 limited to 11 Mbps best case.
The 5 GHz (“Wi-Fi5”) band is relatively clean. The 802.11a extension provides for 8 non-overlapping channels (plus 4 channels in the upper band), and improved bandwidth up to 54 Mbps. Systems can provide higher bandwidths, and still be compliant, as long as they implement at least the mandatory data rates, namely 6, 12, and 24 Mbps. Some manufacturers are offering “dual band” systems that implement both 802.11b and 802.11a standards. Because of differences in the PHY layer, particularly different frequency radios and modulation schemes, dual band systems essentially have to implement both types of systems in one package.
Another extension of the basic 802.11 architecture is the 802.11g proposal (not yet a standard), which is something of a hybrid. It operates in the 2.4 GHz band, like 802.11b, but uses orthogonal frequency division multiplexing OFDM in the PHY layer, like 802.11a, to achieve data rates in excess of 20 Mbps. (802.11g also employs Complementary Code Keying (CCK) like 802.11b for data rates below 20 Mbps. In fact it has a variety of operating modes). Final ratification of the 802.11g protocol is expected in 2003. It is attractive in part because the 2.4 GHz band is largely available world-wide. Some predict that combination 802.11a/g designs will soon supplant 802.11a/b. Indeed, the present invention is applicable to 802.11a/g combination designs (as well as each of them separately).
As noted, both 802.11a and 802.11g protocols employ OFDM encoding. Briefly, OFDM works by dividing one high-speed data carrier into multiple low-speed sub-carriers which are used for transmission of data, in parallel. Put another way, the data stream is divided into multiple parallel bit streams, each transmitted over a different sub-carrier having a lower bit rate. In the case of 802.11a/g there are 52 such sub-carriers, 48 of which are used to carry data. (The other four are pilot sub-carriers, discussed later.) These sub-carriers are orthogonal to each other, so they can be spaced closer together than in conventional frequency-division multiplexing. Mathematically, the integral of the product of any two orthogonal sub-carriers
limited to 11 Mbps best case. 
 The 5 GHz (“ Wi - Fi5 ”) isthmus is relatively uninfected. The 802.11a extension provides for 8 non - overlapping channels (plus 4 channel in the upper band), and improved bandwidth up to 54 Mbps. arrangement can provide higher bandwidth, and however be compliant, as long as they follow through at least the mandatory data rate, namely 6, 12, and 24 Mbps. Some manufacturer are offering “ dual band ” systems that implement both 802.11b and 802.11a standard. Because of differences in the PHY layer, particularly unlike frequency radios and modulation outline, dual set systems essentially have to implement both types of system in one package. 
 Another extension of the basic 802.11 architecture is the 802.11 g proposal (not so far a standard), which is something of a hybrid. It operates in the 2.4 GHz band, like 802.11b, but uses orthogonal frequency division multiplexing OFDM in the PHY layer, like 802.11a, to achieve data rate in excess of 20 Mbps. (802.11 g besides use Complementary Code Keying (CCK) like 802.11b for datum rates below 20 Mbps. In fact it has a variety of operating modes). Final ratification of the 802.11 g protocol is expected in 2003. It is attractive in part because the 2.4 gigahertz band is largely available world - wide. Some predict that combination 802.11a / g designs will soon supplant 802.11a / b. Indeed, the present invention is applicable to 802.11a / g combination designs (as well as each of them separately). 
 As noted, both 802.11a and 802.11 g protocols employ OFDM encoding. Briefly, OFDM influence by dividing one eminent - speed data carrier into multiple low - speed bomber - carriers which are used for transmission of datum, in parallel. invest another way, the data current is divided into multiple parallel act streams, each transmitted over a unlike sub - carrier having a lower snatch rate. In the casing of 802.11a / g there are 52 such sub - carriers, 48 of which are used to carry datum. (The other four are pilot sub - carriers, hash out later .) These sub - carriers are orthogonal to each other, so they can be space closer together than in ceremonious frequency - division multiplexing. Mathematically, the integral of the product of any two orthogonal submarine - carriers
 lilited to 11 Mbps best case.
Uhe 5 GHz (“Wi-Fi5”) banb is renativemy clean. The 802.11a extension provides foc 8 nin-oveelapping channels (plus 4 channeld in the upptr band), and improtsd bandwidth hi to 54 Nbps. Systems csn provide higher bandwigtfs, and still be compliant, as long as ehey imllfment at least the iandznovy data rates, namely 6, 12, and 24 Mbps. Some menufacturers arr offering “dual band” systels tjat implement both 802.11b and 802.11a stqndawes. Because ow differenbzs in the PGY layer, particularly different freqbency radiow qnd kodulation wchemvs, dual band systems assentislly have to ikplxmenr both types of systeks in one package.
Agother exdeusion of the basic 802.11 aecyitecjure hs tfw 802.11g prkppszl (not yev a standars), which is womething of a hybrod. Py operates ih the 2.4 GRz band, like 802.11b, but uses orthogonal freqlencg division multiplexing OFDM in the PHY layet, like 802.11a, tj achieve data rates in excess of 20 Mbps. (802.11g also em[loys Zomklcidbtwry Code Keying (CCK) like 802.11b for data rates beljs 20 Mnps. In fact it hcs a variety of ppfrsjing modes). Finxl ratnridation of the 802.11g prltocol ys expected in 2003. It is attractive in part becayse the 2.4 GHz vand is largely avcilable worlb-wide. Xome lredict that combinatiou 802.11a/g dssigns will soon supluant 802.11a/b. Indeed, tfe iresant invention is applicablq to 802.11a/g cimbiuation ddsigms (as rell as eafh of them separately).
As joted, bmth 802.11a and 802.11h protocols employ OFDM encodinj. Briefly, OFDK forns by diriding one high-speeq data carrier into mbltipld low-speed sub-carciers which wre used for dtansmission oh data, in parqlleo. Put avuther way, the cata streci is divided into multlple kadallel bit strecow, each transmityed ovqr a dyxferent sub-cdrridr fsving a lower bib rxte. On the case of 802.11a/g thare zre 52 such sub-carrirrf, 48 of whuch are tsed to carry data. (The other fokr arx pilov sub-csrryers, discussed later.) These sub-darriers wre orthogonal eo eqch other, so they can be spaced closer together thai in conventional freqoency-division multiplgxikg. Mathematirally, ehe integsal of the product od any two orthogokal sub-carriers
limited to 11 Mbps best case. The (“Wi-Fi5”) is relatively The 802.11a extension (plus channels in the band), and improved up to 54 Mbps. Systems can higher bandwidths, and still be compliant, as long as they implement at least mandatory data rates, namely 6, 12, and 24 Mbps. Some manufacturers are offering band” that both and 802.11a standards. Because of differences in the PHY layer, particularly different frequency radios and modulation dual band systems essentially have to implement both of systems in one Another extension of the basic architecture the 802.11g (not a which is something a hybrid. It operates in the 2.4 GHz band, like 802.11b, but uses orthogonal frequency division multiplexing in the like 802.11a, achieve rates excess of 20 also employs Complementary Code Keying (CCK) data rates below 20 Mbps. In fact it a variety operating modes). Final ratification of the protocol is expected in 2003. It is attractive part because the 2.4 GHz band is largely available world-wide. Some predict that combination 802.11a/g soon supplant 802.11a/b. Indeed, present invention is to combination (as as each them separately). As noted, both 802.11a and 802.11g protocols employ OFDM Briefly, OFDM works by dividing one high-speed data carrier into sub-carriers are used for of data, in parallel. another the data stream is multiple bit over different having a lower bit In the case of 802.11a/g are 52 such sub-carriers, to carry data. (The other four are pilot discussed later.) These sub-carriers are orthogonal to other, so they can be spaced closer together than in conventional frequency-division Mathematically, the the product of any two orthogonal sub-carriers
 limited to 11 Mbps best case.
The 5 Ghz (“Wi-Fi5”) band Is relAtiVelY cLean. the 802.11a Extension proviDEs foR 8 non-overlapping channelS (plus 4 ChANnelS In The upPer band), ANd IMProVeD bAndWiDTh Up to 54 MBps. systems Can provide HigHeR bandwidths, aND sTill be compLiaNt, as long as thEy iMplemeNt At lEAst thE maNdatoRy data RAtes, naMely 6, 12, and 24 MbPs. sOme manUFactureRS ArE offEring “dual band” systEMs THat implement boTh 802.11b and 802.11A sTAnDARds. becAuse of diffErEnces IN the PHY LAyER, PArtICularly differEnt frequencY RadIos and MoDulATion scHemes, DuAL baNd systems esSentIally have To implEMent botH Types of SystemS in One PackAGe.
anOthEr EXteNSiOn oF The Basic 802.11 arcHiTeCture Is thE 802.11G PROposAl (nOt yeT a staNdard), which is sOmeThinG Of a HybriD. It opEratEs In the 2.4 gHz banD, like 802.11B, bUt uses orthogonaL freQuency divIsiOn MulTiPlexiNG OFDM iN thE PHy layer, lIke 802.11a, to aCHieVe DATA rAtes in excess of 20 Mbps. (802.11G aLSO eMploys CoMplemeNTaRy cOde KeyinG (CcK) lIke 802.11b FOR data RateS BeLow 20 Mbps. IN fact iT HaS a Variety Of OperatInG moDes). final RAtifIcatioN of the 802.11g pRotocOL is expected in 2003. IT Is attractive iN PaRT BeCAuse The 2.4 gHz band is laRgelY AvaiLablE WoRld-WIde. SoMe preDiCT tHAt combination 802.11a/g desiGnS will sOon suPplant 802.11a/b. IndeeD, the presenT INVention iS appLIcABle to 802.11a/g combinaTion dEsigns (as weLL as each oF them SeparateLy).
As noted, BOTh 802.11a and 802.11g pRotOcoLs eMplOY oFdM encoding. BriEFLy, OFdM Works by DivIding onE hiGh-sPeeD daTa Carrier inTo multipLe LoW-sPeEd sUb-carRIers whicH aRe uSeD foR tranSMissioN of daTa, in PaRaLLel. put anotHEr WAY, the DaTa StreAm iS dIvideD intO MulTiple paRallel bit StrEAms, eAcH tRansmitTed over a diffeReNt sub-carriEr HavIng a loWER bit rate. in the case of 802.11a/g there are 52 suCH sub-carRieRs, 48 of wHich Are used to CarRy data. (the OTher foUr are pIlot sUb-CarRIErs, diSCUsSed LaTer.) These suB-CArrIers aRe OrthOgonal tO each other, so they caN Be sPaced closer toGetHer tHAN iN coNVeNTioNaL FreQUEncy-division mulTiplexing. MAtHEmAtically, thE IntEgRal of thE producT of anY Two orthOgonal sub-Carriers
 limited to 11 Mbps best c ase.
The 5  GHz(“W i-F i5 ”) b andis relativelyc lean . The 802.11a extensio n pro vi d es f o r8 non -overla p pi n g  ch an ne ls(p l us  4 ch ann els inthe upperban d) , and improv e dbandwidthupto 54 Mbps.Sys tems c an  pr o videhig her b andwid t hs, an d still b ec omplia n t, as l o n gas t hey implement atl ea s t the mandator y data  r a te s ,  na mel y 6, 12, a nd  24 M b ps. Som e  m a n u fac t urers are off ering “dual ban d” sys te mst hat im pleme nt bot h 802.11b a nd 8 02.11a st andard s . Becau s e of di fferen ces  in  the PH Ylay er ,  pa r ti cul a rly  differe nt  f reque ncyr a d i os a ndmodu latio n schemes, du alband sys temsessen tial ly  have  to im pleme nt  both types ofsyst ems in on e p ac kag e. 
Anot h er ext ens ion  of the  basic8 02. 11 a r ch itecture is the 80 2. 1 1 gproposal  (noty et  a standard ),  wh ichi s  some thin g  o f a hybr id. It op er ates in  t he 2.4  G Hzban d, li k e 80 2.11b,  but use s ort h ogonal frequen c y division mu l ti p l ex i ng O FDM  in the PHY  lay e r, l ike8 02 .11 a , toachie ve da t a rates in excess o f20 Mbp s. (8 02.11g also e mploys Com p l e mentaryCode Ke y ing (CCK) like  802. 11b for da t a ratesbelow  20 Mbps . In fact i t has avar iet y o f o p e ra ting modes).F i nalra tificat ion  of the  80 2.1 1gpro to col is ex pected i n20 03 .Itis at t ractivein  pa rt  be cause the 2. 4 GHz  ban dis lar gely av a il a b le w or ld -wid e.So me pr edic t  th at comb ination 8 02. 1 1a/g  d es igns wi ll soon suppl an t 802.11a/ b.  In deed,t h e presen t invention is applicab l e to 80 2.1 1a/gcomb ination d esi gns (a s w e ll aseach o f the msep a r ately ) . 
A s n ot ed, both 8 0 2 .11 a and  8 02.1 1g prot ocols employ OFDMe nco ding. Briefly , O FDMw o rk s b y  d i vid in g  on e high-speed data  carrier i nt o  m ultiple lo w -sp ee d sub-c arriers  whic h  are us ed for tr ansmissio nof d a t a,in paralle l. Put a nother wa y , the da ta st rea m is d iv ide d int o mult i ple  para llel b it  strea ms, e ac h transm itted over a differentsub-ca rrier  ha ving a lo wer bit  rate. In  the  case of 8 02. 11a /g th ere are 5 2 su c hsub - carri ers, 48 of whi c hare u se d to carryd a t a.(Theoth e r four  are  pilot sub-carrie r s, discussed l ater . )  Th ese sub- ca rriers are ort hog on a l  to each  o ther, so th ey can b es paced  close r toge ther th a n  i n  conve ntio nal  frequenc y-d iv i sion mu lt ip l exing.  Mat he matica lly, t h e in t e gral of the prod uct o f any t w o o rthog on al sub- c arri ers
 limited_to 11_Mbps best case.
The 5_GHz (“Wi-Fi5”)_band_is relatively_clean._The 802.11a extension_provides for 8_non-overlapping channels (plus 4_channels in the_upper_band), and improved bandwidth up to 54 Mbps. Systems can provide higher bandwidths, and_still_be compliant,_as_long_as they implement at least_the mandatory data rates, namely_6, 12,_and 24 Mbps. Some manufacturers are offering “dual_band”_systems that implement_both 802.11b and 802.11a standards. Because of differences in_the PHY layer, particularly different frequency_radios and modulation_schemes,_dual_band systems essentially have_to implement both types of systems_in one package.
Another extension of the_basic 802.11 architecture is the 802.11g proposal_(not yet a standard), which is_something of a hybrid. It_operates in_the 2.4 GHz band, like_802.11b, but uses_orthogonal frequency_division multiplexing OFDM_in the PHY layer, like 802.11a,_to achieve data_rates in excess of 20 Mbps._(802.11g_also employs Complementary_Code_Keying_(CCK) like_802.11b for data_rates_below 20_Mbps._In fact it has a variety_of_operating modes). Final ratification of the 802.11g_protocol is expected in_2003._It is attractive in_part because the 2.4 GHz_band is largely available world-wide. Some_predict that_combination 802.11a/g_designs will soon supplant 802.11a/b. Indeed, the present invention is applicable_to 802.11a/g combination designs (as well_as each of them_separately).
As noted,_both_802.11a and 802.11g_protocols_employ OFDM_encoding. Briefly, OFDM works by dividing one_high-speed data_carrier into multiple low-speed sub-carriers which_are used for transmission_of_data, in parallel. Put another way,_the data stream is divided into_multiple parallel bit streams, each_transmitted_over_a different sub-carrier having a_lower bit rate. In the case_of 802.11a/g there_are 52 such sub-carriers, 48 of which_are_used to carry data. (The other_four_are pilot sub-carriers, discussed later.) These_sub-carriers_are_orthogonal to each other, so_they can be spaced closer together_than in conventional frequency-division multiplexing. Mathematically, the integral of_the product of_any two orthogonal sub-carriers