United States Patent [w]

Transcription

1 United States Patent [w] Schilling et al. US A [ii] Patent Number: [45] Date f Patent: II Jun. 13,2000 [54] HIGH EFFICIENCY SPREAD SPECTRUM SYSTEM AND METHD [75] Inventrs: Dnald L. Schilling, Sands Pint, N.Y.; Jseph Gardnick, Centerville, Mass. [73] Assignee: Glden Bridge Technlgy, Inc., West Lng Branch, N.J. [21] Appl. N.: 09020,105 [22] Filed: Feb. 6, 1998 [51] Int. CI. 7 H04B 7216 [52] U.S. CI ; ; ; [58] Field f Search , 335, , 349, 350, 441, 464, 477, 479; , 355, 356 [56] References Cited U.S. PATENT DCUMENTS 5,081, Schilling ,109, Gilhusen et al ,166, Schilling 3751 Primary Examiner Dang Tn Assistant Examiner David R Vincent Attrney, Agent, r Firm David Newman; Chartered [57] ABSTRACT A multichannel-spread-spectrum system fr cmmunicating a plurality f data-sequence signals frm a plurality f data channels using parallel chip-sequence signals in which fewer than all f the channels include header infrmatin. A header device cncatenates a header t a first data-sequence signal n a first channel. Data-sequence signals in parallel channels are sent withut a header, and are timed frm the header in the first channel. 7 Claims, 4 Drawing Sheets 46 diw 32 \ d 2 (t) 33i 38, <Wt> HEADER DEVICE SYNC SYNC SYNC Xx r^r^y^ ; ) ) (x c M B I N E R -45 X FILTER ^ -39 CHIP SEQUENCE GENERATR 27 PRCESSR

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6 HIGH EFFICIENCY SPREAD SPECTRUM SYSTEM AND METHD BACKGRUND F THE INVENTIN This inventin relates t spread-spectrum cmmunicatins, and mre particularly t a highly efficient spread-spectrum system emplying packets having multiple parallel spread-spectrum channels. DESCRIPTIN F THE RELEVANT ART In a spread-spectrum system, ne methd fr cnstructing a spread-spectrum signal transmitted as a packet is t use a header t determine the sampling pint f a matched filter, t time the fields f the received data, t determine the 15 relative amplitudes f the in-phase cmpnent and quadrature-phase cmpnent f the received spreadspectrum signal fr cherent detectin, t detect multipath, and t prvide the cefficients fr maximal rati cmbining. A typical frame f the spread-spectrum signal, transmitted as 20 a packet r a frame f a cntinuus signal, is shwn in FIG. 1 fr the case where the prcessing gain (PG) is 192; that is, fr the example where there are 192 chipssymbl. The term "packet" is used thrughut this disclsure t indicate a packet signal, and als includes frames f cntinuus signals 25 which define packets. With reference t FIG. 1, the time difference f fisec between fields is needed when ne r bth f the terminals, transmitter and receiver, is in mtin at vehicular speeds. ther times are als gd. Less time between headers may 30 be better in a particular applicatin, but typically requires mre headers, and hence mre verhead. Fr the example f FIG. 1, the Dppler shift f the received signal requires mre frequent updates the faster ne f the terminal mves. The example shwn in FIG. 1 is fr a system perating at 2 GHz, a vehicle at 60 miles per hur, and binary-phase-shift-keying (BPSK) mdulatin. The length f the headers, 31 and 15 symbls, is determined by the required signal-t-nise rati f the headers t prvide accurate enugh references fr cherent demdulatin. Fr the example f FIG. 1, 256 symbls are used fr headers, leaving 256 symbls fr data. Thus, this channel is nly 50% efficient. In additin, the maximum data rate, including bearer data, signaling, pwer cntrl, etc., is 25.6 kbps uncded. 45 ne slutin ffered in the prir art is t use a lwer prcessing gain, fr example, 96. Then, there wuld be 1024 symbls per frame and the maximum data rate wuld increase t 51.2 kbps. The channel, hwever, wuld still be nly 50% efficient. The headers wuld have t increase symbl length t make up fr the lss in prcessing gain. Als, if rthgnal cdes were used, then the number f users wuld be limited t 96. Anther methd ffered by prir art is t use parallel 55 spread-spectrum channels, with each channel defined by a different chip-sequence signal. In this methd, by using multiple crrelatrs r matched filters, rthgnal cdes are sent simultaneusly, thereby increasing the data rate while still enjying the advantage f a high prcessing gain. The 60 multiple spread-spectrum channels merely behave as multiple users t a single lcatin. Hwever, the efficiency remains at 50%. SUMMARY F THE INVENTIN A general bject f the inventin is t increase data transmissin efficiency by sending data thrugh parallel spread-spectrum channels while including headers in fewer than all f the channels. The present inventin bradly includes a multichannelspread-spectrum system fr cmmunicating a plurality f data-sequence signals frm a plurality f data channels, ver a cmmunicatins channel. The multichannel-spreadspectrum system includes, at a transmitter, a header device, a prcessr, a chip-sequence generatr, a plurality f prduct devices, a cmbiner, and a transmitter subsystem. At a receiver, the system may further include a translating device, a header-matched filter, a receiver prcessr, and a plurality f data-matched filters. At the transmitter, the header device cncatenates a header t a first data-sequence signal n the first datasequence channel t generate a header frame. As used herein, a "header frame" is defined t be a header fllwed by data and may include multiple headers interspersed with fields f data. Timing is keyed frm the header. The prcessr generates cntrl and timing signals fr synchrnizatin f the secnd, third thrugh the nth data-sequence channels t the header. The chip-sequence generatr generates a plurality f chip-sequence signals, with each chipsequence signal rthgnal t the ther chip-sequence signals f the plurality f chip-sequence signals. A plurality f prduct devices multiplies the utput frm the header device, and each f the remaining data-sequence signals, by a respective chip-sequence signal, thereby generating a plurality f spread-spectrum channels. The plurality f spread-spectrum channels includes a spread-spectrumheader channel and a plurality f spread-spectrum-data channels. The spread-spectrum-header channel is generated by prcessing the header frame with a first chip-sequence signal. Each f the plurality f spread-spectrum-data channels is generated by prcessing a respective data-sequence signal by a respective chip-sequence signal. The cmbiner algebraically cmbines the plurality f spread-spectrum channels as a multichannel-spread-spectrum signal. The transmitter subsystem transmits the multichannel-spreadspectrum signal n a carrier frequency using radi waves ver the cmmunicatins channel. At the receiver, the translating device translates the received multichannel-spread-spectrum signal frm the carrier frequency t a prcessing frequency. The headermatched filter has an impulse respnse matched t the header. The header-matched filter detects, at the prcessing frequency, the header in the multichannel-spread-spectrum signal and utputs, in respnse t detecting the header, a header-detectin signal. The receiver prcessr, in respnse t the header-detectin signal, generates cntrl and timing signals. Each data-matched filter f the plurality f datamatched filters has an impulse respnse matched t a respective chip-sequence signal f the plurality f chipsequence signals. The plurality f data-matched filters despreads the received multichannel-spread-spectrum signal as a plurality f received spread-spectrum channels. Additinal bjects and advantages f the inventin are set frth in part in the descriptin which fllws, and in part are bvius frm the descriptin, r may be learned by practice f the inventin. The bjects and advantages f the inventin als may be realized and attained by means f the instrumentalities and cmbinatins particularly pinted ut in the appended claims. BRIEF DESCRIPTIN F THE DRAWINGS The accmpanying drawings, which are incrprated in and cnstitute a part f the specificatin, illustrate preferred

7 embdiments f the inventin, and tgether with the descriptin serve t explain the principles f the inventin. FIG. 1 illustrates a prir art packet r frame f a spreadspectrum signal; FIG. 2 shws a spread-spectrum signal emplying multiple parallel spread-spectrum channels, having a header fr timing n nly the first spread-spectrum channel; FIG. 3 is a blck diagram f a multichannel spreadspectrum transmitter; and FIG. 4 is a blck diagram f a multichannel spreadspectrum receiver. DETAILED DESCRIPTIN F THE PREFERRED EMBDIMENTS 15 Reference nw is made in detail t the present preferred embdiments f the inventin, examples f which are illustrated in the accmpanying drawings, wherein like reference numerals indicate like elements thrughut the several views. 20 The present inventin prvides a nvel multichannel spread-spectrum system and methd fr cmmunicating n a plurality f data channels using parallel spread-spectrum channels. With the present inventin, increased efeciency is btained by including header infrmatin in fewer than all the channels. Effectively, instead f replicating the frame frmat shwn in FIG. 1 fr each spread-spectrum channel, nly ne frame cntains headers while the ther spreadspectrum channels sent in parallel with different chipsequence signals devte the entire time fr data, as shwn in FIG. 2. The remaining spread-spectrum channels are synchrnized t the first channel by a prcessr. Therefre, the efeciency is increased. ne r mre spread-spectrum channels, but less than the ttal number f spread-spectrum channels, culd have a header fr synchrnizatin. The use f ne spread-spectrum channel with a header, hwever, wuld be mre efecient. Fr example, a system cnstructed fr 384 kbps data rate, FEC rate % cnvlutinal cding, 25.6 kbps maintenance channel fr pwer cntrl, CRC, etc., and prcessing gain f 192, utilizes 16 parallel chipsequence signals and yields a 96.9% efeciency. The multichannel spread-spectrum system might be used as part f a radi-based Ethernet system, r an ATM system, r any ther netwrked system. The multichannel spreadspectrum system culd be used fr cnnectin as well as cnnectinless applicatins. The multichannel spreadspectrum system includes a multichannel spread-spectrum transmitter, and may als include a multichannel spreadspectrum receiver. The present inventin is fr a multichannel spreadspectrum link which, in a preferred embdiment, is frm a user t the base statin. The present inventin is illustrated, by way f example, with a multichannel spread-spectrum transmitter transmitting the multichannel spread-spectrum 55 signal t a multichannel spread-spectrum receiver. The multichannel spread-spectrum signal, in a preferred embdiment, includes a header, in a first data-sequence channel, fllwed in time by the first data-sequence signal. The header is cncatenated with the first data-sequence g signal t generate a header frame. As used herein, a "header frame" is defined t be a header fllwed by data and may include multiple headers interspersed with fields f data. The header is generated frm spread-spectrum prcessing, by using techniques well knwn in the art, a 65 header-symbl-sequence signal with a chip-sequence signal. The header-symbl-sequence signal is a predefined sequence f symbls. The header-symbl-sequence signal may be a cnstant value, i.e., just a series f 1-bits r symbls, r a series f 0-bits r symbls, r alternating 1-bits and 0-bits r alternating symbls, a pseudrandm symbl sequence, r ther predefined sequence as desired. The chip-sequence signal is user-defined and, in a usual practice, is used with a header-symbl-sequence signal. The header, in a preferred embdiment, includes a chip-sequence signal used fr the purpse f synchrnizatin. Each spread-spectrum channel f the multichannelspread-spectrum signal is generated similarly, frm techniques well knwn in the art as used fr the header, by spread-spectrum prcessing a data-sequence signal with a respective chip-sequence signal. The first chip-sequence signal is generated frm a first cde (cde 1). A secnd spread-spectrum channel is defined by a secnd chipsequence signal, which is generated frm a secnd cde (cde 2). Similarly, a third spread-spectrum channel is defined by a third chip-sequence signal, which is generated frm a third cde (cde 3). The data-sequence signal may be derived frm data, r an analg signal cnverted t data, signaling infrmatin, r ther surce f data symbls r bits. The chip-sequence signal can be user defined, and preferably is rthgnal t ther chip-sequence signals used fr generating the plurality f spread-spectrum channels. Demultiplexing data, spreadspectrum mdulating each demultiplexed channel as a spread-spectrum signal and frming a multichannel spreadspectrum signal, keeps prcessing gain (PG) cnstant, independent f data rate. Fr a high data rate, fr example, the multichannel spread-spectrum signal may include 128 channels. Sixty-fur channels may be n an in-phase cmpnent and sixty-fur channels may be n a quadrature-phase cmpnent. The present inventin bradly cmprises a multichannel spread-spectrum system fr cmmunicating data between a plurality f multichannel spread-spectrum transmitters and a plurality f multichannel spread-spectrum receivers, preferably using radi waves. The terms "multichannel spreadspectrum transmitter" and "multichannel spread-spectrum receiver", as used herein, dente the verall system cmpnents fr transmitting and receiving, respectively, data. Each multichannel spread-spectrum transmitter includes header means, prcessr means, transmitter spreadspectrum means, cmbiner means, and transmitter-carrier means. The header means is cupled t the prcessr means. The transmitter-spread-spectrum means is cupled t the header means and t a plurality f data channels. The cmbiner means is cupled between the transmitter-spreadspectrum means and the transmitter-carrier means. The header means is cupled t a first channel f the plurality f data channels. The header means cncatenates a header fr chip-sequence synchrnizatin t the first datasequence signal f the plurality f data sequence signals t generate a header frame. The header is fr chip-sequence synchrnizatin. The prcessr means is cupled t the header means and t each f remaining channels f the plurality f data channels. Respnsive t the header, the prcessr means generates cntrl and timing signals t synchrnize the plurality f data channels t the header. The transmitter-spread-spectrum means spread-spectrum prcesses each f the data-sequence signals, as well as the header frame, with a respective chip-sequence signal. The utput f the transmitter-spread-spectrum means is a plurality f spread-spectrum channels, with each spread-spectrum

8 channel crrespnding t ne f the data inputs. The plurality f spread-spectrum channels includes a spreadspectrum-header channel and a plurality f spreadspectmm-data channels. The spread-spectrum channel is generated by prcessing the header frame with a first chip- 5 sequence signal. Each f the plurality f spread-spectrumdata channels is generated by prcessing a respective datasequence signal by a respective chip-sequence signal. The cmbiner means algebraically cmbines the plurality f spread-spectrum channels as a multichannel-spread- 1 spectrum signal. At the utput f the cmbiner means is the multichannel spread-spectrum signal. The transmittercarrier means transmits, at a carrier frequency, the multichannel spread-spectrum signal, using radi waves, ver a cmmunicatins channel. 15 Each f the multichannel spread-spectrum receivers includes translating means, header-detectin means, prcessr means, and receiver-spread-spectrum means. The translating means is cupled t the cmmunicatins channel. The header-detectin means is cupled between the translating 20 means and the prcessr means. The receiver-spreadspectmm means is cupled t the translating means. At the utput f the receiver-spread-spectrum means are the received data. 25 The translating means translates the received multichannel spread-spectrum signal frm the carrier frequency t a prcessing frequency. The prcessing frequency may be a radi frequency (RF), an intermediate frequency (IF), a baseband frequency, r ther desirable frequency fr prcessing data. The header-detectin means detects, at the prcessing frequency, the header embedded in the spread-spectrumheader channel f the multichannel spread-spectrum signal. The header-detectin means utputs, in respnse t detect-, ing the header, a header-detectin signal. The receiver-prcessr means generates cntrl and timing signals frm the detected header. These signals are used fr cntrlling sequences and timing f the inventin. The receiver-spread-spectrum means despreads the mul- 40 tichannel spread-spectrum signal f the multichannel spread-spectrum signal, as a plurality f data signals. The transmitter-spread-spectrum means, as illustratively shwn in FIG. 3, is embdied as a chip-sequence means and a plurality f prduct devices The chip-sequence 45 means may be embdied as a chip-sequence generatr 39 fr generating a plurality f chip-sequence signals. Alternatively, the transmitter-spread-spectrum means may be embdied as a plurality f EXCLUSIVE-R gates, r equivalent lgic devices r circuitry, cupled between the 50 plurality f data inputs and a memry device fr string the plurality f chip-sequence signals. In this embdiment, the memry device utputs a respective chip-sequence signal t the respective data-sequence signal. A third alternative may include having the transmitter-spread-spectrum means 55 embdied as a memry device, with apprpriate detectin circuitry s that, in respnse t a particular data symbl r data bit at the utput f a particular utput the demultiplexer, a chip-sequence signal is substituted fr that data symbl r data bit. The transmitter-spread-spectrum means may als be s embdied as any ther technlgy knwn in the art capable f utputting a plurality f chip-sequence signals. The cmbining means is embdied as a cmbiner 45. The header means is embdied as a header device 46 fr cncatenating a header with data in the first data channel. The 65 prcessr means is embdied as a prcessr 27. The transmitter-carrier means is embdied as a transmittercarrier subsystem 50. The transmitter-carrier subsystem 50 may include an scillatr 49 and multiplier device 48 fr shifting a signal t a carrier frequency, a filter 58 fr filtering the shifted signal, and a pwer amplifier 59 andr ther circuitry as is well knwn in the art fr transmitting a signal ver a cmmunicatins channel. The signal is transmitted using an antenna 60. As shwn in FIG. 3, the header device 46 is cupled between the first data channel and the first prduct device 51. The chip-sequence generatr 39 is cupled t the plurality f prduct devices and t the prcessr 27. The cmbiner 45 is cupled between the plurality f prduct devices and the transmitter-carrier subsystem 50. The header device 46 cncatenates the header with data using a first data channel f a plurality f data channels. The header device 46 is necessary fr timing f data frm different data channels. Frm timing the data frm the header in a single channel, data in all channels are timed. A plurality f synchrnizatin devices, which may be embdied as buffer memries 32-38, receive timing and cntrl signals frm the prcessr 27 t synchrnize the plurality f data channels t the header n the first data channel. The chip-sequence generatr 39 generates a plurality f chip-sequence signals. Each f the chip-sequence signals f the plurality f chip-sequence signals has lw crrelatin with the ther chip-sequence signals in the plurality f chip-sequence signals, and is preferably rthgnal t the ther chip-sequence signals in the plurality f chip-sequence signals. The chip-sequence generatr 39 equivalently may be embdied as a plurality f chip-sequence generatrs. The plurality f prduct devices 51-58, fr example, may be embdied as a plurality f EXCLUSIVE-R gates cupled between the incming data channels and the chipsequence generatr 39. Each EXCLUSIVE-R gate multiplies a respective data-sequence signal by a respective chip-sequence signal frm the chip-sequence generatr 39. The plurality f prduct devices multiplies each f the data-sequence signals by a respective chip-sequence signal. At the utput f the plurality f prduct devices is a plurality f spread-spectrum channels, respectively. A particular spread-spectrum channel is identified by the chip-sequence signal that was used t spread-spectrum prcess the particular data sequence signal. The plurality f spread-spectrum channels includes a spread-spectrumheader channel and a plurality f spread-spectrum-data channels. The spread-spectrum-header channel is generated by prcessing the header frame with a first chip-sequence signal. Each f the plurality f spread-spectrum-data channels is generated by prcessing a respective data-sequence signal with a respective chip-sequence signal. The plurality f spread-spectrum-data channels is synchrnized t the spread-spectrum-header channel. The cmbiner 45 algebraically cmbines the plurality f spread-spectrum channels, and utputs the cmbined signal as a multichannel-spread-spectrum signal. Preferably, the cmbiner 45 cmbines the plurality f spread-spectrum channels linearly, althugh sme nnlinear prcess may be invlved withut significant degradatin in system perfrmance. The transmitter-carrier subsystem 50 transmits, at a carrier frequency, the multichannel spread-spectrum signal using radi waves ver a cmmunicatins channel. The transmitter-carrier subsystem 50 f the multichannel spreadspectrum transmitter includes apprpriate filters, pwer amplifiers and matching circuits cupled t an antenna 60. The transmitter-carrier subsystem 50 als may include a

9 hard limiter, fr hard limiting the multichannel spreadspectrum signal befre transmitting. At the receiver, as shwn in FIG. 4, the translating means is shwn as receiver RF sectin, which may include a translating device 62 with scillatr 63 and frequency- lcked lp 70. The translating device 62 is cupled thrugh a lw nise amplifier 61 t an antenna 160 t the cmmunicatins channel and thrugh an amplifier 64 t the headermatched filter 79. The translating device 62 is cupled t the scillatr 63, and the scillatr 63 is cupled t the 1 frequency-lcked lp 70. The header-matched filter 79 is cupled t the frequency-lcked lp 70 and t a prcessr 90. The plurality f data-matched filters is cupled between the translating device 62 and a multiplexer 80. The multiplexer 80 is cupled t a receiver-fif memry The translating device 62 translates the received multichannel spread-spectrum-spread-spectrum signal frm the carrier frequency t a prcessing frequency. The translating device 62 may be a mixer, which is well knwn in the art, fr shifting an infrmatin signal, which in this disclsure is 20 the received multichannel spread-spectrum signal mdulated at a carrier frequency, t IF r baseband. The prcessing frequency may be RF, IF, baseband frequency r ther desired frequency fr a digital signal prcessr. The signal fr shifting the received multichannel spread-spectrumspread-spectrum signal is prduced by scillatr 63. The header-detectin means is embdied as a headermatched filter 79. The header-matched filter 79 detects, at the prcessing frequency, the header embedded in the spread-spectrum-header channel f the multichannel spreadspectrum signal. The term "header-matched filter" as used herein, is a matched filter fr detecting the header, by having an impulse respnse matched t the chip-sequence signal and bits f the header f the spread-spectrum-header channel f the multichannel spread-spectrum signal. The headermatched filter may be a digital-matched filter, a surfaceacustic-wave (SAW) device, sftware perating in a prcessr r embdied within an applicatin specific integrated circuit (ASIC). In respnse t detecting the header, the header-matched filter 79 utputs a header-detectin signal. The header-matched filter at a base statin can detect the header embedded in the multichannel spread-spectrum signal frm all users, since the chip-sequence signal fr the header and data is cmmn t all users. The header-detectin means alternatively may be embdied as a header-matched filter, cupled t an utput f a data-matched filter r t the utput f the multiplexer 80. This alternative is taught in U.S. Pat. N. 5,627,855, entitled PRGRAMMABLE TW-PART MATCHED FILTER FR SPREAD SPECTRUM by Davidvici, which is incrprated herein by reference. The frequency-lcked lp 70 is frequency lcked in respnse t the header-detectin signal. The frequencylcked lp 70 lcks the frequency f the scillatr 63 t the 55 carrier frequency f the received multichannel spreadspectrum signal. Circuits fr frequency lcked lps, and their peratin, are well knwn in the art. The prcessr means is embdied as a prcessr 90. The prcessr 90, in respnse t the header-detectin signal, s generates cntrl and timing signals. The cntrl and timing signals are used fr cntrlling sequences and timing f the inventin. The receiver-spread-spectrum means is embdied as a plurality f data-matched filters Each f the plurality 65 f data-matched filters has an impulse respnse matched t a chip-sequence signal f a respective ne f the plurality f chip-sequence signals. The data-matched filters may be embdied as a digital-matched filter, SAW device, sftware perating in a prcessr, r an ASIC. The plurality f data-matched filters despreads the multichannelspread-spectrum signal as a plurality f received spreadspectrum channels. Alternatively, the receiver-spread-spectrum means and the transmitter-spread-spectrum means may be embdied as the plurality f data-matched filters 71-78, thereby using the same hardware. The plurality f data-matched filters in this embdiment are time multiplexed with different cefhcients, between transmit and receive. Each chip-sequence signal in the plurality f chipsequence signals is different, preferably rthgnal t the thers, t avid r reduce interference. The plurality f chip-sequence signals, hwever, preferably is cmmn t all users. Thus, the plurality f data-matched filters can detect the plurality f chip-sequence signals frm any f the users. The present inventin als cmprises a methd. The methd includes the steps f cncatenating a header t a first data-sequence signal f a plurality f data sequence signals t generate a header frame. A used herein, a "header frame" is defined t be a header fllwed by data and may include multiple headers interspersed with fields f data. The input data are in a plurality f data-sequence signals. The plurality f data-sequence signals are synchrnized t the header respnsive t cntrl and timing signals generated by a prcessr. The methd includes generating a plurality f chip-sequence signals, and multiplying each f the data-sequence signals by a respective chip-sequence signal, thereby generating a plurality f spread-spectrum channels. The plurality f spread-spectrum channels includes a spread-spectrum-header channel and a plurality f spread-spectrum-data channels. The spread-spectrumheader channel is generated by prcessing the header frame with a first chip-sequence signal. Each f the plurality f spread-spectrum-data channels is generated by prcessing a respective data-sequence signal with a respective chipsequence signal. Each f the plurality f spread-spectrumdata channels is synchrnized t the spread-spectrum-header channel. The steps include algebraically cmbining the plurality f spread-spectrum channels as a multichannel-spreadspectrum signal, and transmitting n a carrier frequency the multichannel spread-spectrum signal ver a cmmunicatins channel using radi waves. The steps may further include, at a multichannel spreadspectrum receiver, translating the multichannel spreadspectrum signal frm the carrier frequency t a prcessing frequency, and detecting, at the prcessing frequency, the header embedded in the multichannel spread-spectrum signal. The chip-sequence signals used fr the header and the data may be cmmn t all users. In respnse t detecting the header, the methd includes utputting a headerdetectin signal and generating cntrl and timing signals. The steps als include despreading the multichannelspread-spectrum signal as a plurality f received spreadspectrum channels. In the present inventin, assume 800 kbs is first demultiplexed int K channels, where K=32 in a preferred system, althugh any K will suffice. As a result, if K=32, then the transmitted rate is ^25 kbs. Each f these K channels is spread using a different rthgnal spread-spectrum cde f length L. Thus,

10 f J 'Ci(t)Cj(t)dt-- 1 l = j 0 i*j ver the time, T L, crrespnding t the cde length L. Fr example, if the chip rate were 5 megachipss, and there were eight users, then the send rate is 6.4 Mbs 32=200 kbs s that prcessing gain is 25. Nte that the prcessing gain has increased by a factr f 32. Further, the length L f each f the K rthgnal cdes is such that L=K, since there are nly L rthgnal cdes f length L. ne-half f the chip-sequence signals may be sent n an in-phase (I) channel and ne-half n a quadrature-phase (Q) ^ channel, frming quadrature-phase-shift-keying mdulatin (QPSK) r QPAK. Binary-phase-shift-keying mdulatin (BPSK) can als be used. These are standard mdulatin prcedures well knwn in the prir art. Different sectrs and different cells shuld use different 20 rthgnal chip sequences t minimize interference between sectrs and cells. This is dne by multiplying each chip sequence signal, Q, by a chip sequence, g rf (t). Within a sectr, every user uses the same cdeset, Q and g-. Within each sectr f each cell, each user uses the same cdeset, C,-, 25 but each sectr in each cell gets a different g-. Users transmitting at different rates use a subset f the 32 cdes s that the prcessing gain remains a cnstant. If 2 Mbs were the basic data rate, then with FEC and verhead the data rate might be i d =4A Mbs. In this case t 30 achieve a prcessing gain f twenty-five (PG=25) at say f=10 Mchipss requires: 25=KfJf d x8 K=200fjf c =200x4.410=aa The use f 88 rthgnal cdes each f length 88 is certainly within the state-f-the art. It will be apparent t thse skilled in the art that varius mdificatins can be made t the high efficiency spread spectrum packet system f the instant inventin withut departing frm the scpe r spirit f the inventin, and it is intended that the present inventin cver mdificatins and variatins f the high efficiency spread spectrum packet system prvided they cme within the scpe f the appended claims and their equivalents. We claim: 1. A multichannel-spread-spectrum system fr cmmunicating a plurality f data-sequence signals frm a plurality f data channels using parallel chip-sequence signals, cmprising: a header device, cupled t a first data channel f said plurality f data channels, fr cncatenating a header t a first data-sequence signal; a prcessr fr synchrnizing a remaining plurality f data channels t the header in the first data channel; chip-sequence means fr utputting a plurality f chipsequence signals, with each chip-sequence signal s rthgnal t the ther chip-sequence signals in said plurality f chip-sequence signals; a plurality f prduct devices, cupled t said chipsequence means, fr multiplying each f said plurality f data-sequence signals by a respective chip-sequence 65 signal, thereby generating a plurality f spreadspectrum channels, respectively; w a cmbiner, cupled t the plurality f prduct devices, fr algebraically cmbining the plurality f spreadspectrum channels as a multichannel-spread-spectrum signal; a transmitter subsystem, cupled t said cmbiner, fr transmitting the multichannel-spread-spectrum signal n a carrier frequency ver a cmmunicatins channel; a translating device, cupled t the cmmunicatins channel, fr translating the received multichannelspread-spectrum signal frm the carrier frequency t a prcessing frequency; a header-matched filter, cupled t said translating device and having an impulse respnse matched t the header, fr detecting, at the prcessing frequency, the header in the multichannel-spread-spectrum signal, and fr utputting, respnsive t detecting the header, a headerdetectin signal; a receiver prcessr, cupled t said header-matched filter, respnsive t the header-detectin signal, fr generating cntrl and timing signals; and a plurality f data-matched filters, cupled t said translating device, with each data-matched filter having an impulse respnse matched t a respective chipsequence signal f the plurality f chip-sequence signals, fr despreading the received multichannelspread-spectrum signal as a plurality f received spread-spectrum channels, respectively. 2. The multichannel-spread-spectrum system as set frth in claim 1, with said chip-sequence means including a chip-sequence generatr fr generating the plurality f chipsequence signals. 3. The multichannel-spread-spectrum system as set frth in claim 1, with said chip-sequence means including a memry fr string the plurality f chip-sequence signals. 4. The multichannel-spread-spectrum system as set frth in claim 1, said plurality f prduct devices including: a first EXCLUSIVE-R gate, cupled t said chipsequence means and t said header device, fr multiplying the header and a first data-sequence signal with a first chip-sequence signal t generate a spreadspectrum-header channel; a secnd EXCLUSIVE-R gate, cupled t said chipsequence means and t a secnd data channel, fr multiplying a secnd data-sequence signal by a secnd chip-sequence signal, the secnd chip-sequence signal being different frm the first chip-sequence signal, t generate a first spread-spectrum-data channel; a third EXCLUSIVE-R gate, cupled t said chipsequence means and t a third data channel, fr multiplying a third data-sequence signal by a third chipsequence signal, the third chip-sequence signal being different frm the secnd chip-sequence signal and frm the first chip-sequence signal, t generate a secnd spread-spectrum-data channel; an nth EXCLUSIVE-R gate, cupled t said chip sequence means and t an nth data channel, fr multiplying an nth data-sequence signal by an nth chipsequence signal, the nth chip-sequence signal being different frm the third chip-sequence signal and frm the secnd chip-sequence signal and frm the first chip-sequence signal, t generate an nth-1 spreadspectrum-data channel; and the first spread-spectrum-data channel, the secnd spreadspectrum-data channel, and the nth-1 spread-spectrumdata channel synchrnized, respnsive t timing and

11 11 12 cntrl signals generated by the prcessr, t the spread-spectmm-header channel. 5. A multichannel-spread-spectrum transmitter fr cmmunicating a plurality f data-sequence signals frm a plurality f data channels using parallel chip-sequence 5 signals, cmprising: a header device, cupled t a first data channel f said plurality f data channels, fr cncatenating a header t a first data-sequence signal t generate a header frame; a prcessr, cupled t the header device and t the plurality f data channels, fr synchrnizing the plurality f data channels; spread-spectrum means, cupled t the plurality f data channels, fr spread-spectrum prcessing the plurality f data-sequence signals by a plurality f chipsequence signals, respectively, thereby generating a plurality f spread-spectrum channels, the plurality f spread-spectrum channels including a spreadspectrum-header channel generated by prcessing the header frame with a first chip-sequence signal, and a plurality f spread-spectrum-data channels; cmbiner means, cupled t said spread-spectrum means, fr algebraically cmbining the plurality f spreadspectrum channels as a multichannel-spread-spectrum 25 signal; and carrier means, cupled t said cmbiner means, fr transmitting the multichannel-spread-spectrum signal ver a cmmunicatins channel at a carrier frequency. 6. The transmitter as set frth in claim 5, said spread- 30 spectrum means including: means fr generating the plurality f chip-sequence signals; a first EXCLUSIVE-R gate, cupled t said generating means and t said header device, fr multiplying the 35 header frame with the first chip-sequence signal t generate the spread-spectrum-header channel; a secnd EXCLUSIVE-R gate, cupled t said generating means and t a secnd data channel, fr multiplying a secnd data-sequence signal by a secnd chip-sequence signal, the secnd chip-sequence signal being different frm the first chip-sequence signal, t generate a first spread-spectrum-data channel; a third EXCLUSIVE-R gate, cupled t said generating 45 means and t a third data channel, fr multiplying a third data-sequence signal by a third chip-sequence signal, the third chip-sequence signal being different frm the secnd chip-sequence signal and frm the first chip-sequence signal, t generate a secnd spreadspectrum-data channel; an nth EXCLUSIVE-R gate, cupled t said generating means and t an nth data channel, fr multiplying an nth data-sequence signal by an nth chip-sequence signal, the nth chip-sequence signal being different frm the third chip-sequence signal and frm the secnd chip-sequence signal and frm the first chipsequence signal, t generate an nth-1 spread-spectrumdata channel; and the first spread-spectrum-data channel, the secnd spreadspectrum-data channel, and the nth-1 spread-spectrumdata channel synchrnized, respnsive t timing and cntrl signals generated by the prcessr, t the spread-spectrum-header channel. 7. A multichannel-spread-spectrum transmitter fr cmmunicating a plurality f data-sequence signals frm a plurality f data channels using parallel chip-sequence signals, cmprising: a header device, cupled t a first data channel f said plurality f data channels, fr cncatenating a header t a first data-sequence signal t generate a header frame; a prcessr, cupled t the header device and t the plurality f data channels, fr synchrnizing the plurality f data channels; a chip-sequence generatr fr generating a plurality f chip-sequence signals, each f said plurality f chipsequence signals being rthgnal t ther chipsequence signals within the plurality f chip-sequence signals; a plurality f prduct devices, cupled t the plurality f data channels and t said chip-sequence generatr, fr multiplying the plurality f data-sequence signals by a plurality f chip-sequence signals, respectively, thereby generating a plurality f spread-spectrum channels, the plurality f spread-spectrum channels including a spread-spectrum-header channel and a plurality f spread-spectrum-data channels, the spread-spectrumheader channel generated by multiplying the header frame with a first chip-sequence signal, each f the plurality f spread-spectrum-data channels generated by multiplying a respective data-sequence signal by a respective chip-sequence signal; a cmbiner, cupled t said plurality f prduct devices, fr algebraically cmbining the plurality f spreadspectrum channels as a multichannel-spread-spectrum signal; and a transmitter subsystem, cupled t said cmbiner, fr transmitting the multichannel-spread-spectrum signal ver a cmmunicatins channel at a carrier frequency.