Adaptation to changing conditions in the transmission medium is a particularly desired property in optically-routed networks due to their heterogeneous nature. Toward this goal, we propose in this paper rate-adaptive ...
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ISBN:
(纸本)9781424448258
Adaptation to changing conditions in the transmission medium is a particularly desired property in optically-routed networks due to their heterogeneous nature. Toward this goal, we propose in this paper rate-adaptive polarization multiplexed coded multilevel modulation schemes based on non-binary quasi-cyclic low-density parity-check (ldpc) codes and coherent detection. The proposed scheme can support data rates at 100 Gb/s and beyond while offering comparably better forward error correction performance with less computational complexity than bit-interleaved coded modulation schemes. The ability to adapt changing channel conditions is achieved by exploiting the inherent structure of quasi-cyclic ldpccodes.
In this paper, a method to design regular (2, d(c))-ldpccodes over GF(q) with both good waterfall and error floor properties is presented, based on the algebraic properties of their binary image. First, the algebraic...
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In this paper, a method to design regular (2, d(c))-ldpccodes over GF(q) with both good waterfall and error floor properties is presented, based on the algebraic properties of their binary image. First, the algebraic properties of rows of the parity check matrix H associated with a code are characterized and optimized to improve the waterfall. Then the algebraic properties of cycles and stopping sets associated with the underlying Tanner graph are studied and linked to the global binary minimum distance of the code. Finally, simulations are presented to illustrate the excellent performance of the designed codes.
One of the weak points for ldpc encoding is the computational complexity in Communication System. An efficient encoding was presented by Richardson who approached making codeword by using parity check matrices with lo...
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ISBN:
(纸本)9781424423125
One of the weak points for ldpc encoding is the computational complexity in Communication System. An efficient encoding was presented by Richardson who approached making codeword by using parity check matrices with low density. In this paper, we focus on computational complexity of Richardson's ldpc matrix which is composed by matrix A, B, C, D, E and T. We propose two schemes for low complexity encoding. First one accomplishes T-1 = E = I and restricts D consisting of dual diagonal matrices and second one achieves T-1 = phi(-1) = I. Therefore the constraint reduces complexity from O(n +g(2)) to O(n) and efficiently omits some process of encoding. Also, we perform numerical experiments on our matrices. Proposed schemes can be useful for high-rate and high-speed communication systems due to reduced complexity and retrenched processes of encoding.
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