Exploiting known padding data to improve block decode success rate

Abstract

A method and system of decoding a ccnvolutionally encoded data block having known padding bits. A Viterbi decoder is constrained to a state corresponding to k−1 padding bits immediately adjacent to data bits of the data block, where k is a constraint length of a convolution encoder used to encode the data block. Symbols of the encoded data block that have influence only from the padding bits are discarded.

1 - 12 . (canceled) 
     
     
         13 . A method of decoding a convolutionally encoded data block having a predetermined number of known padding bits, the method comprising:
 constraining a Viterbi decoder to a state corresponding to k−1 padding bits immediately adjacent data bits of the data block, where k is a constraint length of a convolutional encoder used to encode the data block, and wherein the k−1 padding bits immediately adjacent data bits of the data block comprise less than the predetermined number of known padding bits; and   discarding symbols of the encoded data block that have influence only from padding bits other than the k−1 padding bits immediately adjacent data bits of the data block.   
     
     
         14 . The method as claimed in  claim 13 , wherein the known padding bits comprise n known padding bits prepended to the data bits, and wherein constraining the Viterbi decoder comprises constraining a Start state of the decoder to a state corresponding to the last k−1 of the n known padding bits prepending the data bits. 
     
     
         15 . The method as claimed in  claim 14 , wherein discarding symbols of the encoded data block comprises:
 disabling operation of the Viterbi decoder while latching the first n bits of the data block into the shift register of the Viterbi decoder.   
     
     
         16 . The method as claimed in  claim 13 , wherein the known padding bits comprise n known padding bits appended to the data bits, and wherein constraining the Viterbi decoder comprises constraining an End state of the decoder to a state corresponding to the first k−1 of the known padding bits appending the data bits. 
     
     
         17 . The method as claimed in  claim 16 , wherein discarding symbols of the encoded data block comprises:
 discarding any remaining bits of the encoded data block after processing the first e=(N−n)+(k−1) bits of the encoded data block through the Viterbi decoder, where N is the total length of the data block.   
     
     
         18 . The method as claimed in  claim 13 , wherein the convolutionally encoded data block is a data block of an Enhanced Data for Global Evolution, EDGE, data frame. 
     
     
         19 . A system for decoding a convolutionally encoded data block having a predetermined number of known padding bits, the system comprising:
 a Viterbi decoder; and   a controller adapted to:
 constrain the Viterbi decoder to a state corresponding to k−1 padding bits immediately adjacent data bits of the data block, where k is a constraint length of a convolution encoder used to encode the data block, and wherein the k−1 padding bits immediately adjacent data bits of the data block comprise less than the predetermined number of known padding bits; and 
 discard symbols of the encoded data block that have influence only from padding bits other than the k−1 padding bits immediately adjacent data bits of the data block. 
   
     
     
         20 . The system as claimed in  claim 19 , wherein the known padding bits comprise n known padding bits prepended to the data bits, and wherein the controller is adapted to constrain a start state of the decoder to a state corresponding to the last k−1 of the known padding bits prepending the data bits. 
     
     
         21 . The system as claimed in  claim 20 , wherein the controller is adapted to discard symbols of the encoded data block including:
 disabling operation of the Viterbi decoder while latching the first n bits of the data block into the shift register of the Viterbi decoder.   
     
     
         22 . The system as claimed in  claim 19 , wherein the known padding bits comprise n known padding bits appended to the data bits, and wherein the controller is adapted to constrain an End state of the decoder to a state corresponding to the first k−1 of the n known padding bits appending the data bits. 
     
     
         23 . The system as claimed in  claim 22 , wherein the controller is adapted to discard symbols of the encoded data block including:
 discarding any remaining bits of the encoded data block after processing and the first e=(N−n)+(k−1) bits of the encoded data block through the Viterbi decoder, where N is the total length of the data block.   
     
     
         24 . The system as claimed in  claim 19 , wherein the convolutionally encoded data block is a data block of an Enhanced Data for Global Evolution, EDGE, data frame. 
     
     
         25 . A computer program product for decoding a convolutionally encoded data block having known padding bits, the computer program product comprising a machine readable medium tangibly embodying instructions to cause a computing device to:
 constrain a Viterbi decoder to a state corresponding to k−1 padding bits immediately adjacent data bits of the data block, where k is a constraint length of a convolutional encoder used to encode the data block, and wherein the k−1 padding bits immediately adjacent data bits of the data block comprise less than the predetermined number of known padding bits; and   discard symbols of the encoded data block that have influence only from padding bits other than the k−1 padding bits immediately adjacent data bits of the data block.   
     
     
         26 . The computer program product as claimed in  claim 25 , wherein the known padding bits comprise n known padding bits prepended to the data bits, and wherein the instructions further cause the computing device to constrain a Start state of the decoder to a state corresponding to the last k−1 of the n known padding bits prepending the data bits. 
     
     
         27 . The computer program product as claimed in  claim 26 , wherein the instructions further cause the computing device to discard symbols of the encoded data block including:
 disabling operation of the Viterbi decoder while latching the first n bits of the data block into the shift register of the Viterbi decoder.   
     
     
         28 . The computer program product as claimed in  claim 25 , wherein the known padding bits comprise n known padding bits appended to the data bits, and wherein the instructions further cause the computing device to constrain an End state of the decoder to a state corresponding to the first k−1 of the known padding bits appending the data bits. 
     
     
         29 . The computer program product as claimed in  claim 28 , wherein the instructions further cause the computing device to discard symbols of the encoded data block including:
 discarding any remaining bits of the encoded data block after processing the first e=(N−n)+(k−1) bits of the encoded data block through the Viterbi decoder, where N is the total length of the data block.   
     
     
         30 . The computer program product as claimed in  claim 25 , wherein the convolutionally encoded data block is a data block of an Enhanced Data for Global Evolution, EDGE, data frame.