High data rate cdma wireless communicati0n system

I- Field of the Invention method and .he present invention relates P“¹^׳ apparatus for high dam rate CDMA w־rdess communication

Π.Description of the Related Art

Wireless communication systems including cellular point to point communication systems use a wireless 1' v modulated radio frequency _signal _{10 f}^oi systems. The use of a wireless link is desirablp fn including increased mobility and reduced infrastr״^ °^f« to Wire line ־־mmutdcatn s^ wireless link is the limited amount nt ' ^™back of using a to limited מתס־«^. * ^aStal&‘^{s additionaI} line

Recognizing the limited nature of RP i״._j processing techniques have been developed for . with which wireless comm!™. « increasing the efficiency bandwidth. ™X~r°ⁿ ” ^{Uffi2e 4}־™ ־ K signal processing technique sftelsXvVth derivatives such as IS-95-A frefe j ^{mt־riace 5}*andard and is ^sucn “ ^⁹⁵־^A ireierred to hereafter collectively as A־ n-־ ״0»~» ^־* indus^aXeZtio״ tmi ^{M witWn ceUuI}״־™* ״XX s standard incorporates code division _{muIti le} access fCDM״ ^&modulation tedmiques to conduct muldple Γ ־־mulsneouriy over the same RF bandwidth. Un ZbX comprehensive power control, conducting multiple comm the samp . ^δ multiple communications over the same bandwrdth !״creases the total number of calls and other satellite and a transmit data between two communications that can be conducted in a wireless com_m, among other things, increasing the frequence ^{Π S}^^stern other wireless telecommunication tecWlogiZ ‘° techniques in a multiDie arrAcc

Patent No. 4,901^7 »tiL .⁰״“״

SYSTEM _USTC SATELLITE 0TZeSJ

Patent No. 5,103,459, entitled ־SYSTEM AND METHOD FOR GENCT^ signal waveforms in λ . “^lrtODF0R generating both of ״ΠκΧ ™^0NE¹ incorporated by reference herein. ° ** ^mvention

Fig. 1 provides a highly simplified mustration of a cell״!״ u system configured in accordance with the use of the IW5X״_d 7 operation, a set of subscriber units in, . a . j ’^{5 tocard}. ^Γ ™8 by establishing one or more RF interfaces wi* ״^{ffeieSS comm!jni}cati°n

- d using CDMA modulated RF signals Each RF ^StaSons “* station 12 and a subscriber unit ^{a base} transmitted fr״_m the base station from the subscriber unit Using these RF interf־ transmitted another user is generally r״״H u ' * ®““™cation with office (MTSO) 14 J ״ * °^f ”⁰“k ^teleP^hone ^‘־htag omce (MISO) !4 and public switch telephone network ,(PSTN) 16 Th־ Tv between base stadons 12, MTSO 14 and PSTN 16 are us^X hne connections, although (he use of additional RF ort 7 ״“* also known. ^{Or rrucT0v/av}e links is

In accordance with the 15-95 c+a«,^ j , transmits user data ™ . . 1 ־. *“* ^subsaiber unit 10 ־״־־®its user data ™ a smgle channel, noncoherent, reverse link *״.! . a maximum data rate of 9.6 or 14 4 kbit״־/־ a 1 “* ’* from a set of rate see is sele^ a Γ ^{? g rate}information is not utilized by the rXM ZT *“* “ ^One “ ^whil:h phase ® which ffie receiver ־χρΧΪΧ1ΖΧ. T ’־ processing. lh_e phase infonnation typL., X _ft “_f *״^ but can also be estimated ft⁷““ צ’. ,» ,״״ *^{e form of}» P^d°t signal, for a set of XTw־Ist2“ ״sed for the foiX !T ־«־“־ ׳ * *

The use of a single channel, noncoherent, reverse link κ . «num data rete of 9.6 of !4.4 li.ri/sec as specified by Ϊ□ or a wire ess cellular telephone system in which the tvoical communication involves the transmission of digifced voice or low^e digital data such a facsimile a ״״ח u because, in a system in which up to 80 siXX with a base station 12 for each 1.2288 MH k ¹θ ^W the necessary pilot data in the transmission frotT^^T^' ^Pr°^Vid”^gwould substantially increase Λα η ^{each subscriber} unit 10 interfere with ״־Tan”

-Ho of foe transmit power of any _ΡΪ XZ * £ ״ “t **'™י^th־significant, and therefore also increase inter-subscribX “ ״״“ ** The use of a single channel reverse link signal was chosXte ^m °niy ^one type of communication at a Ϊ c—XTb^^⁸״“^w? ™ transmissfoXXZSr T vid־־ teleconferX / ״ *“θ“ wih transform foe 4 fo whicXXZ— ®d the conditions under which the associated RF w7 hi particular, data will be transmitted at h 1, ^mterfaces “« conducted, greater variety of possible _rates. XX*.¹״^a become ־»״ssaty as errors in the ttansmission of data al ΧΖΓ ₍Γ enors m the transmission of audio information Addition^. * number of data types win rr^ _{a t} ' ^dlbonalIy׳ the increased simultaneously. examXt J° ^of while maintaX anTX J ^{a data} hnnsuussion from a subscriber unit increases the ״' X “ ** °^f10 communicating with a ba«, ־e.״. umber of subscriber units wim a base station 12 per amount af PP k₃ <4 . j decrease, as the higher data transmission tat־־ will _aUse Z dZ ־־P־dty of th־ base station to be reached with fewer subX some instances, the current IS-<?5 ™ 1 ז bscnber units 10. In an these changes. Therefore the ^{id<־aUy SUited for} higher data ate, bandwidth ־ίβαωΓαΧ7”ί ” '° ^pr°^{Viding a} of communication can

SUMMARY OF THE INVENTION ־_f *he mvenfi״־, a set _of fanned via the use of a set of orthogonal subkannel co!t of PN spreading chips per orthogonal wavefor^X™“ ^{w code rafe} ״f the subchannel codes, gain adjusted, using the other subchannel codes. The rest It™ * ^m°dulated using a user long code and a pseudoran om s! H’ 'tX “ ^m0duIatedconverted for transmission. The use ofTsh״^:ode t^PN code) and provides interference suppression while «n 11 ^o״h05^0I'^aI codes correction coding and repetition for H λ ‘ ^Owin5 extensive error feding commonly experienced in !β־!ΓΧ'1 °^VeKOm־ *' ^Ralei?^h־x^plary embodiment of the inv״־_hon p«vi^Z ** codes are comprised of four Walsh codes each orth/ , ί set and four chips in duration. IheZX!7 7 ' ־־“* it allows shorter orthogonal codes to be used, however X ״ number of channeis and therefore longer codes is eη Γ ’ **“ invention. ⁵ consistent with the

In a preferred exemplary. embodiment ni a. ״ ־~d via a first trans! ~* ׳ ״™״*itted via a second transmit dtanneL XrXl channels are used for fra n cm־,»־ emainmg two transmit dam or sfgr^i ** including user two nonJpX XX , ^mWraM׳ ^one °^f

H urea transmit channels is configured for BPS1C ™״x 1 ״ ־* other for QPSK modulatiom This is donTto ill־״.! _A 7 the system. Both channels could be BPSK modulated or QPSK mX! alternative embodiments of the invention R״f״ ^PSK modulated in specified data is encoded where that en M7 . ׳ ^{U ation}' ⁸״ ״on־heck (CRC) genera.,־ ,«־οηνοΜοηΓ^ΧΐΖ ^־nce repeating and BPSK or QPSK mapping. ByvaXX repeating performed, and not Acting X amountTLXT mteger number of symbol sequences, a wide varietv of ״ ^gfdgh data rates can be achieved.

can also be achieved by transmitting data simultaneously over both no״ specified transmit channels. Also, by frequently updating the gain adjust performed on each transmit channel, the total transmit power 1L fay the generated betw~ ^? ? minimum such that the interference g rated between multiple transmit systems is minimized, thereby increasing the overall system capacity.

BRIEF DESCRIPTION OF THE DRAWINGS ***“*׳ Λ־ present invention win b«ome more apparent fr _>m the detailed desaipdon set forth be!־w w^ aken m conjunehon «th the drawings in which like reference characters identify correspondingly throughout and wherein:

Fig. 1 is a block diagram of cellular telephone system;

Fig-2 is a block diagram of a subscriber unit «id base station “zש»״.״ - ׳. <״־״. ״ ¹*־

-Z ״zs: izxz¹ rr^s ־.״ Fi» ש κι e □. exemplary embodiment of the invention;

g- a block diagram of a receive processing system configured in accordance with the exemplary embodiment of the invention;

Fig. 6 is a block diagram of a finger processing system configured in accordance with one embodiment of the invention; and

Fig. ד is a block diagram of a BPSK channel decoder and a OPSK ״“ X* ^ώ - —y — ם

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A novel and improved method and apparatus for high rate CDMA Z communication is debated in the context of fit־ reveraiS mission portion of a cellular telecommunications system. While the invention is particularly adapted for use within λ ו .

reverse !ink transmission _of a _rgn״_hr ״ . ' ^multlP°־־<״tc-pomt mvendo״ is equafiyapphcable to forward link^an^X XiT many other wireless communication systems will benefitT' of the invention, including satellite b_awi . ו ^{fi by mco1}P^oration _Ρ־ί־־ ״ point wireless ΧΧΧΧ “׳ «x שבט embodiment of the invention. A first set of data (BPSK Γ JT” BPSK channel ״־coder 103, which general TX configured for performing BPSK modulation that is received^ ״ dT” 104. A second set of data fOPsr received by modulator ״״Ch geX םXl™ 7T “ modulation that is also X *״ ^P“^{g QKK}_ro- received by modulator 104. Modulator 104 ak״ ״ .ShX“ 7<. -—״ ״ “־ * ״״ '״ ־*״ “־״ *הר 7״ ם, :ב־®?™ ב. Π RF processing system 106. Rp -״J* ⁵’⁰¹⁵’'י^TOiWupconverts the set of modulation symbols 7 aXL/taX Τ’ transmission to the base station חלד - ^Γ ^^uency for

־.bscnberunitlXXmuJfi^X^ °^M base station 120 in the preyed

-es the שטבטבם with CDMA techniques to prod ^{d־modulation m} accordance decision data ΒΡ5ΓΧΤ7 ^{QKK xlt}^Drsf- channel decoder 128 decodes the rpcv ״a a .

data received fiom demodulator 124 to yield . U־t * ^dKlsIon j_, י rvrvT, yield a best estimate of the rprv data, and QPSK channel decoder 126 decodes the OPSK «J / received by demodulator 124 tn u ^deas1on ^^ata y uemoauiator 124 to produce a best estimate of the npqz r

The best estimate of firm and second set of data 1־ then ava^l־ xxxx- - ם Power of the forward _link ^0 X Xub^

QPSK *¹'¹⁰³“¹״““ ׳^and ־x^plaxy embodiment _{of fte} ־

103 the BPSK data , _rsceived “ “^C°^d־r generates a check sum for each 20 m A ־T ”^״״ ״^<* ftame of data along wi* the CRC ch k °^{f 54־ of} <^. The 132wfd־haPP״־jxxx^Afz״r^ved *ד ^b״~ frame to provide a known X 4 X Γ X“ °' frame including the code tail bits a״_d ajr Αί ^Ths convolutional encoder 134 which performs ^־& * ™ל ^recaved1/4 convolutional ״־codinglXX T ^W ’׳ “θ^(R)toes the ״־coder inpTAZ '״ invention, other ״־X °^f use of rate 1/4 is AXT _t^{Ρ mcMn}* ^rate .״» ‘he characteristics. Block interleaver A 'VX «׳“PWp«formance symbols to provide rime ΧΓΧΓΧΓΧΙ“ fading envirorunents. The resuAg XXX״“ variable starting point repeater 138 wHch XX Γ “X * sequence a sufficient number of times N h, X * ^mterleaTed symbol stream, which corresponds to outpulX X * ““ of the data to overcome fadin״ τ~ λ , maeases the time diversity number of symbols is equalt 6, AΧΑΧ* ““‘י‘ symbol rate 3072 Idlosymbol־ per' seZfksus) Z *״ different starting pom A nA _Λ “8 uses a

When the value trfA to’ ^Κρβ*^{10״η 5}^¹ sequence, an integer, the final repeZZmAZZA“ ״* sequence. The rosul^ 0ΑΧ“ ** mapper 139 which generates a BPSK code ° ’'”^,י'“’ *V ^BPSK

-.,., p״ ״!™״Ξ,“־- *

». ™s» ,_w, ״ , _{ρΜ Μ ΛΜ1־}^ “_K° ״'

AZ* Τ’“^{number of symb01s for} itrun yPSK channel encoder 102 the OP<nr ׳ check sum generator 140 which venerates a chX _f “ The frame including the CKcAeck sum is “ TZ ³ °^f ”י־ °^f tZLdA the frame. The frame, now including the code tail bits and CRC checksum is received by convolutional encoder 144 _{which rf} »ץ« encoding thereby generating symbols at a rate four'll encoder input rate (Er). Block interleaver 146 nerfom,־ to . * ל ״־d the resulting interleaved sy־X^“^ point repeater 148. Variable starting point repeater 148 Xeats the m erleaved symbol sequence a suffident number of times N_R using ddferent starimg point withfo symbol « J *

SXoT^{88 55}™⁶“¹³/־* “⁶ ל ™de symbol rate 6144 woaymbols per second (ksps). When N_R is not an integer, the final repetition is performed for _only a _fte £ res g repeated symbols are received by QPSK mapper W which ~ a QPSK code symbol stream configured for perforating valuXXUT °^f T ^{־ymb01 Stre־m} °^f *1־ ב vXS^ Muadrafore-phase QPSK code symbol steam of ₊1 and 148 ו TS' “ ^{tiVe CTb0dment} <* *־ invention repeater , ^B placed before block interleaver 146 so that block mterieavTi« receives the same number of symbols for each frame.

Fig. 4 is a block diagram of modulator 104 of Hg. 2 configured in ^“׳¹™ ^7נ13קodiment of the invention. The BPSK ^־nbols from BPSK channel encoder 103 are each modulated by Wifch Se w₂ using a multiplier 150b, and the QPSK! »d QPSKq symbol from QPSK . encoder 12־ are each modulated with Walsh code W₃ usij wS“ “^d ־ ד?^e “^ntro1 * ־״< i 1ρΧΓΧ?.Τ ^{P 101־ Gain riiu}“¹⁵² ״“*“ P^a°t oS'Jt ^P “*«*״ »״־״f th־ invention is comprised acco d' .³⁵⁵⁰⁰³^ ^m*P<>־idve voltage, and adjusts the amplitude bmlt® “^OT^P™«d־־no userdata ^ rather provides phase and amplitude information to *e base station so it can coherently demodulate the data carried on the remaining sutc channels, and scale the soft-decision output values for combi״ * .

X¹*״*' ^WlitUde °^{f Ae W־hh} ״^{de W1} ״odulaJ poX frol data aceordmg to gain adjust factor A!, and gain adjust 156 adjusts the amplitude of the Walsh code W2 modulated BPSK channel data 7“ ^{Varabfe A}־. G־* adjusts 158a and b adjust the OKK ^־ h 1 ^m’^{P aSe} ־־de W3 modulated

QPSK symbols respectively according to gain adjust factor The four

HM.» » _tv__s״n

<td> Walsh Code</td><td rowspan="2"> Modulation Symbols + + + +</td>

<td> Wo</td>

<td> W,</td><td> - + ־ +</td>

<td> w₂</td><td> + +--</td>

<td> I W3</td><td> + ־- +</td>

Table L

It will be apparent to one skilled in th־ art that the W _rod. effectively no modulation at all, which is consistent with . ’ modulated with the appropriate Walsh cr*^ t-k ³ 1־ and BPSK data are J י - * ' *θ ^pU0t' P°^{wer controI} data, are transnutted m accordance with rpcv- ־

QPSK data CQPSKr and OPdv > . 7 techniques, and the .,. v , ^Q “ ^accord®« ־״* QPSK techniques as described below. It should also be understood tw . .

altemative embodiment of the invention. ״ “

The use of short orthogonal codes generates and therefore allows for more extensive codinz and ^ 'י compared to systems nm™ .- , S d repetition when ™ ™~_SX“‘— ״״ ״״ *,.״ 7_־ י*־ שט מםלש ״4 .״».׳

~. The use of other numbers of codes and codeΪΓ*““” with the present invention, however the use of al ^consister1t modulation symbols 161. _PN spreading _{code־ pNj PNq}multiphcahon with long code 180 using multipliers 162־ ־nd b. The resulting pseudorandom code provided by multipliers 162־ ־nd 162b ־re used to modulate the summed modulation symbols 161, ־nd gain adjusted quadrature-phase symbols QPSKq 163, via complex multipuX^ multipliers IMa-d and summers 166a and b. The resulting in-phase term » and quadrature-phase term Xq _are then filtered (filtering not shown), and unconverted to the carrier frequency within RF processing system 106 ־ own in a highly simplified form using multipliers 168 and an in-phase and a quadrature-phase sinusoid. An offset QFSK upconversion could also be used in an alternative embodiment of the invention. The resulting inphase and quadrature-phase upconverted signals are summed using summer 170 and amplified by master amplifier 172 according to master gain adjust Am to generate signal s(t) which is transmitted to base station 120 In n°^{f ±e} “ⁿ״״ ־>

to a 1.2288 MHz bandwidth to remain compatible with the bandwidth of existing CDMA channels. ^m ot

By providing multiple orthogonal channels over which data mav be transmitt«!, as well as by using variable rate repeaters that reduce the amount of repeating N_K performed in response to high input data rates, the above dexmbed method and system of tansmit signal processing ־Hows a suigle subscriber unit or other transmit system to transmit data at a variety o ata rates. In particular, by decreasing the rate of repetition Nr perform«! by vanable starting point repeaters 138 or 148 of HG. 3, an increasingly “דל r^{ut rate Er} enfo״hm־nt of foe invention rate 1/2 convolution «coding is performed with the rate of repetition Nr increased by two. A set of exemplary encoder rates Er supported by various rates of repetition Nr ־nd encoding rate R equal to 1/4 ־nd 1/2 for foe BPSK charm־ !־nd the QFSK _chaImej _־hownm Tables H and HI respectively.

<td> Label</td><td>^ER,8PSK (bps)</td><td> Encoder Out R=1/4 (bits/frame)</td><td>ⁿR.R=1/4 (Repetition Rate. R=1/4)</td><td> Encoder Out R=1/2</td><td>ⁿR.R=1/2 (Repetition Rate, R=1/2)</td>

<td> r1!־gn High</td><td> 76.800 70.400</td><td> 6,144 5,632</td><td> _1_______________ 1 1/11</td><td> 3.072</td><td> 2</td>

<td></td><td> 51,200</td><td> 4,096</td><td> 1 1/2</td><td rowspan="2"> 2,816 2,048</td><td> 2 2/11 I</td>

<td rowspan="2"> High</td><td rowspan="2"> , 38,400 25,600</td><td rowspan="2"> 3,072 2,048</td><td> l/fc</td><td> 3</td>

<td> 2 3</td><td> 1,536</td><td> 4</td>

<td> RS2-FuH Rate RSl-Fuil Rate</td><td> 14.400</td><td> 1,152 768</td><td> 5 1/3 _ 8</td><td> 1,024 576</td><td> 6__ 10 2/3</td>

<td> NULL__</td><td> 850</td><td> _____68</td><td> 90 6/17</td><td> 004 0 4</td><td rowspan="2"> 16_______ 180 12/17</td>

<td colspan="4"></td><td></td>

Table IL BPSK Channel

Label ^ER,QPSK (bps)

Encoder Out J N^ R=l/4 l,R=l/4

<img file="IL152113A_D0001.tif" />

153,600 ^,brt&amp;frame'

High Rate-72

High

76,800

70,400

51,200

6,144

5.632 £096

High

38,400

25,600

3,072

2,048

12,288 (Repetition

Rate, Rsl/41

<img file="IL152113A_D0002.tif" />

Encoder

Out R=1/2 (bits/frame) ^NR,R1/2־ (Repetition

Rate, R=1Z2]

6.144

3,072

<img file="IL152113A_D0003.tif" />

<img file="IL152113A_D0004.tif" />

2£15

2.048

1.536

RS2-Full

RS1-Full Rate

14,400

1.024

NULL

9,600

<img file="IL152113A_D0005.tif" />

U52

Table IU.QPSK Channel data rat־־, aa th־ “_{g Wgh} nte ״״־us a constant *^־* ׳^data

-ת-! any other overh״dtransmission of CRC, code tail bits OPSK mori 1 h ormation. As also shown by tables II and דע

QPSK modulation may also be used to increase the dataLnsmission

72ΖΤ^ ρ ״^{e Ρ}™^{lab6!s 5}“* ־־ W Rate72 and High Rate-32. Those rates noted as High Rate-72 “7 “^d High Rate-32 have traffic rates of 71, 64 and 32 kbps ' 7 multiplexed in signaling and other control data with rates 073757^/72 RS^fTp ^y'^m *^{e SXemp1}^״» ־Wiment of the invention' Rates RSl-FuU Rate and RS2-MI Rate correspond to rates used in IMS compliaZ communication systems, and therefore are also exacted tn ^? ^־tantial ך for purposes of compatibility. phe _nuUfr^onof a single bit and is used to indicate a frame erasure, wZ t also part of the IS-95 standard.

Pre date transmission rate may also be increased by simultaneously transmitting^ date over two or more of the multiple orthogonal charm/ performed either in addition to, or instead of, increasing ths t» . rate via reduction of the repetition rate N_K For example ו« ^m,SSIOncouid split a single date source הב °T ^mU“^P‘^־ -h-“ Pt־״, the total transmit rate an be increased via either transmission over a particular channel at higher rates, or multiple transmission performed simultaneously over mutole _dJbo* until thesignal_pro־esi״g ט exceeded and the error rate become unaccepteble, or the maxtaZ *״־־״״t power Of the of the tarsmit system power is reached.

Providmg multiple channels also enhances flexibility _the ־> different types of data. For exampie, the BPSK channel may e designated for voice mformation and the QPSK channel designated for fransmissron of digital data. This _could dating 0־״ channel for transmission of time ״־־sitZ“ ZL 7 ^rale׳ ^{md desi}^ the Other chaz״^ ansmissmn of less time sensitive data such as digital fl־־ fo _Λה; “ב embodrnient of the invention, the BPSK channel perfZ tte admission of date, and the QPSK channel performs overfly sTZT _d “* °^{f 0rth}°^{SOnaI Wakh} or ^bstantialiy reduces any interference among the set of charnels transmitted from a subscriber unit, and thus minimizes *e transmit energy n־ZZ for their successful reception at the base station.

To increase the processing capability at th^ _ra .

the subscriber unit may be utilized pilot data^ 1° the orthogonal channels. Using the pilot data™ ““ performed at the receive systel bX' 7' ** ־־»־tof^reverselmhsZr^T / “״ ^pha־e ^־ntldpath signals received combined m a rake receiver. Once the phase offset is remnv Λ j J proper processing. This decrease in the recwX _r ereatPr . required receive power allows greater transmissions rates to be processed 011^0004 ״ “rr ה^a - d⁰^״::

some additional transmit power is necessary for the - - . ¹ * ״v* -. ״ .״,ζ, ״״, S.tx.7 :־ ״. ““ I»1 ,— - ״־.» than that associated with lower data r־»to ., y er cellular systems Thus within u. c &amp; voice data transmission ' Thus, wtthm a hrgh data rate CDMA system the a/N״ gains achieved by th־ use _{of a} coherent _revese S’

P°^wer necessary to transmit pilot data from each subscriber unit

The use of gain adjusts 1S2 - _{158 ω weJ1 ע} rurther inaeases the decree tn whic.k λ 1 _ו/z types, b particular, the transmit power of a channel that is _fnrproper reception may change over time, and with changing cond^Tm l ך»־ transuut power of the pilot channel would substantially decrease ג״ פהג/ה ם™ ־.״;־:

tolerable of error is being transmitted via the forward link or ihe environment m which the forward link transmission is taking place ' prone to fade conditio־״, the gain adjust _{factor A] My be} need to transmit power control data with a low error rate decreases. In one em 0 unent o e invention, whenever power control adjustment is not necessary the gain adjust factor A! is reduced to aero

In another embodiment of the invention, the ability to gain adjust ״ עעב ^{or enfe revera}«pS ^ז° ¹²⁰ ר ה צ^other^{־מ to} 8J a channel, or of the entire reverse link signal, via the use of power control commands transmitted via the forward link signal. In particular J־ base station may transmit power control information _Λβ׳ *ansmit power of a particular channel or the ״־tire reverse link sigL be rf'Zl b “advantageous in many instances including when tw^es digital data, are being transmitted via the BPSK and QPSK channels. In this ®e, the base station 120 would establish different target error rates for the עע , “'⁰עם^{E artua1 etror rate a} ״ target error rate, the base station would instmct the subscriber unit to reduce the gam adjust of that channel until the actual error rate reached the taj er״r ־ate. This would eventually lead to the gain adjust factor of one ־hannd bemg increased relative to the other. That is, the gain adjust factor ^oraated with the more error sensitive data would be increased relative to the gain adjust factor associated with the less sensitive data In other “׳ the transmit power of the entire reverse link may re^ adjustment due to fade conditions or movement of the subsafoer unit^OO In these instances, the base station 120 can do 0־ via transmission of a single power control command. ⁸

Thus by allowing the gain of the four orthogonal channels to be at^ted independently, as well as in conjunction 4 one another t^e neceXfo‘ L°^We1 ™ ** ^a&lt;״״״!״« ^־ ־»־sary for successful transmission of each dafa type, whether it is pilot data power control data, scaling data, or different typ־ of user data πΤ'ΣΓ'τ ^{SUCC־SSfUi &amp;allsmiss1on} defined differently for each aUowstiT ⁰”^{3 ־}* *י ®”“™“ך“t of power necessary an־״־ the greatest amount of data to be tiansmitted to the base station giZ the We transmit power capability of a subscriber unit, and also reduci the interfere between subscriber units. Ibis reduction in interference increases the total communication capacity of the entire CDMA wireless cellular system.

The power control channel used in the reverse link signal allows the subscriber unit to transmit power control information to the base station at a 5 variety of rates including a rate of 800 power control bits per second. In the preferred embodiment of the invention, a power control bit instructs the base station to increase or decrease the transmit power of the forward link traffic channel being used to transmit information to the subscriber unit. While it is generally useful to have rapid power control within a CDMA 10 system, it is especially useful in the context of higher data rate communications involving data transmission, because digital data is more sensitive to errors, and the high transmission causes substantial amounts of data to be lost during even brief fade con ations. ־ Given that a high speed reverse link transmission is likely to be accompanied by a high speed 15 forward link transmission, providing for the rapid transmission of power control over the reverse link further facilitates high speed communications within CDMA wireless telecommunications systems.

In an alternative exemplary embodiment of the invention a set of encoder input rates Er defined by the particular Nr are used to transmit a 20 particular type of data. That is, data may be tranmitted at a maximum encoder input rate Er or at a set of lower encoder input rates Er, with the associated Nr adjusted accordingly. In the preferred implementation of this embodiment, the maximum rates corresponds to the maximum rates used in IS-95 compliant wireless communication system, referred to above with 25 respect to Tables Π and HI as RSI-Full Rate and RS2-Full Rate, and each lower rate is approximately one half the next higher rate, creating a set of rates comprised of a full rate, a half rate, a quarter rate, and art eighth rate. The lower data rates are preferable generated by increasing the symbol repetition rate Nr with value of Nr for rate set one and rate set two in a 30 BPSK channel provided in Table IV.

<td> Label</td><td> Er.qpsk (bps)</td><td> Encoder Out R=1/4 (brts/frame)</td><td>ⁿR,R=1/4 (Repetition Rate, R=V4)</td><td> Encoder Out R=l/2 ibits/frame)</td><td> I (Repetition Rate, R=1/2)</td>

<td> RS2־Full Rate</td><td> 14,400</td><td> 1.152</td><td> 5 1/3</td><td> 576</td><td> 10 2/3</td>

<td> RS2-Half Rate</td><td> 7,200</td><td> ׳ 576</td><td> 10 2/3</td><td> 288</td><td> 21 1/3</td>

<td> RS2-Ouater Rate</td><td> 3,600</td><td> 288</td><td> 21 1/3</td><td> 144</td><td> 42 2/3</td>

<td> RS2־Eigth Rate</td><td> 1,900</td><td> 152</td><td> 40 8/19</td><td> 76</td><td> 80 16/19</td>

<td> RSI-Full Rate</td><td> 9,600</td><td> 768</td><td> 8</td><td> 384</td><td> 16</td>

<td> RSI-Half Rate</td><td> 4,800</td><td> 384</td><td> 16</td><td> 192</td><td> 32</td>

<td> RSI-Quater Rate</td><td> 2,800</td><td> 224</td><td> 27 3/7</td><td> 112</td><td> 54 6/7</td>

<td> RS1־Eiqth Rate</td><td> 1,600</td><td> 128</td><td> 48</td><td> 64</td><td> 96</td>

<td> NULL</td><td> 850</td><td> 68</td><td> 90 6/17</td><td> 34</td><td> 180 12/17</td>

Table IV. RSI and RS2 Rate Seto in BPSK Channel

The repetition rates for a QPSK channel .is twice that for the BPSK channel.

hi accordance with the exemplary embodiment of the invention, when the data rate of a frame changes with respect to the previous frame the transmit power of the frame is adjusted according to the change in 10 transmission rate. That is, when a lower rate frame is transmitted after a higher rate frame, the transmit power of the transmit channel over which the frame is being transmitted is reduced for the lower rate frame in proportion to the reduction in rate, and vice versa. For example, if the transmit power of a channel during the transmission of a full rate frame is 15 transmit power T, the transmit power during the subsequent transmission of a half rate frame is transmit power T/2. The reduction is transmit power is preferably performed by reducing the transmit power for the entire duration of the frame, but may also be performed by reducing the transmit duty cycle such that some redundant information is blanked out In either 20 case, the transmit power adjustment takes place in combination with a closed loop power control mechanism whereby the transmit power is further adjusted in response to power control data transmitted from the base station.

Fig. 5 is a block diagram of RF processing system 122 and demodulator 124 of Fig. 2 configured in accordance with the exemplary embodiment of the invention. Multipliers 180a and 180b dowconvert the signals received from antenna 121 with an in-phase sinusoid and a quadrature phase 5 sinusoid producing in-phase receive samples Rj and quadrature-phase receive samples Rq receptively. It should be understood that RF processing system 122 is shown in a highly simplified form, and that the signals are algo match filtered and digitized (not shown) in accordance with widely known techniques. Receive samples Rj and Rq are then applied to finger 10 demodulators 182 within demodulator 124. Each finger demodulator 182 processes an instance of the reverse link signal transmitted by subscriber unit 100_z if such an instance is available, where each instance of the reverse link signal is generated via multipath phenomenon. While three finger demodulators are shown, the use of alternative numbers of finger 15 processors are consistent with the invention including the use of a single finger demodulator 182. Each finger demodulator 182 produces a set of soft decision data comprised of power control data, BPSK data, and QPSK! data and QPSKq data. Each set of soft decision data is also time adjusted within the corresponding finger demodulator 182, although time adjustment could 20 be performed within combiner 184 in an alternative embodiment of the invention. Combiner 184 then sums the sets of soft decision data received from finger demodulators 182 to yield a single instance of power control, BPSK, QPSKj and QPSKq soft decision data.

Fig. 6 is block diagram a finger demodulator 182 of Fig. 5 configured in 25 accordance with the exemplary embodiment of the invention. The Rj and Rq receive samples are first time adjusted using timp adjust 190 in accordance with the amount of delay introduced by the transmission path of the particular instance of the reverse link signal being processed. Long code 200 is mixed with pseudorandom spreading codes PNj and PNq using 30 multipliers 201, and the complex conjugate of the resulting long code modulated PNj and PNq spreading codes are complex multiplied with the time adjusted Rj and Rq receive samples using multipliers 202 and summers 204 yielding terms X; and Xq. Three separate instances of the X! and Xq terms are then demodulated using the Walsh codes W_x, W₂ and W₃35 respectively, and the resulting Walsh demodulated data is summed over four demodulation chips using 4 to 1 summers 212. A fourth instance of the X_x and Xq data is summed over four demodulation chips using

IS summers 208, and then filtered using pilot filters 214. In the preferred embodiment of the invention pilot filter 214 performs averaging over a series of summations performed by summers 208, but other filtering techniques will be apparent to one skilled in the art The filtered in-phase and quadrature-phase pilot signals are used to phase rotate and scale the W_pand W₂ Walsh code demodulated data in accordance with BPSK modulated data via complex conjugate multiplication using multipliers 216 and adders 217 yielding soft decision power control and BPSK data. The W₃ Walsh code modulated data is phase rotated using the in-phase and quadrature-phase filtered pilot signals in accordance with QPSK modulated data יי sing .multipliers 218 and adders 220, yielding soft decision QPSK data. The soft decision power control data is summed over 384 modulation symbols by 384 to 1 summer 222 yielding power control soft decision data. The phase rotated W₂ Walsh code modulated data, the W₃ Walsh code modulated data, and the power control soft decision data are then made available for combining. In an alternative embodiment of the invention, encoding and decoding is performed on the power control data as well.

In addition to providing phase information the pilot may also be used within the receive system to facilitate time tracking. Time tracking is performed by also processing the received data at one sample time before (early), and one sample time after (late), the present receive sample frying processed. To determine the time that most closely matches the actual arrival time, the amplitude of the pilot channel at the early and late sample time can be compared with the amplitude at the present sample time to determine that which is greatest If the signal at one of the adjacent sample times is greater than that at the present sample time, the timing can be adjusted so that the best demodulation results are obtained.

FIG. 7 is a block diagram of BPSK channel decoder 128 and QPSK channel decoder 126 (Fig. 2) configured in accordance with the exemplary embodiment of the invention. BPSK soft decision data from combiner 184 (Fig. 5) is received by accumulator 240 which stores the first sequence of 6,144/Nr demodulation symbols in the received frame where N_R depends on the transmission rate of the BPSK soft decision data as described above, and adds each subsequent set of 6,144/N_R demodulated symbols contained in the frame with the corresponding stored accumulated symbols. Block deinterleaver 242 deinterleaves the accumulated soft decision data from variable starting point summer 240, and Viterbi decoder 244 decodes the φ deinterleaved soft decision data to produce hard decision data as well as CRC check sum results. Within QPSK decoder 126 QPSK! and QPSKq soft decision data from combiner 134 (Fig. 5) are demultiplexed into a single soft decision data stream by demux 246 and the single soft decision data strpa m is 5 received by accumulator 24S which accumulates every 6,144/Nr demodulation symbols where Nr depends on the transmission rate of the QPSK data. Block deinterleaver 250 deinterleaves the soft decision data from variable starting point summer 248, and Viterbi decoder 252 decodes the deinterleaved modulation symbols to produce hard decision as well as 10 CRC check sum results. In the alternative exemplary embodiment described above with respect to Fig. 3 m which symbol repetition is performed before interleaving, accumulators 240 and 248 are placed after block deinterl-.avers 242 and 250. In the embodiment of the invention incorporating tue use of rate sets, and therefore in which the rate of particular frame is not known, 15 multiple decoders are employed, each operating at a different transmission rate, and then the frame associated with the transmission rate most likely to have been used is selected based on the CRC checksum results. The use of other error checking methods is consistent with the practice of the present invention.

Thus, a multi-channel, high rate, CDMA wireless communication system has been described. The description is provided to enable any person skilled in the art to make or use the present invention. The various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without the use of the inventive faculty. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.