In this paper, we propose a new implementation of the Extended Min-Sum (EMS) decoder for non-binary LDPC codes. A particularity of the new algorithm is that it takes into accounts the memory problem of the non-binary ...
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In this paper, we propose a new implementation of the Extended Min-Sum (EMS) decoder for non-binary LDPC codes. A particularity of the new algorithm is that it takes into accounts the memory problem of the non-binary LDPC decoders, together with a significant complexity reduction per decoding iteration. The key feature of our decoder is to truncate the vector messages of the decoder to a limited number n(m). of values in order to reduce the memory requirements. Using the truncated messages, we propose an efficient implementation of the EMS decoder which reduces the order of complexity to O(n(m) log(2) n(m)). This complexity starts to be reasonable enough to compete with binary decoders. The performance of the low complexity algorithm with proper compensation is quite good with respect to the important complexity reduction, which is shown both with a simulated density evolution approach and actual simulations.
Future mobile telecommunication systems are obligated to offer advanced multimedia services to a huge number of users. The burden imposed by the signaling operations supporting these services can severely degrade the ...
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ISBN:
(纸本)0780375890
Future mobile telecommunication systems are obligated to offer advanced multimedia services to a huge number of users. The burden imposed by the signaling operations supporting these services can severely degrade the system performance and lead to congestion problems in network equipment (switches, databases, gateways, etc.). Paging operations in a mobile cellular network are responsible for a large part of the signaling load and, therefore, the issue of how to efficiently conduct them becomes of critical importance. The key to its solution lies on the application of multiple-step paging schemes and on the "proper" planning of paging areas. In this paper we devise and solve a version of the paging area planning problem. In particular, we provide a low complexity algorithm capable of reducing the paging cost, at the price of a moderate increase in the call set-up delay.
The constant modulus algorithm (CMA) is commonly used for first stage blind equalization applications. CMA's main advantage is that it will open the eye based on the received signal only. Decision directed (DD) eq...
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ISBN:
(纸本)0780374029
The constant modulus algorithm (CMA) is commonly used for first stage blind equalization applications. CMA's main advantage is that it will open the eye based on the received signal only. Decision directed (DD) equalization is often used as it provides a lower mean square error (MSE) in the equalized signal. Obvious from its name, DD equalization requires estimates of the transmitted symbols in order to adapt the equalizer - the eye must be open. This paper considers an elegant method to transition between CMA and DD equalization (in a decision feedback equalizer structure). A conventional "brute force" approach to perform the transition is to determine the filter coefficients for the DD equalizer through a MMSE design criterion based on the inverse CMA filter coefficients. This may cause a large procession delay at the point of transition between filter types and requires significant computations. The algorithm in this paper is lowcomplexity and does not require a large processing delay when transitioning from CMA to DD LMS.
The author presents a new motion estimation method which reduces the computational complexity in video compression. This is achieved by skipping the motion estimation operation for macro-blocks, where it is determined...
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The author presents a new motion estimation method which reduces the computational complexity in video compression. This is achieved by skipping the motion estimation operation for macro-blocks, where it is determined that this operation does not need to be carried out.
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