Adaptive Modulation for OFDM System by Using Convolutional Coding
and BCH Coding.
d) From 60 until 124 Resolution of cyclic shift ([delta]) 4 Coding scheme Convolutional coding
Interleaver Matrix: 16 x 8 Decoding scheme Soft decision Viterbi Constraint length 7 Coding rate 1/2 Polynomial generator [171 133] Number of branches 3 Channel Uniform (6 paths) Knee factor power amplifier (p) 3 Input backoff (IBO) 0, 2, 4 dB
As such, convolutional coding
contains memory and has to be implemented using sequential logic.
A dependence of a BER on free space path loss for different noise temperatures without coding and with convolutional coding
is shown in Fig.
essentially reduces error probability that leads to a BER vanishing for antennas with a diameter of more than 1.
Both protocols exploit convolutional coding
as the code scheme, which has a constraint of 7 and a code rate of 1/2.
Internal encoder uses convolutional coding
and is a complement to the Reed-Solomon coder and the external interleaver.
However, additional BPSK is required when using Reed-Solomon convolutional coding
A convolutional coding
is done by combining the fixed number of inputs bits.
In the channel coding module, the Reed-Solomon (RS) and convolutional coding
techniques have been included as representative coding methods from the algebraic and statistical coding fields respectively.
A single tail byte is added and the bits are ready for Reed-Solomon and Convolutional Coding
Further details on convolutional coding
can be found in