Title of Invention

METHOD FOR POWER CONTROL FOR POINT-TO-MULTIPOINT SERVICES IN A COMMUNICATION SYSTEM

Abstract

The present invention relates to enable point-to-multipoint communication services in an existing cellular communication system infrastructure, each member subscriber station, i.e., a subscriber station participating in such a service, is receiving a forward link shared channel, and in certain embodiments additionally a forward link dedicated channel. Because transmission on the forward link channels from neighboring sectors presents interference to the transmission from the sector serving the subscriber station, it is desirable to control the forward link channel transmission power to the minimum acceptable power. Additionally, a transmission form each . member subscriber station on a reverse link channel presents interference to other subscriber stations. Therefore, it is desirable to control the reverse link channel transmission to the minimum signal level. Consequently, a method and apparatus for a per. control that enables point-to-multipoint services in an existing infrastructure of a wireless cellular telephone system is disclosed.

Full Text

POWER CONTROL FOR P03NT-T0-MULTJP0INT SERVICES PROVIDED IN COMMUNICATION SYSTEMS BACKGROUND This application claims priority from co-pending Provisional Application No. 60/279,970, filed March 28. 2001, entitled "METHOD AND APPARATUS F-OR GROUP CALLS USING DEDICATED AND COMMON CHANNELS IN WIRELESS NETWORKS; Field [ifK'll The present invention reiatesito point-to-mijltipo'nt ser\'iceS; in a wireline or a v^ireless commurtcaticn system. More spftcificaily, the present invention relates to a n:etftod and an appa-atus for a power c(;niro! in sjch a point-to-multipoint ser/ices comnruinications system. Background [1902] Comrnunicatfon systems hitve lK>€n developed to a!!ow trcnsm'ssion of infomration signals from an origination station to a physically disiinct destination statioii. In transmitting information signa! from tre origination station over a comrrunicaticn cnanne!, die infomration signa! is first convorted into a fonm £i;itaa(e for eff:ci6nt transmission o\/er the communication channel Conversion, or modulatior, of the information signal involves vrifyirg a pararrsler of a carrier wave in accordance with the infcmafion sigr»ai in suc.*^^ a way thai the spectrum of tfte resulting moduiated carrier is cofrfined within the comTiur^cation channei bandv/foth. At (he destination station Lho original informatJon signa? is repiicatsd from :he mo^Julated carrier wave received over the communication channel. Such a replication is generally achieved t?y using an inverse of the modulation process employed by the ordination station. 711J031 Modulation also facilitates multiple-access, i.e.. simultaneous trar^smission and/or reception, of several signals over -d common corrmunicarion channel. Multiplt^-accebs communication systems often include a plurai;^/ of remote subscriber terminals requiring intermittent san/ice ot relaively short duration rather than continuous access to the common corrmunication channel. Several multiple-access techniques are known in the art, such es time division multiple-access (TD^M), frequency division multiple-accHSS (FDMA), and amplitude modulation m.ultlplo-access (AM). Another type of a mul:iple-access technique b a code division multiple-access (CDMA) spread spe<: system that conforms to the tia mobile station-ba station compatibility standard for dual-mode wide-band spread speidtrum cellular hereinafter referred as is-95 standard. us of coma techniques in a multiple-access communication is disclosed u.s. patent no. entitled spectrum using satellite or terrestrial repeaters and method generating waveforms cdma telephone both assigned assignee present inv> il 45.5 Phys!:a( Layer Standard for cdfr.a2000 Spread Spscloim Systems" (the IS-2()C0 stardard). [l(it):3] In a multiple-access comnvjnicatiof: system, connmjnications betv;een users are 'Xinducted through ono or more base -•stcitons. A first ussr on one subscriber sitatlon ccnmunfcate*:; to a sewnd user en a second subscriber station by trncJ subsc:ribet' atatii^n. Likewise, the communication can be conducied between a firr.t user on a mobile sjbscrlber station and a second user on a landline station. A base station receives the data from the user on a reverse lir.k, and routes tlie data through a public switched telephone network (PSTN) to the second user. [1G061 In a wireless communication system, maximizing a capacity of the corrununiccition system in tenns of the number of simultaneous telephone calls that »:an be 'landled is extremely important. The capacity in a upread spectrum conrinunicst-nn system can be nayinvz^ if the transmissior. power of each suD5::nber station is controted sach that each iransmirted signal arrives at a bass statlo-n nsceiver at the same s.'gnal level. However, if a sig^ia! transmitted by a subscriber staton anlves at the base station rocor^er a: a po^^er level that is tco tew. qjaifty communications canno: be achieved dua to interferance from the er siJjscriber statioris. Or the other hand, if the £'Ub3cra5er station transmitted signal rs at a paw%r fevel that is too nigli wtien recsived at the fcase staticin, communication with this particular subscriber station is acceptable t)ut this high per stations. This intedorenco may adx'e.-seiy affect com.^unicatior^s with other subscnTror stations. Therefore, eadi subscriber station ne^ds to transrnil the minimum signa! level expressed as e.g., a signa!-to-nois£ ratio, that allows transmitted data recover^/, llO)'] Conse'qiuenthy, the transmission power of each subscriber station within the coverage area of a base s^ticn is coniroilsd by the base station to produce the same norilnal recer/ed sJgnai power at the base station. In an ideal case, the total signal power raceived at the bai50 station Is equal to the nomhal pc^er received from each sufaschber station multiplied by the numt>er of siitscribOf' ilations transmitting within the coverage area of the base station p^(us tie power received at the fcasa station from subscriber i^taiior.3 'n the coverage area of neighboring base stations. [.'lOCiftj The rece^vcti povver is dets^rrrrined by an BiiBn-jatkyn of the transmitted power by a patn loss cl the link. The patn \o$s can be characterizod ty t\so separate phenomena; average pafh lo^s and fading, (n many communicaticn systerns. e.g.» IS-95., W-CDMA, (S-2GG0, tt\e forv^ard iink and tie r€^v0rse link are allocated separate frequenaiess i.B., the toward link operaes on a diffsrent frequency than the reverse link, However, because YhB forward iink a:id re^ot^e iink frequorv^ies are within the same genera! frequency band, a significant correJation betv^efm Mie average path losses of the two links existfj. On the other hand, fading \s an independent phenomenon for the fonvaid link and reverse link and v?iries as a iunctlon of time. I IOC 91 In an exentplary CDA4A sjystem, eadi subscriber station estimates the path loss oj the fonfl^ard link based on the toial power at the input to the sut>sc1ber station. TC\B total pov/er is the sun of tne pcwer from ^)! base stations operating on the same frequency as^ignrnen! as {)erceivQr} by the 3ut>sc iber station. From the estimate of the averace forj^acti link path loss, the subsciber s^ticn sets the transmit teve! of the reverse !(nk signai. Shouid the reverse Jink channel for one subscriber station Siidden^/ improve co(;^pared to the forward Rnk channel for the same subscriber station due to incfependent fading of the hvo cfianneis^ \i\B signai as received at the base station from this subsciber statk^n would increase in power. T^ls increase in pov^r^r causes additonar interfer-ioce to aJJ signals sharing the same frequency assignmenr. Thus a rapkJ respor^e of a^*e subscriber station rrsnsm;: powor to the sadden improvement in the channel would Improve s/sreni peicrmanco. Therefore, it is recessary to have trie base station continually ccntnbut-a to ttie pov^or contro! mechanism of the subscriber station, il31&J Thus, the subscnber station's fmnsmit fiovver is contrc^led by ot\€f or more cjase s^tafions. Each base station, v4tft which the subscriber st;.«5on is in comrnunicaiioa, measures ttie received signa! strength from tlie subscriber station. The jx^easured s^nai strength is compared to a desired s^naJ strength level lor ti^at partfcular sut«crib6r station. A power adjustment command ts gene^ited by each base station and sent to the subscriber station on the forwaird lin<. in response to the base station povm adjustn command subscriber ritation incrsases or de-creases transmit power by a predete-mined an this method r change channe is effected and average system performance improved. note that typical cellular tic stations are not intimately connected oach baua unaware of level at which other receive sigr> IIOU] When a subscriber station is in communication with more than one base station, power adjustment commands are provided from each base static n. The subscriber station acts upon thei?e multiple base sJation power adjustment commands to avoid transmit power levels that may adversely interfare witii other subscriber station communications, arid yet provide sufficient power to support communication from the subscriber station to at least one of the base stations. This power control mechanism is accomplished by havirg the subscriber station incrt>ase its transmit signal level only if overy base staticn, witi which the subscribar station is in communicaticn, requests an increase in powar level. Tne subscriber station decreases the subscriber station's transmit signal level If any base statior, with v/hich the subscriber station is in ODmrnunication, requests that the power l:e decreaseci, A system for biiae station and subscriber station powar control is dtsclosed in U.S. Pat. No. 5.056.109 entitled "METHOD AND APPARATUS FOR CONTROLLING TRANSMISSION POWER IN A CDMA CELLULAR MOBILE TELEPHONE SYS**EM," issued Oct. 8. 1991. assigned to the assignee of the present invertion. [:,0121 in adcfition to the abC'vedesorlbed reverse Ifnk power contro!, it is also desirable to control the relative pov/er used in e^ch traffic channsi transmitted on a fowaid link by the base station. To enable such a control, each remote ataficn measures the power of traffic channels t^cebred form a base station, gene-ates control information in response^ and trartsmits the control information back to the base station. The primary reason for providing such controi is to accommodate Ihe fact that in certain locations the fonA/ard link may be unusually disadvantaged. Unless the power being, transmitted to the disadvantaged subst:riber station is Increased, the signal quality may become unacceptable. An e;>campl8 of such a location is a point where the patti loss to one or two n slation, i.e., a base station communicating with the subsctibor station. In such a lcc:ation, the total interforeoce would be increased three times over the interference seen by a subscriber station at a point relatively cioss to the active base stailon. In addition, the interference coming from the neighboring base stations vices not fade in unison with the signal from the active base station as wC'Uld be the case for interference coming from the active base station, A siJDscrifaer station in such a situation may require 3 to 4 dB additional signa! p(3WQr from the aclivo base station to achieve adequate performance. At other times, th^ subscriber station nay be located where the slgnal-to-interferance ralio is unusually good. In stct*. a case, the base station ccuM transmit the desired signal using a lower than nomnal transmitter power, reducing jntarference to other signals being transmitted by the system. [1013] The above described wireless communication sen/ice is an example of a pOTit-to^inf communicaricn service. In contrast a potnl-to-muftipo;nt se'vicG Is a service where the information transmitted by a source of th?? inf Drmaton is intendeo for a piura ir/ cf mobile slalions. Ths basic model of £ point-to-mullipoint system ccmixises a sst of users, a group of which is sar.ccj by one o^ more sources cf 'Ofo rna^ion, which provide information with a certain contents, e.g., news, movies, sports events and the like, to be transmitted ro the usBTs. Each usefs subscriber station partcip^ation ?n the point-to-muttipoini se-vice (a member subscriber station) rncr^itors a forward link shared channel Because the source of infcrnation fixedly d8ti>miin54S the content, tfie users are generalry not communicating ba;k. Examples of common usage of such a point-to-muttipDint services communication systems are TV broadcast, radio broadcast, and ttie !iKe. Alternaiively. the source of Information h a user - a mc»mber of the group, which transmits intormadon intended for the remaining mcsmbers of the selected group if the user wishes to talk, he presses a push to taU (PTM button. Typically, the talking user's voice is routad from the su!3scriber station to a transceiver station on a dedicated reverse link. The transceiver station then transmits the talking user's voice over the forward link sh.ared channel. As in case of the polnt-to-pcint communkiation system, such a communbatlcn system allows both landiine and wiieless subscriber station to aoi^ess the system. Such a point-to-multipoini service is also refen-ed to as e group servic3. Examples of the g'oup sorvice communication system use is in cJispaicn se:"'/ices, such as locai police radio systems, tiaxicab dispatch systems, f-edetai Buts^c of intelliyence c.nd secret service operations, ami genc-ra! rnilitajy coaimunication .systems. [IQlA] Ire alwve-nGntioneo point-io-rnultipoint service coiTimufMcaSion systems are generally highly speoiiiizecl purpoae-buiid communlca^Jon systems. With Ihe recent, advancements in wireless QeMat t>^!e(5hone systems thars has been an int€?rest of utilizing the existing infrastructure of the - maJnIy point-to-point ceiluiar telephone systems - tor poirU-to-muitipoint services. As used Iterein, the t3fm "cellular" system encompasses syatern operating on botti cellular and personal communication system (PCS) trequencies. [iOiil The power control mechanism tor subscriber stations acting a^ poinl-to-point units d-sscribed above is not directly applicable to pcint-to-mu!tipolnt services. As discussed, the wii'eless ccllufar teiep'ione systems assign a dedlcjited ton*vard and reverse link between two or ro^ore conimunlcating users. !n corUrast, "he point-to-muftipoinl services typicaity re y on assigning a shared foPA'a'd lin' SUMMARY (.102 5) In ore cispect of the ;nvsniion. the abov^ stiisa coeds a^^ adcre^ed by controlling a reverse link channel power Dy determining sectors whose coverage area contain actrve subscriber stations belonging to ^ group; arKi transmitting reverse (Jnk power controf commands on a fofrvard M subscriber ::tation beionging to a group; and the r^^vcrse link transmbsion powt^r is acijustGd a-, the active subGcriber s^tations foe^onginy io a group in accordance with '.ne rev^irsG link power ccntroi commands contaiDad in the to;vard link com nwn channel. [10.1.7] In aro\her aspect of tiie invention, the above stated needy are addressed b>/ c:ontro'linc] a reverse linK ct^annal powe'- in a poinHo-rr.ultipoint comniunlcaiion system by transnjit*jng usar data on a fon/;ard link common channei; and transmitting reverse [Ink power control commands on a forward link ciedicated channei The above staled needs are further addressed by recei>'ing at e rich subscriber statio.i belonging to a {jroup a forward link common ctiannel; rec:&iving at each subscr)!:>er station belonging to a group a torward link dedicated cliannel; and adjusting at the active subscriber otations belonging to a group rcvgtse link transmission pov/er In accordance with reverse link pov;er contr(j| coa?mfinds contained in the forward link dedicated channel. {10181 In vt*t another aspect of the invention, the above stated needs are aodr£SSCd i?y controlJing a reverse fink chenne) pov^ef in a point-to-multipoint comniunicaiion system by determining at tf^e access ne^vork sectors whose coverage area contain active subscriber sialio^is be-onging tc a group; and iransunitting reverse lick power control cornmande. on a fon,vard link dedicated charmel frotn the determiried set:tors. Tne above stated needs are further addressed o*/ rezehing at eadi sabscfiber statior: berlcnging to a group a fooivard link ccmmcn charvia!; receiving at each [lOitf j la of^a aspect of the invention, the at-ove stated needs an3 addressed by conti'?:»IJfng c. forward link channel power In a point-tv-rrnjitipoint comi'nunicatfon sysiOTi by monitoring at a sector at Jeast one reverse link charne! to detect a qualit/ metric of a foavard link shared channei; and adjusting tha foiv/ard link s(-;ar*3d channel power in accordance wit?? the worst qualitv metric, [10201 In another aspect of the invention, the above stated needs are addressed by corrtroJJJng a foavard link channel pov^er in a point-to-multipolnt communication'^ system by detemnining at each subscriber station beionging to a group a qua!r!>' metric of a foPA'ard link shared channel; and trans:Tiitting the determined cuality rnotric. EiRlEF DESCRiPTION OF THE DRAWINGS jlfllM] FIG-1 illustrates a coriceptuai diagram of a group sen/ices comrnunici^tion sysfern; {iHi2] FIG. 2 illuslrales a conceptual diagram of a forward link channel with fixed rate o' data; and [101:3] FIG. 3 illustrates a conceptual diagram of a forward link cnannel v;ith variaDle rale of data. DETAILED DESCRIPTION Definitions [IC24] The v/orrl "exemplar/' is'used herein to meai "serving as an example, hfitance, or Jlustration," Any eaibodimont dascribeo herein as "exemplary' is not necessari^y to be construed as prefarred o' adva-itageous over other embodiments. [1925] ItB terms pcinc-to-potnt commu^iication is used hereia to mean a communication between t/;o subscriber stations ever a dedicated for-va^-d communicati:>n channel and dedicated reverse ccmmLnication channel {.1026] The term point-tc-rrtuifipofnt ctjmmunicatfon sen^ir^-e is used herein ro mean a corrimunication wherein a plurality cf subscriber stations are recei^/ing corrrnunication fi-om - ti^ptcally - one source. Such setvicss may comprise, e.g.. grcujj servioi^ in which the source is a subscriber station; a broadcc.sr service, fn Vr'hich fe source is a central station; or a multicast sepv'ice, in v/hich the recipients ccrnprise a suthset of the plurality of subscriber stations. [1027] The term access netv/ork is used herein to mean a collection of base stat!c»ns (B3) and one or more base stations" controllers. The ao^ess network transports data packets between multiple subscriber stations. The access netv/ork may be further connected to additional iietvwoiks outside the access nuwork, sucf'i as a corporate intranet cr the Inlernet, and may transport data pa:k8ts between each access terminal and such outside networks. I i'.)2S] The term base station is used herein to mean the hardware with which sut);icr!t)er stations corrjiriunicate. Cell rofers to the harmvare or a geographic coverage area, dhperdlng on the context in wt^ich the lerm is used. A sector is a partition of a cell. BcK^ause a sector has the attributes of a celi, the toE.chings riascribed in terms of cells are readily extended to sectors. |.';U)29j The term subscriber station is used herein to mean the hardware with which an access network communicates. A sjjbscriber station may be jriobile or stationary. A subscriber station may be any data device that communicatos through a wireless channel or through a wired channel, for example using fiber op :ic or coaxla! cables. A subscriber station may further be any of a number of types of devices including but rot limited to PC care, compact flash, external or Internal modem, or wireless or wireline phone. A subscriber station that is In the prccess of establishing an active traffic channel connection with a 6S is said to be In a corir^ection setup state, A subscriber station tf>at has established an active tratf c channel connection witr. a BS is called an active subscriber station. and is said to be in a traffic state. ri030] The tenm for.vard channel/link is used herein to mean a cornmunvcatior channel/link through which a base statico sends ^gnals to an sul)saiber station. (1031] Tne term reverse channel/link is used herein to mean a ccfnmunication channeWink thruL-gh which the subscriber station sends s:gr [1032] The term physical channel is used herein to mean a communication roite over v/hich a signaf propagates described in terms of modulation cl^iaractenstics and coding. 110331 The term iogica! channe? is used horein to mean a communication roite v;itf)in the protocol layers ot either the t:ase station or the subscriber station. 11034] The term communfcaticr^ channel fs used frerein to mean a physical channel or a Icgicai channel in accordance with the context. [1035J The term soft hand-ofi is used heroin to mean a communication between a subscriber station and two or more sectors, wherein each sector bslorgs to a different cell. The reverse link communication is rocoived by both sectcrs, and Vne forward link con^mur^icalk^n is simullaneousiy carried on the two or more rioctors* forward links. [10.\6] The term solter hand-cff is ii-;ad herein to mean a communication ber^'k^en a subscriber station and two or more sectors, wherein each sector beforgts tc :h'=* same cell. The reverse link corrmuoication is received by both sectcrs, and Ihe forward link comrnunicaiion is simuitaneously carried on one of the tv/o or mere sectors' fon/vard links. [1037] The term puncture is used Sierein to mean replacing a first information content of a first size wfth a second infoonation content of a first size. [l.o:5«l The teim dedicaled channel is used herein to mean a channel modulated by inlon:nation specific to an Individual subscriber station. r!0J9J The term common channel Is used herein to mean a channel modulated by information shared among ail subscriber stations. Ii(WO] The term user data or pay load is used herein to mean data other than control data. il(Kll] The term control data is usee heein to rrean data enribling operation of entitios U\ a communication system. Heacr^^tion 11042] RG. 1 illustrates a ccnceplua! diagram of a cornmun>-;a:ion system 103 capable of providing pc»iat-to-multipoir;c seivices \\\ accoraar^ce with erriDodin^eats of the present invention. For tutoriai purposes, the following doscription illustrates a group call: however, one of ordinary skills in the art urderstcnds f^^ow to apply the disclosed concepts to other pcint-to-rnultipoint S£?ivices. A (calling) group is defined by the group's membership, comprising us'^fs of S'jbscrib&r stations talking to one another frequently enough to . esablish tne calling group. The calling group is said to be in a sleep state when no memt^er is either idle or active, e.g., ail nr^embers are either powered off or do not paiticipate in the calling group. The calling group is in the idle state when at least one merr^ber participates in the group. The calling group Is in the aciive state when one of at least two members initiates a group call. A group cail is divided into active and silent periods. The group call io in the active peicd vv;>3n t.iere are transmissions between the rr(em*jers without long idle peiods. The group caS is in a silent pencd \yt\Bn there is no member traismittiriQ ary traffic tw a period extending the long idle period. [1(143] 'n an active period, a group user on a member subscriber static/^ e.c.. me»-^tf)er siA>scriberstation 102(1) communicates user information {voice or da a) to ether grotp users on member subscri*>Gr staticris 102(2) through 102(5) via an access network comprising case stations 104 a>i a controller 110. For Qrevit/, the term •member subscriber station" is used hereinafter to mean "user on a subscriber station" unless stated otherMse. Although the term base station is used, one of ordinary skills in the art r^cccniz85 that fr:a embcxliments art"! equEuly appftcabie to sectors. The base statiors 104 are confiected to the controller 110 by backhauls 112. The terrn backhaul is used to mean a cojTimunit:^2tion link betA'een a controiler and a base station The backhaul 112 can be implemented in a number of connection t/pes irciuding. e.g., a micvowave or wire-line El or T1 ^ cpttoel fiber, and other connection types known to one of ordinary skills in the art The controfler 110 Is connected to an Interface unit 114, interfacing the communication system 100 with other services (nc't shown), e.g., a public switched tefephone network (PSTN), packed data serving rio [lft44J When a memDer subscriDer slatiort. e.g.. the subscribe'^ station 102(1), dtijires to transmit user data to tfie group aver the revfc^rso link, the member subscriber station needs to request a reverse link assignment and request to transmit. In one emoodiment. the subscriber station 102(1), sends an access channel n'V^ssage requesting a reverse link to base station, e.g., base station 104(1). The access message is sent on an access channel. The access chcinnel is a reverse Jink channel used by sutccriber stations for communicating to ihe base station. The access channel is used for short signaling message . exchanges such as call originations, responses to pages» and registration. An access attenopt is sent by the subscriber station m a series of access probes. Each access probe cam'es the same Infomnation but is transmitted at a hfgher pcv^er leve' than the previous one. The access probes continue until a base staJon acknowledgment Is recer/ed at the subscriber station. However, one skilled in the art recognizes that other access arrangements as described in a provisicnel application serial number 60/279,970, entitled "MSTHOD AND AP=>ARATUS FOR GROUP CALLS USING DEDICATED AND COMMON CHANNEi^ »N WIRELESS NETWORKS.' filed March 28. 2001. assigned to the assigree of the present invention are equally applicable. [i 045J 0-Tce the communicating (active) member subscril)er staton 102(t) is assigned a reverse link channel 108(1), the subscriber station 102(1) may transmit information to a base station 104(1). The reverse iink assignment are detjHed ffi the above-mentioned a provisional application serial number 60/279.970, entitled -METHOD AND APPARATUS FOR GROUP CALLS USNG DEDICATED AND COMMON CHANNELS IN WIRELESS NErWORKS." filed March 28» 2001, assigned tc- trie assignee of the present invention are equally applicable. The base station 104(1) routes the received fnfcmiation to base stations 104(2) and 104(3), and trafisniits (he received information on a forward link shared channel 106(1) to the user 102(2). The base stations 104(2) and 104(3) transmit the routed infomiatior. on the fonr^ard link shared channels 106(2) ar>d 106(3). To receive the infotTriation from the acti\/e member subscriber station 102(1), all the member subscriber stations of an active group, i.e., the subscril?er stations 102(1) tfirough 102(5) are assigned to monitor the toward link shared channel(3) 106 of their individual base slations 104 during active grc^up cai!s. fn general, the foo-vard link s\vd(Q^ ciannel? 106(1), 106(2), and 106(3) assianec bv the respective base stations or 1C4(1), 104(2}, and 104(3) are different from one another. However, to allow irnprovec: recepiion of memhe' subGcriber stations 102 located in overlapping CiDverage areas, the fon/vard link shared channel 106 may be transmitted synchrcncusly by more than on& sector or base station 104. "f he method for improved :'ec€ption of the fopjvard link common shared channel in overlapping coverage areas is disclosed in co-pending application serial number 0'3/933.6D7. entitled ^'METHOD AND SYSTEM FOR A HANDOFF IN A BF^OADCAST COMMUNICATION SYSTEM; filed August 20, 2001, assigned to the assignee of the present invention. [19461 tn one embodiment, the fonivard link shared channel 106 is morlulated by the uner information intendc^d to the group member subscriber stations, and control data, necessary for tha call maintenance, e.g., signaling infonr^tion. power cor t^ol infonnation, and other types of inJormation known to one skilled in tho art. However, the *imited capacrty of the fonrt/anj link shared channel may prevent modu'ation by bom the ca!! information and the call maintenance information. Ccnsec,uentJy. in another embodiment, only the user information rs transmitted on the foward link shared channel 106, and ttie call maintenance tntormat'^n may be rrodulated on an additional fonvard link channel. Ir that case, eaciT sutascnbar station 102 m»ust monitor, In add'tion to the fonward link shared ct;annei, the add^ticnii fo^^afd Rnk :;hanne!s, comprising the call rr-iiirtenarce infonnt^tion. Sucfi an additional channel may be a dedicated channel or a common channel, as deserted in the above-mentioned provisional application senal ntmoer 60/279,970. enilled 'METHOD AND APPARATUS FOR GROUP CALLS USING DEDICATED AND COMMON CHANNELS l^; W RELESS NETWORKS; tiled March 28, 2001, assigned to U^ie assignee of the present inventior are equally applicable. 11047] in one embodiment, passive subscriber stations 102(2), 102(3), and 102(4) do not establish reverse links to any of the base stations 104. Note that if subscriber stations 102(2), 102(3), and 102(4) are completely passive, the inc'ividual base stations may be unaware of whether ttue sut>scriber stations are in their corresponding coveraae areas. Even If a subscriber station registers with the base station when it enters the coverage area of a base- station, the base station has no way of kncwng when the sunscribsr station has left the base :5tation c;ovefage area, [IMii] Ever i!" subscriber stations 102(2). 102(3), arid 102(4) are passive, they still may use reve.-se lini:5s channel to signal the base station if they are in need of more powei from the foPA/ard (ink broadcast channel. Such a use of a reverse link channel is dt?scribed in the abcvenmentioned p-ovisional application serial numbar 60/279.970. entitled "METHOD AND APPARATUS FOR GROUP CALLS USING DEDICATED AMD COf^/IMON CHANNELS IN WIRELESS NETV/ORK," filed March 28, 2001. assigned to the assignee of the present inv6nlk)n are equally applicable. {11)49] U is welt known in the art thc^it base stations may be sectorized into two or nore sectors. Consequently, where the term base station is used herein, it is implied Ihat iim term msy refer to an enti'^o base station or to a single sector of a nulti-sectored base station. Furthermore, although in tne descriptfon above, the comrron infonTiauon was proviaed by the subscriber station 102(1). one cf ordincjy skJs in the art dnders:and3 ihat tt^e concepts disclosed are equally appli^zable for \he common information toeing providi^ by a source connected to the ccmmunication system 100 via the interface unit 110. [1950] A stancsrd celiu-ar system »s comprised of a plurality of base stations each of wh^ch provides ccmmunication for subscriber stations located witriin a BmitecJ coverage area. Together the plurality of base stations provides coverage to an entire service area. However, if the foryvard link shared channel is trar:smltted from every base station in the system at ai! times, the cost of the system cari be quite righ. A more efficient and economical nrianner which provices higher overall capacity for the Sy'Statn is to transmit rhe fon/vard lin |ll!51] As thQ description of the poinHo-muitipoini communication system indicates, to maximize capacity, tne pov;er control of the forward link broadcast charno! is required. Furthermore, a pov/er control of any dedicated far.vard link or reverse lir'.k channels is required. Reverse Link Power Control \liS2\ Reverse link power control is the methaj of controlling power of channels comprising the reverse link. In reverse link }^}OviBt control, the base station measures the quality merric of the signal received from the subscriber station transmitting on a reverse link channel, coiTipares the measured quality metre against a threshold (a set point) and requests that the active subscriber station increases or decreases transmitted power level in accordance with a result of the comparison. The term active subscriber station (talker) is used herein to mean a subscriber station transmitting user data on a reverse traffic charnel. As discussed above, in a group call, only one or few subscriber stations beicnging to a group transmit user data on a reverse link at one time. Ccn{»equent!y, no member passive subscriber station (lister-er) has an estalJlished reverse link traffic rtiannei lo any of the base stations. T?ie terni passive is used herein to mean a subscriber station monitoring a fonward link sharsd channel and any additional fon&ard link channel if ii\e addWonal towara link channel is transmitted, arKi not transmitting einy user data on the reverse link. Of coui-se, the passive subsanber stations may transrviit non-user data: i.e., control and feedback data on an appropriate channel of the reverse link. The additioral forward link channel may comprise a dedicated channel over whici the subscnber station receives e.g., signaling infonmation, power control infortiation, overhead information and ether types of infonmation known to one skiile-d in th'r art. The assignrr^ient of channels for tne forward link shared charnel ard the optional additicnai fcn^/ard link chcinnel(s) is communication syst€fm dependent Thus, for example, in a commurication system in accordance with the IS-200C standard, examples of forward channel assignments are listed In Table 1. F-SCH Forward Supplemental Channel F-BCCH Fon^/ard Broadcast Chanmsl F-CCCH Fon/varcl Ccmmon Control Channel F-DCCH Forward Dedicated Control Channel F-FCH FonA^ard Fundamental Channel F-CPCCH FoHA'ard Common Power Control Channel R-DCCH Reverse Dedicated Control Channel R-FCH Reverse Fundamental Channo! Tabid. i 1053] One skilled in fhe at reccgni233, tnat channel assignment given in Teble 1 both for tiio toward ctianneis and the reverse channels is for tutoriai purpose cniy. Consequently, additional combinations of the forward link shared channe! and the optional addltiora! forward link channel exist as disclosed in a co-pending appfk;£t;on serial number XX/XCX.XXX, entitled "METHOD AND AF'PARMUS FOR CHANNEL MANAGEMENT FOR POiNT-TO-MULTtPQlNT SEzRVlOES IN A COMMUNICATION SYSTEf^i," fJled March 28. 20C2, assigned to the assignee of trie present invention. Furthermore, one of ordinary skills in tho art toJI-3d 'm the an will t>e able to adapt the ideas of the invention disclosed in the pigmented embodiments to communication systems in accordance wit^» o:l)er standards. 11054J In a channel assignrrient method utilizing both forv/ard link shared channel and the individually assigned dedicated forward link channels i.e., Group I of Table 1. all the sectors i^hose coverage area contain subscriber stations participating n the group call utilize a power control sub-channel, e.g.. an F-FCSCH, which is punctured at a pre-determined rate, e.g., 800 bits-per second (bps) onto each cf the individually assigned dedicated fonA/ard finK channel, e.g., F-DCCH or F-FCH for the subscriber stations that transmit on a reverse link. [10551 li^' a channel assignment method uti!i:iing oniy the conmon forward linK traffic channel, i.e., Group li of Table 1, in one embodimenf, the sectors wht3se coverage area con^a-ns only listeners participating in the call do not transmit any reverse power con:rol signals. The sector(s) whose coverage area cor!tain(s) (lie active subscriber statfon(s; utilizes a sub-channel, e.g., a forward pov^^er conirol siub-channel (F-PCSCH), v^'nich is punctured at a pre-determined rate), e.g., 300 bits-per seconij (bps) onto tfiB common forvi'ard link traffic chcinnel, for reverse link power control. In an alternative Gmbodiment, the po\*»rer con*:roi information is not punctured into the common fonA^ard link traffic chennel f:s a F-PCSCH, bur the power control information Is transmitted as a sut-stream of a Common Power Control Channel (F-GPCCH), i.e.. the power cortrol infonmation is inserted into a pre-defined position into the common forward link power ccntrol channel. The active subscriber 3tation(3) process the recslved F-PCSCH or tl"»e sub-stream of the F-CPCCH and adjust the transmission power accordingly. Tfje passive subscriber stations in the sectors transmitting the sub-channe* ignore the F-PCSCH or tf)e F-CPCCH information. A control unft located at the individual sector, at a base station comprising the sector, at tie controller, or any other element comprising the access net;vork, detamilnes whether a coverage area cf a sector contains active subscriber stahbn. []^>S6] In a channel assignment method ut'lizing a fonrvard link shared channel and the subscril?er stations transmitting on a reverse link, e.g., Group \\i of Table 1, "n cne embodiment, tne sectors whose coverage area contains only list€»nors jMrticipatlng in the CcJi do not transmit any reverse power control sigr'.als. The sector(3} whose coverage area contcin(s} the acti'/e subscriber stalion(s) utilizes a dedicatee power control sub-cha li-jei, e.g., ttje F-PcSGH, to ea:h of ttie subscriber stations transmitting on a reverse link. F:>rwarcl Link Power Control [vysT] Fonward link power ccntrol is the method of controliing pov^er of the channels comprising the forv/ard link. In a fcrv/ard link shared channel, each group call member subscriber station measures a quality metric of the received common for//ard link traffic channel and transmits a feedback informaticn to the sector(s) tranamidng the common forward link traffic channel for ths member subscriber station. In one embodiment^ the qusiity metric comprises a signal-to-roise ratio expressed in terms of energy per bit over interference (Eb/Nt). Hcwever, one of ordinary skills in t^e art understands tiat other quality metrics, e.g., t^it-erro^rate. trame-error-rate, and other quality metrics kr^own in the art may be usoa. The feedback is transmitted on a reverse (ink established tetA'oen the member subscriber station and the sector. Each sector receives the fesdback from thos3 member subscriber staticns in the sector's coverage area that transmit on reverse link and adjusts ths transmit leve! to ensure that the dcjsired quality of service (QoS) is delivered to all the member subscriber statioris. A control unit located at the individual s€>ctor. at a base station composing the sector, at the controller, or any other element comprising the access netv/or[ [10581 As discussed above, the forward link condition for each subscriber staticr? is different Therefore, the sector is likely to receive conflicting forward Jink quality measurements form each subscriber station. The sector must then proce;>s the conflicting fonvard |jn [1059; In the ebove-described emlx>diment, a!! member subscriber stations report the quality metrfc upon updating the qualit/ metric measurement. To cecrease the reverse link ^gnaling k^ad and increase battery life of a subscriber station, In anc«ther embodiment, tne subscribe*' stations report the measured cualii)' metric back to the base staion only if the measured queJIty metric \s not salistcictory. Thus, each noember subscriber station measures the quality metric and c«Dmpares ttie measured qualit/ metric to a thresnold. If the quality metric is better than tlie threshold, ttie subscriber station abstains from reporfing &ie quality' nrTetic. Consequently, only the subscriber stations wftn a measured quality' metric below the threshold report the quality metric. The base station then s.djusls the common forward link traffk: channel power to satisfy the power requirement of the subscriber station, which reports the worst fonward link qualit)^ metric. [1060] When the subscriber station detem-.ines the forward link channel quality metric, the subscriber station needs lo feed back the fonA/ard link channel quEiiity metric to the base station on a reverse link. As discussed above, only active subscriber slaton(s) transmit a reverse (Ink traffic channel, whi<. may be used for the feedback. consequently passive subscriber stat ons do not have an established reverse traffic channel to any of bas3 stabons. however remote staiions need use a revcirse link communicate wilh base stations information necessary call maiitenar.c9. e.g. handoff me:5sages. power control and other known one ordinary skills in art. furthermore desire lo therefore requesting assignment.> [1061] The different exemplary embodiments of reverse link channel assignment in a communication system in accordance with the IS-2000 stardard are listed in Table 1, and will be discussed in that context. Furthermore, one of ordinary sk lis in the art wil! be able to adapt the ideas of the invention disclosed In the presented emoodiments to communication systems ir accordance with other standards. IlutJ2j In accordance with one cnfUx)di.ment. eacf^ passive subscn*ber statkxi is assigned a reverse fink dedicated channel, e.g.. Dedk;ated Control Channel (R-DCCH), upoa joining an actjva group. (E.g., Grojp I, Group III of Table 1). The substTiber statk)n uses the R-DCCH for signaling both for regular calls, (e.g., report ng of forward link pilots) and signaling related to the group call (e.g., quaity metric reporting of forward link broadcast channel, request for a reverse fink traffic channel assignment.) When transmitting the R-DCCH, the member subijcriber station also transmits a Reverse Pilot Channel (R-PCH) and a Reverse Power Control Sub-channel (R-PCSCH). The R-FCSCH carries feec back on a quality metric of the com.mon broadcas: forward link channel. [Vo63] in one en^odiment, the data rate on the foavard link shared channel is fKed; ;he sector uses full rate (800 bps in accordance with the IS-2000 stardard and 1600 bps in accxjrjance witfi W_CDMA standard) fon^/ard power control. Tlie forward link 200 for a fixed rate as Illustrated in FIG* 2 is defined in tenris of f-ames 202. A frame is a structure comprising a determined time span. Because the data rate Is fixed, each frama 202 « franom.H^w ../.♦K tu^ same pcv/er pf. Thorafore, tne current power control method is able to moasura the quali^/ metric of the Forward Link Shared Channel. A Forv^ard Link Shared darnel quality metric nay comprise, e.g., a signal lo interferenca and noiso ratio (SINK) expressed, for example, as energy per bit over f;oi^.5e (6b/Nt). A required target decvx'er metric performance of the member subscriber stat/on cotermines a Forward Link Shared Channel quality motrlo required tor that stbscritior station. Such a decoder metric may be e.g.. a decoded frame error rate (FER), bit error rata (BER). and/'or other decoder metric known to one sKHIed in cne art. The memb^ir subscrit'er station measures the FoTward Link Shared Channel quaiity metric, adaptive threshold, and sends power control comrr^ands in accordance with tJie cC'mpariRon results, in one embodiment, the power control commands 204 ccmprisG a stream of up or dcv/n commands (similar to FPC^MODE - '000' in accordance v/ith IS-2000 standard). The quality metric measurement and ccmpariscn can be carried out reliably by the subscriber station because, as di'jcussec. th^ data rates or the Forward Link Shared Channel are fixed, tf>3reforE', do not change without notice to the member subscriber station. In ar^ exemplary embodiment of an adaptr/e threshold adjustment, tne threshold is int:reasod by a first step, e.g., 0.5 dB, when a data frame of the Fonrtirard Link Sftared Channel is received ccrrectly. This threshold is decreased by a smaller stijp, e.g., 0.5 dBf'(1 /FERdosjricI), when data frame on the Fonward Link Shared Ctiannei is received incorrectly. The FtRdGstrej represents tne desired frame erasure rate for the Forward Link Shared Channel [10643 !n another emtXKJimerit, utilizing the Forv^ard Link Shared Channel ard the indivdjally assigned dedicated fon/vard traffic channels, the quality' m«5tric of the Fonward Link Shared Channel can be determined form the highest quality metric of the indsvidua^Iy assigned dedicated forward traffic channel used by the rnt^mber subscriber s:ation. Because the rates transmitied on tne Fcnvard Link Shared Chanr»el and the individually assigned dedicated forward traffic chai inels are different, a proper rate translation between *iie Fon^^ard Link Si'ared C^Jann9l and the individually assigned dedicated lory^ard traffic channels must be made. The FcnA^ard Link Shared Channel quality metric is determined by scaling the qua'iti* metric of the individually assigried dedicated forward traffic channel in acconjance with the raie translation- [lOfiS] The sector receives the power controi commands transmitted on the reverse link defeated channel and, In accordaiiCe with one Gmbodiment, decreases a oower transmit level of the Fon^'afd Link Shared Channel by an amouU Q')hf 0.5 dB. when the f*3edback from ali mtimher subscriber station requests docroasa of pov/er. The sector increases the power transmit level by the same aniount when at least ona member subscriber station requests increase of power. [10(;6] In another embodiment, the feedback is in a form of messatjes on R- DCCH. [I0o71 In another enbodimenl. the sectors use a split feedback on the FonA/c.rd Link Shared Channel and tne indi'jidually assigned dedicated foavard traffic channels ff the dedicated forward traffic channels are assigned. Tne split feedback divides the reverse link streaiH pov^^er control commands into t>m sub-streans. As discussed, the powor control stream in accordance with the IS-2000 ^ompris^s e stream of 800 bps. Thus, the first sub-stream can comprise, B.g., |X)iver control commands sane at 400 bps, the second scb-stream then compises. pcwer control comman js send at ^oo bps The sub-streams may be formed, e.g., oy assigning the odd-numbered feedback bits to the first sub-strean and tba even-numbered feedback bits to the second suc-sfream. The first sub-stream »:arries the pcrser control commands for the Forward Link Sharad Channe?, the second sub-stream carries the power control commands for INJ dedicated forward traffic channels. In accordance with this nr^thod, the feedback straam pov/er controi commands for the Forward Link Shared Charifiel frcfr each member subscriber siation in the same sector can be \n the fomi of a sequ6rK:e of up and down commands {similar to FPC^MODE = '001' cr '010' in accordance to IS-2000 standard) or a stream of Erasure Indicator Bits (EIB) (similar to FPC_K-ODE = *n0' in accordance to 13-2000 sta.nda-d). From this s«t of fo&:back for the Foi-vvard Link Shared Channei, tn« sector can set the transnil fevei for that Forward Link Shared Channel to meet the quality rcquirament and conserve power consumption. The E!B feedback aiso gives the b«iS8 station a fast feedback on the member subsc riber station reception of the Fonrt^ard Link Shared Chanr^L This specific feedback facilitates the physxral layer to start the re-transmisslon earlier fnan the NAK (negative acknowledge) from higher layers, If such re-transmission is desired and feasible. The feedback on the dodicaiod chann^-ls is processed in accordance mh any itiothod applicable to point-to-point power control method. i 1068] The sector receives the po^^e' control bits and, ir\ accordance with one ernbccliment, increases a pov^/er transmil levui of t^je broadcast tcward traffic channel by a first amount, e.g., O.o dB, when the feedback fronr. at least one menibsr subsciber staticn reqi^ests increase of po*»ver cr indicates an Gi'iisure. The sectoi' decreases the power transmi-: level by a second annount when each nnember subscriber station requests decrease of pow-^r or indicates no erasure. [iDd^J In another embodimert, the data rate on the forward link shared channel is transmitted with a. variable data rate, as illustrated in FIG, 3. Because the data rate is variable, each frame 3C0 is transmitted witt) a power P coTespondIng to the data rate transmitted In that frame. Thus, e.g., frame 300(n) a full-rate franr>o, Is transmitted with a power PQ. a half-rate frame 300(1) is transmitted with a power Pf2, and an eighth-rate franne 300(2) is transmitted with a power P^. To enable the subscriber slalioo power control to correctly esimate tie foiward link shared charuel qua^i^y metric, the feedback power coitrol commands for reverse link power control utiiize a sub-chani^l. e.g.. a for//ard power control sub-channel (F-PCSCH), which is punctured at a predetermined rate, e,g., 800 (bps) onto the common foward link traffic channel with a constant po-tver In an altemaih-e embodiment, the power centre! infonmatiori is not punctured into the common forward link traffic chiinnel as a F-PCSCH, but the pov/er control information is transmitted as a sut-stream of a Foward Common Power Control Channel (F-CPCCH). i.e., the power contrcl >nft)rmation is inserted into a pre-defrned position into the cominon forward iink common power control channei. The power control bits for reverse link power cwitrol csn be used to measure the ForA'ard Link Sfiard Channel quality metric. Li«70j in one embodim.ent the feedback pov^er conlroi commands for for/^/ard link power control may be sent as messages on thi€ individually astiigned R-DCCH. {1071] in one embodiment, the feedback power control commands for forward iink pov^r conlrcrf may be sent as an E!B on a R-PCSCH, In one embodimeat, the power contro? tnts con-esponding to a frame are grouped to form a singlo EIB, In another embodiment, some bits In a frame are grouped to form an EIB while the Terrtaining bits convey detailed amount of SINR deficit or surpl!js delected by Vr\B member MS. In one embodiment, if no dedicated channels are assigned individually, alt the power conifol cofniT^ands sent on the R-PCSCH arrj utilized to control tne FonA/ard Link Shared Channel. 110;2] Aitemativeiy. the pasi?iv3 member subscriber station are not assigned R-DCCH. (E.g., Group II, Group Ifi of TaWe 1) The passive member subscriber $"ations use access ::hanne!s, e.g., R-ACH, R-EACH. or control channels, e.g.. R-CCCH, or to send any information to the base station. 11075] Consequently, in accordance to one embodiment, instead of providing a pov/er ccnirol feedback in a form of continuous stream of power commands, the power control feedback is prcx'ided in a form of messages modulated on the R-ACH. R-EACH, or the R-CCCH. This alternative is attractive in that the memljer subscriber stations does not continually update the quality metrics of a forward link shared channel, but send a feedback message only when the updaled quality metrics falls below a certain threshold. In one embodiment, the message is sent when a frame error rata (FER) averaged over the most recent 50 tr^tmes is 4% or higher. However, one of ordinary skills in the art recognizes that, n an aheroative embodiment, the message may be generated every time the quality metrics Is updated Within the message, several fjeids or quality irdiccitions nriay be irx:luded. For example, there may be a field indicaling the 3lren!jth at rvhkdi the subscriber station perceives the piici signal from the base staft'on. Alten^tively, there may oe a field indicaiing the straftgth or quality at •Ahicl- the suijscriber station perceives the forwara linK broadcast channe?. There may fcs a ffeW indfcating the signal strength or quality of both ihe pilot i^annel and the fofwaid link broaocast channel. There may be a field which indfccites tho difference between or the ratio of the p lot signal strength to the fonrt^ard link fcroa*Jcast channel strength; the qua«r/ of the group cai{ charuiels. thedes.red increase in received signal to noise and interference ratio, and ether related informaticn known to one skilled in the art. IJ0T4J The base station periodically decreases the forward link shared channel transmit pcw^r level by e first amount if the sector dees net receive a 'eediack message from a men*er subscriber station requesting power increase. The base station Increases the fon^vard link shared channel transmit pov/er (evei by a SGCcnd arncLnt when messat^'es requesting pov;er increase aro received frcm one or more ir-ember subscriber station. 1.L075J The message based power contrci is slower than the bit stream power conl:ol. Consequently, should a nnernher subocriber staiion requirfi fas.e; pcw^r contrci, e.g., dub> :o vyorsening of condition of the link, and, corsequenlly, of the received sgria!, the member subscriber staiion can use a message conveyed on the R-ACH, R-EACH, or control channels, e.g., R-CC3H. to request assignment cf a reverse piiot charinel R-PCH ami R-PCSCH. Alternatively, the base statior* may determine that a particuiar member sutscriber ;5tation consistently requires transmit power level adjustment. The base statii^n then assigns the particular member suDscriber station the R-PCH anc: R-PCSCH. Furthemfiore. the R-PCH/R-PCSCH can be gated. The term gafrng as used herein meems activating transmission cf the R-PCH/R-PCSCH only in pro-cl»^tenT»ined power control groups (PCG). Jf the condition of the link furtier worsen, the subscriber station may request, or be assigned, an R-DC3H, a R FCH or combination. [1976] If there are no indK'iiually assigned F-DCCHs. (e.g., Group !1 o:- Gfcup 111 ol Table 1) al! bits carried on the R-POSCH are used for the power control of liie fonivard link sharec channel. !n one embc ID€!dlcated Forward Link Channel I K'7T\ As discussed in \Y'.e co-pandiovj appiioaJiofi seria! nurriber XX/>XX,XXX. entitled ^^METHOD AND APPARATUS FOR MANAGEMENT FOR POIMTTCMvlULTIPOINT SERVICES IN' A COMMUNICATION SYSTEM;* filed March 28, 2002, the forward link shared cMarine! is modulated by traffic infor'nation, signaling messages necessary to maintain the call, (e.g.. a pilot strer^gth measurement message, liandoff direction message, handcff completion message^ and ether messages known lo one of ordinary skills in the art), and messages related to the group-caii, (e.g., a start and an end of a cai!, requ2st ani grant of a right to transmit, and other messages known to one of ordiran/ slaJIs in the art.) Because the F-SCH(s) Is a common channel, proper subscriber station addressing jnfomiatlon must be employed, so that the subscriber station can discern commor> information Irom information directed to the 5;ubscMi39r station. Because the signaiing mcfSSciges and the overhead of subscriber s^taticn addressing negatively ateci:j the traffic capacity, altemativsiy, the tonvard link shared channel is modulated only by the traffic infOHTiation and the signaling messciges are carried or an adaiticnal forward link chainel. The addftionaJ forward ink channet is a dedicated channel assigns to each indmdual member subscriber .station. ilQli] Because tt^e dedkra'ed fonward link channels are assigned indivdually' to each member subi^criber station, the transmit povisr !e/el of the dedicated channels can be cont'oiied by methods applicable to point-to-point connmunicaticn. Thus, the subsonoer station determines quali^/ metric of the dedicated forward ilnk channel, reports it back to a tase station and the base staton adjusts the povj-er level of ihe dedk:ated fon*vard link channel. f 111751] • The base staton niay utilize the determined transmit power leve! of the cledicatad forward link channel to detemiine a transmit povver level of tne forwjird linV. i^iiared channel by proper rata translalicn of infora»r3tion trer subscriber station. Ihe base station then adjusts the a transmit powt^r level of the forw^ard link shared channel to satisfy the subscriber station wHh the highest power requirement [IflSOl Because the dQdicated fomard link channel is mcdwiated by sjignaling and overhead infomialion. there may be insufficient activity on the foward link channel to assure sufficient accuracy of cJetemninatlDn of transmit, powar level cf the dedicated fon,vard link channel via the rate iranslation. Constjcjusntly, the base staiicn monitors tf)e activity DO bofh the forward link shared channel and the dedicated foward lifik chaniiel, and sends 'keep-alive' frames on the dedicated f :rA'ard link channel to ensure sufficient activity for accuracy of the rate rjanslation, [lOM] Those of ordinary skill in the ar will recognize that although the varices emhofiiments wore described in terms of flo-vrt/cnarts and methods, such was done foi' pedagogical purposes only. The methods can be performed by an apparatus, vi^hich in one embodirrent comprises a processor interfaced with a transmitter, a receiver and any other appropriate biccks of Ihe AT and/or AP. [J0}!21 Those of ordinary skill in the art would understand that infonnation and signals may be represented using any of a variet/ of difforerrt technologies and techniques. For example, data, insfructions, coaimands, informatriDn. signals, bits, sy^mbols, and chips tiat nay be referonced throughout ihe abcvo descrption may be rep'esented by voltages, currents, eiectfomagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof. (lOJtJj Those of skill would further appreciate that the various illustrative logical blocks, modules, circuits, and algorithm steps described in cor>nectlon with ihe embodiments disdosed herein may be implemented as. etectronfc hard'.vare, computer software, or combinations c( both To cfearfy illustrate this interciangeafc'iiity of hardware and softwars, various iliustrative components, blocks, moGuies, circuits, and steps have bean dascit-ed atx>ve generally in temis cf thair functionality. Whethe'- such functionality is implemented as hardware or software depancs sjpon the particular application and design constraints imposed on the overall system. Skilled artisans may impiement the descrbed funcj'onalit/ In varying ways for each particiilar application, but such implementation decisions should not be interpreted as causing a departure from the scx^e of the present invention. [iOMJ The various IHustralive logical blocks, modules, and circuits described in ccrrtection with the embodiments disclosed herein may be implemented or performed with a general purpose processor, a digilal signal processor (DSP), an cipplicaticn specific integrated circijif (ASIC), a fielcJ programmable gate array (FPGA) or orher proCframmable logic device, diocrete gate or transistor log;C( discrete hardware components, or any connbinattcn thereof designed to perform the functions described heroin. A general purpose processor may be a micioprocer:;.5or. but in the alten^iative, the processor may be ar.y conventional prcc;esscr, controller, microcontroller, or stale machine. A processor may also be iT^plenented as a combination of computing cevices» e.g., a combination of a CSP anc a microprocessor, a plurality of microprocessoi^, one or more microproceiiisors in conjunctioo with a DSP core, or any other such conliguratior. [1085] The steps of a method or algorithm described in connection with the emt»odiments disclosed herein may be embodied directly in hardware, In a sofr/vare module executed by a processor, or in a combination of the two. A sofb/vare nodule may reside in RAM memory, flash memory, ROM memory, EPFIOM rrjemory, EEPROM memory, registers, hard disk, a removable disk, a CD-ROM, c any other form of storage medium, known in the art. An exemplary storage medium is coupled to the processor such the processor can read . information from, end write information to, the storage rT:edium. In the aitecnatrve, the storage medium may be integral to the processor. The proc:essor and the storage medium may reside in an ASfC. The ASIC may reside m a user terminal. In the alternative, the processor and the storage medium may reside as discrete components in a user terminal. [l')86] Tne previous description of the disclosed oTbod^ments is provided to enaJ3le any person skilled in t^.e art to make or use the present invention. Vanous mooifications to these embodiments will be readily apparent to tnose skilled in tns art, and the gene.rc principies defined herein may be applied to other emb'>dimems v/ithout depculing from the spirt or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shcrtvn herein but Is to be accorded the widest scope consistent with the principles a/id novel features disclosed herein. ihiS7] A portion of the disclosure of this palont dc»cument contains materia/, whic:h is subject to copyright protection. The copyright owner has no objection to tfte facsimile reproduction by anyone of the patent document or the patent discJosure, as it appears in Ihis Patent and Trademark Office patent file or records, bul. othenArise resep;es all copyright right;? whatsoever. WHAT IS CLAIMED IS: CLAIMS 1. A method for power control for pomt-to-mullipoht services in a communication system, comprising; determining sectors whose coverage area contain act;ve subscnber stations belonging to a group; and transmitting reverse link power control commands on a forward link shared channel from the determined sectors. 2. The method as claimed in claim 1, wherein said transmitting reveise lin deteimined sectors comprises: puncturing the reverse link power control commands into the forward link sharod channel. 3. The metnod as claimed in claim 1, wherein said transmitting reverse link power control commands on a forward link shared channel from the determined sectors comprises: inserting the reverse link power control commands into tne forward link sharod channel. 4. A method for power control for point-to-multipoint services in a communication system, comprising: receiv:ng at a subscriber station belonging to a group a forward link sharod channel; adjusting at an active suoscriber station belonging to the group reverse link :ransmission power in accordance with the reverse link power control commands contained in the forwati link shared channel. 5. The method as claimed in clam 4, further comprising: ignoring at a passive subscriber station belonging to the group the reverse link power control commands contained in the forwaro link shared chamei. 6. A method for power control for point to-multipoint sen/fees in a communication system, comprising transmitting user data on a forward link shared channel; and transmitting reverse link power control commands on a forward link dedicated channel. 7. The method as claimed in claim 6, wherein said transmitting reverse link power control commands on a forward link dedicated channel composes: puncturing Ihe reverse link power control commands into the forward link dedicated channel. 8. The method as claimed in claim 6, wherein said transmitting revsrso link power control commands on a forward link dedicated channel comprises: inserting the reverse link power control conunnrde into the forward iink dedicated channel. 9. A method for power control for pcint-to-muitipcint services in a commijnication system, comprising receiving at a subscriber station belonging to a group a forward link shared channel; receiving at the subscriber stafcon a forward link cedicat9d channel; and adjusting at an active subscriber station belonging to the group reverse link transmission power in accordance with reverse link power control commijnds contained in the forward link dedicated channel, ■10- A method power centre: for pofnt-to-muJtipoint sc-a'ices in a communication system, comprising determining sectors whose coverage area contain active subscriber stations belonging to a group; and transmitting reverse link power control commands on a forward link dedicated channel from the determined sectors. 11. The method as claimed in claim 10: wherein said transmitting reverse link power control commands on a forward link dedicated channel from the determined sectors comprises: puncturing the reverse link power centre! commands into the forward link dedicated channel. 12. The method as claim 3d in claim 10, wherein said transmitting reverse link power control commands on a forward link dedicated channel from the determined sectors comprises: inserting the reverse link power control commands into the forward link dedicated channel. 13. A method for power control for point-to-mufflpolnt services in a communication system, comprising: receiving at a subscriber station belong ng to a group a forward link shared chanr&l; receiving at each active subscriber station belonging to a gtoup s forward link codicatsd channel; and adjusting at the active subsenber station reverse Sink transmission power in aax>rdance with reverse link power control commands contained in the forward link dedicated channel. 14. A method for power control (or point-txruitipoint services in a communication system, comprising: monitoring at a sector at least one reverse Ink channel to detect a quality metric: of a forward link shared channel; and adjusting the forward link shared channel power in accordance with the worst quality metric. 15. The method as claimed in claim 14, wherein said adjusting the forward link shared channel in accordance with the worst quality metric comprises: decreasing the forward link shared channel power by a second amount if quaity metric of ail of the at leas: one reverse 'ink channel indicate decrease in power. 16. The method as c!ai ned in claim U, wherein said adjusting the forward link shared channel powar in accordance with the worst quality metric comprises: increasing the forward link shared channel power by a second amount if quality metric from at least one of the at least one reverse link channel indicate increase in powsr. 17. A method power control for point-to-multipoint services in a communication system, comprising: determining at each subscriber station belonging to a group a quality metric of a brward link shared channel; and transmitting the determined quality metric. 18. TTe metnod as claimed in claim 17, wherein said transmitting the determined quality metric comprises: transmitting the determined quality metric * the determined quality metric is less than a threshold. 19. The method as claimed in claim IS. wherein said transmitting the determined quality metric if the determined quality metric is less than a threshold comprises: transmitting the determined quality metric :f the*; determined quality metric is less than a pre-determined threshold. 20. The method as claimed in claim 13; further comprising: increasing the threshold by a first amount if an information sent or. the forward link shaded channel is received with sufficient decoder metric. 21. The method as claimed in claim 13, further comprising; decreasing the threshold by a second amount if an information sei'rt on the forward link shared channel is received with insufficient decoder metric. 22. The method as claimed in claim 17, wherein said transmittina the determined quality metric comprises: transmitting the determined quality metric on a reverse link dedicated channel, assigned to said subscriber station. 23. The method as claimed in claim 17, whsrein said transmitting trie determined quality metric comprises: transmitting the determined quality metric on a reverse link common channel, monitored by the subscriber station. 24. Th2 method as claimed in claim 23, wherein said transmitting the determined quality metric comprises: raquesiing by a subscriber station an assignment of a reverse link dedicated channel over the reverse link common channel monitored by ths subscriter station; and transmitting the determined qua'it/ metric en the reverse link dedicated channel 2:5. The method as claimed in claim 24, wherein said requesting by a subscrit>er station an assignment of a reverse link dedicated channel comprises; raquesting by a subscriber station an assignment of a reverse link dedicated channel over an access channel. 2:6. An apparatus for power contrci for pcint-tc-muitipcirn services in a communication system, comprising: rieans for determining sectors whose coverage area contain active subscriter stations belonging to a group; and 27. The apparatus as tialmeti in claim 26, wherein said means for transmitting reverse link power control commands on a forward link shared channel from the determined sectors comprises: mesjiS for puncturing the reverse (ink power control commands into the forward link shared channel. 28. The apparatus as claimed in claim 26, wherein said maans for transmitting reverse link power control commands on a forward link shared channel from the determined sectors comprises: means for inserting the reverse link power control commands into the forward link shared channel. 29. An apparatus for power control for point-to-multipoint services in a communication system, comprising; means for receiving at s subscriber station belonging to a group a forward link shared channel; mears for adjusting at an active subscriber station belonging to the group reve-se Rnk transmission power in accordance witn the reverse link power cont'd commands contained in the forward link shared channel. 30. The apparatus as claimed in claim 29, furtfier compnVng: means for ignoring at a passive subscriber station belonging to the group the reverse link power control commands contained in the forward link shared charne*. Group i 31. An apparatus for power control for point-tc-multipoint services in a communication system, comprising: means for transmitting user data on a forward link shared channel; and means for transmitting reverse iink power control commands on a forward link dedicated channel. 32. The apparatus as claimed In claim 31, wherein said means for transmitting reverse link power control commands on a forward link dedicated channel comprises; means fcr puncturing the reverse link power control commands into the forward link dedicated channel. 33. The apparatus as claimed in claim 31, v/herein said means for transmitting reverse link power control commands on a forward link dedicated channel comprises: means for inserting the reverse link power control commands into the fonvarc link dedicated channel. 34. An apparatus for power control for point-to-multipoint services in a communication system, comprising: means for receiving at a subscriber station belonging to a group a forwaro link shared channel; means for receiving at the subscriber station a forward link dedicated channel; and means for adjusting at an active subscriber station belonging to the group reverse link tiansmfssior power in accordance with reverse link power control commands contained in the forward link dedicated channel. 35. Afi apparatus for power control for point-to-multipoint servces in a communication system, comprising: means for determining sectors whose coverage area contain active subscriber stations belonging to a group; and means for transmitting reverse link power control commands on a forward link dedicated channel from the determined sectors. 36. The apparatus as claimed in claim 35, wherein said means for transm tting reverse link power control commands on a forward iink dedicated channel from the determined sectors comprises: means for puncturing the reverse link power control commands into the forwarc. link dedicated channel. 37. The apparatus as claimed in claim 35, wherein said means for transmitting reverse link power control commands on a forward link dedicated channel from the determined sectors comprises: means for inserting the reverse link power contro! commands into the forward link dedicated channel. 38. An apparatus for power control for point-to-multipoini sen/ices in a communication system, comprising: means for receiving at a subscriber station belonging to a group a forward link shared channel; means for receiving at each active subscribe" station belonging to a group a forward link dedicated channel; and means for adjusting at the active subscriber station reverse link transmission power in accordance with reverse link power control commands conta ned In the forward link dedicatee J channel. 39. An apparatus for power control for po nt to-multipoint services in a ccmrnunicaiicn system, comprising: means for monitoring at a sector al least one reverse fink channel to detec: a quality metric cf a forward link shared channel; and means for adjusting the forward link shared channel power in accordance with the worst quality metric. 40. The apparatus as claimed in claim 39, wherein said means for adjusting the *brward link shared channel in accordance with the worst quality metric: comprises: means for decreasing the forward link shaded channel power by a second amount if quality metric of all of tfie at least one reverse link channel indicate decrease in power. 41. The apparatus as claimed in claim 39, wherein said means for adjusting the forward link shared channel power in accordance with the worst quality metric comprises: means for increasing the forward link shared channel power by a second amount if quality metric from at least one of the at least one reverse link channel indicate increase in power. 42. An apparatus for power control for poht-to-multipoint services in a ?omnunication system, comprising: means for determining at each subscriber station belonging to a group a quality metric of a forward link shared channel; and means for transmitting the determined quality metric. 43. The apparatus as claimed in claim 42, wherein said means for transmitting the determined quality metric comprises: means for transmitting the determined quality metric if the determined quality metric is less than a threshold. 44. The apparatus as claimed in claim 43, wherein said means for transmitting tte? determined quality metric if the determined quality metric is less lhan a threshold comprises: means for transmitting the determined quality metric if the determined quality metric is (ess than a pre-determlned threshold. 45. The apparatus as claimed in claim 43, further comprising: means for increasing the threshold by a first amount if an information sent on the toward fink shared channel is received with sufficient decoder matrix. 46. The apparatus as claimed In ciaim 43, further comprising, means for decreasing the threshold by a second amount if an information sent on the toward link shared channel is received with insufficient decoder matrix. 47. The apparatus as claimed In claim 42, wherein said means for transmitting the determined quality metric comprises: means lor transmitting the determined quality metric on a reverse link dedicatee! charnel, assigned to said subsenber station. 48 The apparatus as claimed in claim 42, wherein said means fc-transmitting the determined quality metric comprises: means lor transmitting the determined quality metric en a revise link common charnel monitored by the subscribed staticn. 49. The apparatus as ciaimed in claim 48, wherein said means for transmitting the determined quality metric comprises: mean* for requesting by a subscriber staticn an assignment of a reverse link dedicated channel over the reverse link common channel monitored by the subscriber station; and means for transmitting the determined quality metric on the reverse link dedicated channel. 50. ""Tie apparatjs as ciamed in claim 49, wherein saic means for requesting by a subscriber station an assignment of a reverse link dedicated channel comprises: means for requesting by a subscriber station an assignment of a reverse link dedicated channel ever an access channel. 51. An apparatus for pov*er control for pofnt-tomultipoint services in a communication system, composing: a cor.t'ol unit at an access network configured to determine sectors wnose coverage area contain active subscriber stations belonging to a group; and ; a sector communicatively coupied to said control unit, configured ic transmit reverse link power control commands on a forward link shared channel. 52. Tne apparatus as claimed in claim 51, wherein said sector transmits reverse link power control commands on a forward iink shared channel by being configured to puncture the reverse link power control commands jnto the forward link shared channel. :53. The apparatus as claimed in claim 51, wherein said sector ■;ransnVts reverie link power control commands on a forward link shared shannei by bei ig configured to inset the reverse link power control commands ,ito the forward link shared channel. 54. An apparatjs for power control for point-to-multipoint services in a communication system, comprising: a subscriber station configured to: receive a forward link shared channel: and adjust reverse link transmission power in accordance with the /averse link power control commands contained in the forward link shared channel. 55. The apparatus as claimed in claim 54, wherein said subscriber Mation is further configured to ignore the reverse lin* power control commands ; ontaired in ths forward link shared channel if saio subscrioer station does not iransmt on a reverse link. 56. fin apparatus for power icnuoi for poirt-io-mult/po/nt services in a communication system, comprising: i sector configured to: transmit user data on a forward iink shared channel; and transmit reverse link power control commands on a forward link dedicated channel- 57. The apparatus as claimed in claim 56, wherein said sector :ransm:ts reverse link power control commands on a forward iink dedicated banned by being configured to puncture the reverse iink power control commands into the forward link dedicated channel, 38. The apparatus as claimed in claim 56, wherein said sector transmits reverse link power control commands on a forward link dedicated channel by being configured to insert the reverse firk power control commands ir:o the :oiward link dedicated channel 59. An apparatus for power control for point-to-muitipoint services in a communication system, comprising: a subscriber station configured to* receive a forward link shared channel; receive a forward link dedicated channel; and adjust reverse link transmission power in accordance with revere link power control commands contained in the forward link dedicatee channel. 60. An apparatus for power control for pota-to-multipoint sen/ices in a cornmur icatior. system, comprising: a control unit at an access network configured to determine sectors whose coverage area contain active subscriber stations belonging to a group; a id a sector communicatively coupled to said control unit, configured to transmit reverse link power control cornmanas en a forward link dedicated channel from the determined sectors. 61. The apparatus as claim-sd in cfaim 60, wherein said transmits reverse ink power control commands on a forward Ink dedicated channel by being cenfigured to puncture the reverse I nk power control commands into the ft-ward ink dedicated channel. 62. The apparatus as claimed in ciaim 60, wherein said sector transmits reverse iink power control commands on a forward link dedicated channel by being configured to insert the reverse link power control commands into the forward iink dedicated channel. 63. An apparatus for power control for poinMo-rnultipoint sen/ices in a Oiimmunication system, comprising: information sent on the forward link shared channel is received with sufficient decoder metric 70. The apparatus as claimed in claim 67, wherein said subscriber station is further configured to decrease the threshold by a second amount if an information sent on the forward link snared channel is received with insufficient decoder metric. 71. The apparatus as claimed in claim 66, wherein said subscriber station is further configured to transrrit the determined quality metric on a raverse link dedicated channel, assigned to said subscriber station. 72. The apparatus as claimed in claim 68, wherein said subscriber station is further configured to transmit the determined quality metric on a reverse link common channel monitored by the subscriber station. 73. The apparatus as claimed in claim 66, wherein said subscriber station is further configured to: request an assignment of a reverse iink dedicated channel over the reverse link common channel monitored by the subscriber station; and trans-nit the determined quality metric on the reverse link dedicated channel. 74. The apparatus as claimed i^ claim 73, wherein said subscriber station is further configured to request an assignment of a reverse link dedicated channel over an access channel. A method for power control for point-to-multipoint services in a communication system substantially as herein described with reference to the accompanying drawings. An apparatus for power control for point-to-multipoint services in a communication system substantially as herein described with reference to the accompanying drawings.

Documents:

1540-chenp-2003 abstract granted.pdf

1540-chenp-2003 claims granted.pdf

1540-chenp-2003 description (complete) granted.pdf

1540-chenp-2003 drawing granted.pdf

1540-chenp-2003-claims.pdf

1540-chenp-2003-correspondnece-others.pdf

1540-chenp-2003-correspondnece-po.pdf

1540-chenp-2003-description(complete).pdf

1540-chenp-2003-drawings.pdf

1540-chenp-2003-form 18.pdf

1540-chenp-2003-form 3.pdf

1540-chenp-2003-form 5.pdf

1540-chenp-2003-pct.pdf