Patent Publication Number: US-7907070-B2

Title: Systems and methods for providing unequal error protection using embedded coding

Description:
TECHNICAL FIELD 
     The present invention relates generally to wireless communications and wireless communications-related technology. More specifically, the present invention relates to systems and methods for providing unequal error protection using embedded coding. 
     BACKGROUND 
     A wireless communication system typically includes a base station in wireless communication with a plurality of user devices (which may also be referred to as user equipment, mobile stations, subscriber units, access terminals, etc.). The base station transmits data to the user devices over a radio frequency (RF) communication channel. The terms “downlink” and “forward link” refer to transmission from a base station to a user device, while the terms “uplink” and “reverse link” refer to transmission from a user device to a base station. 
     The 3 rd  Generation Partnership Project (3GPP) is a collaboration of standards organizations throughout the world. The goal of 3GPP is to make a globally applicable third generation (3G) mobile phone system specification within the scope of the IMT-2000 (International Mobile Telecommunications-2000) standard as defined by the International Telecommunication Union. The 3GPP Long Term Evolution (“LTE”) Committee is considering Orthogonal Frequency Division Multiplexing (OFDM) as well as OFDM/OQAM (Orthogonal Frequency Division Multiplexing/Offset Quadrature Amplitude Modulation), as a method for downlink transmission, as well as OFDM transmission on the uplink. 
     Wireless communications systems (e.g., Time Division Multiple Access (TDMA), OFDM, Code Division Multiple Access (CDMA), Frequency Division Multiple Access (FDMA), etc.) may transmit a channel quality indicator signal (CQI), acknowledgment signals (ACK), negative acknowledgment signals (NAK), and many other types of signals. Performance may diminish and/or the acceptable error rates may increase depending on how the signals are coded. Accordingly, benefits may be realized by providing improved systems and methods for embedded coding. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a block diagram illustrating a wireless communication system in which embodiments may be practiced; 
         FIG. 2  is a block diagram illustrating communication channels that may exist between a transmitter and a receiver according to an embodiment; 
         FIG. 3  is one embodiment of a constellation diagram for Quadrature Phase Shift Keying (QPSK) modulation, which may be implemented with the present systems and methods; 
         FIG. 4  is a block diagram illustrating a system for providing unequal error protection using embedded coding; 
         FIG. 5  is a block diagram of an embedded encoder for embedded encoding of two types of information; 
         FIG. 6  is a flow diagram illustrating a method of embedded encoding of two types of information; 
         FIG. 7  is a block diagram illustrating a series of strings being mapped into a series of QPSK symbols using a mapping rule; 
         FIG. 8  is a block diagram of an embedded decoder for embedded decoding of a signal conveying two types of information; 
         FIG. 9  is a flow diagram illustrating a method of embedded decoding; and 
         FIG. 10  illustrates various components that may be utilized in a communications device. 
     
    
    
     DETAILED DESCRIPTION 
     A method for embedded encoding of at least two types of information is disclosed. The types of a first encoder and a second encoder are determined. The rates of the first encoder and the second encoder are determined. A first codeword and a second codeword are generated. A mapping rule is determined for the second codeword. A coding rule is determined for the first codeword. The second codeword is mapped into a plurality of symbols using the mapping rule. A third codeword is determined using the first codeword, the plurality of symbols, and the coding rule. The third codeword is transmitted. The third codeword includes at least two types of information. 
     A first message and a second message may require unequal error protection. The generating may comprise encoding a first message with the first encoder and encoding a second message with the second encoder. The first encoder may be an error-correcting code encoder. The second encoder may be an error-correcting code encoder. The first encoder may be a convolutional encoder. The second encoder may be a Turbo encoder. The symbols may be Quadrature Phase Shift Keying (QPSK) symbols. The coding rule may include instructions for rotating the plurality of symbols around a QPSK constellation based on the first codeword to produce the third codeword 
     A method for embedded decoding of a signal conveying at least two messages is disclosed. A signal is received. A first decoding rule is determined for the signal. The signal is demodulated. The demodulated signal is decoded using the first decoding rule to produce a first message. The first message is encoded to produce a first codeword. The demodulated signal is demapped using the first codeword and a second decoding rule to produce a second codeword. The second codeword is decoded to produce a second message. The first decoding rule may be a probability distribution of the first codeword given a set of possible values for the signal. 
     An apparatus for embedded encoding of at least two types of information is disclosed. The apparatus includes a processor and memory in electronic communication with the processor. Executable instructions are stored in the memory. A first error-correcting encoder and a second error-correcting encoder are determined. The rates of the first encoder and the second encoder are determined. A first codeword and a second codeword are generated. A mapping rule is determined for the second codeword. A coding rule is determined for the first codeword. The second codeword is mapped into a plurality of symbols using the mapping rule. A third codeword is determined using the first codeword, the plurality of symbols, and the coding rule. The third codeword is transmitted. The third codeword includes at least two types of information. 
     An apparatus for embedded decoding of a signal conveying at least two messages is disclosed. The apparatus includes a processor and memory in electronic communication with the processor. Executable instructions are stored in the memory. A signal is received. A first decoding rule is determined for the signal. The signal is demodulated. The demodulated signal is decoded using the first decoding rule to produce a first message. The first message is encoded to produce a first codeword. The demodulated signal is demapped using the first codeword and a second decoding rule to produce a second codeword. The second codeword is decoded to produce a second message. 
     A computer-readable medium for embedded encoding of at least two types of information is disclosed. The computer-readable medium comprises executable instructions. The types of a first encoder and a second encoder are determined. The rates of the first encoder and the second encoder are determined. A first codeword and a second codeword are generated. A mapping rule is determined for the second codeword. A coding rule is determined for the first codeword. The second codeword is mapped into a plurality of symbols using the mapping rule. A third codeword is determined using the first codeword, the plurality of symbols, and the coding rule. The third codeword is transmitted. The third codeword includes at least two types of information. 
     A computer-readable medium for embedded decoding of a signal conveying at least two messages is disclosed. The computer-readable medium comprises executable instructions. A signal is received. A first decoding rule is determined for the signal. The signal is demodulated. The demodulated signal is decoded using the first decoding rule to produce a first message. The first message is encoded to produce a first codeword. The demodulated signal is demapped using the first codeword and a second decoding rule to produce a second codeword. The second codeword is decoded to produce a second message. 
     Channel coding, also known as forward error correction (FEC), is a system of error control for data transmission whereby a sender may add redundant data to a transmitted message. This may allow a receiver of the message to detect and correct errors in the message under some circumstances and within some boundaries. FEC may be accomplished by adding redundant data to the transmitted information using a predetermined algorithm. Traditionally, the emphasis in this type of coding has been the design of channel capacity approaching codes, e.g., Turbo codes and low-density parity-check (LDPC) codes. Therefore, the main question addressed by most researchers has been how to design codes that achieve a particular point on the rate-distortion curve for one type of message. 
     Embedded coding, as used herein, may refer to a system of error control for data transmission, whereby the sender adds redundant data to multiple simultaneously transmitted messages. Thus, embedded coding may be channel coding for multiple types of messages. The term “embed” comes from the fact that one or more types of information may be hidden in the codeword of another message. The terms “message” and “information” may be used interchangeably. 
     Embedded coding, as described herein, solves a different problem than traditional channel coding. Specifically, the problem addressed is the situation where multiple levels of reliabilities (in terms of error probability) are sought for different types of information/messages. In other words, one advantage of embedded coding is the ability to support a variety of applications with different quality-of-service (QoS) requirements. Therefore, providing unequal error protection (UEP) is one of the functions of embedded coding. 
     For example, different control messages may need different reliability. A channel quality indicator (CQI) and acknowledgment/negative acknowledgement (ACK/NACK) are two types of control signals in a cellular system. Typically, the desired quality for CQI and ACK/NACK are different. In one configuration, the desired quality is a function of a message error rate and delay. Table 1 illustrates an example of desired target qualities for these two types of signals. 
     
       
         
           
               
             
               
                 TABLE 1 
               
             
            
               
                   
               
               
                 Control Signals Target Quality 
               
            
           
           
               
               
               
            
               
                   
                 Event 
                 Target Quality 
               
               
                   
               
               
                   
                 NACK to ACK error 
                 10 −4 -10 −3   
               
               
                   
                 CQI block error rate 
                 10 −2 -10 −1   
               
               
                   
               
            
           
         
       
     
     As another example, real-time multimedia applications, such as multimedia, may need lower delay and higher reliability as compared to non-real-time applications. 
     If an overall system is designed for a fixed rate-distortion operating point, the CQI and ACK/NACK may be jointly coded and then multiplexed together as a single type of information. An advantage of this embodiment includes an improvement in performance. However, if jointly coded, the CQI and ACK/NACK may have the same error target quality, which may not be desired. In particular, resources may be over-provisioned, which could otherwise be flexibly allocated to different applications. In other words, channel resources may be wasted by overprotecting one or several of these quantities. Alternatively, one or several of these quantities may not be sufficiently protected if enough channel resources are not used to protect them. 
       FIG. 1  is a block diagram illustrating a wireless communication system  100  in which embodiments may be practiced. A base station  102  may be in wireless communication with a plurality of user devices  104  (which may also be referred to as user equipment, mobile stations, subscriber units, access terminals, etc.). A first user device  104   a , a second user device  104   b , and an Nth user device  104   n  are shown in  FIG. 1 . The base station  102  may transmit data to the user devices  104  over a radio frequency (RF) communication channel  106 . 
     As used herein, the term “transmitter” refers to any component or device that transmits signals. A transmitter may be implemented in a base station  102  that transmits signals to one or more user devices  104 . Alternatively, or in addition, a transmitter may be implemented in a user device  104  that transmits signals to one or more base stations  102 . 
     The term “receiver” refers to any component or device that receives signals. A receiver may be implemented in a user device  104  that receives signals from one or more base stations  102 . Alternatively, or in addition, a receiver may be implemented in a base station  102  that receives signals from one or more user devices  104 . 
     The communications system  100  may be an Orthogonal Frequency Division Multiplexing (OFDM) system. In addition, the system  100  may be a Code Division Multiple Access (CDMA) system, a Time Division Multiple Access (TDMA) system, a Frequency Division Multiple Access (FDMA) system, etc. 
       FIG. 2  is a block diagram illustrating communication channels  206  that may exist between a transmitter  202  and a receiver  236  according to an embodiment. As shown, communication from the transmitter  202  to the receiver  236  may occur over a first communication channel  206   a . Communication from the receiver  236  to the transmitter  202  may occur over a second communication channel  206   b.    
     The first communication channel  206   a  and the second communication channel  206   b  may be separate communication channels  206 . For example, there may be no overlap between the transmission band of the first communication channel  206   a  and the transmission band of the second communication channel  206   b . The first communication channel  206   a  may also be referred to as a downlink, forward link, etc. The second communication channel  206   b  may be referred to as an uplink, reverse link, etc. 
       FIG. 3  is one embodiment of a constellation diagram  300  for Quadrature Phase Shift Keying (QPSK) modulation, which may be implemented with the present systems and methods. However, other digital modulation schemes may also be used, e.g., 16QAM, 64QAM, etc. QPSK modulation may use four points  302 ,  304 ,  306 ,  308  on the constellation diagram  300 , equispaced around a circle. With four points  302 ,  304 ,  306  and  308 , QPSK modulation may encode two bits of a message into a symbol. For example, a message may include the bits “01”. These bits may be encoded as the symbol “B”. In a similar manner, the bits “00” may be encoded as the symbol “A”, the bits “10” may be encoded as the symbol “C” and the bits “11” may be encoded as the symbol “D”. 
       FIG. 4  is a block diagram illustrating a system  400  for providing unequal error protection using embedded coding. The system  400  may have a transmitter  402  and a receiver  436 . The transmitter  402  may include type  1  information (W 1 )  404 , type  2  information (W 2 )  406 , an embedded encoder  408 , and a modulator  434 . Specifically, type  1  information (W 1 )  404  may have different error protection requirements than type  2  information (W 2 )  406 . However, the type  1  information (W 1 )  404  may have similar characteristics as the type  2  information (W 2 )  406 , e.g., bit-length, purpose, origin, etc. Alternatively, the type  1  (W 1 )  404  and type  2  (W 2 )  406  information may have different characteristics such as bit-length. For the purpose of illustration, the type  1  information (W 1 )  404  is treated herein as having a higher priority than the type  2  information (W 2 )  406 . However, another configuration may accommodate type  2  information (W 2 )  406  with higher priority than the type  1  information (W 1 )  404 . The modulator  434  may perform a modulation on the one or more encoded signals. The modulator  434  may produce a plurality of data symbols. 
     In one example, type  1  information (W 1 )  404  may be an ACK/NACK signal and type  2  information (W 2 )  406  may include a CQI signal, or any other signal sent from the transmitter  402  to the receiver  436 . In another example, type  1  information (W 1 )  404  may be a control signal while type  2  information (W 2 )  406  may be normal user data from the transmitter  402  to the receiver  436 . 
     The embedded encoder  408  may include a first encoder  410 , a second encoder  416 , a first mapper  422 , a second mapper  424 , a mapping rule  426 , a coding rule  428 , a first set of symbols (T)  430  and a second set of symbols (Y)  432 . The first encoder  410  may include a first codebook  412 . This codebook  412  may be generated from the type  1  information (W 1 )  404  and may include a plurality of codewords  414 . One of the plurality of codewords  414  may encode the type  1  information (W 1 )  404 . Likewise, the second encoder  416  may include a codebook  418  generated from the type  2  information (W 2 )  406 . The codebook  418  may also include a plurality of codewords  420 . One of the plurality of codewords  420  may encode the type  2  information (W 2 )  406 . For the purpose of illustration, X 1  may be used to denote the codeword  414  used to encode the type  1  information (W 1 )  404  and X 2  may be used to denote the codeword  420  used to encode the type  2  information (W 2 )  406 . X 1    414  and X 2    420  may be digital signals in binary form. The first mapper  422  may be used to map X 2    420  into the first set of symbols (T)  430  based on the mapping rule  426 . The second mapper  424  may be used to map X 1    414  into the second set of symbols (Y)  432  based on the coding rule  428  and the first set of symbols (T)  430 . The second set of symbols (Y)  432  may be further modulated by the modulator  434  before transmitted to the receiver  436 . 
     The receiver  436  may include an estimate of type  1  information (W 1 ′)  438 , an estimate of type  2  information (W 2 ′)  440 , a demodulator  442  and an embedded decoder  444 . W 1 ′  438  and W 2 ′  440  may correspond to the W 1    404  and W 2    406 , respectively. In other words, W 1 ′  438  may be an attempt to reproduce W 1    404 , and W 2 ′  440  may be an attempt to reproduce W 2    406  after decoding and demodulation. The demodulator  442  may demodulate one or more signals transmitted to the receiver  436 . 
     The embedded decoder  444  may include a first decoder  446 , a second decoder  448 , an encoder  450 , a demapper  452 , a first  454  and second  456  decoding rule, a first codeword estimate (X 1 ′)  458 , a second codeword estimate (X 2 ′)  460 , an estimate of a first set of symbols (T′)  462 , and an estimate of a second set of symbols (Y′)  464 . The data included in the embedded decoder  444  may be an attempt to reproduce the data in the embedded encoder  408 , e.g., X 1 ′, X 2 ′, T′, and Y′ may be attempts to reproduce X 1 , X 2 , T, and Y, respectively. 
     The first decoder  446  may be used to decode Y′  464  after demodulation. This decoding may utilize the first decoding rule  454  to produce the estimate of type  1  information (W 1 ′)  438 . The first decoding rule  454  may be derived from the mapping rule  426  and/or the coding rule  428  and may be expressed in terms of the probability distribution of a combination within X 1 ′  458  for all possible symbol combinations within a portion of Y′  464 . This will be explained in more detail below. The encoder  450  may be used to derive the estimate of X 1  (X 1 ′)  458  from the estimate of type  1  information (W 1 ′)  438 . This encoder  450  may be similar to the first encoder  410  on the transmitter  402 . The demapper  452  may decode Y′  464  using the second decoding rule  456  to produce an estimate of the second codeword estimate (X 2 ′)  460 . The second decoding rule  456  may also be derived from the mapping rule  426  and/or the coding rule  428 . The second codeword estimate (X 2 ′)  460  may then be decoded using the second decoder  448  to produce the estimate of type  2  information (W 2 ′)  440 . The second decoder  448  may be designed as the counterpart to the second encoder  416  on the transmitter  402 . In other words, the second decoder  448  may be designed to decode the encoding performed by the second encoder  416 . 
     In the illustrated system  400 , the receiver  436  may be able to accurately reproduce an estimate of the information sent by the transmitter  402  while providing unequal error protection to the two types of information, thus efficiently using the system resources. The system  400  and methods will be described in further detail below. 
       FIG. 5  is a block diagram of an embedded encoder  508  for embedded encoding of two types of information. Embedded coding may be described as the selection of a final codeword (Y)  532  based on the codeword of Type  1  information (X 1 )  514  and the codeword of Type  2  information (X 2 )  520 . In other words, the final output codeword (Y)  532  may implicitly convey both Type  1  information (W 1 )  504  and Type  2  information (W 2 )  506 . 
     For the purpose of illustration, and without limitation, assume W 1    504  and W 2    506  are k 1  and k 2  bits long, respectively, and X 1    514  and X 2    520  are n 1  and n 2  bits long, respectively. Thus, the rates, r 1  and r 2 , of the first encoder  510  and second encoder  516  may be r 1 =k 1 /n 1  and r 2 =k 2 /n 2  respectively. Also, assume W 1    504  has higher priority than W 2    506 . Note that the first encoder  510  and the second encoder  516  may utilize any error-correcting code with coding rates of r 1  and r 2 , respectively. In one example, the first encoder  510  may be a convolutional encoder, and the second encoder  516  may be a Turbo encoder. However, other error-correcting codes, such as Low-Density Parity Check (LDPC) code or Reed-Solomon (RS) code, may be used here as well. In another example, the first encoder  510  may be a Turbo code encoder, and the second encoder  516  may be a LDPC encoder. The types of the first encoder  510  and the second encoder  516  may be chosen based on a desired performance target and other constrains such as implementation limitation, etc. Embedded encoding, or the process of choosing Y  532 , will now be described with reference to  FIG. 5 . 
     First, using available values, the embedded encoder  508  may determine the rates of the first encoder  510  and second encoder  516 . Assume here, that h denotes the size of Y  532  in number of bits. Note that h may be determined outside the embedded encoder  508 . Also assume here, that q denotes the number of bits carried by each modulation symbol. Assuming QPSK modulation, then q=2. Note that q may be determined outside the embedded encoder  508 . Additionally, X 1    514  may be split into strings of size m 1  bit(s) and X 2    520  may be split into strings of size m 2  bit(s), resulting in n 1 /m 1  and n 2 /m 2  strings, respectively. Using these values, the following definitional equations (1), (2) may be used:
 
 h/q=p   1   ×n   1   /m   1    (1)
 
 h/q=p   2   ×n   2   /m   2    (2)
 
     where p 1 , p 2 , m 1  and m 2  are all positive integers, and may be chosen to produce a desired performance. Given h, p 1 , p 2 , m 1 , m 2 , k 1 , and k 2 , the embedded encoder  508  may then determine n 1 , n 2 , r 1  and r 2  using the following equations (3), (4), (5), (6):
 
 n   1   =hm   1   /qp   1    (3)
 
 n   2   =hm   2   /qp   2    (4)
 
 r   1   =k   1   /n   1    (5)
 
 r   2   =k   2   /n   2    (6)
 
     In one example, that will be repeatedly revisited below, h=288, q=2, k 1 =8, and k 2 =132. Furthermore, if m 1 =2, m 2 =3, p 1 =2 and p 2 =2 are chosen, then the following values may result: n 1 =144, n 2 =216, r 1 = 1/18, and r 2 = 11/18. 
     The value p 1  may define the number of symbols in the second set of symbols (Y)  432 , which carry the information for each X 1  string of size m 1  bit(s). Likewise, the value p 2  may define the number of symbols in the first set of symbols (T)  430 , which carry the information for each X 2  string of size m 2  bit(s). In the above example, every 2 (since p 2 =2) QPSK symbols in the first set of symbols (T)  530  may carry the information contained in a 3 (m 2 =3) bits X 2  string and every 2 (since p 1 =2) QPSK symbols in the second set of symbols (Y)  532  may carry the information contained in a 2 (m 1 =2) bits X 1  string. Note that p 1 , p 2 , m 1  and m 2  may be different values. The values of p 1 , p 2 , m 1  and m 2  may be chosen based on a desired performance target and other constrains such as complexity limit. Thus n 1 , n 2 , r 1  and r 2  may change accordingly. 
     Second, following the rate determination, the embedded encoder  508  may generate the codewords X 1    514  and X 2    520  through two conventional encoders  510 ,  516  at the rates determined above. In the above example, the first encoder  510  may be a rate 1/18 convolutional encoder (using r 1 = 1/18) and the second encoder  516  may be a rate 11/18 Turbo encoder (using r 2 = 11/18). These coding rates may be achieved by repeating or puncturing bits in the intermediate codewords to get the final codewords, X 1    514  and X 2    520 . Additionally, other techniques such as complex rate matching algorithms may be used to reach these coding rates. Also, as mentioned previously, other error-correcting codes, such as LDPC, or RS code may be used here as well. 
     Third, after generating X 1    514  and X 2    520 , the embedded encoder  508  may map X 2    520  into a first set of symbols (T)  530 . First, X 2    520  may be grouped into binary strings of length m 2 . Then, a first mapper  522  may map, or encode, each string of m 2  bits into p 2  symbol(s) based on a mapping rule  426 . This may result in n 2 /m 2  (which is equal to h/qp 2 ) strings that may map into h/q symbols (T)  530 . Note that the order of X 2    520  may be kept even when X 2    520  is grouped into strings and mapped into symbols (T)  530 . The terms “map” and “encode” may refer to any modification of data and may be used interchangeably herein. 
     Following the above example, where m 2 =3 and p 2 =2, Table 2 shows a possible mapping rule  426 . Since m 2 =3, there may be 8 (2 3 =8) possible combination of bits in each X 2  string. Furthermore, since p 2 =2, each X 2  string combination may be mapped into 2 consecutive QPSK symbols. Note that this table is merely an example and that many different rules may easily be derived. Note also that any correlation of the bits in the X 2  string and of QPSK symbols may be used as long as a given combination of bits in the X 2  string maps to at most one set of p 2  QPSK symbols (e.g., “000” maps to “DA” for the example rule below). 
     
       
         
           
               
             
               
                 TABLE 2 
               
             
            
               
                   
               
               
                 Example mapping of X 2  string 
               
            
           
           
               
               
               
            
               
                   
                 Combination of 
                 Mapped 
               
               
                   
                 bits in the X 2  string 
                 QPSK symbols 
               
               
                   
               
               
                   
                 000 
                 DA 
               
               
                   
                 001 
                 CA 
               
               
                   
                 010 
                 BC 
               
               
                   
                 011 
                 BA 
               
               
                   
                 100 
                 AD 
               
               
                   
                 101 
                 AB 
               
               
                   
                 110 
                 AC 
               
               
                   
                 111 
                 AA 
               
               
                   
               
            
           
         
       
     
     Lastly, a second mapper  524  may determine Y  532  from T  530 , X 1    514 , and a coding rule  428 . The codeword X 1    514  may first be grouped into binary strings of length m 1 , similar to the steps taken for X 2    520  above. This may result in n 1 /m 1  (which is equal to h/qp 1 ) strings used to control T  530 . Additionally, the output of the step above, T  530 , may be grouped into h/qp 1  symbols, with each group including p 1  symbol(s). Then, each X 1  string (m 1  bits) may be used to map p 1  symbol(s) of T  530  to p 1  symbol(s) of Y  532  based on the coding rule  428 . 
     Following the above example, where m 1 =2 and p 1 =2, Table 3 shows a possible coding rule  428 . Since m 1 =2, there may be 4 (2 2 =4) possible combination of bits in each X 1  string. Furthermore, since p 1 =2 each combination may be used to control 2 consecutive QPSK symbols of T  530 . Note that this table is merely an example and that many different rules may easily be derived. 
     
       
         
           
               
             
               
                 TABLE 3 
               
             
            
               
                   
               
               
                 Example coding rule of X 1  string onto T symbols 
               
            
           
           
               
               
            
               
                 Combination of 
                   
               
               
                 bits in the X 1  string 
                 Rule 
               
               
                   
               
               
                 00 
                 Counter-clockwise rotate 0 degree 
               
               
                 01 
                 Counter-clockwise rotate 90 degrees 
               
               
                 11 
                 Counter-clockwise rotate 180 degrees 
               
               
                 10 
                 Counter-clockwise rotate 270 degrees 
               
               
                   
               
            
           
         
       
     
     The following example illustrates the coding rule  428  when two QPSK symbols in T  530  are “BA,” although it is appreciated that the coding rule  428  applies to any combination possible on the constellation diagram  300 . When the X 1  string is “00,” the two corresponding symbols in the final output (Y)  532  may be “BA” which is the same as those of T  530 , since there may be no rotation for a combination of “00” in X 1  according to the example coding rule  428 . In other words, the symbols in Y  532  will be the same as T  530  for this X 1  string according to the coding rule  428 . On the other hand, if the X 1  string is “01,” the two corresponding symbols in the final output, Y  532 , may be “DB” because there may be a rotation of 90 degrees counter-clockwise around the constellation diagram  300  in  FIG. 3  for a combination of “01.” Thus, the “B” may become a “D” and the “A” may become a “B.” Likewise, if the X 1  string is “10”, the two corresponding symbols in the final output, Y  532 , may be “AC”. And, if the X 1  string is “11”, the two corresponding symbols in the final output, Y  532 , may be “CD.” 
     Note that in this above example, each two symbols of Y  532  may not be unique. In other words, two different combinations of X 1  and X 2  strings may produce the same output. For example, a combination of “10” in X 1    514  and “011” in X 2    520  will output “AC” just as a combination of “00” in X 1    514  and “110” in X 2    520 . 
       FIG. 6  is a flow diagram illustrating a method  600  of embedded encoding of two types of information. First, an embedded encoder  408  may receive  666  a first message and a second message  406 . The first message may be type  1  information (W 1 )  404  and the second message may be type  2  information (W 2 )  406 . These two messages may have unequal error protection requirements. The embedded encoder  408  may then determine  668  the rates of a first encoder  410  and a second encoder  416 . This determining may be done using a plurality of values representing the bit-length of type  1  (W 1 )  404  and type  2  (W 2 )  406  information, the bit-length of a desired first codeword (X 1 )  414  and second codeword (X 2 )  420 , a desired third codeword (Y)  432 , etc. The embedded encoder may then generate  670  a first codeword (X 1 ) for the first message (W 1 )  404  using the first encoder  410  and a second codeword (X 2 )  420  for the second message (W 2 )  406  using the second encoder  416 . The first encoder  410  may be a convolutional encoder and the second encoder  416  may be a Turbo encoder, although other error correcting codes, such as LDPC or RS code may also be used. 
     The second codeword (X 2 )  420  may then be mapped  672  into a plurality of symbols (T)  430  based on a predetermined mapping rule  426 . This may include grouping the second codeword into a series of strings and then mapping each string into one or more QPSK symbols (T)  430  using a mapping rule  426 . Alternatively, other modulation schemes such as 16QAM, 64QAM, etc. may also be used. A third codeword (Y)  432  may then be determined  674  using the first codeword (X 1 )  414 , the plurality of symbols (T)  430 , and a predetermined coding rule  428 . This determining  674  may include grouping the first codeword (X 1 )  414  into a series of strings and then, based on those strings, modifying the plurality of symbols (T)  430  according to the coding rule  428 . This third codeword (Y)  432  may also be a plurality of QPSK symbols. The third codeword (Y)  432  may then be transmitted  676 . 
       FIG. 7  is a block diagram illustrating a series of strings  778  being mapped into a series of QPSK symbols using a mapping rule  426 . This mapping may correspond to step  672  in  FIG. 6 . Initially, a codeword, such as X 2    420 , may be grouped into a series of strings  778 . Each string  778  may be m 2  bits. And, following the same example above, since X 2    420  may be n 2  bits long, this grouping may result in n 2 /m 2  (which is equal to h/qp 2 ) strings  778 . Then, each string  778  may be mapped into p 2  (which is equal to h/q) QPSK symbols  780  using a predetermined mapping rule  426 . Combined together, these symbols  780  may be T  430 , which may then be coded into Y  432  to be transmitted to a receiver  436 . Note that each string  778  is then mapped into p 2  QPSK symbols  780 . So, for the example of p 2 =2 shown, each string  778  is mapped into 2 QPSK symbols  780 . However, if p 2  were chosen to be 1, then each string  778  may be mapped into 1 QPSK symbol. Also, note that even though X 2    420  is first grouped into a series of strings  778  and then mapped into a series of QPSK symbols  780 , the order of X 2    420  is maintained throughout. 
       FIG. 8  is a block diagram of an embedded decoder  844  for embedded decoding of a signal conveying two types of information. Embedded decoding may be described as the deriving of an estimate of type  1  information (W 1 ′)  838  and type  2  information (W 2 ′)  840  from a received estimate of symbols (Y′)  864 . In other words, embedded decoding may be an attempt to estimate W 1    404  and W 2    406  residing on a transmitter  402  from a codeword Y′  864  received by a receiver  436   
     First, an embedded decoder  844  may determine a first decoding rule  854  for a type  1  codeword X 1    414 . The first decoding rule  854  may be derived from a combination of steps performed in the embedded encoder  508  described above. This decoding rule  854  may be expressed in terms of the probability distribution of an X 1  string for the symbols in Y′  864 . 
     For the purpose of illustration, and without limitation, the same values will be used to describe the embedded decoder  844  as were used to describe the embedded encoder  508  (h=288, q=2, k 1 =8, k 2 =132, m 1 =2, m 2 =3, p 1 =2, p 2 =2, n 1 =144 and n 2 =216). For two (p 1 =2) QPSK symbols in Y′  864 , there may be 16 possible combinations (4 2 =16). Considering Table 2 and Table 3 above, however, there may be 32 X 1  string and X 2  symbol possible combinations (8 possible X 2  symbol combinations from Table 2 multiplied by 4 possible X 1  string combinations from Table 3). Thus, the following Table 4 may be derived from Table 2 and Table 3 above. The value of “⅛” in this table comes from the assumption that the X 2  string is uniformly distributed as shown in Table 2. In other words, for a given combination of two Y′  864  QPSK symbols and X 1  string combinations in Table 3, there may be eight possible X 2  symbol combinations in Table 2 equally likely to produce that combination of QPSK symbols in Y′  864 . The following equations (7), (8), (9), (10) may be used to derive Table 4: 
     
       
         
           
             
               
                 
                   
                     
                       ∑ 
                       
                         u 
                         ∈ 
                         Y 
                       
                     
                     ⁢ 
                     
                       
                         p 
                         ⁡ 
                         
                           ( 
                           
                             
                               X 
                               1 
                             
                             = 
                             
                               
                                 “ 
                                 00 
                                 ” 
                               
                               | 
                               u 
                             
                           
                           ) 
                         
                       
                       ⁢ 
                       
                         p 
                         ⁡ 
                         
                           ( 
                           u 
                           ) 
                         
                       
                     
                   
                   = 
                   1 
                 
               
               
                 
                   ( 
                   7 
                   ) 
                 
               
             
             
               
                 
                   
                     
                       ∑ 
                       
                         u 
                         ∈ 
                         Y 
                       
                     
                     ⁢ 
                     
                       
                         p 
                         ⁡ 
                         
                           ( 
                           
                             
                               X 
                               1 
                             
                             = 
                             
                               
                                 “ 
                                 01 
                                 ” 
                               
                               | 
                               u 
                             
                           
                           ) 
                         
                       
                       ⁢ 
                       
                         p 
                         ⁡ 
                         
                           ( 
                           u 
                           ) 
                         
                       
                     
                   
                   = 
                   1 
                 
               
               
                 
                   ( 
                   8 
                   ) 
                 
               
             
             
               
                 
                   
                     
                       ∑ 
                       
                         u 
                         ∈ 
                         Y 
                       
                     
                     ⁢ 
                     
                       
                         p 
                         ⁡ 
                         
                           ( 
                           
                             
                               X 
                               1 
                             
                             = 
                             
                               
                                   
                                 
                                   “ 
                                   11 
                                   ” 
                                 
                               
                               | 
                               u 
                             
                           
                           ) 
                         
                       
                       ⁢ 
                       
                         p 
                         ⁡ 
                         
                           ( 
                           u 
                           ) 
                         
                       
                     
                   
                   = 
                   1 
                 
               
               
                 
                   ( 
                   9 
                   ) 
                 
               
             
             
               
                 
                   
                     
                       ∑ 
                       
                         u 
                         ∈ 
                         Y 
                       
                     
                     ⁢ 
                     
                       
                         p 
                         ⁡ 
                         
                           ( 
                           
                             
                               X 
                               1 
                             
                             = 
                             
                               
                                   
                                 
                                   “ 
                                   10 
                                   ” 
                                 
                               
                               | 
                               u 
                             
                           
                           ) 
                         
                       
                       ⁢ 
                       
                         p 
                         ⁡ 
                         
                           ( 
                           u 
                           ) 
                         
                       
                     
                   
                   = 
                   1 
                 
               
               
                 
                   ( 
                   10 
                   ) 
                 
               
             
           
         
       
     
     The variable u represents the possible p 1 -symbol pair found in Y′  864 . Note that this decoding rule  854  may be pre-determined, and therefore be stored in the receiver  436  once encoding rules  426 ,  428  are decided in the embedded encoder  508 . 
     
       
         
           
               
             
               
                 TABLE 4 
               
             
            
               
                   
               
               
                 Example decoding rule of Y′ symbols onto X 1   
               
            
           
           
               
               
            
               
                   
                 Probability of X 1  string given the 
               
               
                   
                 QPSK symbols in Y′: p(X 1 |u) 
               
            
           
           
               
               
               
               
               
            
               
                 QPSK 
                 p(X 1  = 
                   
                   
                   
               
               
                 symbols 
                 “00”|u) 
                 p(X 1  = “01”|u) 
                 p(X 1  = “11”|u) 
                 p(X 1  = “10”|u) 
               
               
                   
               
               
                 AA 
                 ⅛ 
                 0 
                 0 
                 0 
               
               
                 AB 
                 ⅛ 
                 ⅛ 
                 0 
                 0 
               
               
                 AC 
                 ⅛ 
                 0 
                 ⅛ 
                 0 
               
               
                 AD 
                 ⅛ 
                 0 
                 ⅛ 
                 ⅛ 
               
               
                 BA 
                 ⅛ 
                 ⅛ 
                 0 
                 0 
               
               
                 BB 
                 0 
                 ⅛ 
                 0 
                 0 
               
               
                 BC 
                 ⅛ 
                 ⅛ 
                 ⅛ 
                 0 
               
               
                 BD 
                 0 
                 ⅛ 
                 0 
                 ⅛ 
               
               
                 CA 
                 ⅛ 
                 0 
                 ⅛ 
                 0 
               
               
                 CB 
                 0 
                 ⅛ 
                 ⅛ 
                 ⅛ 
               
               
                 CC 
                 0 
                 0 
                 ⅛ 
                 0 
               
               
                 CD 
                 0 
                 0 
                 ⅛ 
                 ⅛ 
               
               
                 DA 
                 ⅛ 
                 ⅛ 
                 0 
                 ⅛ 
               
               
                 DB 
                 0 
                 ⅛ 
                 0 
                 ⅛ 
               
               
                 DC 
                 0 
                 0 
                 ⅛ 
                 ⅛ 
               
               
                 DD 
                 0 
                 0 
                 0 
                 ⅛ 
               
               
                   
               
            
           
         
       
     
     Second, once the decoding rule  854  has been determined, Y′  864  may be demodulated. As noted earlier, Y′  864  may include h/q received QPSK symbols. The demodulator  842  used may be a conventional demodulator  842 . Also recall that Y′  864  may be mapped into a series of p 1 -symbol pairs, denoted by y′, in the embedded encoder  508 . So, demodulation may include calculating the probability of a specific p 1 -symbol pair being transmitted. In this way, the demodulator  842  may produce a soft output, or one denoting a value and a probability that the value is correct. 
     Following the prior example, the embedded decoder  844  may calculate the probabilities p(u|y′) where u belongs to the set of {AA, AB, AC, AD, BA, BB, BC, BD, CA, CB, CC, CD, DA, DB, DC, DD} which is the set of all possible combinations with 2 QPSK symbols transmitted. Any method known in the art may be used to calculate these probabilities. For example, log-likelihood ratio (LLR) algorithm may be used to calculate p(u=“AA”|y′), p(u=“AB”|y′), p(u=“AC”|y′), etc. Recall that in this example, Y′  864  includes  144  (h/q) QPSK symbols and has been divided into groups of 2 (p 1 =2) symbols. Thus, there may be 72 (h/qp 1 ) pairs of QPSK symbols, y′, in Y′  864 . Further, each of these 16 probabilities may be calculated for each y′. For example, there may be 1152 probabilities calculated by the demodulator  842 , 16 probabilities for each of the 72 pairs, y′, in Y′  864 . 
     Third, the embedded decoder  844  may decode an estimate of type  1  information (W 1 ′)  838 . This may include using the first decoder  846 . The value p(X 1 |y′) may be calculated using the p(X 1 |u) values in the decoding rule  854  and the p(u|y′) values produced by the demodulator  842 . Thus for each possible value of X 1    858 , p(X 1 |y′) may be calculated using Bayes&#39; theorem as shown in equation (11): 
     
       
         
           
             
               
                 
                   
                     p 
                     ⁡ 
                     
                       ( 
                       
                         
                           X 
                           1 
                         
                         = 
                         
                           i 
                           | 
                           
                             y 
                             ′ 
                           
                         
                       
                       ) 
                     
                   
                   = 
                   
                     
                       ∑ 
                       
                         u 
                         ∈ 
                         U 
                       
                     
                     ⁢ 
                     
                       
                         p 
                         ⁡ 
                         
                           ( 
                           
                             
                               X 
                               1 
                             
                             = 
                             
                               i 
                               | 
                               u 
                             
                           
                           ) 
                         
                       
                       ⁢ 
                       
                         p 
                         ⁡ 
                         
                           ( 
                           
                             u 
                             | 
                             
                               y 
                               ′ 
                             
                           
                           ) 
                         
                       
                     
                   
                 
               
               
                 
                   ( 
                   11 
                   ) 
                 
               
             
           
         
       
     
     In equation (11) U is the set of all possible combinations for a p 1 -symbol pair, y′, and i is the element of the set of all possible values taken by an m 1 -length binary strings. In the continuing example, since m 1 =2, there may be four (2 2 =4) possible values for i, “00,” “01,” “10,” “11.” Then, a first decoder  846  corresponding to the first encoder  410  may be used to decode the codeword of Y′  864 . In other words, the first decoder  846  may take the p(X 1 |y′) values and using the decoding rule  854 , produce an estimate of type  1  information (W 1 ′)  838 . Note that soft input may be used for this decoder  846  of Type- 1  strings and the output of this step may be an estimate of type  1  information (W 1 ′)  838  that is k 1  bits long. 
     Still using the example, this decoding is now illustrated. Initially, four probabilities p(X 1 =“00”|y′), p(X 1 =“01”|y′), p(X 1 =“11”|y′) and p(X 1 =“10”|y′) may be calculated for each pair of QPSK symbols, y′. There may be 72 total pairs, y′, in Y′  864 . Those values may then be inputted for each pair of QPSK symbols, y′, into the first decoder  846 . The first decoder  846  may be a convolutional decoder using some standard convolutional decoding method such as Viterbi decoding. The output of the first decoder  846  may be the estimate of type  1  information, (W 1 ′)  838 , that is 8 (k 1 =8) bits long. 
     Lastly, the embedded decoder  844  may decode an estimate of type  2  information  840 . An estimate of a first codeword (X 1 ′)  858  may be generated by an encoder  850  from the estimate of type  1  information (W 1 ′)  838 . The encoder  850  may use coding identical to the first encoder  410  on the transmitter  402 . 
     Next, the demapper  852  may demap Y′  864  using a second decoding rule  456 . The codeword X 1 ′  858  may be grouped into binary strings of length m 1 . Then, the received symbols Y′  864  may also be grouped into h/qp 1  symbol groups, and each group may include p 1  symbol(s). For each X 1 ′ string (m 1  bits long), the second decoding rule  456  may be used to control p 1  symbol(s), y′, of Y′  864 . The second decoding rule  456  may be derived from the mapping rule  426  and/or the coding rule  428 . For example, where m 1 =2 and p 1 =2, as in the continuing example, Tables 5 and 6 show a possible second decoding rule  456 . The rule  456  may be the inverse rule in Tables 3 and 2, respectively. The received symbols Y′  864  may be controlled based on Table 5 and X 1 ′  858  to get the intermediate results that may correspond to T  430 , denoted herein by T′. Then these intermediate results T′ may be further decoded based on the decoding rule such as in Table 6. The final output of the demapper  852  may correspond to X 2    420  and is denoted herein by X 2 ′  862 . 
     
       
         
           
               
             
               
                 TABLE 5 
               
             
            
               
                   
               
               
                 Example decoding rule of X 1 ′ string onto T′ symbols 
               
            
           
           
               
               
            
               
                 Combination of 
                   
               
               
                 bits in the string of X 1 ′ 
                 Rule 
               
               
                   
               
               
                 00 
                 Clockwise rotate 0 degree 
               
               
                 01 
                 Clockwise rotate 90 degrees 
               
               
                 11 
                 Clockwise rotate 180 degrees 
               
               
                 10 
                 Clockwise rotate 270 degrees 
               
               
                   
               
            
           
         
       
     
     
       
         
           
               
             
               
                 TABLE 6 
               
             
            
               
                   
               
               
                 Example decoding rule of T′ string 
               
            
           
           
               
               
               
            
               
                   
                 Most likely to be 
                 Combination of bits 
               
               
                   
                 mapped QPSK symbols in T′ 
                 in the X 2 ′ string 
               
               
                   
               
               
                   
                 DA 
                 000 
               
               
                   
                 CA 
                 001 
               
               
                   
                 BC 
                 010 
               
               
                   
                 BA 
                 011 
               
               
                   
                 AD 
                 100 
               
               
                   
                 AB 
                 101 
               
               
                   
                 AC 
                 110 
               
               
                   
                 AA 
                 111 
               
               
                   
               
            
           
         
       
     
     Finally, X 2 ′  862  may go through a second decoder  856 , which may be a standard decoder corresponding to the second encoder  416  on the transmitter  402 . This may produce an estimate of type  2  information (W 2 ′)  840 . 
       FIG. 9  is a flow diagram illustrating a method  900  of embedded decoding. First, an embedded decoder  444  may receive  982  a signal. The signal may be Y′  864  and may include information relating to type  1  information (W 1 )  404  and type  2  information (W 2 )  406 , each with different error protection requirements. The embedded decoder  444  may then determine  984  a first decoding rule  454  for the signal Y′  864 . This determining  984  may be expressed in terms of the probability distribution of an X 1  string for a set of symbols in the signal, Y′  864 . The embedded decoder  444  may then demodulate  986  the signal. This may include calculating a series of probabilities for each set of symbols within Y′  864 . The demodulated signal may then be decoded  988  using the first decoding rule  454  to produce a first message. This first message may be an estimate of type  1  information (W 1 ′)  838 . The embedded decoder  444  may then encode  990  the first message (W 1 ′)  838  to produce a first codeword (X 1 ′)  858 . This encoding may be identical or similar to the encoding performed by the first encoder  410  in the transmitter  402 . The signal Y′  864  may then be demapped  992 , based on the first codeword (X 1 ′)  858  and a second decoding rule  456 , into a second codeword (X 2 ′)  862 . The second codeword (X 2 ′)  862  may then be decoded  994  to produce a second message (W 2 ′)  840 . This decoding  994  may be performed by the second decoder  856 , which may correspond to the second encoder  416  on the transmitter  402 . The second message may be an estimate of type  2  information (W 2 ′)  840 . 
       FIG. 10  illustrates various components that may be utilized in a communications device  1002 . The communications device  1002  may include any type of communications device such as a mobile station, a cell phone, an access terminal, user equipment, a base station transceiver, a base station controller, etc. The communications device  1002  includes a processor  1006  which controls operation of the communications device  1002 . The processor  1006  may also be referred to as a CPU. Memory  1008 , which may include both read-only memory (ROM), random access memory (RAM) or any type of device that may store information, provides instructions  1009  and data to the processor  1006 . A portion of the memory  1008  may also include non-volatile random access memory (NVRAM). Alternatively, or in addition to, instructions  1007  may reside in the processor  1006 . Instructions  1007  loaded onto the processor  1006  may also include instructions  1009  from memory  1008  that were loaded for execution by the processor  1006 . 
     The communications device  1002  may also include a housing  1022  that contains a transmitter  1012  and a receiver  1014  to allow transmission and reception of data. The transmitter  1012  and receiver  1014  may be combined into a transceiver  1024 . An antenna  1026  is attached to the housing  1022  and electrically coupled to the transceiver  1024 . Additional antennas (not shown) may also be used. 
     The communications device  1002  may also include a signal detector  1010  used to detect and quantify the level of signals received by the transceiver  1024 . The signal detector  1010  detects such signals as total energy, pilot energy, power spectral density, and other signals. 
     A state changer  1016  controls the state of the communications device  1002  based on a current state and additional signals received by the transceiver  1024  and detected by the signal detector  1010 . The communications device  1002  may be capable of operating in any one of a number of states. 
     The various components of the communications device  1002  are coupled together by a bus system  1020  which may include a power bus, a control signal bus, and a status signal bus in addition to a data bus. However, for the sake of clarity, the various buses are illustrated in  FIG. 10  as the bus system  1020 . The communications device  1002  may also include a digital signal processor (DSP)  1018  for use in processing signals. The communications device  1002  illustrated in  FIG. 10  is a functional block diagram rather than a listing of specific components. 
     As used herein, the term “determining” encompasses a wide variety of actions and, therefore, “determining” can include calculating, computing, processing, deriving, investigating, looking up (e.g., looking up in a table, a database or another data structure), ascertaining and the like. Also, “determining” can include receiving (e.g., receiving information), accessing (e.g., accessing data in a memory) and the like. Also, “determining” can include resolving, selecting, choosing, establishing and the like. 
     The phrase “based on” does not mean “based only on,” unless expressly specified otherwise. In other words, the phrase “based on” describes both “based only on” and “based at least on.” 
     The term “processor” should be interpreted broadly to encompass a general purpose processor, a central processing unit (CPU), a microprocessor, a digital signal processor (DSP), a controller, a microcontroller, a state machine, and so forth. Under some circumstances, a “processor” may refer to an application specific integrated circuit (ASIC), a programmable logic device (PLD), a field programmable gate array (FPGA), etc. The term “processor” may refer to a combination of processing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration. 
     The term “memory” should be interpreted broadly to encompass any electronic component capable of storing electronic information. The term memory may refer to various types of processor-readable media such as random access memory (RAM), read-only memory (ROM), non-volatile random access memory (NVRAM), programmable read-only memory (PROM), erasable programmable read only memory (EPROM), electrically erasable PROM (EEPROM), flash memory, magnetic or optical data storage, registers, etc. Memory is said to be in electronic communication with a processor if the processor can read information from and/or write information to the memory. Memory may be integral to a processor and still be said to be in electronic communication with the processor. 
     The terms “instructions” and “code” should be interpreted broadly to include any type of computer-readable statement(s). For example, the terms “instructions” and “code” may refer to one or more programs, routines, sub-routines, functions, procedures, etc. “Instructions” and “code” may comprise a single computer-readable statement or many computer-readable statements. 
     The functions described herein may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions may be stored as one or more instructions on a computer-readable medium. The term “computer-readable medium” refers to any available medium that can be accessed by a computer. By way of example, and not limitation, a computer-readable medium may comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and that can be accessed by a computer. Disk and disc, as used herein, includes compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk and Blu-ray® disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. 
     Software or instructions may also be transmitted over a transmission medium. For example, if the software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of transmission medium. 
     The methods disclosed herein comprise one or more steps or actions for achieving the described method. The method steps and/or actions may be interchanged with one another without departing from the scope of the claims. In other words, unless a specific order of steps or actions is required for proper operation of the method that is being described, the order and/or use of specific steps and/or actions may be modified without departing from the scope of the claims. 
     It is to be understood that the claims are not limited to the precise configuration and components illustrated above. Various modifications, changes and variations may be made in the arrangement, operation and details of the systems, methods, and apparatus described herein without departing from the scope of the claims.