International Journal of Electronics Engineering Research

Puncturing is the process of deleting some parity bits from the codeword according to a puncturing matrix.

Puncturing is the tradeoff between rate and performance. Puncturing increases code rate without increasing complexity for code rate from 1/3 to ½ or more and decreases free distance of code. The redundant bits in coding decrease the bandwidth efficiency. The bandwidth efficiency decreases with increase in redundant bits in coding. the puncturing pattern adjust code rate To achieve system requirement, the puncturing pattern adjust code rate. The performance of punctured turbo code is worse than without puncturing turbo code but coding scheme improve bandwidth efficiency. The design principles of puncturing for turbo code are based on the minimization of puncturing of systematic bits and to provide puncturing of parity bits of the two encoders.

Performance level varies with different puncturing pattern. since different punctured location affect different performance at the receiver. The puncturing patterns are analyzed to compare their performances. When the bit in codeword has high weight, avoid puncturing of systematic bit sequence since it has high weight but puncturing preference is given to bits having lower weight.In high rate system selection of good pattern plays very important role. Coding on different number of punctured bit has been suggested. Uniformly distributed puncturing pattern perform better than puncturing non-uniformly distributed pattern.