BACKGROUND OFTHEINVENTION 1. Field ofthe Invention The invention relates generally to wireless communication and more particularly to systems and methods for wireless communication overawide bandwidth channel using a plurality of sub-channels. 2. Background Wireless communication systems are proliferating at the Wide Area Network (WAN), Local Area Network (LAN), and Personal Area Network (PAN) levels. These wireless communication systems use a variety of techniques to allow simultaneous access to multiple users. The most common of these techniques are Frequency Division Multiple Access (FDMA), which assigns specific frequencies to each user, Time Division Multiple Access (TDMA), which assigns particular time slots to each user, and Code Division Multiple Access (CDMA), which assigns specific codes to each user. But these wireless communication systems and various modulation techniques are afflicted by a host of problems that limit the capacity and the quality of service provided to the users. The following paragraphs briefly describe a few of these problems torthe purpose ofillustration. One problem thatcan exist ina wireless communication system ismultipalh interference. Multipath interference, or muMpath, occurs because some ofthe energy in a transmitted wireless signal bounces offof obstacles, such as buildings or mountains, as it travels from source to destination The obstacles in effect create reflections of the transmitted signal and the more obstacles there are, themore reflections they generate. The reflections then travel along their own transmission paths to the destination (or receiver). The reflections will contain the same information as the original signal; however, because of the differing transmission path lengths, the reflected signals will be out of phase with the original signal As a result, they will often combine destructively with the original signal in the receiver. This is referred to as fading. To combat fading, current systems typically try to estimate the multipath effects and then compensate for them in the receiver using an equalizer. In practice, however, it is very difficult to achieve effective multipath compensation. A second problem that can affect the operation of wireless communication systems is interference from adjacent communication cells within the system In FDMA/TDMA systems, this type of interference is prevented through a frequency reuse plan Under a frequency reuse plan, available communication frequencies are allocated to communication cells within the communication system such that the same frequency will not be used in adjacent cells. Essentially, the available frequencies are split into groups. Thenumberofgroupsistermedthereuse factor. Thenthe communication cells are grouped into clusters, each cluster containing the same number of cells as there are frequency groups. Each frequency group isthen assigned to acell in each cluster. Thus, if a frequency reuse factor of 7 is used, for example, then a particular communication frequency will be used only once in every seven communication cells. As a result, in any group of seven communication cells, each cell can only use Iff* of the available frequencies, Le., each cell is only able to use I//1 of the available bandwidth. In aCDMA communication system, eachcelluses thesame wideband communication channel. In older to avoid interference with adjacent cells, each communication cell uses a particular set of spread spectrum codes to differentiate communications within thecell from those originating outside ofthe cell Thus, CDMA systems preserve the bandwidth in the sense that they avoid limitations inherent to conventional reuse planning. But as will be discussed, there are other issues that limit the bandwidth inCDMA systems aswell Thus, in overcoming interference, system bandwidth is often sacrificed. Bandwidth is becoming a very valuable commodity as wireless communication systems continue to expand by adding moreand more users. Therefore, trading off bandwidth for system performance is a costly, albeit necessary, proposition that is inherent in all wireless communication systems. The foregoing arejusttwo examples ofthe types of problems thatcan affect conventional wireless carmiunication systems. The examples also illustrate that there aremany aspects of wireless communication system performance thatcanbe improvedthroughsystemsandmethodsthat,forexample,reduceinterf ererK^increase bandwidth, orboth. Not only are conventional wireless communication systems effected by problems, such as those described in the preceding paragraphs, but also different types of systems are effected in different ways and to different degrees. Wireless communication systems can be split into three types: 1) Kne-of-signt systems, which can include point-to-point or point-to- multipoint systems; 2) indoor non-line of sight systems; and 3) outdoor systems such as wireless WANs. line-of-sight systems are least affected by the problems described above, while indoor systems are more affected, due for example to signals bouncing off of building walls. Outdoorsystems areby fartire most affected ofthe three systems. Because these types of problems are limiting factors in the design of wireless transmitters and receivers, such designs must be tailored to the specific types of system in which it will operate, In practice, each type of system implements unique communication standards that address the issues unique to the particular type of system Even if an indoor system used the same communication protocols and modulation techniques as an outdoor system, for example, the receiver designs would still be different because multipath and other problems are unique to a given type of system and must be addressed with unique solutions. This would not necessarily be the case if cost efficient and effective methodologies can be developed to combat such problems as described above that build in programmability so that a device can be reconfigured for different types of systems and still maintain superior performance. SUMMARYOFTHEINVENTION In order to combat the above problems, the systems and methods described herein provide a novel channel access technology that provides a cost efficient and effective methodology that builds in programmability so that a device can be reconfigured for different types of systems and still maintain superior performance. In one aspect of the invention, a method of communicating ova a wideband-communication channel divided into a plurality of sub-channels is provided. The method comprises dividing a single serial message intended foroneof the plurality of communication devices into a plurality of parallel messages, encoding each of the plurality of parallel messages onto at least some of the plurality of sub-channels, and transmitting the encoded plurality of parallel messages to the communication device over the wideband communication channel. When symbols are restricted to particular range of values, the transmitters and receivers can be simplified to eliminate high power consuming components such as a local oscillator, synthesizer and phase locked loops. Thus, in one aspect a transmitter comprises a plurality of pulse converters and differential amplifiers, to convert a balanced trinary data stream into a pulse sequence which can be filtered to reside in the desired frequency ranges and phase. The use of the balanced trinary data stream allows conventional components to be replaced by less costly, smaller components that consume less power. Similarly, in another aspect, a receiver comprises detection of the magnitude and phase ofthe symbols, which can be achieved with an envelope detector and sign detector respectively. Thus, conventional receiver components can be replaced byless costly, smaller components that consume less power. Other aspects, advantages, and novel features ofthe invention will become apparent from the following Detailed Description ofPreferred Ernbodiments, when considered in conjunction withthe accompanying drawings. BRIEF DESCRIPTION OFTHE DRAWINGS Preferred embodiments ofthe present inventions taught herein are illustrated by way of example, andnotby way of limitation, in the figures ofthe accompanying drawings, in which: Figure 1 is a diagram illustrating an example embodiment of a wideband channel divided into a plurality of sub-channels in accordance with the invention; Figure 2 is a diagram illustrating the effects ofmultipathina wireless communication system; Figure 3 is a diagram illustrating another example embodiment ofa wideband communication channel divided into a plurality of sub-channels in accordance with the invention; Figure 4 is a diagram illustrating the application of a roll-off factor to the sub-channels of figures 1 , 2 and 3; Figure 5A is a diagram illustrating the assignment of sub-channels tor a wideband communication channel in accordance with the invention; Figure 5B is a diagram illustrating the assignment of time slots for a wideband communication channel in accordance with the invention; Figure 6 is a diagram illustrating an example embodiment of a wireless communication in accordance with the invention; Figure 7 is a diagram illustrating the useof synchronization codes in the wireless communication system of figure 6 in accordance withthe invention; Figure 8 is a diagram illustrating a correlator that can be used to correlate synchronization codes in the wireless communication system of figure 6; Figure9isadiagramillustratingsynchronizationcode∞irelation macxx3idancewiththe invention; Figure 10 is a diagram illustrating the cross-correlation properties of synchronization codes configured in accordance withthe invention; Figure 11 is a diagram illustrating another example embodiment of a wireless communication system in accordance with the invention; Figure 12A is a diagram illustrating how sub-channels of a wideband communication channel according to the present invention canbe grouped in accordance with the present invention; Figure 12B is a diagram illustrating the assignment of the groups of sub-channels of figure 12A in accordance with the invention; Figure 13 isadiagramillustratingthegroupassignmentsoffigure 12Binthetimedomain; Figure 14 is a flow chart illustrating the assignment of sub-channels based on SIR measurements in the wireless communication system of figure 11 in accordance withthe invention; Figure 15 is a logical block diagram of an example embodiment of transmitter configured in accordance with the invention; Figure 16 is a logical block diagram of an example embodiment of a modulator configured in accordance with the present invention foruseinthe transmitierof figure 15; Figure 17 is a diagram illustrating an example embodiment of a rate controller configured in accordance with the inventionforuseinthemodulatoroffigure 16; Figure 18 is a diagram illustrating another example embodiment of arate controller configured in accordance with the invention for useinthe modulator of figure 16; Figure 19 is adiagram illustratingan exampleembodimentofa maccordancewifli the invention foruseinthe modulator of figure 16; Figure 20 is a logical block diagram of an example embodiment of aTDMFDM block configured in accordance withthe invention foruseinthe modulator of figure 16; Figure 21 is a logical block diagram of another example embodiment of a TDM/FDM block configured in accordance with the invention foruseinthe modulator of figure 16; Figure 22 is a logical block diagram of an example embodiment of a frequency shifter configured in accordance withthe invention foruseinthe modulator offigure 16; Figure 23 isa logical block diagram ofa receiver configured in accordance with die invention; Figure 24 is a logical block diagram of an example embodiment of a demodulator configured in accordance with the invention for usein the receiver of figure 23; Figure 25 is a logical block diagram of an example embodiment of an equalizer configured in accordance with the present invention foruseinthe demodulator of figure 24; Figure 26 isa logical block diagram of an example embodiment of a wireless communication device configured in accordance with the invention; Figure 27 is a flow chart illustrating an exemplary method for recovering bandwidth in a wireless communication network in accordance withthe invention; Figure 28 isa diagram illustrating an exemplary wireless communication network in which the method of figure 27 canbe implemented; Figure29isalogicalblockdiagramillustratinganexemplarytransmi tta-fliatcanbeusedinthe network offigure 28 to implement the method of figure 27; Figure 30 is a logical block diagram illustrating another exemplary transmitter that can be used in the network of figure 28 to implement the method of figure 27; Figure 31 is a diagram illustrating another exemplary wireless communication network in which the method of figure 27canbe implemented; Figure 32 isa diagram illustrating an example receiver configured to implement path diversity, Figure 33 isa diagram illustrating correlated multipath signals received using the receiver of figure 33; and Figure 34 is a diagram illustrating a receiver configured to implement switching diversity in accordance with the systemsandmethodsdescribedherein DETAILED DESCRIPTION OFTHE PREFERRED EMBODIMENTS 1. Introduction In order to improve wireless communication system performance and allow a single device tomove fiomonetype of system to another, while still maintaining superiorperformance, the systems and methods described herein provide various communication methodologies that enhance performance of transmitters and receivers with regard to various common problemsthatafflictsuchsystemsandthatallowthetransmitters and/or receivers tobereccMguredfø in a variety of systems. Accordingly, the systems and methods described herein define a channel access protocol that uses a common wideband communication channel for all communication cells. The wideband channel, however, is then divided into a plurality of sub-channels. Different sub-channels are then assigned to one or more users within each cell But the base station, or service access point, within each cell transmits one message that occupies the entire bandwidth ofthe wideband channel. Each user's communication device receives the entire message, but only decodes those portions of the message that reside in sub-channels assigned to the user. For a poirt-to-point system, for example, a single user may be assigned all sub-channels and, therefore, has the full wide band channel available to them. In a wireless WAN, on the other hand, the sub-channels maybe divided among a plurality of users. Inthe descriptions of example embodiments that follow, implementation differences, or unique concerns, relating to differenttypesofsystemswillbepointedouttotheextentpossible. Butitshouldbeunderstoodthatthesystemsandmethods described herein are applicable to any type of communication systems. In addition, terms such as communication cell, base station, service access point, etc. areused interchangeably to refer to the common aspects of networks at these different levels. To begin illustrating the advantages ofthe systems and methods described herein, one can start by looking at the multipath effects for a single wideband communication channel 100 of bandwidth B as shown in figure IA Communications sent over channel 100in a traditional wireless communication system will comprise digital data symbols, or symbols, that are encoded and modulated onto a RF carriσ that is centered at frequency fc and occupies bandwidth B. Generally, the width of the symbols (or the symbol duration) T is defined as IfB. Thus, if the bandwidth B is equal to 1OOMHz, thenthe symbol duration 7is defined bythe following equation: T= IfB = 1/100MHZ= 10ns. (1) When a receiver receives the communication, demodulates it, and then decodes it, it will recreate a stream 104 of data symbols 106as illustrated in figure 2. Butthereceiverwill alsoreceivemultipath versions 108 ofthesamedata stream Becausemultipathdatastreams 108aredelayedintimerelativetodatastream 104by delaysdl,d2,d3,andd4,for example, theymay combine destructively withdata stream 104. A delay spread 4is defined asthe delay from reception ofdata stream 104to the reception ofthe last multipath data stream 108 that interferes with the reception of data stream 104. Thus, in the example illustrated in figure 2, the delay spread ds is equal to delay d4. The delay spread ds will vary for different environments. An environment with a lot of obstacles will create a lot of multipath reflections. Thus, the delay spread 4 will be longer. Experiments have shown that for outdoor WAN type environments, the delay spread ds canbe as long as 20μs. Using the 10ns symbol duration of equation (1), this translates to 2000 symbols. Thus, with a very large bandwidth, such as lOOMHz, multipath interference can cause a significant amount of interference at the symbol level for which adequate compensation is difficult to achieve. This is true even for indoor environments. For indoor LAN type systems, the delay spread 4 is significantly shorter, typically about 1us. Fora 10nssymbolduration,thisisequivalentto 100symbols,which ismere manageable but stillsignificanL By segmenting the bandwidth B into a plurality of sub-channels 200, as illustrated in figure 3, and generating a distinct data stream for each sub-channel, the multipath effect can be reduced to a much more manageable leveL For example, ifthe bandwidth B of each sub-channel 200 is 500KHz, then the symbol duration is 2μs. Thus, the delay spread ds for each sutxhannel is equivalent to only 10 symbols (outdoor) or half a symbol (indoor). Thus, by breaking up a message that occupies the entire bandwidth B into discrete messages, each occupying the bandwidth B of sub-channels 200, a very wideband signal that suffers from relatively minor multipath effects is created. Before discussing further features and advantages of using a wideband communication channel segmented into a plurality of sub-channels as described, certain aspects of die sub-channels will be explained in more detail. Referring back to Thus, the sub-channel 200 that is immediately to the right offc is offset from fc by b/2, where b isthe bandwidth of each sub-channel 200. The next sub-channel 200 isoffset by 3b/2, thenextby 5b/2, andsoon To the leftof fc, each sub-channel 200is offset by -b/s, -3b/s, - 5b/2,etc. Preferably, sub-channels 200arenon-overlapping as this allows each sub-channel tobe processed independently in the receiver. To accomplish this, a roll-off factor is preferably applied to the signals in each sub-channel in a pulse-shaping step. The effect of such a pulse-shaping step is illustrated in figure 3 by the non-rectangular shape ofthe pulses in each sub-channel 200. Thus, the bandwidth B ofeach sub-channel canbe represented byan equation suchasthe following: b = 0+r)/T; (2) Where r = the roll-off factor, and T= the symbol duration Without the roll-off factor, i.e., b = IfT, the pulse shape would be rectangular in the frequency domain, which

ordertoillustratetheproblemsassociatedwitharectangularpul seshape andtheneedtousea roll-offfactor. As canbe seen, main lobe402 comprises almost all of signal 400. But someof the signal also resides in side lobes 404, which stretch out indefinitely inboth directions frommain lobe402. Side lobes 404make processing signal 400much more difficult, which increases the complexity of the receiver. Applying a roll-offfactor r, as in equation (2), causes signal 400 to decay faster, reducing the number of side lobes 404. Thus, increasing the roll-off factor decreases the length of signal 400, i.e., signal 400 becomes shorter in time. But including the roll-off factor also decreases the available bandwidth in each sub-channel 200. Therefore, r mustbe selected so as to reduce the number of side lobes 404 to a sufficient number, e.g., 15, while still maximizing the available bandwidth ineach sub-channel 200. Thus, the overall bandwidth B for communication channel 200is given by the following equation: B =N(l+r)/T; (3) or B =MT; (4) Where M=(l+r)N. (S) For efficiency purposes related to transmitter design, it is preferable that r is chosen so thatM in equation (5) is an integer. Choosing r so that Mis an integer allows for more efficient transmitters designs using, for example, Inverse Fast Fourier Transform (IhFl) techniques. Since.M=/v'+ N(r), andvVis alwaysaninteger, thismeansthatr mustbe chosen so that N(r) is an integer. Generally, it is preferable forr to be between 0.1 and 0.5. Therefore, if TVis 16, for example, then .5 couldbeselectedforr sothat N(r) isaninteger. Alternatively,ifavalueforr ischosenintheaboveexamplesothat/V(^isnot an integer, B canbemade slightlywiderthanMTto compensate. In this case, it is still preferable that r bechosen so that /V(^ is approximately an integer. 2. ExanpleEmbodiment ofaWirelessCommunicationSystem With the above in mind, figure 6 illustrates an example communication system 600 comprising a plurality of cells 602 that each use a common wideband communication channel to communicate with communication devices 604 within each cell 602. The common communication channel is a wideband communication channel as described above. Each communication cell 602 is defined as the coverage area of a base station, or service access point, 606 within the celL One such base station 606 is shown for illustration in figure 6. For purposes of this specification and the claims that follow, the term base station will be used generically to refer to a device that provides wireless access to the wireless communication system for a plurality of communication devices, whether the system is alineofsight, indoor, or outdoor system. Because eachcell 602 uses thesame communication channel, signals inone cell 602 must be distinguishable from signals in adjacent cells 602. To differentiate signals from one cell 602 to another, adjacent base stations 606 use different synchronization cαies accordingto acodereuseplan In figure6, system600usesasynchronizationcodereuse factorof4, althoughthereusefactorcanvarydependingontheapplication Preferably, the synchronization code is periodically inserted into a communication from a base station 606 to a communicationdevice604asillustratedinfigure7. Afterapredetemrmednumber ofdatapackets702, inthiscasetwo,the particular syrchronization code 704 is inserted into the information being transmitted by each base station 606. A synchronization code isa sequence ofdatabits known toboththebase station 606 andany communication devices 604 with which itis communicating ThesyrxiironizaticnccdeaHowssuchaccrc^ that ofbasestation606,which, inturn, allowsdevice604to decodethedataproperry. Thus,incell 1 (see lightly shaded cells 602 infigure6), for example, synchronizationcode 1 (SYNCl) isinsertedintodata stream 706, which is generated bybase station606incell 1 ,aftereverytwopackets702; incell2 SYNC2isinsertedaftereveiytwo packets 702; incell3 SYNC3 is inserted; andincell4SYNC4isinserted. Useofthesynchronizationcodesisdiscussedinmoredetailbelow. In figure 5A, an example wideband communication channel 500 for use in communication system 600 is divided into 16 sub-channels 502, centered at frequencies fo to //5. Abase station 606 at the center of each communication cell 602 transmits a single packet occupying the whole bandwidth B of wideband channel 500. Such a packet is illustrated by packet 504 in figure 5B. Packet 504 comprises sub-packets 506 that are encoded with a frequency offset corresponding to one of sub-channels 502. Sub-packets 506 in effect define available time slots in packet 504. Similarly, sub-channels 502 can be said to define available frequency bins in communication channel 500. Therefore, the resources available in communication cell 602 are time slots 506 and frequency bins 502, which can be assigned to different communication devices 604 within eachcell602. Thus, for example, frequency bins 502 and time slots 506 can be assigned to 4 different communication devices 604 within a cell 602 as shown in figure 5. Each communication device 604 receives the entire packet 504, but only processes those frequency bins 502 andOr timeslots 506 that are assigned to h. Preferably, each device 604 is assigned non- adjacent frequency bins 502, as in figure 5. This way, if interference corrupts the information in a portion of communication channel 500, then the effects are spread across all devices 604 within a cell 602. Hopefully, by spreading out the effects of interference inthismannertheeffectsarernirrirnizedandtheentireinfcαrriat icnsentto each device 604canstiUbe recreated from the unaffected information received in other frequency bins. For example, if interference, such as fading, corrupted the information in bins frf* then each user 14 loses one packet of data But each user potentially receives three unaffected packets from the other bins assigned to them. Hopefully, the unaffected data in the other three bins provides enough information to recreate the entire message for each user. Thus, frequency diversity canbe achieved by assigning non-adjacent bins to eachof multiple users. Ensuringthatthebinsassignedtooneuserareseparatedbymorethanth ecohererκ^barMiwidthensιires frequency diversity. As discussed above, thecoherencebandwidth is approximatelyequal to IZd3. Foroutdoorsystems, whereds is typically 1μs, Vd5 = 1/1us= IMHz. Thus, the non-adjacent frequency bands assigned toauserare preferably separated by at least 1 MHz. It canbeevenmore preferable, however, ifthe coherence bandwidth plussome guard band to ensure sufficient frequency diversity separate the non-adjacent bins assigned to each user. For example, it is preferable in certain implementations to ensure that at least 5 times the coherence bandwidth, or 5MHz in the above example, separates the non- adjacent bins. Another way to provide frequency diversity is to repeat blocks of datain frequency bins assigned to a particular user that are separated by more than the coherence bandwidth. In other words, if 4 sub-channels 200 are assigned to a user, then datablocka canberepeated inthefirstandthirdsub-channels200anddatablcck6∞nbe repeated inthe second and fourth sub-channels202,providedthesub-channelsaresufficientlysepara ted in frequency. Inthis case, the system canbesaidtobe using a diversity length factor of 2. The system can similarly be configured to implement other diversity lengths, e.g., 3,4, ..., /. It should be noted that spatial diversity can also be included depending on the embodiment Spatial diversity can comprise transmit spatial diversity, receive spatial diversity, or both. In transmit spatial diversity, the transmitter uses a plurality of separate transmitters and a plurality of separate antennas to transmit each message. In other words, each transmittertransmitsthesamemessageinparalleL Themessagesarethenreceivedfromthetransrnittersand combined intiie receiver. Because the parallel transmissions travel different paths, if one is affected by lading, the others will likely not be affected. Thus, when they are combined in the receiver, the message should be recoverable even if oneor moreof the other transmission paths experienced severe fading. Receive spatial diversity uses a plurality of separate receivers and a plurality of separate antennas to receive a single message. If an adequate distance separates the antennas, then the transmission path for the signals received by the antennas willbe different Again,this differenceinthetransmissionpathswillprovideimperviousnessto fading whenthe signalsfioni the receivers are combined. Transmit and receive spatial diversity can also be combined within a system such as system 600 so that two antennas areusedto transmitandtwo antennasare usedto receive. Thus, eachbase station 606 transmitter canincludetwo antennas, for transmit spatial diversity, and each communication device 604 receiver can include two antennas, for receive spatial diversity. If only transmit spatial diversity is implemented in system 600, then h canbe implemented in base stations 606 or in communication devices 604. Similarly, if only receive spatial diversity is included in system 600, then it can be implemented inbase stations 606or communication devices 604. The number of communication devices 604 assigned frequency bins 502 and/or time slots 506 in each cell 602 is preferably programmable inreal time. In other words, the resource allocation within a communication cell 602 is preferably programmable in the face of varying external conditions, i.e., multipath or adjacent cell interference, and varying requirements, i.e., bandwidth requirements for various users within the celL Thus, if user 1 requires the whole bandwidth to download a large video file, for example, thenthe allocation ofbins 502canbe adjust to provide user 1 with more, orevenall, of bins 502. Once user 1 no longer requires such large amounts of bandwidth, the allocation ofbins 502 can be readjusted among allof users 1 -4. It should alsobenotedthat allofthebinsassignedtoaparticularusercanbeused forboth the forward and reverse link. Alternatively, somebins 502 can be assigned as the forward link and some can be assigned for use on the reverse link, depending onthe implementation To increase capacity, the entire bandwidth B is preferably reused in each communication cell 602, with each cell 602 being differentiated by a unique synchronization code (see discussion below). Thus, system 600 provides increased immunitytomultipathandfadingaswellasincreasedbandwidthduetot he eliminationoffhΞquerκ;yieuserequirements. 3. Synchronization Figure8 illustratesanexampleembodimentofasynchronizationcode correlator 800. Whena device 604incell 1 (see figure 6), for example, receives an incoming communication from thecell 1 base station 606, it compares the incoming data with SYNCl in correlator 800. Essentially, the device scans the incoming data trying to correlate the data with the knownsytKhronizationcode, inthiscaseSYNCl. Oncecorrelator800matchestheincomingdatatoSYNCl itgeneratesa correlation peak 804 at the output Multipath versions of the data will also generate correlation peaks 806, although these peaks 806aregenerallysmallerthancorrelationpeak804. Thedevicecanthenusethecorrelationpeakstoperformchannel estimation, which allows the device to adjust for the multipath using, e.g., an equalizer. Thus, in cell 1, if correlator 800 receives a data stream comprising SYNCl, it will generate correlation peaks 804 and 806. If, on the other hand, the data stream comprisesSYNC2, forexample,thennopeakswillbegenerated andthe devicewiU essentiallyigrcrettieirexaiiing communication. Even though a data stream that comprises SYNC2 will not create any correlation peaks, it can create noise in correlator 800 thatcan prevent detection of correlation peaks 804 and 806. Several steps can be taken to prevent this from occurring. Onewayto minimize theirøiseabatedm∞ 600sothateachbasestation 606transmitsatthesametime. Thisway,the synchronization codescanpreferablybegenerated in such a manner that only the synchronization codes 704 of adjacent cell data streams, e.g, streams 708, 710, and 712, as opposed to packets 702 within those streams, will interfere with detection of the correct synchronization code 704, e.g., SYNC1. The synchronization codes canthenbe further configured to eliminate or reduce the interference. For example, the noise or interference caused by an incorrect synchronization code is a function of the cross correlation ofthat synchronization code with respect to the correct code. The better the cross correlation between the two, the lower the noise leveL When the cross correlation is ideal, then the noise level willbe virtually zero as illustrated in figure 9 by noise level 902. Therefore, a preferred embodiment of system 600 uses synchronization codes that exhibit ideal cross correlation, Le., zero. Preferably, the ideal cross correlation of the synchronization codes covers a period 1 that is sufficient to allowaccuratedetectionofmultipaihcorrelationpeaks906aswellas correlation peak904. Thisisimportantsothataccurate channel estimation and equalization can take place. Outside of period 1, the noise level 908 goes up, because the data in packets 702 is random and will exhibit low cross correlation withthe synchronization code, e.g., SYNC1. Preferably, period 1 isactuallyslightlylongerthenthemultipathlengthinordertoensur ethatthe multipath canbe detected. a Synchronization code generation Conventional systems use orthogonal codes to achieve cross correlation in correlator 800. Ih system 600 for example, SYNCl, SYNC2, SYNC3, and SYNC4, corresponding to cells 14 (see lightly shaded cells 602 of figure 6) respectively,willallneedtobegeneratedinsuchamannerthattheywi llhaveidealcross correlation witheach other. Inone embodiment,ifthedatastreamsinvolvedcomprisehighandlowdatabit s, thenthe value"1"canbe assigned tothehighdata bits and "-1" to the low data bits. Orthogonal data sequences are then those that produce a "0" output when they are exclusively ORed (XORed) together in correlator 800. The following example illustrates this point for orthogonal sequences I and2: sequence 1: 1 1 -1 1 sequence2: 1 1 1 -1 1 1 -1 -1=0 Thus,whentheresultsofXORingeachbitpairareadded,theresultis'O ." But in system 600, for example, each code must have ideal, or zero, cross correlation with each of the other codes used in adjacent cells 602. Therefore, in one example embodiment of a method for generating synchronization codes exhibiting the properties described above, the process begins by selecting a 'perfect sequence" to be used as the basis for the codes. A perfect sequence is one that when correlated with itself produces a number equal to the number of bits in the sequence. For example: Perfect sequence1: 1 1 -1 1 1 1 -1 1 1 1 1 1 =4 But each time a perfect sequence is cyclically shifted by one bit, the new sequence is orthogonal with the original sequence. Thus, for example, if perfect sequence 1 is cyclically shifted by one bit and then correlated with the original, the correlation produces a"0"asinthe following example: Perfect sequence1: 1 1 -1 1 1 1 1-1 1 1 -1-1 =0 If the perfect sequence 1 is again cyclically shifted by one bit, and again correlated with the original, then it will producea"0". In general, you can cyclically shiftaperfectsequencebyanynumberofbits up to its length and correlatethe shiftedsequencewiththeoriginaltoobtaina 'O* '. Oncea perfect sequence ofthe correct length is selected, the first synchronization code is preferably generated inone embodiment by repeating the sequence 4 times. Thus, ifperfect sequence 1 isbeingused,thenafirstsynchronizationcodey would bethe following: y= l 1-1 11 1-1 11 1-1 11 1-1 1. O- in generic form y=x(0)x(lK2K3M0)x(lK2)x(3)x(0)x(l)x(2M3)x(0)x(l)x(2)x(3). Fora sequence oflengthL: y=xφχ\)..jφκφχ\)..x^χθ)κ([)..x(Lχoχ\)..x(L). Repeating the perfect sequence allows correlator 800 a better opportunity to detect the synchronization code and allows generation of other uncorrelated frequencies as welL Repeating has the effect of sampling in the frequency domain This effect is illustrated by the graphs in figure 10. Thus, in trace 1, which corresponds to synchronization codey, a sample 1002 is generated every fourth sample bin 1000. Each sample bin is separated by 1/(4LxT), where Jis the symbol duration Thus in the above example, where L = 4, each sample bin is separated by 1/(16x1) in the frequency domain Traces 2-4 illustrate the next three synchronization codes. As can be seen, the samples for each subsequent synchronization code are shifted by one sample bin relative to the samples for the previous sequence. Therefore, noneof sequences interfere with each other. To generatethe subsequentsequences, correspondingtotraces2-4, sec[uence^mustbe shifted in frequency. This canbe accomplished using the following equation:

forr= 1 toZ,(#c/sequences)and/?j=0to4*Z,-l (time);and where: I(m) = each subsequent sequence, y(m) = thefirstsequence,and n= thenumberoftimesthesequenceisrepeated It will be understood that multiplying by an exp(j2π(r*m/N)) factor, where N is equal to the number of times the sequenceisrepeated(n) multipliedbythe lengthoftheunderlyingperfectsequence Z, inthetimedcπiiainresults ina shift in thefrequencydomain Equation(5)resultsinthedesiredshiftasillustratedinfigure 10foreachofsynchronizationcodes 2-4, relative to synchronization code 1. The final step in generatingeachsynchronizationcode istoappend the copies ofthe last M samples, where M is the length of the multipath, to the front of each code. This is done to make the convolution with the multipath cyclic and to allow easier detection ofthe multipath. Itshouldbenotedthatsynchronizationcodescanbegeneratedfrommor ethanone perfect sequence using thesame methodology. Forexample, aperfect sequencecanbegeneratedandrepeatedfortimesandthenasecond perfect sequence can be generated and repeated four times to get a n factor equal to eight The resulting sequence can then be shifted as described above to create the synchronization codes. b. Signal Measurements Using Synchronization Codes Therefore, when a communication device is at the edge of a cell, it will receive signals from multiple base stations and, therefore, willbe decoding several synchronization codes at the same time. Thiscanbe illustrated withthe helpof figure 11, which illustrates another example embodiment of a wireless communication system 1100 comprising communication cells 1102, 1104,and 1106aswellascommunicationdevice 1108,whichisincommunicationwithbase station 1110ofcell 1102butalsoreceivingcommunicationfrombasestations 1112and 1114ofcells 1104and 1106, respectively. If communications from base station 1110 comprise synchronization code SYNCl and communications from base station 1112 and 1114 comprise SYNC2 andSYNC3 respectively, then device 1108 will effectively receive thesumof thesethreesynchronizationcodes. Thisisbecause, asexplainedabove, base stations 1110, 1112, and 1114are configured to transmit at the same time. Also, the synchronization codes arrive at device 1108 at almost the same time because they are generated in accordance withthe description above. Again as described above, the synchronization codes SYNC1 , SYNC2,and S YNC3 exhibit ideal cross correlation Therefore, when device 1108 correlates thesumx of codes SYNCl, SYNC2, and SYNC3, the latter two will not interfere with proper detection of SYNCl by device 1108. Importantly, the sum x can also be used to determine important signal characteristics, because the sumx is equal to the sum of the synchronization code signal in accordance with the following equation: x = SYNCl + SYNC2 + SYNC3. (6) Therefore, when SYNCl is removed, thesumofSYNC2 and SYNC3 is left, as shown inthe following: x - SYNCl = SYNC2 + SYNC3. (J) Theenergycomputedfromthesum(SYNC2 + SYNC3)isequaltothenoiseorinterference seenby device 1108. Sincethepurposeofcorrelatingthesynchronizationcodeindevice hastheenergyinthesignal frombasestation 1110, i.e.,theenergy represented by SYNCl. Therefore, device 1106 can use the energy of SYNCl and of (SYNC2 + SYNC3) to perform a signal-tD-interferenee measurement for the communication channel over which it is communicating with base station 1110. The result of the measurement is preferably a signal-to- rnterference ratio (SIR). The SIR measurement can then be communicated back to base station 1110 for purposes that will be discussed below. The ideal cross correlation of the synchronization codes also allows device 1108 to perform extremely accurate determinations of the Channel Impulse Response (CIR), or channel estimation, from the correlation produced by correlator 800. This allows for highly accurate equalization using low cost, low complexity equalizers, thus overcoming a significant drawbackof conventional systems. 4. Sub-channel Assignments Asmentioned,theSIRasdeterminedbydevice 1108canbecommunicatedbacktobase station 1110foruseinthe assignment of slots 502. Inone embodiment, dueto the feetthat each sub-channel 502 is processed independently, the SIR foreachsub-channel 502 canbemeasuredand communicated backtobase station 1110. Insuchan embodiment, therefore, sub-channels502canbedividedintogroupsandaSIRmeasurementforea ch group canbesenttobase station 1110. Thisis illustrated in figure 12A, which shows a wideband communication channel 1200 segmented into sub-channels j6 Thus,inone embodiment,device 1108andbase station 1110 communicate overa channel suchas channel 1200. Sub-channels in the same group are preferably separated by as many sub-channels as possible to ensure diversity. In figure 12Afor example, sub-channels within thesame group are7 sub-channels apart, e.g., group Gl comprises/ø and/?. Device 1102 reports aSIR measurement for eachofthe groups Gl toG8. These SIR measurements are preferably comparedwithathresholdvaluetodeterminewHchsub-channels groups areuseablebydevice 1108. This comparison can occurindevice 1108 orbase station 1110. Ifitoccurs in device 1108, thendevice 1108cansimplyreporttobasestation 1110 whichsub-channelgroupsareuseablebydevice 1108. SIR reporting will be simultaneously occurring for a plurality of devices within cell 1102. Thus, figure 12B illustrates the situation where two communication devices corresponding to userl and user2 report SIR levels above the threshold forgroupsGl, G3, G5, andG7. Basestation 1110preferablythenassigns sub-charmel groups to userl anduser2 based on the SIR reporting as illustrated in Figure 12B. When assigning the "good" sub-channel groups to userl and user2, base station 1110 also preferably assigns them based on the principles of frequency diversity. In figure 12B, therefore, userl and user2 are alternately assigned every other ' 'good' 'sub-charmeL The assignment of sub-channels in the frequency domain is equivalent to the assignment of time slots in the time domain Therefore, as illustrated in figure 13, two users, userl and user2, receive packet 1302 transmitted ova communication channel 1200. Figure 13 also illustrated the sub-channel assignment of figure 12B. While figure 12 and 13 illustrate sub-channel/time slot assignment based on SIR for two users, the principles illustrated can be extended for any numberofusers. Thus, apacketwithincell 1102 canbereceivedby3 ormoreusers. Although, asthenumberofavailable sub-channelsisreducedduetohighSIR,soistheavailablebandwidth. Inotherwords,asavailablesub-channelsarereduced, thenumberofusersthatcangainaccesstocommunication channel 1200isalso reduced. PoorSIRcanbecausedforavarietyofreasons,butfrequentlyitresult s from adeviceattheedgeofacell receiving communication signals from adjacent cells. Because each cell is using the same bandwidth B, the adjacent cell signals will eventually raise the noise level and degrade SIR for certain sub-channels. In certain embodiments, therefore, sub-channel assignmentcanbecoordinated betweencells, suchascells 1102, 1104,and 1106in figure l l,morder to prevent interference fromadjacentcells. Thus, if communication device 1108 is near the edge of cell 1102, and device 1118 is near the edge of cell 1106, thenthetwocaninterferewitheachother. Asaresult,theSIRmeasurementsthatdevice 1108and 1118reportbacktobase stations 1110 and 1114, respectively, will indicate that the interference level is too high. Base station 1110 can then be configured to assign only theodd groups, i.e., Gl, G3, G5, etc., to device 1108, while base station 1114 canbe configured to assigntheevengroupstodevice 1118 inacoordinated føhioa Thetwodevices 1108 and 1118 willthennotinterferewith each other dueto thecooidinated assignment of sub-channel groups. Assigning the sub-channels in this manner reduces the overall bandwidth available to devices 1108 and 1118, respectively. In this casethebandwidthisreducedbya factoroftwo. But it shouldberemembered thatdevicesoperating closer to each base station 1110 and 1114, respectively, will still be able to use all sub-channels if needed Thus, it is only devices,suchasdevice llOδjtøareneartheedgeofaceUthatwillravetheavailablebar^ Contrast thiswith aCDMAsystem, forexample, inwhichthebandwidthforallusersisreduced,duetothe spreadingtechnicpαesusedinsuch systems, by approximately a factor of 10 at all times. It can be seen, therefore, that the systems and methods for wireless communication overawide bandwidth channel using a plurality of sub-channels notonly improves the quality of service, but canalso increase the available bandwidth significantly. Whentherearethreedevices 1108, 1118,and 1116neartheedgeoftheirrespectiveadjacentcells 1102, 1104,and 1106,the sub-channelscanbedividedbythree. Thus,device 1108, forexample,canbeassignedgroupsGl,G4,etc.,device 1118 can be assigned groups G2, G5, etc., and device 1116 can be assigned groups G3, G6, etc. In this case the available bandwidth for these devices, Le., devices near the edges of cells 1102, 1104, and 1106, is reduced by a factor of 3, butthis is stillbetterthanaCDMAsystem, forexample. The manner in which such a cooidinated assignment of sub-channels can work is illustrated by the flow chart in figure 14. First in step 1402, a communication device, suchas device 1108, reports the SIR for all sub-channel groups Gl to G8. The SIRs reported are then compared, in step 1404, to a threshold to determine if the SIR is sufficiently low for each group. Alternatively, device 1108 can make the determination and simply report which groups are above or below the SIR threshold Ifthe SIR levels aregood foreach group, thenbase station 1110canmakeeach group available to device 1108, in step 1406. Periodically, device 1108 preferably measures the SIR level and updates base station 1110 in case the SIR as deteriorated For example, device 1108 may move from near the center of cell 1102 toward the edge, where interference froman adjacent cellmay affect theSIRfor device 1108. If the comparison in step 1404 reveals that the SIR levels are not good then base station 1110 can be preprogrammed to assign either theodd groups ortheeven groups only to device 1108, which it willdoinstep 1408. Device 1108then reportsthe SIRmeasurements fortheoddorevengroupsitisassignedinstep 1410, andtheyare again compared toaSIR threshold instep 1412. It is assumed thatthepoorSIR level is due to the feetthat device 1108 is operating at theedgeofcell 1102 and is therefore being interfered withbya device suchas device 1118. But device 1108 willbe interfering with device 1118 atthe same time. Therefore, the assignment ofoddor even groups instep 1408 preferably corresponds withthe assignment ofthe opposite groups to device 1118, by base station 1114. Accordingly, when device 1108 reports the SIR measurements for whichever groups, odd or even, are assigned to it, the comparison in step 1410 should reveal that the SIR levels are now below the threshold leveL Thus, base station 1110 makes the assigned groups available to device 1108 in step 1414. Again, device 1108preferablyperiodicallyupdatestheSIRmeasurementsbyreturni ng tostep 1402. Itispossibleforthecomparisonofstep 1410torevealthattheSIRlevelsarestillabove the threshold, which should indicate that a third device, e.g., device 1116 is still interfering with device 1108. In this case, base station 1110 can be preprogrammed to assign every third group to device 1108 in step 1416. This should correspond with the corresponding assignments of non-interfering channels to devices 1118 and 1116 by base stations 1114 and 1112, respectively. Thus, device 1108 should be able to operate on the sub-channel groups assigned, i.e., Gl, G4, etc., without undue interference. Again, device 1108 preferably periodically updates the SIR measurements by returning to step 1402. Optionally, a third comparison step (not shown) can be implemented after step 1416, to ensure that the groups assigned to device 1408 posses an adequate SIR level for proper operation Moreover, if there are more adjacent cells, i.e., if it is possible for devices in a4th or even a 5h adjacent cell to interfere with device 1108, then the process of figure 14 would continue and the sub-channel groups would be divided even further to ensure adequate SIR levels onthe sub-channels assigned to device 1108. Eventhoughtheprocessoffigure 14reducesthebandwidthavailable to devices attheedgeof cells 1102, 1104,and 1106, the SIRmeasurementscanbeusedinsuchamannerasto increasethedatarateand therefore restore oreven increase bandwidth. To accomplishthis, thetransmitters andreceiversusedinbase stations 1102, 1104, and 1106, and in devices in communication therewith, e.g, devices 1108, 1114, and 1116 respectively, must be capable of dynamically changing the symbol mapping schemes used for some or all of the sub-channel For example, in some embodiments, the symbol mapping scheme can be dynamically changed among BPSK, QPSK, 8PSK, 16QAM, 32QAM, etc. As the symbol mapping scheme moves higher, i.e., towand 32QAM, the SIR level required for proper operation moves higher, i.e., lessand less interference can be withstood Therefore, once the SIR levels are determined for each group, the base station, e.g., base station 1110, can then determine what symbol mapping scheme can be supported for each sub-channel group and can change the modulation scheme accordingly. Device 1108 must also change the symbol mapping scheme to correspond to that of the base stations. The change can be effected for all groups uniformly, or it can be effected for individual groups. Moreover, the symbol mapping scheme canbe changed onjust the forward link, just the reverse link, or both, depending on the embodiment Thus, by maintaining the capability to dynamically assign sub-channels and to dynamically change the symbol mapping scheme used for assigned sub-channels, the systems and methods described herein provide the ability to maintain higher available bandwidths with higher performance levels than conventional systems. To fully realize the benefits described, however, the systems and methods described thus far must be capable of implementation in a cost effect and convenient manner. Moreover, the implementation must include reconfigurability so that a single device canmove between different types of communication systems and still maintain optimum performance in accordance with the systems and methods described herein. The following descriptions detail example high level embodiments ofhardwans implementations configured to operate in accordance with the systems and methods described herein in such a manner as to provide the capability just described above. 5; Sample Transmitter Embodiments

Figure 15 is logical block diagram illustrating an example embodiment of a transmitter 1500 configured for wireless communication in accordance with the systems and methods described above. The transmitter could, for example be within abase station, e.g., base station 606, or within a communication device, such as device 604. Transmitter 1500 is provided to illustrate logical components that can be included in a transmitter configured in accordance with the systems and methods described herein It is not intended to limit the systems and methods for wireless communication over a wide bandwidth channel using a plurality of sub-channels to any particular transmitter configuration or any particular wireless communication system. With this in mind, it can be seen that transmitter 1500 comprises a serial-to-parallel converter 1504 configured to receive a serial data stream 1502 comprising adatarate R. Serial-to-parallel converter 1504 converts data stream 1502 into N parallel data streams 1504, where N is the number of sub-channels 200. It should be noted that while the discussion that follows assumes that a single serial data stream is used, more than one serial data stream can also be used ifrequired or desired In any case, the data rate of each parallel data stream 1504 is then RN. Each data stream 1504 is then sent to a scrambler, encoder, and interleaver block 1506. Scrambling, encoding, and interleaving are common techniques implemented inmany wireless communication transmitters andhelp to provide robust, secure communication Examples of these techniques willbe briefly explained for illustrative purposes. Scramblingbreaksupthedatatobetransmittedinanefforttosmoothou tthe spectral densityofthetransmitted data For example, if the data comprises a long string of "l"s, there will be a spike in the spectral density. This spike can cause greater interference within the wireless communication system. By breaking up the data, the spectral density can be smoothed out to avoid anysuch peaks. Often, scrambling is achieved byXORingthedatawitha random sequence. Encoding, or coding, the parallel bit streams 1504can, for example, provide Forward Error Correction (FEQ. The purpose of FEC is to improve the capacity of a communication channel by adding some carefully designed redundant informationtothedatabeingtransmittedthroughthechannel. TheprOcessofaddingthisredurκlantinforrnationislαiownas channel coding. Convolutionalcodingandblockcodingarethetwomajorforms of channel coding Convohώonal codes operate on serial data, oneorafewbitsata time. Blockcodesoperateonrelativelylarge(typically, uptoacoupleofhundred bytes) message blocks. There area variety of useful convolutional and block codes, and a variety of algorithms for decoding the received coded information sequences to recover the original data For example, convolutional encoding or turbo coding with Vrterbi decoding is a FEC technique that is particularly suited to a channel in which the transmitted signal is corrupted mainly by additive white gaussian noise (AWGN)orevena channel that simply experiences lading. Convohrtional codesare usuallydescribedusingtwoparameters: thecederate andthe constraint length. Tte rate, k/n, is expressed as a ratio of the number ofbits into the convolutional encoder (k) to the number of channel symbols («) outputbytheconvolutional encoder inagivenencodercycle. Acommoncoderateis 'Λ, whichmeansthat 2 symbols are produced for every 1-bit input into the coder. The constraint length parameter, K, denotes the "length" of the convolutional encoder, ie. how many k-bit stages are available to feed the cornbinatorial logic that produces the output symbols. Closely relatedtoK istheparameterm, whichindicateshowmanyencoderc>clesanirputbitis retained andused for encoding after it first appears at the input to the convolutional encoder. The m parameter can be thought of as the memory length of the encoder. Interleaving is used to reduce the effects of lading. Interleaving mixes up the order of the data so that if a lade interferes with a portion of the transmitted signal, the overall message will not be effected This is because once the message is de-interleaved and decoded in the receiver, the data lost will comprise non-contiguous portions of the overall message. Ih other words, the lade will interfere with a contiguous portion of the interleaved message, but when the message is de- interleaved, the interfered with portion is spread throughout the overall message. Using techniques such as FEC, the missing information can thenbe filled in,orthe impact ofthe lostdatamayjustbe negligible. After blocks 1506, each parallel data stream 1504 is sent to symbol mappers 1508. Symbol mappers 1508 apply the requisite symbol mapping, e.g., BPSK, QPSK, etc., to each parallel data stream 1504. Symbol mappers 1508 are preferably programmable sothatthe modulation applied to parallel data streams canbe changed, for example, in response to the SIR reported for each sub-channel 202. It is also preferable, that each symbol mapper 1508 be separately programmable so that the optimum symbol mapping scheme for each sub-channel canbe selected and applied to each parallel data stream 1504. Aftersymbolmappers 1508,paralleldatastreams 1504aresentto modulators 1510. Importantaspectsandfeatures of example embodiments of modulators 1510 are described below. After modulators 1510, parallel data streams 1504 are sent to summer 1512, which is configured to sum the parallel data streams and thereby generate a single serial data stream 1518 comprising each of the individually processed parallel data streams 1504. Serial data stream 1518 is then sent to radio module 1512, where it is modulated with an RF carrier, amplified, and transmitted via antenna 1516 according to known techniques. Radiomoduleembodimentsthatcanbeusedinccqjuncticnwiththe systems andmeώodsdescnlDedherein are described below. The transmitted signal occupies the entire bandwidth B of communication channel 100 and comprises each of the discrete parallel data streams 1504 encoded onto their respective sub-channels 102 within bandwidth B. Encoding parallel datastreams 1504onto theappropriatesub-channels 102rec[uirestøeachparaM data stream 1504beshiftøm byanappropriateoffset Thisis achieved in modulator 1510. Figure 16 is a logical block diagram of an example embodiment of a modulator 1600 in accordance with the systems and methods described herein. Importantly, modulator 1600 takes parallel data streams 1602 performs Time Division Modulation (TDM) or Frequency Division Modulation (FDM) oneach data stream 1602, filters them using filters 1612, and then shifis each data stream in frequency using frequency shifter 1614 so that they occupy the appropriate sub-channel. Filters 1612 apply the required pulse snapping, i.e., they apply the roll-offfactor described in section 1. The frequency shifted parallel data streams 1602 are then summed and transmitted. Modulator 1600 can also include rate controller 1604, frequency encoder 1606, andinterpolators 1610. Allofthe componentsshowninfigure 16aredescribedin more detail in the following paragraphs andincoηjunction with figures 17-23. Figure 17 illustrates one example embodiment of a rate controller 1700 in accordance with the systems and methods described herein Rate control 1700 is used to control the data rate of each parallel data stream 1602. In rate controller 1700, thedata rate is halved by repeating data streams d(0) to d(7), for example, producing streams a(0) to a(15) in which a(0) is the same as a(8), a(l) is the same as a(9), etc. Figure 17 illustrates that the effect of repeating thedata streams in this manner is to take the data streams that are encoded onto the first 8 sub-channels 1702, and duplicate them on the next 8 sub-channels 1702. As can be seen, 7 sub-channels separate sub-channels 1702 comprising the same, or duplicate, data streams. Thus, if fading effects one sub-channel 1702, for example, the other sub-channels 1702 carrying the samedatawill likely not be effected, i.e., there is frequency diversity between the duplicate data streams. So by sacrificing data rate, in this case half the data rate, more robust transmission is achieved Moreover, the robustness provided by duplicating the data streamsd(0) tod(8) canbefurtherenhancedbyarjplyirgsαamblingtothedφHcateddatas beamsvia scramblers 1704. It should be noted that the datarate can be reduced by more than half, e.g., by four or more. Alternatively, the data rate can also be reduced by an amount other than half For example if information from n data stream is encoded onto m sub-channels, where m >n. Thus, to decrease the rate by 2θ, infoimation from one data stream can be encoded on a first sub-channel, informationfromaseconddatastreamcanbeencodedonasecond data(±armel, andthesumor difference of thetwodatastreamscanbeencodedonathiidchannel. Inwhichcase,properscalingwillneedtobeappliedtothepowerin the third chaπneL Otherwise, tor example, the power inthe third channel canbe twice the power inthefirst two. Preferably, rate controller 1700 is programmable so that the data rate can be changed responsive to certain operational factors. For example, if the SIR reported for sub-channels 1702 is low, then rate controller 1700 can be programmed to provide more robust transmission via repetition to ensure that nodatais lost due to interference. Additionally, different types of wireless communication system, e.g, indoor, outdoor, line-of-sight, may require varying degrees of robustness. Thus, rate controller 1700 canbe adjusted to provide the minimum required robustness for the particular type of communication system. Thistypeofprogrammabilitynotonly ensures robust communication, itcanalsobeused to allow a single device tomove between communication systems and maintain superior performance. Figure 18 illustrates an alternative example embodiment of a rate controller 1800 in accordance with the systems and methods described. In rate controller 1800 the data rate is increased instead of decreased. This is accomplished using serial-to-parallel converters 1802 to convert each data streams d(0) to d(15), for example, into two data streams. Delay circuits 1804 then delay one of the two data streams generated by each serial-to-parallel converter 1802 by Vi a symbol, period. Thus, datastreamsd(0) to d(15) are transfσirnedinto datastreams cφ) to aβl). The data streams generated by a particular serial-to-parallel converter 1802 and associate delay circuit 1804 must then be summed and encoded onto the appropriate sub-channeL For example, data streams a(0) and a(l) mustbe summed and encoded onto the first sub-charmeL Preferably, thedata streams are summed subsequent to eachdata stream Thus, rate controller 1604 is preferably programmable so that the data rate can be increased, as in rate controller 1800, or decreased, as in rate controller 1700, as required by a particular type of wireless communication system, or as required by the communication channel conditions or sub-channel conditions. In the event that the data rate is increased, filters 1612 arealsopreferablyprogrammablesothattheycanbeccMguredto apply pulsesh_φpirigtodata streamsα(Q)to a(31), forexample, andthensumtheappropriatestreamstogeneratetheappropriateriumb erofparaUel datastrearnstosend to frequencyshifter 1614. Theadvantageofincreasingthedatarateinthemannerillustrated m figure 18 istliathigher symbol mapping rates canessentiallybeachieved,withoutchangingthesymbolmappingused in symbol mappers 1508. Oncethedata streams are summed, the summed streams are shifted in fiequency so that theyreside in the appropriate sub-channeL But because the number ofbitspereach symbol hasbeen doubled, the symbol mapping ratehasbeen doubled Thus, for example, a4QAM symbolmappingcanbeconvertedtoa 16QAMsymbolmapping,eveniftheSIRistoohighfor 16QAMsymbol mapping to otherwise be applied Inotherwoκls,progranτrningratecontroller 1800toincreasethedatarateinthemamerillustrated in figure 18 can increase the symbol mapping even when channel conditions would otherwise not allow it, which in turn can allow a communication device to maintain adequate or even superior performance regardless of the typeof communication system The draw back to increasing the data rate as illustrated in figure 18 is that interference is increased, as is receiver complexity. The former is due to the increased amount of data The latter is due to the fact that each symbol cannot be processed independently because of the symbol overlap. Thus, these concerns must be balanced against the increase symbol mapping ability when implementing arate controller suchasrate controller 1800. Figure 19 illustrates one example embodiment of a frequency encoder 1900 in accordance with the systems and methods described herein. Similar to rate encoding, frequency encoding is preferably used to provide increased communication robustness. In frequency encoder 1900thesumOTdiffeerκ»ofmulφleα^streamsareencodedontoeach subchannel. This is accomplished using adders 1902 to sum data streams d(0) to d(7) with data streams d(8) to d(15), respectively, while adders 1904 subtract data streams d(0) to d(7) from data streams d(8) to d(15), respectively, as shown Thus, data streams a(0) to a(15) generated by adders 1902 and 1904 comprise information related to more than one data streams d(0) to d(15). For example, a(0) comprises the sum ofd(0) and d(8), i.e., d(0) + d(8), while a(8) comprises d(8) - d(0). Therefore, if either a(0) or a(8) is not received due to fading, for example, then both of data streams d(0) and d(8) can still be retrieved fromdata stream aβ). Essentially, the relationship between data stream d(0) to d(15) and a(0) to a(l 5) is a matrix relationship. Thus, ifthe receiver knows the correct matrix to apply, it can recover the sums and differences ofd(0) to d(15) from a(0) to a(15). Preferably, frequency encoder 1900 is programmable, so that it canbe enabled and disabled in order to provided robustness whenrequired Preferable, adders 1902and 1904areprogrammablealso sotødifferent matrices canbeappHedtoc^Q)to d(15) . After frequency encoding, if it is included, data streams 1602 are sent to TDM/FDM blocks 1608. TOMZFDM blocks 1608 performTOMorFDM onthedatastreams asrequiredbythepartcularembodiment Figure 20 illustrates an example embodiment ofaTOM/FDM block 2000 configured to perform TOMonadata stream. TOMZFDM block 2000 isprovidedtoillustratethelogicalcomponentsthatcanbeEluded maTOMZFDM block configured toperibmiTOMona data stream. Depending on the actual implementation, some of the logical components may or may not be included. TDMZFDM block 2000 comprises a sub-block repeater 2002, a sub-block scrambler 2004, a sub-block terminator 2006, a sub-block repeater 2008, andaSYNC inserter 2010. Sub-block repeater 2002 is configured to receive a sub-block of data, such as block 2012 comprising bits a(0) to a(3) for example. Sub-block repeater is then configured to repeat block 2012 to provide repetition, which in turn leads to more robust communication. Thus, sub-blockrepeater2002 generatesblock 2014, whichcomprises 2 blocks 2012. Sub- block scrambler 2004 is then configured to receive block 2014 and to scramble it, thus generating block 2016. One method of scrambling can be to invert half of block 2014 as illustrated in block 2016. But other scrambling methods can also be implemented depending onthe embodiment. Sub-block terminator 2006 takes block 2016 generated by sub-block scrambler 2004 andadds a termination block 2034 to the front of block 2016 to form block 2018. Termination block 2034 ensures that each block can be processed independently in the receiver. Without termination block 2034, some blocks maybe delayed due tomultipath, for example, and they would therefore overlap part of thenext block of data Butby including termination block 2034, the delayed block canbe prevented from overlapping anyofthe actual datainthenext block. Termination block 2034 canbe a cyclic prefix termination 2036. A cyclic prefix termination 2036 simply repeats the last few symbols ofblock2018. Thus, for example, if cyclic prefix termination 2036 is three symbols long, thenit would simply repeat the last three symbols of block 2018. Alternatively, termination block 2034 can comprise a sequence of symbols thatare known toboththe transmitter andreceiver. The selection ofwhat type ofblock termination 2034 tousecan impact what type of equalizer is used in the receiver. Therefore, receiver complexity and choice of equalizers must be considered when determining whattypeof termination block 2034 touseinTOMZFDM block 2000. After sub-block terminator 2006, TOMZFDM block 2000 can include a sub-block repeater 2008 configured to perform a second block repetition step in which block 2018 is repeated to form block 2020. In certain embodiments, sub- block repeater can be configured to perform a second block scrambling step as welL After sub-block repeater 2008, if included, TOMZFDM block 2000 comprises a SYNC inserter 210 configured to periodically insert an appropriate synchronization code 2032 after a predetermined number of blocks 2020 andZor to insert known symbols into each block. The purpose of synchronization code2032 is discussed in section 3. Figure21 ,ontheotherhand,illustratesanexampleembodimentofaTOMZFDM block 2100 configured forFDM, which comprises sub-block repeater 2102, sub-block scrambler 2104, block coder 2106, sub-block transformer 2108, sub- block terminator 2110, and SYNC inserter 2112. Sub-block repeater 2102 repeats block 2114 and generates block 2116. Sub-blocksciamblαtheriscramblesblock2116, generatingblock2118. Sub-blockcoder2106takesblock2118 andcodes it, generating block 2120. Codingblock correlates the data symbols togetherand generates symbols ά. This requiresjoint demodulation in the receiver, which is more robust but also more complex. Sub-block transformer 2108 then performs a transformation on block 2120, generating block 2122. Preferably, the transformation isanIFFTofblock2120, which allows for more efficient equalizers to be used in the receiver. Next, sub-block terminator 2110 terminates block 2122, generating block 2124 and SYNC inserter 2112 periodically inserts a synchronization code2126 after a certain number ofblocks2124 and/or insert known symbols into each block. Preferably, sub-block terminator 2110 only uses cyclic prefix termination as described above. Again this allows formore efficient receiver designs. TDM/FDMblock2100isprovidedtoillustratethelogical∞rrrpcnent sthatcanbe includedmaTDM/TOMblock configured to perform FDM on a data stream Depending on the actual implementation, some of the logical components may or may not be included. Moreover, TDM/FDM block 2000 and 2100 are preferably programmable so that the appropriate logical components can be included as required by a particular implementation This allows a device that incorporates one of blocks 2000 or 2100 to move between different systems with different requirements. Further, it is preferable that TDM/FDM block 1608 in figure 16be programmable so that it canbe programmed to perform TDM, such as described in conjunction with block 2000, or FDM, such as described in conjunction with block 2100, as required by a particular communication system. After TDM/FDM blocks 1608,infigure 16,theparaπeldatastieamsarepreferablypassedtointerpolators 1610. After interpolators 1610, the parallel data streams are passed to filters 1612, which apply the pulse shapping described in conjunction with the roll-off factor of equation (2) in section 1. Then the parallel data streams are sent to frequency shifter 1614, which is configured to shift each parallel data stream by the frequency offset associated with the sub-channeltowhichtheparticularparalleldatastreamisassociate d. Figure 22 illustrates an example embodiment of a frequency shifter 2200 in accordance with die systems and methods described herein As can be seen, frequency shifter 2200 comprises multipliers 2202 configured to multiply each parallel datastreambythe appropriate exponentialto achievetherequired frequency shift. Each exponential is ofthe form:

in figure 16 is programmable so that various chaπnel/sub-channel configurations canbe accommodated for various different systems. Alternatively, an IFFT block can replace shifter 1614 and filtering can be done after the H7FT block. This type of implementation canbemore efficient depending onthe implementation After the parallel data streams are shifted, they are summed, e.g., in summer 1512 of figure 15. The summed data stream is then transmitted using the entire bandwidth B of the communication channel being used FJut the transmitted data stream also comprises each of the parallel data streams shifted in frequency such that they occupy the appropriate sub-chaπneL Thus, eachsub-channelmaybeassignedtooneuser,oreachsιιrκ±annel different users. The assignment of sub-channels is described in section 3b. Regardless ofhow the sub-channels are assigned, however, each user will receive the entire bandwidth, comprising all the sub-channels, but will only decode those sub-channels assigned to the user. 6. Sample Receiver Embodiments Figure 23 illustrates an example embodiment of a receiver 2300 that can be configured in accordance wiih the present invention Receiver 2300 comprises an antenna 2302 configured to receive a message transmitted by a transmitter, suchas transmitter 1500. Thus,antenna2302isconfiguredtoreceiveawidebandmessagecorrrpr isingtheeritirebandwidth B ofa wide band channel that is divided into sub-channels of bandwidth B. As described above, the wide band message comprises a plurality of messages each encoded onto each of a corresponding sub-channel. All of the sub-channels may or may not be assigned to a device that includes receiver 2300; therefore, receiver 2300 may or may not be required to decode allofthe sub-channels. After the message is received by antenna 2300, it is sent to radio receiver 2304, which is configured to remove the carrier associated with the wide band communication channel and extract a baseband signal comprising the data stream transmitted by the transmitter. Example radio receiver embodiments are described inmore detail below. The baseband signal is then sent to correlator 2306 and demodulator 2308. Correlator 2306 is configured to correlatedwithasynchronizationcodeinsertedinthedatastreamasd escribed in section 3. Itisalso preferably configured to perform SIR and multipath estimations as described in section 3(b). Demodulator 2308 is configured to extract the parallel data streams from each sub-channel assigned to the device comprising receiver 2300 and to generate a single data stream therefrom Figure 24 illustrates an example embodiment of a demodulator 2400 in accordance withthe systems and methods described herein Demodulator2402 comprisesafrequencyshifter2402, whichisconfiguredtoapplya frequency offset to the baseband data stream so thatparallel datastreamscomprisingthebaseband datastream canbe independently processed in receiver 2400. Thus, the output of frequency shifter 2402 is a plurality of parallel data streams, which are then preferably filteredbyfilters2404. Filters2404applyafiltertoeachparalleldatastreamthat corresponds tothe pulse shape applied inthe transmitter, e.g., transmitter 1500. Alternatively, an H7FT block can replace shifter 1614 and filtering can be done after the H7FT block. Thistypeof implementation canbemore efficient depending onthe implementation. Next, receiver 2400 preferably includes decimators 2406 configured to decimate the data rate of the parallel bit streams. Samplingathigherrateshelps to ensure accuraterecreationofthedata Butthehigherthedatarate, thelargerand more complex equalizer 2408 becomes. Thus, the sampling rate, and therefore the number of samples, can be reduced by decimators2406toanadequatelevelthatallowsforasmallerandlessc ostlyequalizer 2408. Equalizer 2408 is configured to reduce the effects ofmultipath in receiver 2300. Its operation will be discussed more fully below. After equalizer 2408, the parallel data streams are sent to de-scrambler, decoder, and de-interieaver 2410, which perform the opposite operations of scrambler, encoder, and interieavσ 1506 so as to reproduce the original data generated in the transmitter. The parallel data streams are then sent to parallel to serial converter 2412, which generates a single serial data stream fromthe parallel data streams. Equalizer 2408 uses the multipath estimates provided by correlator 2306 to equalize the effects of multipath in receiver 2300. In one embodiment, equalizer 2408 comprises Single-In Single-Out (SISO) equalizers operating on each paralleldatastreamindemodulator2400. Inthiscase,eachSBOequalizercomprisingequalizer2408receives a single input and generates a single equalized output Alternatively, each equalizer can be a Mulάple-In Multiple-Out (MMO) or a Multiple-b Single-Out (MlSO) equalizer. Multiple inputs can be required for example, when a frequency encoder or rate controller, such as frequency encoder 1900, is included in the transmitter. Because frequency encoder 1900 encodes infomiationfrommorethanoneparalleldatastreamontoeachsub-dian nel,each equalizers∞mprisingequalizer 2408need to equalize more than one sub-channeL Thus, for example, if a parallel data stream in demodulator 2400 comprises d(l) + d(8), then equalizer 2408 will need to equalize both d(l) and dβ) together. Equalizer 2408 can then generate a single output corresponding to d(l) or d(8) (MISO)oritcan generate both d(l) and d(8) (MIMO). Equalizer2408 can alsobeatimedomainequalizer(TDE)orafrequerκ;ydcmahequalizer (FDE) depending on the embodiment. Generally, equalizer 2408 is aTDE ifthe modulator in the transmitter performs TDM on the parallel data streams, and a FDE if the modulator performs FDM. But equalizer 2408 can be an FDE even if TDM is used in the transmitter. Therefore, the preferred equalizer type should be taken into consideration when deciding what type of block termination to use in the transmitter. Because of power requirements, it is often preferable to use FDM on the forward link andTDMonthereverselinkinawirelesscommunicationsystem As with transmitter 1500, the various components comprising demodulator 2400 are preferably programmable, so thatasingledevicecanoperateinapluralityofdifferentsystems andstillniaintam advantage of the systems and methods described herein. Accordingly, the above discussion provides systems and methods for implementing a channel access protocol that allows the transmitter and receiver hardware to be reprogrammed slightly depending onthe communication system Thus, whena device moves fromone system to another, it preferably reconfigures the hardware, i.e. transmitter and receiver, as required and switches to a protocol stack corresponding to the new system An important part of reconfiguring the receiver is reconfiguring, or programming, the equalizer because multipath is amain problem for each type of system The multipath, however, varies depending on the type of system, which previously has meant that a different equalizer is required for different types of communication systems. The channel access protocol described in the preceding sections, however, allows for equalizers tobeusedthatneedonlybe reconfigured slightly for operation in various systems. a Sample Equalizer Embodiment Figure 25 illustrates an example embodiment ofa receiver 2500 illustrating one way to configure equalizers 2506in accordance with the systems and methods described herein. Before discussing the configuration ofreceiver 2500, it should be noted that one way to configure equalizers 2506 is to simply include one equalizer per channel (for the systems and methods described herein, a channel is the equivalent of a sub-channel as described above). A correlator, such as correlator 2306 (figure 23), can then provide equalizers 2506 with an estimate of the number, amplitude, and phase of any muhrpaths present, up to some maximum number. This is also known as the Channel Impulse Response (CIR). The maximum number ofmultipaths is determined based on design criteria for a particular implementation The more muWpaths included in theCIR themorepath diversity the receiver has and themore robust communication in the system willbe. Path diversity is discussed a little more fully below. If there is one equalizer 2506 per channel, the CIR is preferably provided directly to equalizers 2506 from the correlator (not shown). If such a correlator configuration is used, then equalizers 2506 canberunat aslow rate, butthe overall equalization process is relatively fast For systems with a relatively small number of channels, such a configuration is therefore preferable. The problem, however, is that there is large variances in the number of channels used in different types of communication systems. Forexample, anoutdoorsystemcanhavehasmanyas 256channels. This would require 256 equalizers 2506, which would makethe receiver design too complex and costly. Thus, for systems withalotof channels, the configuration illustrated in figure 25 is preferable. In receiver 2500, multiple channels share each equalizer 2506. For example, each equalizer can be shared by 4 channels, e.g., CH1-Ch4, Ch5-CH8, etc., as illustrated in figure 25. In which case, receiver 2500 preferably comprises a memory 2502 configured to store information arriving oneach channel. Memory 2502 is preferably divided into sub-sections 2504, which are each configured to store information for a particular subset of channels. Information for each channel in each subset is then alternately sent to the appropriate equalizer 2506, which equalizes the information based on the QR provided for that channel. In this case, each equalizer must run much faster than it would if there was simply one equalizer per channel. For example, equalizers 2506 would need to run4 ormore times asfastin older to effectively equalize 4 channels as opposed to 1. Inaddition,extramemory2502isrequiredto buffer the channel information But overall, the complexity ofreceiver 2500 is reduced, because there are fewer equalizers. This should also lower the overall cost to implement receiver 2500. Preferably, memory 2502 andthe number of channels thataresentto a particular equalizer is programmable. Inthis way, receiver 2500 can be reconfigured for the most optimum operation for a given system. Thus, if receiver 2500 were moved from an outdoor system to an indoor system with fewer channels, then receiver 2500 can preferably be reconfigured so that there are fewer, even as few as 1, channel per equalizer. Therate atwhichequalizers 2506arenm isalso preferably programmable suchthat equalizers 2506canberunatthe optimum rateforthe number of channels being equalized. In addition, if each equalizer 2506 is equalizing multiple channels, then the QR for those multiple paths must altemately be provided to each equalizer 2506. Preferably, therefore, a memory (not shown) is also included to buffer the CIR information for each channel. The appropriate CIR infoimation is then sent to each equalizer from the QR memory (not shown) when the corresponding channel information is being equalized. The QR memory (not shown) is also preferably programmable to ensure optimum operation regardless ofwhattypeof system receiver 2500is operating in Returning to the issue of path diversity, the number of paths used by equalizers 2506 must account for the delay spread 4 in the system. For example, if the system is an outdoor system operating in the 5GHz range, the communication channel can comprise a bandwidth of 125MHz, e.g., the channel can extend from 5.725GHz to 5.85GHz. If the channel is divided into 512 sub-channelswitharoll-offfactorr of.125, then each sub-channel willhave a bandwidth of approximately 215KHz, which provides approximately a4.6μs symbol duration. Since the worst case delay spread ^ is 20μs, the number ofpathsusedby equalizers 2504canbesettoa maximum of5. Thus, there would bea first pathPl atOμs, a second pathP2 at4.6μs,athird pathP3 at92μs,afourthpathP4at 13.8us,andfiflh pathP5at 18.4us,whichis close tothe delay spread<4 In another embodiment, a sixth pathcanbe included soas to completely cover the delay spread ds; however, 20μsis the worst case. In fact, a delay spread ds of3μs is a more typical value. In most instances, therefore, the delay spread ds will actually be shorter and an extra path is not needed. Alternatively, fewer sub-channels can be used, thus providing a larger symbol duration,insteadofusinganextrapath.Butagain,thiswouldtypical ly notbe needed As explained above, equalizers 2506 are preferably configurable so that they can be reconfigured for various communication systems. Thus, for example, the number of paths used must be sufficient regardless of the type of commurricaiion system. But this is also dependent on the number of sub-channels used. If, for example, receiver 2500 went fromoperatingintheabovedescribedoutdoorsystemto an then receiver 2500can preferably be reconfigured for 32 sub-channels and 5 paths. Assuming thesame overall bandwidth of 125 MHz, the bandwidth ofeach sub-channel is approximately 4MHzandthe symbol duration is approximately 250ns. Therefore, there will be a first path Pl at Oμs and subsequent paths P2 to P5 at 250ns, 500ns, 750ns, and lμs, respectively. Thus, the delay spread 4 should be covered for the indoor environment Again, the 1μsds is worst case so the lus ds provided in the above example will often be more than is actually required. This is preferable, however, for indoor systems, because it can allow operation to extend outside of the inside environment, e.g.,just outside the building in which the inside environment operates. For campus style environments, where auser is likely tobe traveling between buildings, thiscan be advantageous. 7. SampleEmbodimentofaWirelessCommunicationdevice Figure 26 illustrates an example embodiment of a wireless communication device in accordance with the systems and methods described herein. Device 2600 is, for example, a portable communication device configured for operation ina plurality of indoor and outdoor communication systems. Thus, device 2600 comprises an antenna 2602 for transmitting and receiving wireless communication signals ova a wireless communication channel 2618. Duplexor 2604, or switch, canbe included so that transmitter 2606 and receiver 2608 can both use antenna 2602, while being isolated from each other. Duplexors,or switches usedforthis purpose, are well known and willnotbe explained herein Transmitter 2606 is a configurable transmitter configured to implement the channel access protocol described above. Thus, transmitter 2606 is capable of transmitting and encoding a wideband communication signal comprising a plurality of sub-channels. Moreover, transmitter 2606 is configured such that the various subcomponents that comprise transmitter 2606 can be reconfigured, or programmed, as described in section 5. Similarly, receiver 2608 is configured to implement the channel access protocol described above and is, therefore, also configured such that the various sub¬ components comprising receiver 2608canbe reconfigured, orreprogrammed,as described in section 6. Transmitter 2606 and receivσ 2608 are interfaced with processor 2610, which can comprise various processing, controller, and/or Digital Signal Processing (DSP) circuits. Processor 2610 controls the operation of device 2600 including encoding signals tobe transmitted by transmitter 2606 and decoding signals received by receiver 2608. Device 2610can also include memory 2612, which can be configured to store operating instructions, e.g., firmware/software, used by processor 2610tocontroltheoperationofdevice2600. Processor2610isalsopreferablyconfiguredtoreprogramtrananitt� �2606ardrecdvα2608 via control interfaces 2614 and 2616, respectively, as required by the wireless communication system in which device 2600 is operating. Thus, for example, device 2600 canbe configured to periodically ascertain the availability is a preferred communication system. If the system is detected, then processor 2610 can be configured to load the corresponding operating instruction from memory 2612andreconfiguretransmitter2606andreceiver2608foroperation inthe preferred system. For example, it may preferable for device 2600 to switch to an indoor wireless LAN if it is available. So device 2600 may be operating in a wireless WAN where no wireless LAN is available, while periodically searching for the availability of an appropriate wireless LAN. Once the wireless LAN is detected, processor 2610 will load the operating instructions, e.g., the appropriate protocol stack, for the wireless LAN environment and will reprogram transmitter 2606 and receiver 2608 accordingly. In this manner, device 2600canmovefromonetypeof communication system to another, while maintaining superior performance. Itshouldbenotedthatabasestationconfiguredinaccordancewiththe systems and methods herein will operate ina similar manner as device 2600; however, because thebase station doesnotmove fromone typeof system to another, there is generallynoneedtoconfigureprocessor2610toreconfiguretransmit ter2606andrerøvα2608 for operation in accordance with the operating instruction for a different type of system. But processor 2610 can still be configured to reconfigure, or reprogram the sub-components of transmitter 2606 and/or receiver 2608 as required by the operating conditions within the system as reported by communication devices in communication with thebase station Moreover, suchabase station canbe configured in accordance with the systems and methods described herein to implement morethanonemodeof operation In which case, controller 2610canbe configured to reprogram transmitter 2606and receiver 2608 to implement the appropriate modeofoperation 8. Bandwidth recovery As described above in relation to figures 11-14, when a device, such as device 1118 is near the edge of a communication cell 1106, itmay experience interference frombase station 1112 of an adjacent communication cell 1104. In thiscase,device 1118 willreportalow SIRtobasestation 1114,whichwillcausebasestatics 1114to reduce the number of sub-channels assigned to device 1118. As explainedmrelation to figures 12and 13,thisreductm 1114 assigning only even sub-channels to device 1118. Preferably, base station 1112 is correspondingly assigning only odd sub-channels to device 1116. In this manner, base station 1112 and 1114perfomicomplementaryreducticαis 1116 and 1118 in order to prevent interference and improve performance of devices 1116 and 1118. The reduction in assigned channels reduces the overall bandwidth available to devices 1116 and 1118. But as described above, a system implementing such a complementary reduction of sub-channels will still maintain a higher bandwidth than conventional systems. Still, it is preferable to recover the unused sub-channels, or unused bandwidth, created by the reduction of sub-channels in response toalow reported SIR. One method for recovering the unused bandwidth is illustrated in the flow chart of figure 27. First, in step 2702, basestation lll4recdvesSIRreportsforditfei^tgroupsofsu^ Ifthegroup SIR reports are good, then base station 1114 can assign all sub-channels to device 1118 in step 2704. If, however, some of thegroupSIRreportsreceivedinstep2702 arepoor,thenbasestation 1114canreduce the number ofsub-charrnelsassigned to device 1118, e.g., by assigning only even sub-channels, in step 2706. At the same time, base station 1112 is preferably performing a complementary reduction in the sub-channels assigned to device 1116, e.g, by assigning only odd sub-channels. At this point, each base station has unused bandwidth with respect to devices 1116 and 1118. To recover this bandwidth, base station 1114 can, in step 2708, assign the unused odd sub-channels to device 1116 in adjacent cell 1104. It should be noted that even though cells 1102, 1104, and 1106 arc illustrated as geometrically shaped, non-overlapping coverage areas, the actual coverage areas do not resemble these shapes. The shapes are essentially fictions used to plan and describe a wireless communication system 1100. Therefore, base station 1114 can in feet communicate with device 1116, even though it isin adjacent cell 1104. Oncebasestation 1114hasassignedtheoddsub-channelstodevice 1116, instep2708,base station 1112and 1114 communicate with device 1116 simultaneously over the odd sub-channels in step 2710. Preferably, base station 1112 also assignstheunusedevensub-channelstodevice 1118inoldertorecovertheunusedbandwidth incell 1104aswelL In essence, spatial diversity is achieved by having bothbase station 1114 and 1112 communicate with device 1116 (and 1118) over the same sub-channels. Spatial diversity occurs when the same message is transmitted simultaneously over statistically independent communication paths to the same receiver. The independence of the two paths improves the overall immunityofthe system to fading. This is because the two paths will experience different fading effects. Therefore, if the receiver cannot receive the signal ovaone path due to fading, then it will probably still be able to receive the signal over the other path, because the fading that effected the first path will not effect the second. As a result, spatial diversity improves overall system performance by improving the Bit Error Rate (BER) in the receiver, which effectively increases the deliverable datarate to the receiver, i.e., increase the bandwidth. For effective spatial diversity, base stations 1112 and 1114 ideally transmit the same information at the same time ovathesame sub-channels. As mentioned above, eachbase station in system 1100is configured to transmit simultaneously, i.e., system 1100 is aTDM system with synchronizedbase stations. Base stations 1112 and 1114 also assigned the same sub-channels to device 1116 in step 2708. Therefore, all that is left is to ensure that base stations 1112 and 1114 send the same information Accordingly, the information communicated to device 1116bybase stations 1112 and 1114is preferably coordinated so that the same information is transmitted at the same time. The mechanism for enabling this coordination is discussed more fully below. Such coordination, howevα, also allows encoding that can provide furfhα pαformanee enhancementswithinsystem 1100andallowagreatαpercenlageoftheunusedbandwidlhtoberecove red. One example coordinated encoding scheme that can be implemented between base stations 1112 and 1114 with respect to communications with device 1116 is Space-Time>Coding (STQ diversity. STC is illustrated by system 2800 in figure 28. In system 2800, transmitter 2802 transmits a message ova channel 2808 to receivα 2806. Simultaneously, transmitter2804transmits a message ova channel2810toreceivα2806. Becausechannels2808and2810areindependent, system 2800 will have spatial diversity with respect to communications from transmitters 2802 and 2804 to receivα 2806. In addition, howevα, thedata transmitted byeach transmittα 2802 and2804canbe encoded toalso provide time diversity. The followingequationsillustratetheprocessof encodingandde∞dingdatamaSTCs^ten%suchas system 2800. First,channel2808canbedenotedhn andchannel2810canbedenoted^,where:

Second, we can look at two blocks of data 2812a and 2812b to be transmitted by transmitter 2802 as illustrated in figure28. Blcck2812acomprisesN-symbolsderiotjedasααβ/. β-i ", ciN-ι,oca(0:N-l). Block2812btransmitsTV-symbolsof datadenotedb(0:N-l). Transmitter2804simultaneouslytransmitstwoblockofdata2814aand 2814b. Block 2814aisthe negative inverse conjugate of block 2812b and can therefore be described as -b*(N-l:0). Block 2814b is the inverse conjugate of block 2812a and can therefore be described as a*(N-l:0). It should be noted that each block of data in the forgoing description will preferably comprise a cyclical prefix as described above. Whenblocks2812a,2812b,2814a,and2814barereceivedinreceiver280 6,theyarecombinedanddecoded inthe following manner First, the blocks will be combined in the receiver to form the following blocks, after discarding the cyclical prefix: Blockl = a(0:N-l) ®hn - bψ-l:0) Θ& and (3) Block2 = b(0:-N-l) Θhn + a*(N-l:0) ®& (4) Where the symbol ® represents a cyclic convolution. Second, by taking anIFFTofthe blocks, the blocks canbe described as: Blockl = An^n- Bn*. Gn; and (5) Block2= Bn*Hn- An* .G11. (6) Where«= OtoN-1. In equations (5) and (6) Hn and Gn will be known, or can be estimated. But to solve the two equations and determine An and Bn, it is preferable to turn equations (5) and (6) into two equations with two unknowns. This can be achieved using estimated signalsXn and Yn as follows: Xn = An * Hn-Bn*. G1;and (7) Yn =Bn *Hn +A* *Q, (8) To generate two equations and two unknowns, the conjugate of Yn can be used to generate the following two equations:

Yn* =Bn*. Hn* +An . Gn*. (10)

unknowns as follows:

Which canbe rewritten as:

Signals 4,and5ncanbedeteiminedusingequation(12). Itshouldbenoted,thattheprocessjustdescribedisnotthe only way to implement STC. Other methods can also be implemented in accordance with the systems and methods described herein Importantly, however, by adding time diversity, such as described in the preceding equations, to the space diversity already achieved by using base stations 1112 and 1114 to communicate with device 1116 simultaneously, theBER canbereducedevenfiirthertorecoverevenmorebandwidth. Anexampletransmitter2900configuredtocommunicateijsirigSTC inacxx)idancewiththe systems and methods described herein is illustrated in figure 29. Transmitter 2900 includes a block storage device 2902, a serial-to-parallel converter 2904, encoder 2906, and antenna 2908. Block storage device 2902 is included in transmitter 2900 because a 1 blockdelayisnecessarytoimplementthecodingillustratedinfigure 28. Thisisbecausetrananitter2804 firsttransmits-bn* (n =N-l to0). Butbn isthesecondblock,soiftransmitter2900isgoingtotransmit-ό,,* first, itmust store two blocks,e.g.,(^, andbn, andthengenerateblock2814aand2814b(see figure 28). Serial-to-parallel converter 2904 generates parallel bit streams from thebitsofblocks an and bn. Encoder 2906 then encodes thebit streams as required, e.g., encoder 2906 can generate -bn* and a * (see blocks 2814a and 2814b in figure 28). The encoded blocks are then combined into a single transmit signal as described above and transmitted via antenna 2908. Trananitter 2900 preferably uses TDM to transmit messages to receiver 2806. An alternative transmitter 3000 embodimentthatusesFDM isillustratedin figure30. Transmitter3000alsoincludes blockstoragedevice 3002, aserial-to- parallel converter 3004, encoder 3006, and antenna 3008, which are configured to perfoαn in the same manner as the corresponding components in transmitter 2900. Butin addition, transmitter 3000 includes IFFTs3010 to take theIFFTofthe blocks generated by encoder 2906. Thus, transmitter 3000 transmits -Bn* and An* as opposed to -bn* and a *, which provides space, frequency, andtime diversity. Figure 31 illustratesanalternativesystem 3100thatalsousesFDMbutthatelirninatesthe 1 block delay associated with transmitters 2900 and 3000. In system 3100, transmitter 3102 transmits over channel 3112 to receiver 3116. Transmitter 3106 transmits over channel 3114 to receiver 3116. As with transmitters 2802 and 2804, transmitters 3102 and 3106 implement an encoding scheme designed to recover bandwidth in system 3100. In system 3100, however, the coordinated encoding occurs atthe symbol level instead ofthe block level. Thus, forexample,transmitter3102 cantransmitblock3104comprising symbolsαftα/,α2,andα.?. In which case, transmitter 3106 will transmit a block 3108 comprising symbols -af, ctf -ΛJ*, and a?. As can be seen, this is the same encoding scheme used by transmitters 2802 and 2804, but implemented at the symbol level instead of the block level. As such, there isnoneedtodelayoneblockbeforetransmitting. AnIFFTofeachblock 3104and 3108 canthenbetaken and transmittedusingFDM AnFFT3110ofblock3104isshowninfigure31 forpurposes ofillustration. Channels 3112 and 3114 can be described by H^ and G,h respectively. Thus, in receiver 3116 the following symbols willbe formed: (Ao^Ho)-(A1* •Go) (A1 .H1H(A0* 'G1) (A2.H2)-(A3* .G2) (A3.H3)+(A2* .G3). In frequency,eachsymbolAn (n = 0 to 3) occupies aslightly different frequency. Thus, each symbol An is transmitted over a slightly different channel, i.e., Hn (n = 0 to 3) orGn(n = 0 to 3), whichresultsinthecombinationsabove. As canbe seen, the symbol combinations formed in the receivσareofthe same form as equations (5) and (6) and, therefore, canbe solved inthesame manner, but without theone block delay. In order to implement STC or Space Frequency Coding (SFQ diversity as described above, bases stations 1112 and 1114 must be able to coordinate encoding of the symbols that are simultaneously sent to a particular device, such as device 1116 or 1118. Fortunately, base stations 1112 and 1114 are preferably interfaced with a common network interface server. For example, in aLAN, base stations 1112 and 1114 (which would actually be service access points in the caseof a LAN) are interfaced with a common network interface server that connects the LAN to a larger network such as a Public Switched Telephone Network (PSTN). Similarly, in a wireless WAN,base stations 1112 and 1114 are typically interfaced witha common base station control center or mobile switching center. Thus, coordination ofthe encoding canbe enabled via the common connection with the network interface server. Bases station 1112 and 1114 can then be configured to share infoimation through this common connection related to communications with devices at the edge of cells 1104 and 1106. The sharing of information, in turn, allows timeor frequency diversity coding as described above. It should be noted that other forms of diversity, such as polarization diversity or delay diversity, can also be combined with the spatial diversity in a communication system designed in accordance with the systems and methods described herein. The goal being to combine alternative forms ofdiversity with the spatial diversity in order to recover larger amounts of bandwidth. It should also be noted, that the systems and methods described can be applied regardless of he number ofbase stations, devices, and communication cells involved. Briefly, delay diversity can preferably be achieved in accordance with the systems and methods described herein by cyclical shifting the transmitted blocks. For example, one transmitter can transmit a block comprising AQ, AI, A2, and A3 in that order, while the other transmitter transmits the symbols in the following oider A3, AQ, AI, and A2. Therefore, it can be seen that the second transmitter transmits a cyclically shifted version of the block transmitted by the first transmitter. Further, the shifted block canbe cyclically shifted bymorethenone symbol of required bya particular implementation 9. Diversity As mentioned above, some form of spatial diversity can be incorporated into a receiver configured in accordance with the systems and methods described herein For example, as illustrated in figure 32, a receiver 3200 configured in accordancewiththesystemsandmethodsdescribedherein(^noorrrpri sea firstantenm3202arda secondaritenm3204to are interfaced with a receive radio circuit 3208 via a switching module 3206. Receive radio circuit 3208 can in turn be interfacedwithabasebandcircuit3210thatcanbeconfiguredtopro&l t;^sssigr-alsreceived by antennas 3202and3204. As can be seen, when transmitter 3212 transmits a signal, each of antennas 3202 and 3204 can receive multiple versions of the signal, Le., each antenna will receive a plurality ofmultipath signals. Sione embodiment, the signal quality for thesignalsbeingreceivedbyantenna3202canbeassessed, thenthesignalquaKtyforthe signals recdvedbyanterrna3204 can be subsequently assessed Switching module 3206 can then be controlled such that the antenna with the better signal quality is selected Itshouldbenotedthatsignalqualitycanbemeasuredinavarietyofway s. Forexample, signalstrength, SNR, bit error rate, etc. Further, the assessment can, depending on the embodiment, be made in either radio receive circuit 3208 or baseband circuit 3210. Forpurposesofillustration, ifthe signal transmittedbybansrdtter3212 is designated for antenna 3202, for example, canbe represented as: y<t)=αi,*x(t-71)+α,2*x(t-τ2)+oi3*x(t-T3)+ ... In other words, the receive signal is the combination of attenuated versions ofeachofthemultipath signals. Each multipath signal is also delayed, e.g., out of phase, with the other multipath signals. This canbe illustrated by the graph in figure 33, which illustrates the results of correlating the multipath signals received by antenna 3202. The delay spread (dsi) forantenna3202canbeseentobethetimefromwhenthefirstsignalisre ceivedtothetimethelastmuMpafliis received. Onceallmultipalhsignalsarecombined,thecombinedsignalcanberep resented ascΛcf(),where: Cή =O4i +012 +043 + . . . Thus, for example, is larger than C£, then antenna 3202 can be switched in via switching module 3206 instead of antenna 3204, or vis versa The signal received by one antenna can become more attenuated than the signal being received by another when, for example, the delay between multipaths is too small, Le, the delay spread (d^ is small compared to the symbol duration When this occurs, the multipath signals can combine destructively. This type of situation is referred to as a flat fading and is the worst type of fading that can effect a wireless communications system But, do to the diversity provided by having more than one antenna, if one antenna is experiencing flat fading, then the other antenna should be fine. Thus, by providing diversity such as that depicted in figure 32, improved receiverperformancecanbe achieved. The diversity scheme depicted in figure 32 is referred to as spartial diversiry. A problem with diversity, however, canoccurwhenthesignalsqualityforeachantennaapproximately the same. Thisisnotsuchaproblemifthesignalquality foreachantennaisgood,butitcanbeaproblemifthesignalqualityism arginal,or poor, foreach antenna Insucha situation, it is preferable tousethe receive signals frommorethanone antenna Figure34 isadiagramofareceiver3400thatcanbeconfiguredtodojusttøin accordance withthe systems and methods described herein. The diversity provided by receiver 3400 can be referred to as path diversity. Instead of determiningwhichantennahasthebestassociatedsignalqualityandt henswitching tothat antenna, receiver 3400 delays the signals being received by subsequent antennas so that signals from all antennas can be decoded independently and then combined in baseband circuit 3416. Thus, for example, signals received by antennas 3404and3406canbe delayed by delay blacks 3408 and 3410, respectively. The signals from each antenna can then be combined, e.g., by combiner 3412 and processed by receive radio circuit 3414 and baseband circuit 3416. In one embodiment, for example, maximum ratio combining can be usedby baseband circuit 3416 to process the signals from the plurality of antennas. The delay applied to each subsequent antenna should be sufficient to ensure that processing of signals from one antennawillnotinterferewiththeprocessingofsignalsfromanother . Dependingontheembodiment,thedelaycanbestatic or dynamic or a combination ofboth. For example, in certain environments, suchasa fixed indoor environment, it is possible to knowwhatthe transmittime fiomtransmittertoreceive antermashould be asweU as thernaximum delay spread forthe receive antenna Insuchsituations, thedelayscanbesetsuchthattheyarelongerthanthe delay spread (4) sothat processing of signals fiom various antennas does not overlap. The delays should not need to be changed unless the transmitter andfor receiver are moved In more dynamic environments, however, the delays can be set dynamically. For example, the signals from antenna 3402 can be received and processed, with the delay spread (ώ) for antenna 3402 being determined. Baseband circuitry 3416 can be configured to then set delay 3408 to be slightly longer than the delay spread (dj as determined for antenna 3402. Subsequent delays can then be set in a similar manner to avoid interference in the processing ofthe signals received by the various antennas. It shouldbenotedthatthe(d) used tordeterminingthedelaytobeapplied bythe delay blocks canbe based onthe average delay spread oronthe maximum delay spread as required bya particular implementation In another embodiment, a fixed delay canbeused initially, with dynamic updates changestherein. Itshouldalsobenotedthatinadynamicembodiment,thedelayscanbe continuously updated, ortheycan be updated periodically ornonperiodicallyas opposed to continually. Thegaininsignal tonoiseratio (SNR)thatcanbeachievedusingpathdiversity canbe significant For example, if there isonlyone path, thentheSNRis:

where: N0 = Noise level Inatypicalmultipathsituationwithoneantenna:

Inthe receiver of figure 34, however, theSNRis: tø3f +... ) +0Qfe,j2 + |θ62f + |Q!af +... ) + -yNo Accordingly, it canbe seen that implementation ofpath diversity can improve performance significantly, especially combined with other ofthe systems and methods described herein. While embodiments and implementations of the invention have been shown and described, it should be apparent thatmanymore embodiments and implementations are within the scope ofthe invention Accordingly, the invention isnotto be restricted, except in light of the claims and their equivalents.