.
`
`United States Patent
`Su et al,
`
`[19]
`
`LAATAAA
`{11] Patent Number:
`5,258,995
`’
`’
`[45] Date of Patent:
`Nov. 2, 1993
`
`US005258995A
`
`'
`
`.
`
`.
`
`by J. Hagensuer, N. Seshandri C-E. W. Sundberg, pp.
`[54] WIRELESS COMMUNICATION SYSTEM
`139-146,
`[75]
`Inventors BehtschRerkeley: KeithJaret.
`IEEETransactions on Communications, vol. 38, No. 7,
`
`
`
`75) tors:.Chun-M1 Su, Lafayette; S: . oo
`
`
`Oakland; HuihungLu, Danville;
`Jul. 1990, “The Performance ofRate-Compatible Punc-
`Christopher Flores, Oakland; David
`tured Convolutional Codes for Digital Mobile Radio”,
`G. Messerschmitt, Moraga,all of
`C.-E. W. Sundberg, J. Hagenauer, N. Seshandri, pp.
`Calif.
`966-980.
`TEEE Transactions on Communications, vol. COM-32,
`sigs
`No. 3, Mar. 1984, “High-Rate Punctured Convolu-
`[73] Assignee: earn ommunications Systems,
`tional Codes for Soft Decision Viterbi Decoding”, Y.
`Gry Berkeley,
`Call.
`Yasuda, K. Kashiki, Y. Hirata, pp. 315-319.
`[21] Appl. No.: 789,292
`
`[22]|File a Apr. 1988, “Rate-Compatible Punctured Convolutional
`
`TEEETransactions on Communications, vol. 36, No. 4,
`:
`,
`s
`22)
`Filed:
`Nov. 8, 1991
`eam
`[51]
`F111© HO4K 1/00
`Codes (CPC Codes) and their Applications”, J.
`
`[52] US. CD. ceescsessssossrssssesassssssseresssersuavsveseensenes 3785/1
`Hagenauer, pp. 389-400.
`[58] Field of Search .........cccssssccesseeewe 3375/1; 380/34
`.
`Primary Examiner—Salvatore Cangialosi
`[56]
`References Cited
`Attorney, Agent, or Firm—Limbach & Limbach
`U.S. PATENT DOCUMENTS
`[57]
`ABSTRACT
`_
`/
`.
`.
`4,271,524
`6/1981 Goodmanet al. ow. 375/1
`In the present invention a wireless communication sys-
`4,644,560 2/1987 Torre etal.
`.
`4,703,474 10/1987 Foschini et al. occ 375/1
`tem is disclosed. A base unit communicates with a re-
`4,783,844 11/1988 Higashiymaetal. .
`mote unit. The system comprises means for transmit-
`4,905,221
`2/1990 Ichiyoshi.
`ing.
`using
`CD
`base
`unit and the
`re.
`
`
`
`5,099,493 ‘INGusing CDMA,between thebaseunit3/1992 Zeger et al. csccscssssessssnmen 375/1 er
`5,103,459 4/1992 Gilhousen et al.
`mote unit, in one ofa plurality of frequencies channels
`5375/1
`
`5,128,959
`7/1992 Bruckert....
`sae 378/1
`selected. In one period of time, the base unit transmits
`
`5,136,612
`8/1992 Bi sc...
`sae 3575/1
`and in another period of time, different from the one
`
`5,150,377 9/1992 Vannucci
`w ST5/1
`period, the remote unit transmits. Further, the system
`
`5,151,919
`9/1992 Dent..........
`we STS/I
`comprises means for changing the one frequency chan-
`5,161,168 11/1992 Schilling
`vo STS/I
`nel selected to another frequency channel, different
`
`2.164,958 11/1992 Omura .......
`v 375/1
`from the one frequency channel,
`in response to interfer-
`5,193,101
`3/1993 McDonald et al. voces 375/1
`.
`,
`.
`ence in the one frequency channel. Thus, communica-
`OTHER PUBLICATIONS
`tion between the base unit and the remote unit is then
`38th IEEE Vehicular Technology Conference, Jun.
`affected over the another frequency channel.
`1988, “‘Variable-Rate Sub-Band Speech Coding and
`Matched Channel Coding for Mobile Radio Channels”,
`
`20 Claims, 7 Drawing Sheets
`
`ane
`
`SPEAKER
`PHONE
`TERMINAL
`
`INTERFACE
`AND
`MULTIPLEXER
`
`VOICE/DATA
`PROCESSOR
`
`BASEBAND
`PROCESSING
`UNIT (BPU)
`
`_f
`
`APPLICATION
`CONTROLLER
`
`GAIN
`FREQ. CODE
`SEL
`SEL CONTROL
`| a
`
`PROTOCOL AND CONTROL
`UNIT (PCu)
`
`aa
`
`Page 1 of 19
`
`SAMSUNG EXHIBIT 1015
`
`Page 1 of 19
`
`SAMSUNG EXHIBIT 1015
`
`

`

`U.S. Patent
`
`Noy. 2, 1993
`
`Sheet 1 of 7
`
`5,258,995
`
`DJ[oet+8rANg
`09Zanvaasva!FOVANGINI
`
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`a1rla
`
`VLVO/3010AvLVd
`
`LINN
`
`Page 2 of 19
`
`Page 2 of 19
`
`
`

`

`U.S. Patent
`
`Nov. 2, 1993
`
`Sheet 2 of 7
`
`5,258,995
`
`JIGVN=~)nouyoriNaA
`#f-7LINN“ONAS
`TOULNODGNV1O90LOUd
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`WNINYSL
`
`Page 3 of 19
`
`Page 3 of 19
`
`
`
`
`
`
`
`
`

`

`U.S. Patent
`
`Nov. 2, 1993
`
`Sheet 3 of 7
`
`5,258,995
`
`DOL
`
`DEL
`
`b9/
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`Dg/
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`ANOD-NMOG
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`Page 4 of 19
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`
`Page 4 of 19
`
`
`
`
`
`
`
`
`
`
`

`

`U.S. Patent
`
`Novy. 2, 1993
`
`Sheet 4 of 7
`
`5,258,995
`
`"aS‘0344
`YIZISSHLNAS
`NONINOIS
`
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`
`Page 5 of 19
`
`Page 5 of 19
`
`
`
`
`
`
`
`

`

`U.S. Patent
`
`Noy. 2, 1993
`
`Sheet 5 of 7
`
`5,258,995
`
`1240
`
`1260 BINARY
`
`DATA
`
`
`160
`
`1/Q CODED DATA
`(TO RRC FILTER)
`
`FIG. 3c
`
`Page 6 of 19
`
`Page 6 of 19
`
`

`

`U.S. Patent
`
`Nov. 2, 1993
`
`Sheet 6 of 7
`
`5,258,995
`
`INTERFACE AND MULTIPLEXER
`
`MULTIPLEXER
`
`SWITCH MATRIX
`
`DATA TERM
`SPEAKER
`PHONE
`
`PSTM/ISDN |CLT
`;AX|
`
`
`CONTROLUNITrT
`|
`TERMINAL
`
` INTERFACE
`
`
`APPLICATIONS
`CONTROLLER
`
`FIG. 6
`
`
`
`PANEL
`
`APPLICATIONS pF
`PROCESSOR
`
`AND
`MULTIPLEXER
`
`PROTOCOL AND
`CONTROL UNIT
`
`FIC. 7
`
`Page 7 of 19
`
`Page 7 of 19
`
`

`

`U.S. Patent
`
`Nov. 2, 1993
`
`Sheet 7 of 7
`
`5,258,995
`
`.o MHz
`
`|
`902 MHz
`
`l
`
`Loses
`
`|
`
`|
`928 MHz
`
`
`
`—XMIT BY EACH REMOTE 40
`XMIT BY BASE 10
`FIG. 9
`
`USC-B
`SYNC
`cS i
`ASWilsw2]daATABcc|data|upc-BY
`
`ne
`CSC~B
`
`
`UC-B
`
`FIC. 10
`
`UC-R
`CSC-R
`oTSe
`
`APA|CSRYjPAZ|USC-R|UBC-RY
`
`FI¢.
`
`11
`
`Page 8 of 19
`
`Page 8 of 19
`
`

`

`1
`
`5,258,995
`
`2
`
`WIRELESS COMMUNICATION SYSTEM
`
`SUMMARYOF THE INVENTION
`
`5
`
`10
`
`20
`
`30
`
`35
`
`45
`
`55
`
`TECHNICAL FIELD
`
`The present invention relates to a wireless communi-
`cation system for communicating between a base unit
`and a remote unit, and more particularly to a wireless
`communication system for communication between a
`base unit portion and a remote unit portion of a digital
`cordless phone.
`
`BACKGROUNDOF THE INVENTION
`Wireless communication between a base unit and one
`Or more remote units is well knownin the art. One well
`known methodis Frequency Division Multiple Access
`(FDMA). In FDMA,the available electromagnetic
`communication spectrum is divided into a plurality of
`frequency channels. Communication between the base
`unit and oneof the remote units is effected over one of
`the frequency channels. Communication between the
`base unit and a different remote unit is effected over a
`different frequency channel.
`Time Division Multiple Access (TDMA)is also well
`knownin the art. In TDMA communication, transmis-
`sion between the base unit and a first remote unit is
`effected over-a first “slice” in time. Transmission be-
`tween the base unit and a second remoteunit is effected
`over a second “slice” of time, different from thefirst
`“slice”.
`Finally, in Code’ Division Multiple Access (CDMA)
`the communication between a base unit and one or more
`remote units is accomplished through spread spectrum
`transmission over a frequency range wherein a unique
`Pseudo Noise (PN) codedistinguishes the communica-
`tion between a base unit and a first remote unit and a
`different code distinguishes the communication be-
`tween the base unit and a different remote unit. There
`are several types of CDMA systems such as ‘Direct
`Sequence, Frequency Hopping, and Time-Hopping.
`Direct Sequence spread spectrum systems encode a low
`rate data stream into a high rate data stream at the trans-
`mitier. At the receiver the high rate data stream is de-
`coded back into the low rate data stream.
`Establishment of protocol between a remote unit and
`a base unit prior to the communication session is well
`known in the modem communication art. Thus, for
`example, in packet communications, prior to the com-
`munication session in accordance with the X.25 proto-
`col the remote unit and the base unit negotiate the
`packet size. In addition, in the modem communication
`art, modems having different transmission rate capabili-
`ties determine, prior to the communication session, the
`fastest speed at which both units can accommodate one
`another.
`In the priorart, it is known that the transmit power
`can be adjusted based on a priori knowledge of the
`transmitted power and the expected received power by
`the other side. However, this prior art is normally lim-
`ited in that it assumes a fixed channel attenuation.
`In the priorart, it is also known to commandadjust
`the dynamic power control by using a feedback loop.
`However, for a TDMAsystem,the delay that is com-
`posed of the measuring time, the transmission time and
`the application time results in large degradation. Also,
`the amount of message rate that needs to be allocated
`for power control is sometimes large which results in a
`loss of capacity.
`
`A wireless communication system for communica-
`tion between a base unit and one or more remoteunits
`is disclosed. The system comprises means for transmit-
`ting, using CDMA,between the base unit and the re-
`mote unit in one of a plurality of frequency channels
`selected, wherein in one period of time the base unit
`transmits and in another period of time different from
`the one period, the remote unit transmits. The system
`also comprises means for changing the one frequency
`channel selected to another frequency channel, differ-
`ent from the one frequency channel,
`in response to
`interference in the one frequency channel, whereby the
`communication between the base unit and the remote
`unit is then affected over the another frequency chan-
`nel.
`The present invention also relates to a wireless com-
`munication method for communicating between a base
`unit and one or more remote units.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`FIG. 1 is a block level diagram of a base unit of the
`present invention.
`FIG.2 is a blocklevel diagram of a remote unit of the
`present invention.
`FIG.3 is a detailed block level diagram ofthe RF/IF
`analog portion of the base unit shown in FIG. 1.
`FIG.4 is a detailed block level diagram of the RF/IF
`analog portion of the remote unit shown in FIG.2.
`FIGS. 5(a-c) are portions of the block level diagram
`of the standby and syncunit of the remote unit shown in
`FIG. 2 and the base unit shown in FIG. 1.
`FIG.6 is a detailed block level diagram ofthe inter-
`face and multiplexer portion of the remote unit shown
`in FIG. 2 and of the base unit shown in FIG. 1.
`FIG.7 is a detailed block level diagram ofthe appli-
`cation controller portion of the remote unit shown in
`FIG. 2 and of the base unit shown in FIG. 1.
`FIG.8 is a schematic diagram of the frequency spec-
`trum in which the preferred embodiment of the commu-
`nication system of the present invention is intended to
`operate.
`FIG. 9 is a timing diagram ofthe protocol of commu-
`nication between the base unit and the remote unit.
`FIG. 10 is a detailed timing diagram of FIG.9, show-
`ing the portion transmitted by the base unit.
`FIG.11 is a detailed timing diagram of FIG. 9, show-
`ing the portion transmitted by the remote unit.
`DETAILED DESCRIPTION OF THE
`DRAWINGS
`
`Referring to FIG. 1 there is shown a block level
`diagram ofa base unit 10. The base unit 10 is adapted to
`communicate with one or more remote units 40 shown
`in FIG.2. In the preferred embodiment, collectively the
`base unit 10 and the remote unit 40 comprise a digital
`cordless phone 8. Thus, the base unit 10 has an interface
`12 for connection with a public switch telephone net-
`work (PSTN) such as an RJ11 jack or an ISDNinter-
`face.
`The PSTN portion of the interface 12 handles PSTN
`telephoneactions, such as on/off hook, multi-tone gen-
`eration etc. The signals received by the interface 12 are
`sent to the interface and multiplexer 18 and to the appli-
`cation controller 22,
`The ISDN portion of the interface 12 translates
`ISDN messages into correspondingsignals such as on/-
`
`Page 9 of 19
`
`Page 9 of 19
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`

`

`3,258,995
`
`_ 0
`
`20
`
`3
`off hook echo, DTMFtoneecho, dial tone or signaling
`messages such as ringing.
`The base unit 10 is hardwired to communicate with —
`the telephone switching network and communicates
`wirelessly with one or more remote units 40. The base
`unit 10 also comprises a speaker phone terminal 14.
`Thus, with a speaker phoneterminal 14, the base unit 10
`can also be used to communicate directly with the tele-
`phone network through the PSTN/ISDNinterface 12
`or wirelessly with one or more remote units 40. In addi-
`tion, the base unit 10 comprises a data terminal interface
`16 for receiving digital data for communication to the
`telephone network over the PSTN/ISDNinterface 12
`or wirelessly with one or more remote units 40. Thus,
`for example, data from sources such as a computer, can
`be supplied to the base unit 10 at the data terminal inter-
`face 16 for transmission and reception over the tele-
`phone network through the PSTN/ISDNinterface 12
`or wirelessly with one or more remote units 40.
`The PSTN/ISDNinterface 12, the speaker phone
`termina] 14 and the data terminal interface 16 are all
`connectedto an interface and multiplexer 18. The inter-
`face and multiplexer 18, shownin greaterdetail in FIG.
`6, serves to interface the various signals received from
`the speaker phone terminal 14 and the data terminal 16
`and places them on the telephone network through the
`. PSTN/ISDNinterface 12 orto be transmitted to one or
`more of the remote units 40.
`Thebase unit 10 also comprises a panel 20 comprising
`of lights and switches, and a keypad. Thesignals from
`the panel 20 are supplied to an application controller 22
`and the signals from the application controller are sup-
`plied to the panel 20. The application controller 22 is
`shownin greater detail in FIG. 7.
`The application controller 22 interfaces with the
`interface and multiplexer 18. The function of the appli-
`cation controller 22 is to interface with the user of the
`system 8, to interpret the user commands, entered from
`the panel 20, and to provide responses from the system
`8 to the user.
`The interface and multiplexer 18 and the application
`controller 22 communicate with the base unit trans-
`ceiver 30. The base unit transceiver 30 comprises a
`system clock 35, a protocol and control unit 32, a
`standby and sync unit 34, an RF/IF analog unit 36, and
`at least one combination of voice/data processor 38a
`andits associated base band processing unit 28a. In the
`base unit 10, there are as many voice/data processors
`38a and its associated base band processing unit 28a as
`there are the numberof remote units 40 which is or are
`served simultaneously by the base unit 10. Thus, if the
`base unit 10 is adapted to service three (3) remote units
`40 simultaneously, then within the transceiver 30 are
`three voice/data processors 38 each with its associated
`base band processing unit 28.
`Each of the voice/data processors 38 is connected
`with its associated base band unit 28. The voice data
`processor 38 is also connected to the interface and mul-
`tiplexer 18 and with the protocol! and contro! unit 32.
`The base band processing unit 28 is connected to the
`RF/IF analog unit 36 and with the protocol and control
`unit 32.
`The RF analog unit 36 is connected to the standby
`and sync unit 34. In addition, the RF/IF unit 36 is con-
`nected to a pair of antenna 26a, and 26, with each of
`the antennas 26a and 26d serving to both transmit and
`receive.
`
`4
`Finally, the protocol and control unit 32 is connected
`to the application controller 22.
`The remote unit 40 is shownin block diagram form in
`FIG.2. The remote unit 40 comprises a phone/terminal
`42 which comprises a handset and aninterface terminal
`to receive data. The phone terminal 42 is connected to
`an interface and multiplexer 44 which is similar to the
`interface and multiplexer 18 of the base unit. The re-
`mote unit also comprises a handset panel 46. The hand-
`set panel 46 has lights and switches. The handset panel
`46 communicates with an application controller 22
`which is similar to the application controller 22 in the
`base unit 10. Similar to the base unit 10, the application
`control 22 is connected to the interface and multiplexer
`44.
`The remote unit 40 also comprises a remote unit
`transceiver 50. The remote unit transceiver 50, similar
`to the base unit transceiver 30, comprises a protocol and
`control unit 52 which is similar to the protocol and
`contro] unit 32 of the base unit 10.
`The remote unit
`transceiver 50 also comprises a
`standby and sync unit 34, which is same as the standby
`and syne unit 34 of the base unit 10. The remote unit
`transceiver 50 also comprises an RF/IF analog unit 56,
`whichis similar to the RF/IF analog 36ofthe base unit
`transceiver 30, and is connected to a transmitting and
`receiving antenna $8a and a receiving antenna 586.
`The remote unit transceiver 50 also comprisesa sin-
`gle voice data processor 38a and its associated base
`band processing unit 282. The voice/data processor 38
`and its associated base band processing unit 28a are
`same as the voice/data processor 38a andits associated
`base band processing unit 28a of the base unit trans-
`ceiver 30.
`The remote unit transceiver 50 thus comprises a pro-
`tocol and control unit 52, a standby and sync unit 34, an
`RF/IF analog unit 56, a voice/data processor 38a and a
`base band processing unit 28a. The connection of these
`units is identical to the connection for the components
`of the base unit transceiver 30. The protocol and con-
`trol unit 52 is connected to the application controller 22
`and to the voice/data processor 38a and the base band
`unit 28a, and to the standby and sync unit 34. The voi-
`ce/data processor 38a is connected to the base band
`processing unit 28a andto the interface and multiplexer
`44. The base band processing unit 28a is connected to
`the RF/IF analog unit 56. The RF/IF analog unit 56.is
`connected to the standby and sync unit 34 and to the
`antennas 58a and b,
`Referring to FIG. 3 there is shown a detailed block
`diagram of the RF/IF analog unit 36 of the base unit
`transceiver 30. The function of the RF/IF analog unit
`36 is to convert the frequency of the transmitted or
`received signal by the antenna 26a and 266 from radio
`frequencyto an intermediate frequency. In addition,the
`unit 36 has power control capability to control the
`transmission power of the transmitted signal. Finally,
`the unit 36 modulates and demodulates the in-phase and
`quadrature-phase components of the base bandsignal.
`The unit 36 is shown as comprising twosets of anten-
`nas 26a and 266 both for transmitting and for receiving.
`The use of two antennas 26(a and b) and twosets of
`matching circuits is to insure that in case one antennais
`located in a “dead spot” that the other antenna would
`receive and transmit the requisite signals to the remote
`unit 40. The signal received by one of the antennas 26a
`is supplied to an RF filter and low noise amplifier
`(LNA) 70a, which functions to filter and amplify the
`
`35
`
`40
`
`45
`
`55
`
`60
`
`65
`
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`25
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`
`5,258,995
`5
`signal received from the antenna 26a. The output of the
`RFfilter and LNA 70ais supplied to an RF-to-IF down
`converter 72a. The function of the RF-to-IF down
`converter 72a is to convert the received RF signal into
`an intermediate frequency signal. The conversion from
`RF-to-IF is dependent upon the difference frequency
`supplied to the RF-to-IF down converter 72a. This
`difference frequency is generated by a frequency syn-
`thesizer 74 based upon a frequencyselect input signal.
`From the RF-to-IF down converter 72a, the interme-
`diate frequency is then supplied to an IF filter and am-
`plifier 76c, The function of the IF filter and amplifier
`76a is to filter the received IF signal and to amplify that
`signal. In addition the IF filter and amplifier 76a in-
`creases the gain of the filtered signal based upon a gain
`control signal supplied thereto.
`The amplified and filtered IF signal is then supplied
`to an 1/Q demodulator 78a. The I/Q demodulator 782 is
`an in-phase and quadrature-phase demodulator and
`generates as its output thereof a base band frequency
`signal. The demodulation of the input signal is based
`upon a IF frequency signal supplied from a temperature
`compensated crystal oscillator 82. The base band fre-
`quencysignalis then supplied to an RRC MF80a. The
`RRC MF80q is a root raised cosine signal matched
`filter whose output,
`in the absence of carrier phase
`error,is a positive or a negative impulse signal for each
`ofthe in-phase and quadrature-phase componentsof the
`signal. The in-phase and quadrature-phase components
`comprises a complex signal.
`Similarly, the signal from the antenna 26b is supplied
`along a second identical circuit. First, the signal from
`the antenna 26d is supplied to an RFfilter and a LNA
`circuit 70b. The output of the RFfilter and LNAcircuit
`706 is supplied to an RF-to-IF down converter 72b. The
`difference frequency generated by the frequency syn-
`thesizer 74 is supplied to the RF-to-IF down converter
`72b. The output of the RF-to-IF down converter 726 is
`supplied to an IF filter and amplifier 76b, whose gain is
`also to the IFfilter and amplifier 76a.
`The signal from the IF filter and amplifier 760 is then
`in-phase and quadrature-phase demodulated by the IF
`1/Q demodulator 78). The in-phase and quadrature-
`phase demodulation is based upon the IF frequency
`signal supplied from the temperature compensated crys-
`tal oscillator 82. The output of the IF 1/Q demodulator
`785 is supplied to the RRC MFcircuit 80d.
`In the transmission phase, the +1 binary signals cor-
`responding to the in-phase and quadrature-phase com-
`ponents ofthe “spread”data signal (to be described in
`greater detail hereinafter) are supplied to the RRCfilter
`84..The RRC 84 serves to generate a positive or nega-
`tive root raised cosine signal if the input signal is a +1
`or —1 respectively. The output of the RRCfilter 84 is
`supplied to an RF 1/Q modulator 86. The RF I/Q mod-
`ulator 86 takes the root raised cosine signal and directly
`converts it into a radio frequency modulated signal for
`transmission. The output of the frequency synthesizer
`74 which determinesthe selected radio frequency signal
`to be modulated and the output of the TCXO 82 which
`determines the RF frequency of the modulation are
`both supplied to a mixer 88. The output of the mixer 88
`is then supplied to the RF I/Q modulator 86 and is
`modulated by the output of the RRCfilter 84,
`The output of the RF I/Q modulator 86 is then sup-
`plied to an RFfilter and amplifier 90, whose amplifica-
`tion portion has a gain which is controlled by the gain
`control signal. The output of the RFfilter and amplifier
`
`6
`90 is supplied to the RF linear amplifier 92a for trans-
`mission over the antenna 26d.In addition, the output of
`the RFfilter and amplifier 90 is supplied after a delay of
`“chip” time T,, by a delay 94, to a second RF linear
`amplifier 925 for transmission over the antenna. 26a.
`Since two signals are produced (one delayed from the
`other), the signals can be received by the remote unit 40
`and combined. Further, since the two signals are de-
`layed, this permits the remote unit 40 to receive both
`signals using only a single antenna.
`The frequency synthesizer 74 generates a difference
`frequency between the RF and IF frequencies. The
`difference frequency varies depending upon the fre-
`quency select signal supplied to the synthesizer 74.
`Thus, the frequency synthesizer 74 coversall frequency
`bands. In the event the synthesizer 74 can generate both
`the difference frequency (supplied to the RF to IF con-
`verter 72) and the selected RF frequencyfor transmis-
`sion, andis able to switch rapidly between thosesignals,
`then the mixer 88 is not required. In that event, the
`selected RF frequency output of the synthesizer 74 can
`be supplied directly to the RF 1/Q modulator 86.
`Referring to FIG.4, there is shown in detailed block
`level diagram the RF/IF analog unit 56 of the remote
`transceiver unit 50. Similar to the RF/IF analog unit 36,
`the RF/IF analog unit 56 comprises an antenna 58a or
`585 for receiving the incoming signal. The received
`signal is supplied to an RFfilter and low noise amplifier
`70 which serves to filter and amplify the received RF
`signal. From the RF filter and LNA circuit 70, the
`signal is supplied to a RF-to-IF down converter 72. The
`RF-to-IF down converter 72 converts the received RF
`signal into an intermediate frequencysignal based upon
`the difference frequency signal generated by the fre-
`quency synthesizer 74. The difference frequency signal
`generated by the frequency synthesizer 74 can be se-
`lected by a frequencyselect signal. From the RF-to-IF
`down converter 72, the IF signal generated therebyis
`supplied to an IF filter and amplifier 76, whose gain is
`controlled by a gain control signal. The output of the IF
`filter and amplifier 76 is then supplied to an IF 1/Q
`demodulator 78.
`The IF 1/Q demodulator 78 also receives a IF fre-
`quency signal generated by the temperature compen-
`sated crystal oscillator 82. The demodulated in-phase
`and quadrature-phasesignals from the IF 1/Q demodu-
`lator 78 are then supplied to an RRC matchedfilter 80.
`The outputof the RRC matchedfilter 80, in the absence
`of carrier phase error, are positive or negative impulses
`representing a -t 1 binary signal for each of the in-phase
`and quadrature-phase componentsofthe signal.
`The transmission portion of the RF/IF analog unit 56
`receives the “spread”signal from the base band process-
`ing unit 28a. Thesignal is supplied to the RRC filter 84.
`Theoutput of the RRCfilter 84 is a positive or negative
`root raised cosine signal which is generated in response
`to a £1 binary in-phase or quadrature-phase component
`of the “spread”signal. The outputsignal of the RRC
`filter 84 is supplied to an RF I/Q modulator 86. The
`output ofthe oscillator 82 and of the frequency synthe-
`sizer 74 are both supplied to a mixer 88 which generates
`the requisite RF modulation signal whichis supplied to
`the RF 1/Q modulator 86. Thus, the output of the RF
`I/Q modulator 86 is an RF modulated signal which is
`supplied to an RF filter and amplifier 90. The RFfilter
`and amplifier 90 has a amplifier whose gain is controlled
`by the gain control signal. The outputof the RFfilter
`and amplifier 90 is supplied to the RFlinear amplifier 92
`
`35
`
`40
`
`45
`
`35
`
`60
`
`65
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`5,258,995
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`5
`
`10
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`15
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`25
`
`7
`8
`whichis then supplied to a transmitting antenna 585 for
`then supplied back to the PN code generator 134. In this
`transmission.
`.
`manner, the PN code generator 134 is maintained in a
`Referring to FIGS. 5(a-c) there is shown detailed
`synchronizedstate by a delay locked loop. The low pass
`schematic block level diagram of the standby and sync
`filters 124 (a and b) have a bandwidth around the bit
`unit 34, The standby and sync unit 34 comprises a por-
`rate and may be implemented as an integrate and dump
`tion which acquires and verifies the signal (FIG. 5a)
`circuit. An integrate and dumpcircuit is a simple imple-
`synchronizes the signal (FIG. 5) and detects the signal
`mentation ofa low passfilter. The controlled clock 132
`(FIG. 5c).
`also drives a system clock 35.
`Referring to FIG. 5a there is shown the acquisition
`Referring to FIG. 5c there is shown a modulating and
`and verification portion 100 of the standby and synchro-
`demodulating portion 140 of the standby and sync unit
`nization unit 34. The acquisition and verification unit
`34. The modulator and demodulator portion 140 re-
`100 comprises a preamble matched filter 102 which
`ceives the signal from the RRC matchedfilter circuit
`receivesas its input thereof, the output of the RRC MF
`80. The signal is supplied to a first complex multiplier
`circuit 80. The function of the preamble matched filter
`142a. The output of the PN code generator 134 is also
`circuit 102 is to detect the preamble portion of SYNC
`supplied to the first complex multiplier 142¢. The out-
`signal generated by the base unit 34 or the preamble
`put of the first complex multiplier 142a is supplied to a
`portion of the PA1 signal generated by the remote unit
`first low pass filter 144¢. From thefirst low pass filter
`(discussed in greater detail hereinafter). The output of
`1442,the signal is supplied toafirst one bit delay 1462.
`the preamble matchedfilter circuit 102 is supplied to an
`Theoutputofthe first one bit delay 146c is supplied to
`20
`energy detection circuit 104. The energy detection cir-
`a first conjugate multiplier 148a to which the output of
`cuit 104 serves to obtain the signal magnitude from the
`the first low pass filter 1442 is also supplied. The output
`in-phase and quadrature-phase components. The output
`of the first conjugate multiplier 148a is supplied to a
`of the energy detection circuit 104 is supplied to a
`multipath combiner 150. From the multipath combiner
`threshold detection circuit 106. The threshold detection
`150, the signal is supplied to a threshold detector 152
`circuit 106 serves to detect the presence or absence of
`which generates the binary data signal.
`the preamble signal. Typically the threshold is first high
`Thesignal from the RRC MFcircuit 80 is also sup-
`to prevent false detection and then lowered to increase
`plied to a second path comprising of a second complex
`the probability of detection. The output ofthe threshold
`multiplier 1425 whichis also supplied with the output of
`detection circuit 106 is supplied to a verification counter
`the PN code generator 134. The output of the second
`108. The verification counter 108 can optionally be fed
`complex multiplier 142d is supplied to a second low pass
`back to the threshold detection circuit to control the
`filter 1445. The output of the second low passfilter 1445
`threshold detection circuit in a feedback loop. The out-
`is supplied to a second onebit delay 146d. The output of
`put of the verification counter 108 is an enable signal,
`the one bit delay 1465 is supplied to a second conjugate
`whichis used in the other components of the stand-by
`multiplier 1485. to which the output of the second low
`and sync unit 34. In the event the signal received by the
`pass filter 1440 is also supplied. The output of the sec-
`RF/IF analog unit 36 or 56 is the correct signal, the
`ond conjugate multiplier 1485 is supplied to the multi-
`enable signal would be high.
`path combiner 150. In the case where the standby and
`Referring to FIG. 5d there is shown the synchroniza-
`sync unit 34 is used with the RF/IF analog unit 36 of
`tion portion 120 of the standby and synchronization unit
`the base unit transceiver 30, two paths for the signals
`34. The synchronization portion 120 comprises
`a
`from the two RRC MFcircuits 80a and 808 are pro-
`Pseudo Noise (PN) code generator 134, which receives
`vided. In the event the standby and sync unit 34 is used
`as its input thereof, a code select signal. The PN code
`with the RF/IF analog unit 56 of the remote unit trans-
`generator 134 generates a PN code which is determined
`ceiver 50, the multipath combiner 150 would be used if
`by the code select signal. In addition,it generates a code
`the base unit 10 transmitted two signals delayed from
`which is earlier in phase, by half a “chip” time T,, than
`one anotherby a single chip.
`the code selected by the codeselect signal and is sup-
`The data detection portion 140 also comprisesa dif-
`plied to a first complex multiplier 122a. The PN code
`ferential encoder 160 which receives the binary data
`generator 134 also generates a code which is later in
`from the base band processing unit 28a. The output of
`phase,by half a ‘“‘chip” time T,, than the one selected by
`the differential encoder 160 is supplied to a complex
`the code select signal and is supplied to the second
`multiplier 162 to which the PN code generator 134 is
`complex multiplier 1228,
`also supplied. The output of the complex multiplier 162
`The output of the RRC matchedfilter circuit 80 is
`is the “spread” signal which is supplied to the RRC
`supplied to the first and second complex multipliers
`filter 84 for transmission by the RF/IF analog unit 36 or
`122a and 1226respectively. The outputs of the complex
`56.
`multiplitrs 122¢ and 1220 are supplied to low passfilters
`The base band processing unit 28 is similar to the
`124¢ and 124d respectively. The outputs of the low pass
`filters 124a and 1248 are supplied to energy detection
`standby and sync unit 34 in that it comprises an acquisi-
`tion andverification unit (shownin FIG.5a), a synchro-
`circuits 126a and 1265 respectively. The low pass filter
`nization unit (shown in FIG. 5b) and a data detection
`and the energy detection circuit 126 (a and b) function
`unit 140 shown in FIG. 5c. The difference, as will be
`to obtain the signal magnitude from the in-phase and
`explained hereinafter, is that the base band processing
`quadrature-phase components. The output of the en-
`ergy detection circuits 126¢ and 1264