Patent Publication Number: US-8996949-B2

Title: Encoding system and method for a transmitter in wireless communications

Description:
CROSS REFERENCE TO RELATED PATENTS/PATENT APPLICATIONS 
     The present U.S. Utility patent application claims priority pursuant to 35 U.S.C. §120, as a continuation, to the following U.S. Utility patent application which is hereby incorporated herein by reference in its entirety and made part of the present U.S. Utility patent application for all purposes: 
     1. U.S. Utility patent application Ser. No. 11/056,154, entitled “Encoding system and method for a transmitter in wireless communications,” filed Feb. 14, 2005, pending, which claims priority pursuant to 35 U.S.C. §119(e) to the following U.S. Provisional patent applications:
         a. U.S. Provisional Patent Application Ser. No. 60/544,605, entitled “Multiple protocol wireless communications in a WLAN,” filed Feb. 13, 2004.   b U.S. Provisional Patent Application Ser. No. 60/545,854, entitled “WLAN transmitter having high data throughput,” filed Feb. 19, 2004.   c. U.S. Provisional Patent Application Ser. No. 60/568,914, entitled “MIMO protocol for wireless communications,”, filed May 7, 2004.   d. U.S. Provisional Patent Application Ser. No. 60/573,781, entitled “Encoder and decoder of a WLAN transmitter having high data throughput,”, filed May 24, 2004.       

    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates generally to wireless communication systems and more particularly to a transmitter transmitting at improved data rates with such wireless communication systems and methods of encoding signals to achieve the data rate. 
     2. Description of the Related Art 
     Wireless and wire lined communications may occur between wireless or wire lined communication devices according to various standards or protocols. Communication systems and networks may include national or international cellular telephone systems, the Internet, point-to-point or in-home wireless networks and the like. A communication system is constructed, and may operate in accordance with the standard. For example, wireless communication systems may operate in accordance with one or more standards including, but not limited to, IEEE 802.11, Bluetooth, advanced mobile phone services (AMPS), digital AMPS, global system for mobile communications (GSM), code division multiple access (CDMA), local multi-point distribution systems (LMDS), multi-channel-multi-point distribution systems (MMDS), and the like. 
     Wireless local area networks (WLAN) that may use IEEE 802.11, 802.11a, 802.11b, or 802.11g that employ single input, single output (SISO) wireless communications. Other types of communications include multiple input, single output (MISO), single input, multiple output (SIMO), and multiple input, multiple output (MIMO). With the various types of wireless communications, it may be desirable to use the various types of wireless communications to enhance data throughput within a WLAN. 
     For example, improved data rates may be achieved with MIMO communications in comparison to SISO communications. Most WLAN, however, include legacy wireless communication devices that are devices compliant with an older version of a wireless communication standard. Thus, a transmitter capable of MIMO wireless communications also may be backward compatible with legacy devices to function in a majority of existing WLANs. One factor for backward compatibility is that transmitters, receivers, and the like assume all signals within a system are valid. 
     BRIEF SUMMARY OF THE INVENTION 
     A system for generating a signal for wireless communication is disclosed. The system includes an outer encoder to execute outer encoding having a first rate on a signal to generate at least one code word. The system also includes an interleaver to interleave the at least one code word into a byte sequence. The system also includes an inner encoder to execute convolutional encoding having a second rate on the byte sequence to generate an encoded signal. The first rate and the second rate produce an overall coding rate corresponding with a spectral efficiency. 
     A method for generating a signal for wireless communication also is disclosed. The method includes executing an outer encoding process on a signal. The outer encoding process has a first rate. The method also includes generating at least one code word from the outer encoding. The method also includes interleaving the at least one code word into a byte sequence. The method also includes convolutionally encoding the byte sequence according to a second rate. The convolutionally encoding includes generating an encoded signal according to an overall coding rate produced by the first rate and the second rate. The overall coding rate corresponds to a spectral efficiency 
     A method for encoding a signal for wireless transmission also is disclosed. The method includes generating a code word from a signal using a Reed-Solomon encoding process. The Reed-Solomon encoding process has a first rate. The method also includes generating an encoded signal from said code word using a convolutional encoding process having a second rate. The first rate and the second rate produce an overall coding rate having a spectral efficiency applicable for a wide bandwidth transmission. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       For proper understanding of the present invention, reference should be made to the accompanying drawings: 
         FIG. 1  illustrates a wireless communication system in accordance with the present invention; 
         FIG. 2  illustrates a wireless communication device in accordance with the present invention; 
         FIG. 3  illustrates an encoding system in accordance with the present invention; 
         FIG. 4  illustrates a transmitter in accordance with the present invention; and 
         FIG. 5  illustrates a flowchart for encoding data in accordance with the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Reference will now be made to the following detailed description of the preferred embodiments of the present invention. Examples of preferred embodiments may be illustrated by the accompanying drawings. 
       FIG. 1  depicts a communication system  10  according to the present invention. Communication system  10  may be a wireless communication system having networks supported by various wireless communication standards or protocols. Communication system  10  includes base stations  12 ,  14  and  16 . Base stations  12 ,  14  and  16  may provide access for wireless devices and components to communication system  10 . Communication system  10  may provide services and content to the devices and components via base stations  12 ,  14  and  16 . 
     Communication system  10  also may include wide area networks (WANs), local area networks (LANs), wireless local area networks (WLANs), ad-hoc networks, virtual networks, and the like to facilitate the exchange of information or data. For example, network  20  may be coupled to base stations  12 ,  14  and  16  and support communications with communication system  10 . 
     Communication system  10  may forward data or information in the form of signals, either analog or digital. Wireless devices within the individual base stations may register with the base stations and receive services or communications within communication system  10 . The wireless devices may exchange data or information via an allocated channel. Network  20  may set up LANs to support the channel. To support the wireless communication, communication system  10  and its applicable networks may use a standard of protocol for wireless communications. For example, the IEEE 802.11 specification may be used. The IEEE 802.11 specification has evolved from IEEE 802.11 to IEEE 802.11b to IEEE 802.11a and to IEEE 802.11g. Wireless communication devices that are compliant with IEEE 802.11b (standard 11b) may exist in the same wireless local area network as IEEE 802.11g (standard 11g) compliant wireless communication devices. Further, IEEE 802.11a (standard 11a) compliant wireless communication devices may reside in the WLAN as standard 11g compliant wireless communication devices. 
     These different standards may operate within different frequency ranges, such as 5 to 6 gigahertz (GHz) or 2.4 GHz. For example, standard 11a may operate within the higher frequency range. One feature of standard 11a is that portions of the spectrum from between 5 to 6 GHz may be allocated to a channel. The channel may be 20 megahertz (MHz) wide within the frequency band. Standard 11a also may use orthogonal frequency division multiplexing (OFDM). OFDM may be implemented over sub-carriers that represent lines, or values, within the frequency domain of the 20 MHz channels. A wireless signal may be transmitted over many different sub-carriers within the channel. The sub-carriers are orthogonal to each other so that information may be extracted off each sub-carrier about the signal without appreciable interference. 
     Legacy devices may exist within communication system  10 . Legacy devices are those devices compliant with earlier versions of the wireless standard, but reside in the same WLAN as devices compliant with a current or later version of the standard. A mechanism may be employed to ensure that legacy devices know when the newer version devices are utilized in a wireless channel to avoid interference or collisions. 
     Thus, newer devices or components within communication system  10  may use current standards that have backward compatibility with already installed equipment. The devices and components may be adaptable to legacy standards and current standards when transmitting information within communication system  10 . Legacy devices or components may be kept off the air or off the network so as to not interfere or collide with information or data that they are not familiar with. For example, if a legacy device receives a signal or information supported by standard 11n, then the device should forward the information or signal to the appropriate destination without modifying or terminating the signal or its data. Further, a received signal may not react to the legacy device as if the legacy device is a device compatible with a new or current standard. 
     Communication system  10  may operate according to the IEEE 802.11n (standard 11n) protocol for wireless communications. Alternatively, communication system  10  may operate under a variety of standards or protocols, such as standard 11a, standard 11g and standard 11n and may include legacy devices or components. For example, certain components may comply with standard 11a while newer components may comply with standard 11n. Standard 11n may occupy the 5 to 6 GHz band, or, alternatively, standard 11n may occupy the 2.4 GHz band. Standard 11n may be considered an extension of standard 11a. Standard 11n devices and components may operate with a data rate that exceeds 100 Mbps. The devices and components within communication system  10  may know the physical layer rate for standard 11n devices and components may be greater than those of previous standards. 
     Bandwidth for wireless channels under standard 11n may be 20 MHz or 40 MHz. Thus, standard 11n may implement wider bands than previous standards, such as standard 11a. For example, standard 11n may put two 20 MHz bands together as a 40 MHz band and may send twice as much data as previous standards. Moreover, information or data may be filled in a gap between the two 20 MHz bands. The gap results due to falloff between the two bands. By filling in the gap, data or information may be sent according to standard 11n at a rate twice as much as previous standards, if not more. 
     Communication system  10  also may include a multiple input, multiple output (MIMO) structure. MIMO structures may be implemented in communication system  10  to improve the robustness of wireless communications. To better improve robustness, communication system  10  also may set the number of data streams to be less than the number of transmitters of a wireless device. 
     Communication system  10  may resolve the issue of signals generated by legacy devices or components and having the signals operate within a MIMO system using multiple antennas. For example, communication system  10  may determine how the standard 11a signals will work within the wider bandwidth of the channels for standard 11n. Communication system  10  may increase the probability of reception of signals transmitting large amounts of data under current standards or protocols. Further, it may be presumed that all the devices and components within communication system  10  may receive all transmitted signals, no matter what format, protocol or standard is used. 
       FIG. 2  depicts a wireless communication device  200  according to the present invention. Wireless device  200  includes host device  18  and an associated radio  60 . For cellular telephone hosts, radio  60  may be a built-in component. For personal digital assistants hosts, laptop hosts, personal computer hosts and the like, radio  60  may be built-in or an externally coupled component. 
     Host device  18  may include processing module  50 , memory  52 , radio interface  54 , input interface  58  and output interface  56 . Processing module  50  and memory  52  may execute instructions that are done by host device  18 . For example, for a cellular telephone host device, processing module  50  may perform the corresponding communication functions in accordance with a particular cellular telephone standard, such as standard 11n. 
     Radio interface  54  may allow data to be received from and sent to radio  60 . For data received from radio  60 , such as inbound data, radio interface  54  provides the data to processing module  50  for further processing or routing to the output interface  56 . Output interface  56  may provide connectivity to an output display device such as a display, monitor, speakers and the like, such that the received data may be displayed. Radio interface  54  also may provide data from the processing module  50  to radio  60 . Processing module  50  may receive the outbound data from an input device such as a keyboard, keypad, microphone an the like, via input interface  58  or may generate the data itself. For data received via input interface  58 , processing module  50  may perform a corresponding host function on the data or route it to radio  60  via the radio interface  54 . 
     Radio  60  may include a host interface  62 , a baseband processing module  64 , memory  66 , a plurality of radio frequency (RF) transmitters  68 - 72 , a transmit/receive (T/R) module  74 , a plurality of antennas  82 - 86 , a plurality of RF receivers  76 - 80 , and a local oscillation module  100 . Baseband processing module  64 , in combination with operational instructions stored in memory  66 , may execute digital receiver functions and digital transmitter functions, respectively. Baseband processing modules  64  may be implemented using one or more processing devices. Memory  66  may be a single memory device or a plurality of memory devices. When processing module  64  implements one or more of its functions via a state machine, analog circuitry, digital circuitry, or logic circuitry, memory  66  storing the corresponding operational instructions is embedded with the circuitry comprising the state machine, analog circuitry, digital circuitry, or logic circuitry. 
     Radio  60  may receive outbound data  88  from host device  18  via host interface  62 . Baseband processing module  64  receives outbound data  88  and, based on a mode selection signal  102 , produces one or more outbound symbol streams  90 . Mode selection signal  102  may indicate a particular mode. 
     Baseband processing module  64 , based on mode selection signal  102 , may produce one or more outbound symbol streams  90  from output data  88 . For example, if mode selection signal  102  indicates that a single transmit antenna is being utilized for the particular mode that has been selected, baseband processing module  64  may produce a single outbound symbol stream  90 . Alternatively, if mode selection signal  102  indicates 2, 3 or 4 antennas, baseband processing module  64  may produce 2, 3 or 4 outbound symbol streams  90  corresponding to the number of antennas from output data  88 . 
     Depending on the number of outbound streams  90  produced by baseband module  64 , a corresponding number of the RF transmitters  68 - 72  may be enabled to convert outbound symbol streams  90  into outbound RF signals  92 . Transmit/receive (T/R) module  74  may receive outbound RF signals  92  and provides each outbound RF signal to a corresponding antenna  82 - 86 . 
     When radio  60  is in a receive mode, T/R module  74  may receive one or more inbound RF signals via antennas  82 - 86 . T/R module  74  provides inbound RF signals  94  to one or more RF receivers  76 - 80 . RF receivers  76 - 80  may convert inbound RF signals  94  into a corresponding number of inbound symbol streams  96 . The number of inbound symbol streams  96  may correspond to the particular mode in which the data was received. Baseband processing module  60  may receive inbound symbol streams  90  and converts them into inbound data  98 , which are provided to the host device  18  via the host interface  62 . 
       FIG. 3  depicts an encoding system  300  for use with wireless communications according to the present invention. Encoding system  300  may be coupled to a transceiver to code signals for transmission within a wireless network or system. Alternatively, encoding system  300  may be coupled to other devices or components for wireless communications. Further, encoding system  300  may be within the transceiver. Encoding system  300  also may operate or encode according to an applicable wireless communication standard or protocol. For example, encoding system  300  may operate according to standard 11n, so that encoded signals are formatted to take advantage of the improvements of standard 11n over legacy standards. 
     Encoding system  300  may include outer encoder  302 , interleaver  304  and inner encoder  306 . Encoding system  300  receives data or information as signal  310  at outer encoder  302 . Inner encoder  306  outputs coded signal  312 . A code rate may be determined by comparing signal  310  with coded signal  312 . The code rate also may be referred to as an overall coding rate. For example, a code rate may be the ratio of uncoded bits in signal  310  to the coded bits in coded signal  312 . For example, the code rate may be the ratio of the data rate to the coded data rate, or data rate/coded data rate. Encoding system  300  may improve the code rate over legacy systems so as to comply with standard 11n. 
     The overall code rate may correspond to a specified spectral efficiency. The specified spectral efficiency may be known as a high spectral efficiency. The spectral efficiency may be the ratio of the data rate to the signal bandwidth. For example, a code rate may be 0.8 or higher to support a high spectral efficiency corresponding with the larger signal bandwidth of standard 11n. Further according to the example, coding system  300  may include a code rate of 0.8 at 100 megabits/second for a channel having a 40 MHz bandwidth. Constraints applied by standard 11n may warrant a high code rate to increase the ratio of uncoded bits to coded bits over legacy standards. Thus, outer encoder  302 , interleaver  304  and inner encoder  306  may operate according to the constraints and a target code rate of 0.8. 
     Encoding system  300  may code bits to improve performance over a system of uncoded bits. A tradeoff, however, may exist between performance and complexity of encoding system  300 . Thus, if encoding system  300  becomes too complex, any benefit from improved performance may be offset by higher costs in constructing and implementing encoding system  300 . 
     Outer encoder  302  may include a Reed-Solomon (R-S) encoder. An R-S encoder may be applicable for coding longer frames. When encoding, encoding system  300  may forward longer frames with an increased probability of being received correctly. Outer encoder  302  may implement the R-S encoder even if the applicable wireless standard uses short frames. Further, outer encoder  302  may be separable from any convolutional coding, such as that done by inner encoder  306 . Outer encoder  302  may receive data or information as bits or bytes and then codes the bits or bytes for interleaver  304 . For example, outer encoder  302  may generate 2-5 code words comprised of bytes. In the example, a code word  320  may include about 255 bytes with about 239 information bytes. Thus, codeword  320  also may include about 16 redundant bytes. 
     Interleaver  304  receives code word  320  to perform interleaving on the bytes in code word  320 , and to generate bits or bytes  330 . Interleaver  304  may be a byte interleaver to interleave one sequence of bytes into a new sequence of bytes before entering outer encoder  306 . Interleaver  304  may reduce an error rate of encoding system  300  by resolving errors before the errors arrive at inner encoder  306 . Bit or byte errors from outer encoder  302  may be randomly generated, but also may occur in bursts. Interleaver  304  may operate according to a specified rate or operator. 
     Inner encoder  306  receives bits or bytes  330  and performs convolutional coding to generate coded signal  312 . Inner encoder  306  may be a convolutional encoder that in conjunction with outer encoder  302  establishes the desired code rate. For example, inner encoder  306  and outer encoder  302  may work together to develop a code rate of about 0.8. Inner encoder  306  and outer encoder  302 , however, may be separable from each other. Thus, outer encoder  302  and its encoding schemes may be removed or changed within encoding system  300  without impacting inner encoder  306 , or its convolutional code. Thus, modularity between the encoding schemes may exist to improve performance without increased complexity to existing systems, or the need of new code or devices for encoding system  300 . 
     Further, the convolutional code of inner encoder  306  may be punctured at ⅞s on a binary convolutional code. The coding rate of inner encoder  306  may generate a code rate of 0.8 for encoding system  300 , when combined with the code rate of outer encoder  302 . Referring back to the R-S encoder, examples of the R-S code may have a rate that is multiplied by the code rate of a ⅞s convolutional code to achieve a code rate 0.8. Further, inner encoder  306  may be a convolutional encoder operable with legacy standards, such as standard 11a. 
     Coded signal  312  may include frame  332 . Frame  332  may be one of many frames within coded signal  332 . Frame  332  includes preamble, or header, field  334  and data field  336 . Preamble field  334  may be referred to as a preamble. Preamble field  334  may include data or information regarding frame  332  or coded signal  312 . The information may include, but is not limited to, length of frame  332 . Alternatively, preamble field  334  may include information regarding code words from outer encoder  302  or information about coded signal  312 . Preamble field  334 , however, is not so large as to make frame  332  unreadable or unusable. Preamble field  334  also may include short and long training fields. 
     With regard to inner encoder  306 , it may be the same convolutional encoder as used in conjunction with standard 11a. Puncturing of the convolutional code according to standard 11a may also be ⅔ and ¾. Options may be added for these codes, such as a 256 state code or new puncturings for rates of ⅘, ⅚ and ⅞, as discussed above. Thus, inner encoder  306  may be an encoder having the above puncture rates. Moreover, the options listed above may be combined, if desired. 
     Interleaver  304  may be in different states for operation within encoding system  300 . One state may be an “off” state, wherein encoding system  300  acts as if no interleaver  304  is present. Another state may be as an interleaver having sufficient depth to randomize the demodulated bits over R-S code words, such as code word  320 . 
     Outer encoder  302  may operate or generate code words having multiple lengths. As noted above, code word  320  may have a length of about 255, or n, with an information sequence length of about 239 bits, or k. Thus, a correction of up to 8 byte errors may be allowed per code word from outer encoder  302 . 
     For an effective code rate of about 0.8, encoding system  300  may execute a coding process having a high spectral efficiency that achieves a gain of about 4 dB, or above, over the convolutional coding scheme alone. Further, additional components may be included in encoding system  300  that facilitate the coding process. Moreover, the coding processes of outer encoder  302  and inner encoder  306  may differ from each other. 
       FIG. 4  depicts a block diagram of a transmitter  400  according to the present invention. Transmitter  400  includes scrambler  472 , channel encoder  474 , interleaver  476 , demultiplexer  470 , a plurality of symbol mappers  480 ,  482  and  484 , a plurality of inverse fast Fourier transform (IFFT) modules  486 ,  488  and  490  and encoder  492 . Transmitter  400  also may include a mode manager module  475  that receives a mode selection signal and produces settings for transmitter  400 . 
     Scrambler  472  may add a pseudo-random sequence to outbound data bits  488  so that the applicable data or information may appear random. A pseudo-random sequence may be generated from a feedback shift register having a generator polynomial to produce scrambled data. Channel encoder  474  may receive the scrambled data and generate a new sequence of bits having redundancy. The new sequence may enable improved detection at a receiver. Channel encoder  474  may operate in one of a plurality of modes. These modes may correspond to standards or protocols for wireless communications. For example, modes may be assigned to standard 11a, standard 11g, or standard 11n. Backward compatibility with standard 11a and standard 11g may be achieved. Further, channel encoder  474  may be a convolutional encoder with 64 states and a rate of ½. The output of channel encoder  474 , as a convolutional encoder, may be punctured at rates of ½, ⅔ and ¾. For backward compatibility with standard 11b and the CCK modes of standard 11g, channel encoder  474  may have the form of a CCK code as defined in standard 11b. 
     For improved data rates, such as those desired by standard 11n, channel encoder  474  may use the convolutional encoding, as described above. Alternatively, channel encoder  474  may use a more powerful code, including a convolutional code with more states, a parallel concatenated, or turbo, code or a low-density parity check block code. In addition, any one of these codes may be combined with an R-S code of an outer encoder. As discussed above, the outer encoder may be a Reed-Solomon encoder. The choice of applicable code may be determined according to backward compatibility and low-latency requirements. 
     Interleaver  476  may receive the encoded data and distribute the data over multiple symbols. This distribution may allow improved detection and error correction capabilities at a receiver. Interleaver  476  may follow standard 11a or standard 11g in backward compatible modes. For increased performance modes, such as those associated with standard 11n, interleaver  476  may interleave data over multiple transmit streams. Thus, these modes may be applicable to MIMO configurations. Demultiplexer  470  may convert the interleave stream from interleaver  476  into parallel streams for transmission. 
     Symbol mappers  480 ,  482 , and  484  may receive a corresponding one of the parallel paths of data from demultiplexer  470 . Transmitter  400  may include any number of symbol mappers and is not limited to the aspects shown by  FIG. 4 . Further, the number of parallel data streams may vary according to the requirements of transmitter  400 . For example, the number of data streams may correspond to a number of antennas used for transmitting. Further, the number of symbol mappers may correspond to the number of antennas. 
     Symbol mappers  480 ,  482  and  484  may map the bit streams, or data streams, to quadrature amplitude modulated (QAM) symbols. The map symbols generated by symbol mappers  480 ,  482  and  484  may be provided to IFFT modules  486 ,  488  and  490 . IFFT modules  486 ,  488  and  490  may be referred to as cyclic prefix addition modules. The number of IFFT modules may correspond to the number of symbol mappers and data streams. IFFT modules  486 ,  488  and  490  may perform frequency domain to time domain conversions and may add a prefix that allows removal of inter-symbol interference at a receiver. The length of the IFFT and any applicable cyclic prefix may be defined. For example, a 64 point IFFT may be used for 20 MHz channels and 128 point IFFT may be used for 40 MHz channels, used according to standard 11n. 
     Encoder  492  may receive the parallel paths of the time domain symbols and convert them into output symbols. Encoder  492  also may be referred to as a space/time encoder. The number of input paths to encoder  492  may equal the number of output paths. Alternatively, the number of output paths may equal the number of input paths plus 1. For each of the paths, encoder  492  multiplies the input symbols with an encoding matrix having a form shown in Equation 01 below. 
     
       
         
           
             
               
                 
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     The rows of the encoding matrix may correspond to the number of input paths and the columns may correspond to the number of output paths. Thus, outbound data bits  488  may be encoded and prepared for transmission by transmitter  400 , and converted to multiple output streams. Thus, transmitter  400  may support multiple output structures and operations. 
       FIG. 5  depicts a flowchart for encoding data for wireless communications according to the present invention. The steps shown in  FIG. 5  may be used for converting outbound data into one or more outbound data streams for multiple output transmission. Step  502  executes by receiving data bits for transmission. The bits may be generated or created for transmission in a wireless network or system according to a standard or protocol. For example, standard 11n may be applicable to the system or network that exchanges the data bits. Alternatively, the applicable system or network may have standard 11a and standard 11n devices or components. Thus, the received bits may be received by legacy devices. 
     Step  504  executes by encoding the bits according to an outer encoder, such as outer encoder  302  in  FIG. 3 . The outer encoder may encode the bits or bytes according to the specified encoding process, such as Reed-Solomon encoding. For example, the outer encoder may be an R-S encoder. The R-S encoder may be effective in coding longer frames. Step  504  performs the outer encoding of the received bits. Step  506  executes by generating code words from the outer encoder. The code words may be bytes. As discussed above, the code words may include about 255 bytes. 
     Step  508  executes by interleaving the code words from bytes into bytes or bits. Thus, the received code words from the outer encoder may be interleaved into bits or bytes for use with multiple data streams. Alternatively, codeword bytes may be interleaved from one sequence of bytes into a new sequence of bytes. An interleaver, such as interleaver  304 , may be implemented. Moreover, step  508  may be skipped if no outer encoding is performed on the received bits. For example, the received bytes may be meant for a network or system having only legacy devices, such as those compatible with standard 11a. The received bytes, in this example, may not undergo outer encoding to improve performance and to increase throughput. Thus, step  508  may be skipped. 
     Step  510  executes by encoding the interleaved bytes according to an inner encoder, such as inner encoder  306 . For example, the inner encoder may be a convolutional encoder. The convolutional encoder may encode the bits using convolutional coding techniques. The convolutional encoder may encode the bits to produce a sequence of coded output. The convolutional encoder may process multiple symbols at a time. The inner encoder also may be specified such that if the encoder receives a number of input streams, then an input vector length may be determined. An output vector length also may be determined according to the number of output streams. Thus, the received bits or bytes may be coded according to the convolutional encoder, or the inner encoder. The inner encoder may code to a specified rate, such as ½. Alternatively, the inner encoder may code to other rates, such as ¾, ⅘ and ⅞. 
     Step  512  executes by puncturing the coded bits or bytes. Step  512  may periodically remove bits or bytes from the encoded bit streams received from the inner encoder. Thus, the code rate may be increased, along with the spectral efficiency corresponding to the wider bandwidth for standard 11n. A puncture pattern may be specified by a puncture vector parameter. A puncture vector may be a binary column vector that indicates a bit in a corresponding position of an input vector is sent to the output vector, or is removed. Thus, bits in various positions may be transmitted while bits and other positions may be removed. For example, for every 7 bits of input, the punctured code generates 8 bits of output. Thus, the puncture rate may be ⅞. The code rate may be determined by the puncture convolutional code rate and the code rate of the outer encoder. As discussed above, a code rate may be equal to about 0.8 or greater. 
     Thus, various embodiments of an encoder system and applicable methods for use in wireless communication systems is disclosed. As one of average skill in the art will appreciate, other embodiments and variations thereof may be derived from the teaching of the present invention without deviating from the scope of the claims and their equivalents.