United States Patent [19J
`Tiedemann, Jr. et al.
`
`[54]
`
`SPREAD SPECTRUM COMMUNICATION
`SYSTEM WHICH DEFINES CHANNEL
`GROUPS COMPRISING SELECTED
`CHANNELS THAT ARE ADDITIONAL TO A
`PRIMARY CHANNEL AND TRANSMITS
`GROUP MESSAGES DURING CALL SET UP
`
`[75]
`
`Inventors: Edward G. Tiedemann, Jr.; Yu-Cheun
`Jou, both of San Diego; Joseph P.
`Odenwalder, Del Mar, all of Calif.
`
`[73] Assignee: QUALCOMM Incorporated, San
`Diego, Calif.
`
`[21] Appl. No.: 656,649
`
`[22] Filed:
`
`May 31, 1996
`
`Int. Cl.6
`............................... H04B 7/216; H04J 3/24
`[51]
`[52] U.S. Cl. .......................... 370/335; 370/441; 370/473;
`370/522
`[58] Field of Search ..................................... 370/335, 441,
`370/468, 473, 433, 329, 336, 337, 203,
`208, 209, 522
`
`[56]
`
`References Cited
`
`U.S. PATENT DOCUMENTS
`
`3,310,631
`3,715,508
`4,052,565
`4,135,059
`4,220,821
`4,256,925
`4,291,406
`4,291,409
`4,298,979
`4,301,530
`4,319,353
`4,322,845
`4,339,818
`4,369,434
`4,373,151
`4,383,315
`4,424,417
`4,445,213
`4,455,649
`4,460,992
`
`3/1967 Brown ....................................... 179/15
`2/1973 Blasbalg ............................. 179/15 BC
`10/1977 Baxter et a!. .. ... ... ... ... .... ... ... . 179/1.5 S
`1!1979 Schmidt ... ... ... .... ... ... ... ... ... .... ... . 179/15
`9/1980 Lucas ...................................... 370/110
`3/1981 Goode ..................................... 370/104
`9/1981 Bah! et a!. ................................ 371/44
`.......................... 375/1
`9/1981 Weinberg et a!.
`11/1981 Dobyns et a!.
`......................... 370/104
`11/1981 Gutleber .................................... 370/18
`3/1982 Alvarez, III et a!. ................... 370/104
`3/1982 Fennel, Jr. et a!. ..................... 370/104
`7/1982 Gruenberg .............................. 370/112
`1!1983 Mueller ................................... 340/347
`2/1983 Houdard eta!. ........................ 329/104
`5/1983 Torng . ... ... ... ... .... ... ... ... ... ... .... ... . 370/89
`1!1984 Chavey et a!. .......................... 179/2 E
`4/1984 Baugh eta!. ............................. 370/94
`6/1984 Esteban et a!. ........................... 370/80
`7/1984 Gutleber ... ... ... .... ... ... ... ... ... .... ... . 370/19
`
`111111
`
`1111111111111111111111111111111111111111111111111111111111111
`US005859840A
`[11] Patent Number:
`[45] Date of Patent:
`
`5,859,840
`Jan. 12, 1999
`
`4,472,815
`4,477,900
`4,491,947
`4,494,232
`4,547,880
`4,562,572
`4,587,652
`4,594,476
`4,635,221
`4,688,035
`4,726,014
`4,730,340
`
`9/1984 Gutleber .................................... 375/34
`10/1984 Gruenberg .............................. 370/112
`1!1985 Frank ........................................ 370/94
`1!1985 Dambrackas eta!. .................... 370/80
`10/1985 De Vita et a!. ........................... 370/91
`12/1985 Goldman et a!. ......................... 370/80
`5/1986 Goldman .............................. 370/110.1
`6/1986 Freeman ................................. 179/6.08
`1!1987 Kerr ... ... ... .... ... ... ... ... .... ... ... ... .. 364/821
`8/1987 Gray et a!. ......................... 340/825.52
`2/1988 Goldman et a!. ......................... 370/58
`3/1988 Frazier, Jr ................................... 375/1
`
`(List continued on next page.)
`
`FOREIGN PATENT DOCUMENTS
`
`2/1991 European Pat. Off. .......... H04B 1!56
`0412583
`3/1991 European Pat. Off . ........ H04L 12/56
`0418865
`9/1991 European Pat. Off. ........ H04B 1!212
`0444592
`2022365 12/1979 United Kingdom ............. H04Q 7/04
`5/1987 United Kingdom .............. H04J 3/00
`2182528
`9107030
`5/1991 WIPO ............................... H04J 3/06
`
`OTHER PUBLICATIONS
`
`Kreyszig, Erwin, "Advance Engineering Mathematics",
`John Wiley & Sons, Section 4.7, 1979, pp. 186-190.
`
`Primary Examiner-Douglas W. Olms
`Assistant Examiner-David R. Vincent
`Attorney, Agent, or Firm-Russell B. Miller; Bruce W.
`Greenhaus
`
`[57]
`
`ABSTRACT
`
`The present invention is a method and apparatus for trans(cid:173)
`mitting a high rate data packet in a CDMA communication
`system. The transmission system transmits a first channel
`assignment message indicating the at least one additional
`channel that will be used to support the high rate data packet.
`The first channel assignment message is sent in advance of
`the onset of high rate data communications. In addition the
`present invention provides within the first frame of high rate
`data a duplicate channel assignment message. A remote
`receiver uses the channel assignment messages to initialize
`its demodulation elements to receive the additional infor(cid:173)
`mation carried on the at least one additional channel.
`
`4 Claims, 3 Drawing Sheets
`
`40
`
`CELL
`REQ
`~-------'-1.-j CONTROLLER CHANNEL ASSIGNMENT
`
`ACK
`
`Cisco Systems, Inc., Exhibit 1109
`Page 1
`
`

`
`5,859,840
`Page 2
`
`FOREIGN PATENT DOCUMENTS
`
`4,774,987
`4,805,167
`4,839,892
`4,870,642
`4,872,200
`4,876,698
`4,899,337
`4,901,307
`4,930,118
`4,933,952
`4,939,745
`4,965,796
`4,970,648
`5,003,533
`5,003,534
`5,068,849
`5,101,501
`5,103,459
`5,107,377
`
`10/1988 Sepling ............................... 144/208 B
`2/1989 Leslie ...................................... 370/540
`6/1989 Sasaki ....................................... 370/95
`9/1989 Nohara et a!. ............................ 370/75
`10/1989 Jansen ... ... ... ... .... ... ... ... ... ... .... ... . 380/34
`10/1989 Boisson et a!. ... ... ... ... .... ... ... ... .. 37 5 !25
`2/1990 Hirai .. ... ... ... ... .... ... ... ... ... ... .... ... . 370/80
`2/1990 Gilhousen et a!.
`....................... 370/18
`5/1990 Sugihara .. ... ... .... ... ... ... ... ... .... ... . 370/16
`6/1990 Albrieux et a!. ............................ 375/1
`7/1990 Kirimoto eta!. ........................... 375/1
`10/1990 Petty ....................................... 370/112
`11/1990 Capots ............................... 364/424.06
`3/1991 Watanabe ............................... 370/85.5
`3/1991 Gerhardt et a!. .......................... 370/94
`11/1991 Tanaka ................................... 370/85.5
`3/1992 Gilhousen et a!.
`....................... 455/33
`4/1992 Gilhousen et a!.
`......................... 375/1
`4/1992 Ballard ...................................... 360/40
`
`5,115,429
`5,121,383
`5,168,575
`5,172,375
`5,179,549
`5,212,684
`5,212,687
`5,216,503
`5,231,649
`5,276,730
`5,280,537
`5,293,640
`5,305,308
`5,349,580
`5,351,240
`5,381,412
`5,400,328
`5,420,861
`5,440,542
`5,442,625
`
`5/1992 Hluchyj et a!. ........................... 370/84
`6/1992 Golestani .................................. 370/60
`12/1992 Cizek eta!. ........................... 455/33.1
`12/1992 Kou ........................................ 370/95.3
`1!1993 Joos et a!. ................................. 370/17
`5/1993 MacNamee et a!.
`..................... 370/24
`5/1993 De La Bourdonnaye ................ 370/84
`6/1993 Paik et a!. ............................... 358/133
`7/1993 Duncanson ................................ 375/38
`1!1994 Cimini, Jr. eta!. ...................... 379/60
`1!1994 Sugiyama et a!. .......................... 375/1
`3/1994 Gunmar eta!. ........................ 455/33.1
`4/1994 English eta!. ......................... 370/32.1
`9/1994 Hester et a!.
`............................. 370/84
`9/1994 Highsmith ................................. 370/84
`1!1995 Otani ......................................... 370/84
`3/1995 Burren et a!. ............................. 370/79
`5/1995 De La Bourdonnaye ................ 370/84
`8/1995 Procter et a!.
`............................ 370/18
`8/1995 Gitlin et a!.
`.............................. 370/18
`
`Cisco Systems, Inc., Exhibit 1109
`Page 2
`
`

`
`U.S. Patent
`
`Jan. 12, 1999
`
`Sheet 1 of 3
`
`5,859,840
`
`14
`
`MOBILE
`TELEPHONE ~___,
`• • •
`SWITCHING
`OFFICE
`
`TO/FROM
`PUBLIC TELEPHONE
`SWITCHING NETWORK
`
`12
`
`CELL
`BASE
`STATION
`12
`
`CELL
`BASE
`STATION
`
`•
`•
`•
`
`12
`
`CELL
`BASE
`STATION
`
`10
`
`MOBILE
`STATION
`
`FIG.l
`
`Cisco Systems, Inc., Exhibit 1109
`Page 3
`
`

`
`(
`
`- -
`
`DE-
`~
`DATA
`MUX
`SOURCE
`
`~
`
`--
`
`r
`PRIMARY
`PRIMARY
`PRIMARY
`FORMATTER f-- ENCODER ~ INTERLEA VER
`
`(
`
`r
`
`PRIMARY
`
`.r-35
`
`DE-
`
`~ ADDITIONAL
`MODULATOR
`
`36
`
`....
`
`-
`
`TMTR -
`;r32a
`..
`...
`
`f-
`
`1-1-
`
`~~
`
`r- 25
`{ 27
`ADDITIONAL r-- ADDITIONAL
`~ FORMATTER
`
`r 29
`
`ADDITIONAL
`
`ENCODER • INTERLEA VER ~
`
`MUX •
`•
`•
`
`•
`•
`
`,r32n
`
`--
`
`.. MODULATOR
`...
`t •
`•
`f
`~ ADDITIONAL
`MODULATOR
`.. ~
`
`,...4o
`
`REQ
`
`CELL
`CONTROLLER CHANNEL ASSIGNMENT
`
`ACK
`
`I
`
`FIG.2
`
`d •
`\Jl
`•
`~
`~ ......
`~ = ......
`
`~
`~
`?
`'"""' ~N
`'"""'
`'0
`'0
`'0
`
`'JJ. =(cid:173)~
`~ .....
`N
`0 ......,
`~
`
`Ul
`....
`00
`Ul
`\C
`....
`00
`
`""-=
`
`Cisco Systems, Inc., Exhibit 1109
`Page 4
`
`

`
`110
`111
`r.L _____ l
`~
`114
`,_..;...-------.
`I ,c128
`I
`PRIMARY
`RCVR
`~DEMODULATOR
`
`118
`PRIMARY
`~ DE-
`INTERLEA VER
`
`122
`PRIMARY1
`DECODER~
`
`,cJ11
`
`•
`
`I
`FINGER
`I COMBINEru
`I
`. - - - - - ' 1
`I
`120a I
`ADDITIONAL
`DEMODULATOR
`
`I
`1
`
`HIGH RATE
`DEMODULATION
`CONTROLLER
`
`117
`
`MUXI ~30
`~DATA
`SINK
`
`ADDITIONAL
`DE-
`INTERLEA VER
`
`126
`ADDITIONAL1
`....._
`DECODER ~
`
`lr---..L--L-:..::.:::,
`ADDITIONAL
`I DEMODULATOR
`
`I
`
`~
`
`I
`
`I
`
`I
`
`TO OTHER
`FINGERS
`
`FIG. 3
`
`•
`•
`•
`
`I
`I
`I
`I
`
`I
`I
`I
`
`•
`•
`•
`120n
`ADDITIONAL
`l
`r DEMODULATOr..-,-
`I
`1
`
`L FROM OTHE~IN;~RS _j
`
`. I
`•
`
`I
`
`I
`
`• h
`
`'----.......----'
`
`d •
`\Jl
`•
`~
`~ ......
`~ = ......
`
`~
`~
`?
`'"""' ~N
`'"""'
`'0
`'0
`'0
`
`'JJ. =-~
`~ .....
`
`~
`0 ......,
`~
`
`Ul
`....
`00
`Ul
`\C
`....
`00
`
`""-=
`
`Cisco Systems, Inc., Exhibit 1109
`Page 5
`
`

`
`5,859,840
`
`1
`SPREAD SPECTRUM COMMUNICATION
`SYSTEM WHICH DEFINES CHANNEL
`GROUPS COMPRISING SELECTED
`CHANNELS THAT ARE ADDITIONAL TO A
`PRIMARY CHANNEL AND TRANSMITS
`GROUP MESSAGES DURING CALL SET UP
`
`BACKGROUND OF THE INVENTION
`
`5
`
`10
`
`2
`to allow the users of the resource to provide data at varying
`rates thereby using only the minimum amount of the com(cid:173)
`munication resource to meet their service needs. An example
`of variable rate data source is a variable rate vocoder which
`is detailed in U.S. Pat. No. 5,414,796, entitled "VARIABLE
`RATE VOCODER," assigned to the assignee of the present
`invention and incorporated herein by reference. Since
`speech inherently contains periods of silence, i.e. pauses, the
`amount of data required to represent these periods can be
`reduced. Variable rate vocoding most effectively exploits
`this fact by reducing the data rate for these silent periods.
`A variable rate speech encoder provides speech data at
`full rate when the talker is actively speaking, thus using the
`full capacity of the transmission frames. When a variable
`rate speech coder is providing speech data at a less than
`15 maximum rate, there is excess capacity in the transmission
`frames. A method for transmitting additional data in trans(cid:173)
`mission frames of a fixed size, wherein the data source is
`providing data at a variable rate is described in detail in U.S.
`Pat. No. 5,504,773, entitled "METHOD AND APPARATUS
`20 FOR THE FORMATTING OF DATA FOR
`TRANSMISSION", assigned to the assignee of the present
`invention and incorporated by reference herein. In the above
`mentioned patent application a method and apparatus is
`disclosed for combining data of differing types from differ-
`25 ent sources in a data packet for transmission.
`
`SUMMARY OF THE INVENTION
`A communications resource is typically divided into com(cid:173)
`munications channels. The present invention is described in
`the context of a CDMA communication system, wherein
`each channel is provided by spreading the data by a different
`spreading sequence. In the exemplary embodiment, the
`spreading sequences used are orthogonal Walsh sequences.
`In the present invention, each user is provided with a
`dedicated channel, referred to herein as the primary channel.
`In addition, each user is provided with selective access to a
`pool of common channels, referred to herein as additional
`channels which can be shared by all users of the commu(cid:173)
`nication system.
`When the rate of a user's transmission exceeds the
`capacity of the primary channel, the communication system
`determines whether sufficient additional channels are avail(cid:173)
`able for the transmission of the high rate data. If sufficient
`additional channels are available, they are assigned to the
`user for transmission of the high rate data.
`In the present invention, after determining that sufficient
`additional channels are available but prior to the onset of the
`high rate transmission, the transmitter sends a message,
`referred to herein as the first channel assignment message, to
`50 the receiver indicating a forthcoming high rate data trans(cid:173)
`mission. In the exemplary embodiment, the channel assign(cid:173)
`ment message identifies the additional channels that will be
`used to support the high rate data service. In the exemplary
`embodiment, the first channel assignment message is trans-
`55 mitted two frames in advance of the high rate transmission.
`By using the first channel assignment message the receiving
`system need not demodulate all possible channels at all
`times which greatly reduces power consumption of the
`mobile station.
`In an improved embodiment, a secondary channel assign-
`ment message containing the same information as the first
`channel assignment message is provided on the primary
`channel at the onset of the high rate data communication.
`This provides a second indication of the high rate data
`65 transmission which can be relied upon if the frame carrying
`the first channel assignment message is not properly
`received.
`
`I. Field of the Invention
`The present invention relates to communications. More
`particularly, the present invention relates to a novel and
`improved communication system wherein a user transmits
`data on a primary channel. However, when the user's
`transmission exceeds the capacity of the primary channel,
`the user is provided use of an additional channel or set of
`channels for use in conjunction with the primary channel to
`enable the transmission of high rate data. The present
`invention provides for dynamic channel assignment for the
`transmission of high rate data and provides a highly efficient
`system for the transmission of variable rate data.
`II. Description of the Related Art
`The present invention is concerned with multiple users
`sharing a communications resource such as in a cellular
`CDMA system. The use of code division multiple access
`(CDMA) modulation techniques is one of several techniques
`for facilitating communications in which a large number of
`system users are present. Other multiple access communi(cid:173)
`cation techniques, such as time division multiple access
`(TDMA), frequency division multiple access (FDMA) and 30
`AM modulation schemes such as amplitude companded
`single sideband (ACSSB) are known in the art. However, the
`spread spectrum modulation technique of CDMA has sig(cid:173)
`nificant advantages over these other modulation techniques
`for multiple access communication systems. The use of 35
`CDMA techniques in a multiple access communication
`system is disclosed in U.S. Pat. No. 4,901,307, entitled
`"SPREAD SPECTRUM MULTIPLE ACCESS COMMU(cid:173)
`NICATION SYSTEM USING SATELLITE OR TERRES(cid:173)
`TRIAL REPEATERS", assigned to the assignee of the 40
`present invention and incorporated by reference herein. The
`use of CDMA techniques in a multiple access communica(cid:173)
`tion system is further disclosed in U.S. Pat. No. 5,103,459,
`entitled "SYSTEM AND METHOD FOR GENERATING
`SIGNAL WAVEFORMS IN A CDMA CELLULAR TELE- 45
`PHONE SYSTEM", assigned to the assignee of the present
`invention and incorporated by reference herein.
`CDMA by its inherent nature of being a wideband signal
`offers a form of frequency diversity by spreading the signal
`energy over a wide bandwidth. Therefore, frequency selec(cid:173)
`tive fading affects only a small part of the CDMA signal
`bandwidth. Path diversity is obtained by exploiting the
`multipath environment through spread spectrum processing
`by allowing a signal arriving with different propagation
`delays to be received and processed separately. Furthermore,
`space or path diversity is obtained by providing multiple
`signal paths through simultaneous links between a mobile
`user and two or more base stations. Examples of the utili(cid:173)
`zation of path diversity are illustrated in U.S. Pat. No.
`5,109,390 entitled "DIVERSITY RECEIVER IN A CDMA 60
`CELLULAR TELEPHONE SYSTEM", and U.S. Pat. No.
`5,101,501 entitled "SOFT HANDOFF IN A CDMA CEL(cid:173)
`LULAR TELEPHONE SYSTEM", both assigned to the
`assignee of the present invention and incorporated by ref(cid:173)
`erence herein.
`An additional technique that may be used to increase the
`efficiency of the allocation of the communication resource is
`
`Cisco Systems, Inc., Exhibit 1109
`Page 6
`
`

`
`5,859,840
`
`3
`In the present invention, the receiving system initializes a
`set of additional demodulators to demodulate the high rate
`data in accordance with the information provided in the first
`channel assignment message. The high rate data is demodu(cid:173)
`lated by the primary channel demodulator and the additional 5
`channel demodulators and the demodulated frames are com(cid:173)
`bined and provided to the user.
`If a frame erasure occurs, the receiving system demodu(cid:173)
`lates all possible additional channels as though a first
`channel assignment message had been received in the erased 10
`frame. The receiving system then uses the secondary chan(cid:173)
`nel assignment message to re-assemble the frame and to
`initialize the additional demodulators for receiving the next
`frames.
`
`35
`
`A multiple access communication resource is divided into
`channels. This division is usually called multiplexing, three
`specific types being: frequency division multiplexing
`(FDM), time division multiplexing (TDM), and code divi(cid:173)
`sion multiplexing (CDM). The basic unit of information
`transmitted and received in a communication system is
`referred to as a frame.
`Referring now to the figures, FIG. 1 illustrates an exem(cid:173)
`plary implementation of the present invention in a mobile
`communication system. Mobile station 10 transmits infor(cid:173)
`mation to and receives information from cell base station 12.
`Cell base station 12, in turn, transmits information to and
`receives information from mobile telephone switching office
`(MTSO) 14. MTSO 14, in turn, transmits information to and
`receives information from a public switching telephone
`network (not shown).
`In the exemplary embodiment, the signals transmitted by
`cell base station 12 to mobile station 10 are spread spectrum
`signals as are the signals transmitted from mobile station 10
`to cell base station 12. The generation of spread spectrum
`communication signals is described in detail in the afore(cid:173)
`mentioned U.S. Pat. Nos. 4,901,307 and 5,103,459. The
`exemplary embodiment of the present invention is described
`in terms of a method for providing high rate data packets
`from cell base station 12 to mobile station 10 referred to
`herein as forward link transmissions. However, the present
`invention is equally applicable to the reverse link transmis- 60
`sian of data from mobile station 10 to cell base station 12.
`In the exemplary embodiment, mobile station 10 is
`assigned a primary channel for communications with base
`station 12. In the exemplary embodiment, a single channel
`is provided by a unique Walsh spreading sequence as is
`described in detail in the aforementioned U.S. Pat. Nos.
`4,901,307 and 5,103,459. In the present invention, cell base
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`The features, objects, and advantages of the present
`invention will become more apparent from the detailed
`description set forth below when taken in conjunction with
`the drawings in which like reference characters identify
`correspondingly throughout and wherein:
`FIG. 1 is a diagram illustrating an exemplary implemen(cid:173)
`tation of the present invention in a mobile communication
`system;
`FIG. 2 is a block diagram of the transmission system of
`the present invention; and
`FIG. 3 is a block diagram of a receiver system of the
`present invention.
`
`DETAILED DESCRIPTION OF THE
`PREFERRED EMBODIMENTS
`
`25
`
`30
`
`4
`station 12 uses additional channels to provide high rate data
`transmission to mobile station 10.
`As referred to herein, high rate data packets are those
`which require more capacity than the primary channel for
`their transmission. In the exemplary embodiment, the data is
`transmitted in packets. If a packet contains high rate data, its
`contents are divided into a plurality of frames, each of which
`can be transmitted on a single channel and recombined at the
`receiver.
`FIG. 2 illustrates a block diagram of the exemplary
`embodiment of the transmission system of the present
`invention. Data source 20 provides the packets of data for
`transmission from cell base station 12 to mobile station 10.
`Data source 20 is provided for illustrative purposes. It
`15 should be noted that bases station 12 is typically relaying
`information from remote location and data source 20 is
`simply a convenient way to illustrate a source of the packets
`of data for transmission. Data source 20 can provide both
`packets of data less than capacity limits of the primary
`20 channel and high rate data requiring the use of the primary
`channel plus one or more additional channels to carry the
`packet.
`When the data packet for transmission can be transmitted
`using only the assigned primary channel, data source 20
`provides the packet of data through de-multiplexer (DE(cid:173)
`MUX) 22 to primary formatter 24. In the exemplary
`embodiment, primary formatter 24 generates a set of redun(cid:173)
`dant bits for the packet in accordance with error correction
`and detection methods that are well known in the art. In the
`exemplary embodiment, formatter 24 generates a set of
`cyclic redundancy check (CRC) bits and a set of code tail
`bits and appends those sets of bits to the outgoing packet, the
`generation of which is detailed in the aforementioned U.S.
`Pat. No. 5,550,773.
`Primary formatter 24 outputs the packet to primary
`encoder 26 which encodes the packet to provide encoded
`symbols. In the exemplary embodiment, primary encoder 26
`is a rate Y2 convolutional encoder, the design and implemen-
`40 tation of which are well known in the art. In an exemplary
`embodiment, the convolutional encoder is implemented
`using a digital shift register. Primary encoder 26 provides the
`encoded data packet to primary interleaver 28.
`Primary interleaver 28 reorders the binary digits of the
`45 encoded packet in accordance with a predetermined reor(cid:173)
`dering format. In the exemplary embodiment, primary inter(cid:173)
`leaver 28 is a block interleaver. In a block interleaver, the
`data is written into memory in columns and output in rows.
`In conjunction with error correcting code, interleaving
`50 increases the time diversity of the data, and therefore
`increases the robustness against bursty channel errors.
`The interleaved packet is provided by primary interleaver
`28 to primary modulator 30. Primary modulator 30 modulate
`the frames in order to provide the frame on the assigned
`55 primary channel. In the exemplary embodiment modulator
`30 is a code division multiple access (CDMA) modulator as
`described in detail in U.S. Pat. Nos. 4,901,307 and 5,103,
`459. In the exemplary embodiment, each frame is spread by
`a Walsh sequence (W n) that is unique to that channel and
`orthogonal to all other Walsh sequences used by all other
`channels upon which data is transmitted from base station
`12. In the exemplary embodiment, data on the primary
`channel can be variable rate in accordance with the industry
`standard TINEINIS-95-A Mobile Station-Base Station
`65 Compatibility Standard for Dual-Mode Wideband Spread
`Spectrum Cellular System, whereas data provided on the
`additional channels is scheduled at a fixed rate.
`
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`5
`In the exemplary embodiment, the spread frame is then
`covered using a pseudorandom noise (PN) sequence which
`provides greater separation in code space and identification
`for each base station 12. Each channel is distinguished
`uniquely by its Walsh sequence. There are a limited number 5
`of available orthogonal sequences, so the greater the number
`of users transmitting at high rates the fewer the number of
`users that can be accommodated by base station 12. Modu(cid:173)
`lator 30 provides the modulated frame to transmitter
`(TMTR) 34, which frequency upconverts and amplifies the
`modulated frame, and transmits the signal through antenna
`36.
`When data source 20 prepares to transmit high rate data
`packet, it provides a request signal (REQ) to cell controller
`40 of cell base station 12. Cell controller 40 responds by
`providing an acknowledgment of the request (ACK). Cell
`controller 40 selects additional channels which will be used
`for the transmission of the high rate data. In the exemplary
`embodiment, the pool of possible additional channels that
`can be used for the transmission of high rate data is
`pre-defined so that selection can be performed by a simple
`masking technique as is well known in the art. In another
`exemplary embodiment sets of additional channels are pre(cid:173)
`defined and channel assignment messages simply identify
`one of the predefined sets. In an improved embodiment, the
`pre-defined sets consist of different number of additional
`channels. Cell controller 40, generates a channel assignment
`message, which indicates the additional Walsh channel or
`channels that will be used to carry the high rate data two
`frames ( 40 ms) later and provides that message to primary
`formatter 24.
`The channel assignment message can be provided with its
`own CRC check bits to provide additional reliability or can
`be transmitted without its own check bits using only a
`minimum number of additional bits. If the present invention
`is to be used in a time division multiple access communi(cid:173)
`cation system, then the channel assignment messages would
`specify additional time slots where data will be provided to
`mobile station 10. Similarly if the present invention is
`applied to a frequency division multiple access communi(cid:173)
`cation system, then the channel assignment messages would
`specify additional frequencies which will be used to provide
`data to mobile station 10.
`In the exemplary embodiment, the channel assignment
`message is provided as additional signaling data which is
`combined with the outgoing data on the primary channel.
`The channel assignment message transmitted in advance of
`the onset of the high rate data transmissions is referred to
`herein as the first channel assignment message. A method for
`combining outgoing traffic data with signaling data is
`described in detail in the aforementioned U.S. Pat. No.
`5,550,773. In an alternative embodiment, the first channel
`assignment message is punctured into the outgoing data
`frame on the primary channel by methods well known in the
`art.
`The frame containing the first channel assignment mes(cid:173)
`sage is formatted as described above by primary formatter
`24 and encoded by primary encoder 26 as described above.
`The encoded symbols are then provided to primary inter(cid:173)
`leaver 28 which reorders the symbols as described above. In 60
`the exemplary embodiment, the channel assignment
`message, signaling messages (if they exist), control mes(cid:173)
`sages (if they exist) and part of the data are all transmitted
`on the primary channel by primary modulator 30, the
`additional channels only carry data. In the exemplary 65
`embodiment, power control bits if they exist are punctured
`into the primary channel data to provide closed loop power
`
`6
`control of the type described in the aforementioned U.S. Pat.
`No. 5,109,501. The primary channel can be variable or fixed
`rate or it can be used as a dedicated control channel. The
`modulated frame is upconverted and amplified by transmit(cid:173)
`ter 34 and transmitted through antenna 36.
`In the exemplary embodiment, the first channel assign(cid:173)
`ment message is provided two frames in advance of the
`onset of high rate data transmissions to provide sufficient
`time for the receiver (illustrated in FIG. 3) to prepare for its
`reception. In the exemplary embodiment, during the call
`set-up, the additional channels are grouped by cell controller
`40 and transmitted to mobile station 10. In the exemplary
`embodiment, this group of additional channels can be
`updated during the call. Defining the set of possible addi(cid:173)
`tional channels in advance allows the channel assignment
`15 message to require only a few bits to identify the channels
`to be used. Instead of sending a signal identifying the
`additional channels to be used, the base station can send a
`mask signal that will allow high rate demodulation control(cid:173)
`ler 117 to identify the additional channels.
`Because there is a chance that the frame carrying the first
`channel assignment message may be received in error, the
`present invention provides the channel assignment informa(cid:173)
`tion redundantly in a secondary channel assignment message
`transmitted on the primary channel.
`At the onset of high rate data transmissions, data source
`20 provides the high rate data packet to de-multiplexer 22.
`De-multiplexer 22 divides the high rate data packet into two
`parts. The first part is contained in a frame to be transmitted
`30 on the primary channel. The second part is contained in
`frames to be transmitted on additional channels. The frame
`to be transmitted on the primary channel is processed as
`described above.
`The data bits for the additional channels are provided to
`35 additional formatter 25. Additional formatter 25 generates a
`set of CRC bits for the incoming data and a set of code tail
`bits. The formatted data from additional formatter 25 is
`provided to additional encoder 27 which encodes the data to
`provide encoded symbols. In the exemplary embodiment,
`40 additional encoder 27 is a convolutional encoder.
`The encoded symbols are provided to additional inter(cid:173)
`leaver 29, which as described above reorders the encoded
`symbols in accordance with a predetermined ordering for(cid:173)
`mat. In a first embodiment of primary interleaver 28 and
`45 additional interleaver 29, the interleavers use the same
`number of addresses but variable words size to accommo(cid:173)
`date different sized blocks of data for interleaving. In an
`alternative embodiment of primary interleaver 28 and addi(cid:173)
`tional interleaver 29, the interleavers use a variable number
`50 of addresses and a fixed word size to accommodate varying
`block size. The reordered encoded symbols are provided to
`de-multiplexer (DE-MUX) 35 which divides the additional
`frame into frames each of which is carried on an additional
`channel.
`Each of the additional frames from de-multiplexer 35 is
`provided to a different one of additional modulators
`32a-32n. In the exemplary embodiment, the modulated
`additional frames from additional modulators 32a-32n are
`combined with the modulated frame from primary modula(cid:173)
`tor 30 by transmitter 34 before transmission. Transmitter 34
`upconverts and amplifies the combined signal and transmits
`that signal through antenna 36.
`Now referring to FIG. 3, the signal broadcast through
`antenna 36 of FIG. 2 is received at the by antenna 110 and
`provided to receiver (RCVR) 112. Receiver 112
`downconverts, filters and amplifies the received signal and
`provides the received signal to demodulation circuit 111.
`
`20
`
`25
`
`55
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`Demodulation circuit 111 represents one "finger" of a
`decisions for each of the additional frames. The improved
`soft decisions of the demodulated frames are provided to
`RAKE receiver should such a design be used. In a RAKE
`multiplexer (MUX) 123 which re-assembles the packet
`receiver implementation, multipath signals received at
`containing the additional data. In the exemplary
`mobile station 10 with different propagation path delays are
`5 embodiment, multiplexer 123 operates in accordance with a
`demodulated separately and the results of those demodula(cid:173)
`signal from high rate demodulation controller 117 which
`tion operations are then combined in finger combiner 128.
`indicates the additional demodulators that are being used
`The design and implementation of a RAKE receiver is
`and how to re-assemble the p