Hi, I don't understand the specification 802.16, concerning FEC/Reed-Solomon. May be someone can guide me to an answer? I developped RS coder, decoder(255,239,8). It works fine. I have the same results with the specification example. "The first test vector refers to full bandwidth (16 subchannels) using QPSK and overall coding rate 3/4. The RS code you use is (40,36,2). According to the test vectors, if the input to the RS coder is "D4 BA A1 12 F2 74 96 30 27 D4 88 9C 96 E3 A9 52 B3 15 AB FD 92 53 07 32 C0 62 48 F0 19 22 E0 91 62 1A C1 00" (where the last 00 is added manually as specified), the spec says the first 4 bytes of the parity should "49 31 40 BF" ". I have the same bytes. The problem occurs when I use shortened and punctured code. I can't understand how can I decode: 0..202 = 0; 203..239 = D4 BA A1 12 F2 74 96 30 27 D4 88 9C 96 E3 A9 52 B3 15 AB FD 92 53 07 32 C0 62 48 F0 19 22 E0 91 62 1A C1 00; 240..244 = 49 31 40 BF; 244..254 =0 I mean how can I find the errors, if the parity bytes are shortened? I'm stuck.... How do I need this shortening to be done correctly? please.. just a brief answer...
REED-SOLOMON for 802.16
Started by ●September 13, 2007
Reply by ●September 18, 20072007-09-18
>Hi, >I don't understand the specification 802.16, concerningFEC/Reed-Solomon.>May be someone can guide me to an answer? >I developped RS coder, decoder(255,239,8). It works fine. I have thesame>results with the specification example. "The first test vector refers to >full >bandwidth (16 subchannels) using QPSK and overall coding rate 3/4. TheRS>code you use is (40,36,2). According to the test vectors, if the inputto>the RS coder is "D4 BA A1 12 F2 74 96 30 27 D4 88 9C 96 E3 A9 52 B3 15AB>FD 92 53 07 32 C0 62 48 F0 19 22 E0 91 62 1A C1 00" (where the last 00is>added manually as specified), the spec says the first 4 bytes of the >parity should "49 31 40 BF" ". I have the same bytes. >The problem occurs when I use shortened and punctured code. I can't >understand how can I decode: 0..202 = 0; 203..239 = D4 BA A1 12 F2 74 96 >30 27 D4 88 9C 96 E3 A9 52 B3 15 AB FD 92 53 07 32 C0 62 48 F0 19 22 E091>62 1A C1 00; 240..244 = 49 31 40 BF; 244..254 =0 >I mean how can I find the errors, if the parity bytes are shortened? I'm >stuck.... >How do I need this shortening to be done correctly? >please.. just a brief answer... >Yep, everyting is fine. Just erasures correction was't implemented ;)