YWi44
`
`SAOWAY
`
`OWjAQ
`
`Xd
`
`802
`
`O8t
`
`Ol‘Sls
`
`ppy
`
`a1jok9
`
`Xl
`
`L0¢
`
`tw1441
`
`12
`
`12
`
`
`
`
`
`
`

`

`U.S. Patent
`
`Nov.7, 2000
`
`Sheet 11 of 26
`
`6,144,711
`
`wsuel|
`
`Ly#euualuy
`
`JOSS8001d
`
`Lk“Old
`
`Nulg
`
`uole|NpoWJO\WUSURL|
`welshs44nMpue
`
`
`
`heLN#fenedsWwsuel)0€Z
`
`|#BULa]UY
`
`wa}shs4H
`
`WWSUEJ| L#
`
`pue
`
`uolveinpoyy Joywsued|
`
`
`
`jewedsseywsued|9012
`
`
`
`(SMS)siubiem
`
`(W'L)Z
`
`13
`
`13
`
`
`
`
`
`

`

`U.S. Patent
`
`Nov.7, 2000
`
`Sheet 12 of 26
`
`6,144,711
`
`
`
`(smsu)sIuBIam
`
`feeds18A19004
`
`OrZ~yenedsJeAlo0ey
`
`902
`
`JOSSB001d
`
`ctOld
`
`Nulg
`
`002
`
`Ocl
`
`@NIB08}
`
`YW#euusuy
`
`JOAI900Y
`
`YW#dOS
`
`uolyejnpoweqNS
`iN#WayshS4pueZO
`
`|Ulg
`
`002
`
`or
`
`Nulg
`
`|Ulg
`
`J@AI98Y
`
`|#dOS
`
`iwashs44
`
`uoyeinpowedSN
`pueZO
`
`aNl0eY
`
`|#BUUdUY
`
`e@e
`
`14
`
`14
`
`
`
`
`

`

`U.S. Patent
`
`Nov.7, 2000
`
`Sheet 13 of 26
`
`6,144,711
`
`LS
`
`Ly#euujuy
`
`pue)BuoneinpoyJOW|WSUEA|(2'N)MSL
`pueBp\suoveInpoyJOYIWSUEA|(2'L)MSL
`LW#°Pwwaisks4Ha4a0lZ©
`nusTE|LE[rr|#BUUBIUY%oH_—ywsued|4}:L#wwwalshs4440sqole°
`WWSUeL|lz
`e°e°ee
`061IeOlzZ
`
`
`
`ElOld062>._(dS)lossedolgjenedsywusueL
`|ulgQ>|(HL)MSL
`
`I
`
`(W'N)MSL
`
`POL?
`
`(LN)MSL
`
`Ler eee EE ee ee ee ee eeee
`
`= <
`
`=N
`
`(L°N)Z
`
`(Z'N)Z
`
`(W'L)2
`
`15
`
`15
`
`
`
`

`

`U.S. Patent
`
`Nov.7, 2000
`
`Sheet 14 of 26
`
`6,144,711
`
`Ove
`
`(dS)ossed0ldjenedsaais09}
`
`
`
`
`
`
`
`(L°L)x
`
`(Z'4)x
`
`(W‘L)x
`
`(1‘N)X
`
`(Z°N)Xx
`
`(W'N)X
`
`IlI||||\|l||I||I|II|III1I{l||||||]|IIl|
`
`qoze_*
`
`0022
`
`e
`
`202
`
`(Ms|:
`
`zi)msu|
`
`(Wi)ms|
`
`a0ze_*
`
`{022
`
`e
`
`eee
`
`('N)MSH]spoze
`
`Zn)msu|
`
`(W'N)MSH]
`
`I
`
`L#1dOS
`|ugI002
`uone|npoweqiOc}
`feZOWE}SAS4u
`
`JOAI808Y
`
`pue
`
`—_e oe oe oe ol
`
`Nulg
`
`002
`
`rat
`
`dw#Buualuy
`
`JOAISO9}
`
`YW#dos
`
`pue
`
`uole|npoweq~~
`
`@AIg08}msZOwayshsJY
`
`eee
`
`@Nl09}
`
`|#BUUd|UY
`
`16
`
`16
`
`
`
`

`

`U.S. Patent
`
`Nov.7, 2000
`
`Sheet 15 of 26
`
`6,144,711
`
`soyWsuel|
`
`L#dOS
`
`Jaywsuel
`
`LW#408
`
`061
`
`Nulg
`
`III|lIIII|II
`
`061bamnmmmmnn
`
`17
`
`SltOlds
`
`r--
`
`
`
`
`
`
`
`0&2y(dSL)sosse00/qjeyedsWwsued|
`
`17
`
`
`
`
`

`

`U.S. Patent
`
`Nov.7, 2000
`
`Sheet 16 of 26
`
`6,144,711
`
`(L°4)x
`
`(L'N)x
`
`Ove
`
`(dS)sosse00lgjeuBls
`
`91“Dld
`
`aalgo0y uigJedMS8UO
`
`
`
`
`
`00¢
`
`J8N8084
`
`L#dOS
`
`Nulg
`
`00¢
`
`JaA809}
`
`YW#dOS
`
`18
`
`18
`
`
`

`

`U.S. Patent
`
`Nov.7, 2000
`
`Sheet 17 of 26
`
`6,144,711
`
`ywsuel|
`
`|#BuUajUY
`
`pueB'suolRINpOWsG
`L#PNwa}sAs44
`
`e®e
`
`jwsuel|
`
`Ly#euuajuy
`
`LW#PNwaysks44
`PApue
`1Suoleijnpoweq
`
`ZtSls
`
`B01
`
`|#MSL
`
`G02
`
`MSL
`
` #
`
`O61
`
`e|#dOSeJayWUSUed|
`
`e
`
`eee
`
`061
`
`eW#d0SeJoywsuel|
`
`e
`
`(L‘N)Z
`
`(W'})Z
`
`(W'N)Z
`
`19
`
`19
`
`
`
`

`

`(44)xe0e¢pe
`
`00¢
`
`Od!
`
`uoneinpoweg
`
`(L°N)X
`
`ee|#dOSL#
`
`JAAI3084MSYeL#wajsds4Y
`
`9Al308Y<"
`
`|#BUUa}UY
`
`U.S. Patent
`
`Nov.7, 2000
`
`Sheet 18 of 26
`
`6,144,711
`
`(W‘N)X
`
`
`
` “iN#ewalshsJYW#dOSW#uPep;JOAIQ00YMSYuoneinpowag
`
`@Ale08}<~~
`
`Uw#BuUajuy
`
`8SIs
`
`(Wi)Noce
`
`002Oet
`
`eeee
`
`ee
`
`20
`
`20
`
`
`

`

`U.S. Patent
`
`Nov.7, 2000
`
`Sheet 19 of 26
`
`6,144,711
`
`>|(LN)MSL
`-|(LHMSL
`(WL)MSL
`
`Wt)
`
`2012
`
`qol2
`
`9042
`
`pOLZ
`
`2012
`
`Ole
`
`:(2‘N)MSL°9Japoouz
`
`eee.L.Buiaeayayuy>|iss——}842p00u
`eeeeeeq
`eoe
`
`°NeHulaeapeyu
`
`61“Old
`
`21
`
`21
`
`
`
`

`

`U.S. Patent
`
`Nov.7, 2000
`
`Sheet 20 of 26
`
`6,144,711
`
`e
`
`e
`
`F012
`
`qote
`
`9012
`
`POL?
`
`8012
`
`j012
`
`
`
`jenedsJayiwsues)
`
`
`
`(SMS_L)sbunyBien,
`
`OeDIs
`
`OL
`
`|HulAee9}U|919p00UN
`
`@Bulaeayeyuj®JapooUZ
`
`NHulaeapyayu|¥Japoou
`
`Beg
`
`22
`
`22
`
`
`
`
`
`

`

`U.S. Patent
`
`Nov. 7, 2000
`
`Sheet 21 of 26
`
`6,144,711
`
`-
`:
`
`-
`:
`
`:
`
`TSW(1,1)
`
`TSW(1,2)
`
`@ e e
`
`210a
`
`210b
`
`210c
`
`TSW (1,M)
`
`6 @ e
`
`TSW (N,1)
`
`TSW (N,2)
`
`e e e
`
`210d
`
`210e
`
`Encoder &
`Interleaving
`
`1,1
`1,2
`
`Encoder &
`Interleaving
`
`1,M
`
`Encoder &
`Interleaving
`
`Data
`
`e
`
`Encoder &
`Interleaving
`
`N,1
`Interleaving
`
`Encoder &
`
`NM
`
`Encoder &
`Interleaving
`
`210f
`
`TSW(NM)
`
`|:
`
`Transmitter Spatial
`Weightings (TSWs)
`
`FIG. 21
`
`23
`
`23
`
`

`

`Joyiwsuel|
`
`U.S. Patent
`
` Jayng¥JapooUy!O6lSOLsonst|tdOS:!Joyiwsuel|IMI}LoI!OFJOSS8001q-8l4
`
`‘ba:4-s9edsx]40}SulaeayeajujpueBuipoouy
`
`
`|JOACB9}Uoun
`0619}U|
`
`Nov.7, 2000
`
`Sheet 22 of 26
`
`6,144,711
`
`Pomnnnrne14q0z2!YWdOS
`ouuoJONIBOOY
`
`IJayng4019819IW00¢
`
`
` 9OuJaneapaluled
`
`00¢
`
`1wdos
`
`JON@08H
`
`aSlOAdy
`
`
`
`J@UUBUD[O.NUOD
`
`JaAlaoay
`
`dos
`
`24
`
`24
`
`
`
`
`
`
`

`

`U.S. Patent
`
`Nov.7, 2000
`
`Sheet 23 of 26
`
`6,144,711
`
`b(k)
`
`
`
`Trellis
`
`Encoder interleaving
`
`
`Channel State
`Information
`
`|
`I
`
`Space-Frequency
`Subchannel1
`
`Space-Frequency
`Subchanne! NMT
`
`Trellis Encoder & Interleaver 420
`
`1
`
`FIG. 23
`
`25
`
`25
`
`

`

`U.S. Patent
`
`Nov.7, 2000
`
`Sheet 24 of 26
`
`6,144,711
`
`jeyeds
`
`L#BUUaUY
`
`JayILUSUed|
`
`JWSUPL|aNWA
`
`walshsJY
`
`pue
`
`L#
`
`Ss
`
`UdHE|NPOY|
`
`Jd}IWwsuel|
`
`L#dOS
`
`062061iOle
`
`Ly#euudjuy
`
`ywusuel|RNA\S
`UoleE|NPOY|
`Ly#wa}skS44
`
`pue
`
`
` 1w#d0OS}WSUBL| JOSS890/d
`Joywsuel|Bunnoy
`
`
`
`pTTTTTTcscscccsccos4
`
`
`
`
`
`09zZJeAeeajU]joquAS
`
`joquiAs
`
`gouanbes
`
`-Npoweq
`
`JO}e|
`
`|4apoouy
`
`OW#yndjng
`
`joquiAs
`(4)q
`
`Hulpoouz
`ugyndu|
`
`gouanbes
`
`26
`
`26
`
`
`
`
`
`
`

`

`U.S. Patent
`
`Nov.7, 2000
`
`Sheet 25 of 26
`
`6,144,711
`
`aouanbes
`
`
`
`Ugyndyng|48P098q
`
`I|I|III1II
`
`L
`
`J8PO09UF
`
`L#|ynding|
`
`Japoous|
`
`OW#Inding
`
`cmL_aeweo
`
`
`
`Q|jeuueYyQ
`
`002
`
`Ove
`
`Oc}
`
`JOAIB00Y
`
`,#dOS
`
`-powaq
`
`uole|n
`
`
`
`012saneapaiulagjoquixgGoOld
`
`(OW'n)ug
`
`JBAI909}Y
`
`joquiAs
`
`Ja}noy
`
`JANI90904
`
`Ow#dOS
`
`JeAIs09}4
`
`jeyeds
`
`JOSS890/d
`
`27
`
`Och
`
`-poweq
`
`uoleyn
`
`dypue
`
`UW#waysks
`
`27
`
`
`
`
`
`
`
`
`

`

`U.S. Patent
`
`Nov.7, 2000
`
`Sheet 26 of 26
`
`6,144,711
`
`Y,
`
`ORFABSOOSOSA
`ELFRISER
`
`<—XSNLDLWNWCE
`
`SLgEINESOCIO
`SUONISUBL}jalfesedOUSUOIISUBL}jalferedOUSUOIISUBL]fal/eredZSUONISUEjal[esedpZ+UBUC}10}S}Iq|,+UGUO}40}SHI¢U8UO}
`
`
`
`
`JO}Sq€}-UQUO}10}SIIq7pjoquis
`€JOqUAgZjoquiAg|joquiAs
`OveveCveOve
`
`
` J.PSApASRDESKSPASSESKSAWSSESKES:oY
`etaaS
`)Z”
`
`\
`
`28
`
`
`
`

`

`6,144,711
`
`1
`SPATIO-TEMPORAL PROCESSING FOR
`COMMUNICATION
`
`STATEMENT OF RELATED APPLICATIONS
`
`The present application claims priority from two provi-
`sional applications: SPATIO-TEMPORAL CODING FOR
`WIRELESS COMMUNICATION, U.S. Prov. App. No.
`60/025,227 and SPATIO-TEMPORAL CODING TECH-
`NIQUES FOR RAPIDLY FADING WIRELESS
`CHANNELS, U‘S. Prov. App. No. 60/025,228, both filed on
`Aug. 29, 1996. The contents of both provisional applications
`are herein incorporated by reference for all purposes. These
`applications claim the benefit of U.S. Provisional Applica-
`tion No. 60/025,227, filed Aug. 29, 1997 and U.S. Provi-
`sional Application No. 60/025,228 the disclosure of which is
`incorporated by reference.
`BACKGROUND OF THE INVENTION
`
`The present invention relates to digital communication
`and more particularly to a space-time communication sys-
`tem.
`
`The ability to communicate through wireless media is
`made difficult by the inherent characteristics of how trans-
`mitted signals propagate through the environment. A com-
`munication signal transmitted through a transmitter antenna
`elementtravels along multiple paths to the receiving antenna
`element. Depending on many factors including the signal
`frequency and the terrain, the paths along which the signal
`travels will exhibit different attenuation and propagation
`delays. This results in a communication channel which
`exhibits fading and delay spread.
`It is well knownthat adaptive spatial processing using
`multiple antenna arrays increases the communications qual-
`ity of wireless systems. Adaptive array processing is known
`to improvebit error rate, data rate, or spectral efficiency in
`a wireless communication system. The prior art provides for
`methods involving some form of space-time signal process-
`ing at either the input to the channel,
`the output to the
`channel, or both. The space-time processing step is typically
`accomplished using an equalization structure wherein the
`time domain equalizer tap settings for a multitude of anten-
`nas are simultaneously optimized. This so-called “space-
`time equalizaion”leadsto high signal processing complexity
`if the delay spread of the equivalent digital channel
`is
`substantial.
`
`Thereis priorart teaching the use of conventional antenna
`beams or polarizations to create two or more spatially
`isolated communication channels between a transmitter and
`
`a receiver, but only under certain favorable conditions. The
`radiation pattern cross talk between different physical trans-
`mit and receive antenna pairs must provide sufficientspatial
`isolation to create two or more substantially independent
`communication channels. This can lead to stringent manu-
`facturing and performance requirements on the physical
`antenna arrays as well as the receiver and transmitter elec-
`tronics.
`In addition, when large objects in the wireless
`propagation channel cause multipath reflections, the spatial
`isolation provided by the prior art between any twospatial
`subchannels can be severely degraded, thus reducing com-
`munication quality.
`What is needed is a system for more effectively taking
`advantage of multiple transmitter antennas and/or multiple
`receiver antennas to ameliorate the deleterious effects of the
`inherent characteristics of wireless media.
`
`SUMMARYOF THE INVENTION
`
`The present invention provides a space-time signal pro-
`cessing system with advantageously reduced complexity.
`
`10
`
`15
`
`20
`
`25
`
`30
`
`40
`
`45
`
`55
`
`60
`
`65
`
`2
`The system may take advantage of multiple transmitter
`antenna elements and/or multiple receiver antenna elements,
`or multiple polarizations of a single transmitter antenna
`element and/or single receiver antenna element. The system
`is not restricted to wireless contexts and may exploit any
`channel having multiple inputs or multiple outputs and
`certain other characteristics. In certain embodiments, multi-
`path effects in a transmission medium cause a multiplicative
`increase in capacity.
`One wireless embodiment operates with an efficient com-
`bination of a substantially orthogonalizing procedure (SOP)
`in conjunction with a plurality of transmitter antenna ele-
`ments with one receiver antenna element, or a plurality of
`receiver antenna elements with one transmit antenna
`element, or a plurality of both transmitter and receiver
`antenna elements. The SOP decomposes the time domain
`space-time communication channel
`that may have inter
`symbol
`interference (ISI) into a set of parallel, space-
`frequency, SOP bins wherein the ISIis substantially reduced
`and the signal received at a receiver in one bin of the SOP
`is substantially independent of the signal received in any
`other bin of the SOP. Amajorbenefit achieved therebyis that
`the decomposition of the ISI-rich space time channel into
`substantially independent SOP bins makes it computation-
`ally efficient
`to implement various advantageous spatial
`processing techniques embodied herein. Theefficiency ben-
`efit
`is due to the fact
`that
`the total signal processing
`complexity required to optimize performance in all of the
`SOP bins is often significantly lower than the processing
`complexity required to jointly optimize multiple time
`domain equalizers.
`Anotherbenefit is that in many types of wireless channels
`where the rank of the matrix channel that exist between the
`transmitter and the receiver within each SOPbinis greater
`than one, the combination of an SOP with spatial processing
`can be usedto efficiently provide multiple data communi-
`cation subchannels within each SOP bin. This has the
`desirable effect of essentially multiplying the spectral data
`efficiency of the wireless system. A further feature is the use
`of spatial processing techniques within each transmitter SOP
`bin to reduce radiated interference to unintentional receiv-
`ers. A still further feature is the ability to perform spatial
`processing within each receiver SOP bin to reduce the
`deleterious effects of interference from unintentional trans-
`mitters.
`
`One advantageous specific embodiment for the SOPis to
`transmit with IFFT basis functions and receive with FFT
`basis functions. This particular SOP is commonlyreferred to
`as discrete orthogonal frequency division multiplexing
`(OFDM), and each SOP bin is thus associated with a
`frequency bin. This embodiment enhances OFDM with the
`addition of efficient spatial processing techniques.
`According to the present invention, space-frequency pro-
`cessing may adaptively create substantially independent
`spatial subchannels within each SOP bin even in the pres-
`ence of significant cross talk interference between two or
`more physical transmit and receive antenna pairs. A further
`advantageis that the space-frequency processing can advan-
`tageously adaptto cross talk interference between the physi-
`cal antenna pairs even if this cross-talk is frequency
`dependent, or time varying, or both. Thus,
`the present
`invention may provide two or more substantially indepen-
`dent communication channels even in the presence of severe
`multipath and relatively poor physical antenna radiation
`pattern performance.
`A further understanding of the nature and advantages of
`the inventions herein may berealized by reference to the
`remaining portions of the specification and the attached
`drawings.
`29
`
`29
`
`

`

`6,144,711
`
`3
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`FIG. 1 depicts a transmitter system according to one
`embodiment of the present invention.
`FIG. 2 depicts a particular substantial orthogonalizing
`procedure (SOP) useful in one embodiment of the present
`invention.
`
`FIG. 3 depicts a receiver system according to one embodi-
`ment of the present invention.
`FIG. 4 depicts a first communication scenario where
`multipath is found.
`FIG. 5 depicts a second communication scenario where
`multipath is found.
`FIG. 6 depicts a third communication scenario where
`multipath is found.
`FIG. 7 depicts a multiple-input, multiple-output (MIMO)
`channel with interference.
`
`FIG. 8 depicts the use of an SOP in a single-input
`single-output (SISO) channel.
`FIG. 9 depicts the use of an SOP in a MIMOchannel
`according to one embodiment of the present invention.
`FIG. 10 depicts the operation of an SOPin the context of
`one embodiment of the present invention.
`FIG. 11 depicts the application of spatial processing to a
`particular SOP bin at the transmitter end according to one
`embodiment of the present invention.
`FIG. 12 depicts the application of spatial processing to a
`particular SOP bin at the receiver end according to one
`embodiment of the present invention.
`FIG. 13 depicts the application of spatial processing to N
`SOPbins at the transmitter end according to one embodi-
`ment of the present invention.
`FIG. 14 depicts the application of spatial processing to N
`SOPbinsat the receiver end according to one embodiment
`of the present invention.
`FIG. 15 depicts the use of a single spatial direction at the
`transmitter end for each bin of an SOP according to one
`embodiment of the present invention.
`FIG. 16 depicts the use of a single spatial direction at the
`receiver end for each bin of an SOP according to one
`embodiment of the present invention.
`FIG. 17 depicts the use of one or more commonspatial
`weighting vectors for all SOP bins at the transmitter end
`according to one embodiment of the present invention.
`FIG. 18 depicts the use of one or more commonspatial
`weighting vectors for all SOP bins at
`the receiver end
`according to one embodiment of the present invention.
`FIG. 19 depicts the use of an encoder for each SOP bin
`according to one embodiment of the present invention.
`FIG. 20 depicts the use of an encoder for each spatial
`direction according to one embodimentof the present inven-
`tion.
`
`FIG. 21 depicts the use of an encoder for each space/
`frequency subchannel according to one embodiment of the
`present invention.
`FIG. 22 depicts distribution of encoder output over all
`space/frequency subchannels according to one embodiment
`of the present invention.
`FIG. 23 depicts a detailed diagram of an encoder/
`interleaver system according to one embodiment of the
`present invention.
`FIG. 24 depicts a transmitter system wherein multiple
`space/frequency subchannels are employed without spatial
`
`10
`
`15
`
`20
`
`25
`
`30
`
`35
`
`40
`
`45
`
`50
`
`55
`
`60
`
`65
`
`4
`orthogonalization according to one embodiment of the
`present invention.
`FIG. 25 depicts a receiver system wherein multiple space/
`frequency subchannels are employed without spatial
`orthogonalization according to one embodiment of the
`present invention.
`FIG. 26 depicts an exemplary technique for bit loading
`with a trellis coder that uses a one-dimensional QAM
`symbol constellation.
`DESCRIPTION OF SPECIFIC EMBODIMENTS
`Definitions
`A “channel” refers to the input symbol to output symbol
`relationship for a communication system. A “vector chan-
`nel” refers to a channel with a single input and multiple
`outputs (SIMO), or multiple inputs and a single output
`(MISO).Each h, entry in the vector channelh describes one
`of the complex path gains present in the channel. A “matrix
`channel” refers to a channel with multiple inputs and mul-
`tiple outputs (MIMO). Each entry H,; in the matrix H
`describes the complex path gain from input j to output 1. A
`“space time channel” refers to the input to output relation-
`ship of a MIMO matrix channel, or a SIMOor MISO vector
`channel, that occurs when multipath signal propagation is
`present so that the channel contains delay elements that
`produce inter-symbolinterference (ISI) as explained below.
`A “spatial direction”is a one dimensional subspace within
`a matrix or vector communication channel. Spatial direc-
`tions need not be orthogonal. A spatial direction is typically
`characterized by a complex input vector and a complex
`output vector used to weight transmitted or received signals
`as explained herein.
`A “sub-channel” is a combination of a bin in a substan-
`tially orthogonalizing procedure (SOP) as explained below
`and a spatial direction within that bin. A group of spatial
`subchannels within an SOP bin may or may not be orthogo-
`nal.
`
`An “orthogonal dimension” is one member in a set of
`substantially orthogonal spatial directions.
`Achannel“subspace”is a characterization of the complex
`m-space direction occupied by one or more m-dimensional
`vectors. The subspace characterization can be based on the
`instantaneousor average behavior of the vectors. A subspace
`is often characterized by a vector-subspace of a covariance
`matrix. The covariance matrix is typically a time or fre-
`quency averaged outer product of a matrix or vector quan-
`tity. The covariance matrix characterizes a collection of
`average channel directions and the associated average
`strength for each direction.
`A“two norm”metric for a vectoris the sum of the squared
`absolute values for the elements of the vector.
`
`A “Euclidean metric” is a two norm metric. “Intersymbol
`interference” (ISDrefers to the self interference that occurs
`between the delayed and scaled versions of one time domain
`symbol and subsequent symbols received at the output of a
`delay spread communication channel. The channel delay
`spread is caused by the difference in propagation delay
`between the various multipath components combined with
`the time domain response of the RF and digital filter
`elements.
`A “substantially orthogonalizing procedure” (SOP) is a
`procedure that plays a part in transforming a time domain
`sequence into a parallel set of substantially orthogonal bins,
`wherein the signals in one bin do not substantially interfere
`with the signals from other bins. Typically, the transforma-
`tion from a time domain sequence to a set of substantially
`orthogonal bins requires a transmitter SOP with a set of
`input bins, and a receiver SOP with a set of output bins.
`30
`
`30
`
`

`

`6,144,711
`
`10
`
`15
`
`20
`
`25
`
`30
`
`35
`
`40
`
`6
`numberof bits that are mapped to a given encoder symbol,
`and the signal powerassignedto that symbol, are determined
`based upon the measured communication quality of the
`space-frequency information subchannel
`that carries the
`symbol stream.
`After the digital data is encoded into a sequence of
`symbols, a Training Symbol Injection block 20 may be used
`to place a set of known training symbol values in the
`transmitter symbol stream. The purpose of the training
`symbols is to provide a known input within a portion of the
`transmitted symbol stream so that a receiver may estimate
`the communication channel parameters. The channel esti-
`mate is used to aid in demodulation and decoding of the data
`sequence. The training symbols maybe injected periodically
`in time, periodically in frequency, or both. It will be obvious
`to one skilled in theart that blind adaptive spatial processing
`techniques can be utilized within each SOP bin at
`the
`receiver as an alternative to tra