1,721,031 research outputs found
Mapping interleaving laws to parallel turbo decoder architectures
No full textFor high data rate applications, the implementation of iterative turbo-like decoders requires the use of parallel architectures posing some collision-free constraints to the reading/writing process in the soft-input soft-output (SISO) decoders. Contrary to the literature belief, we prove in this paper that the parallelism constraints can be met by any permutation law employed by the turbo-interleaver, and we give a constructive method to satisfy those constraints
Mapping interleaving laws to parallel turbo and LDPC decoder architectures
No full textFor high-data-rate applications, the implementation of iterative turbo-like decoders requires the use of parallel architectures posing some collision-free constraints to the reading/writing process from/into the memory. This consideration applies to the two main classes of turbo-like codes, i.e., turbo codes and low-density parity-check (LDPC) codes. Contrary to the literature belief, we prove in this paper that there is no need for an ad hoc code design to meet the parallelism requirement, because, for any code and any choice of the scheduling of the reading/writing operations, there is a suitable mapping of the variables in the memory that grants a collision-free access. The proof is constructive, i.e., it gives an algorithm that obtains the desired collision-free mapping. The algorithm is applied to two simple examples, one for turbo codes and one for LDPC codes, to illustrate how the algorithm works
Optimal and suboptimal receivers for maximal-rate root-LDPC codes over MIMO block-fading channels
No full textRanking a Set of Objects using Heterogeneous Workers: QUITE an Easy Problem
Full text linkWe focus on the problem of ranking objects starting from a set of noisy pairwise comparisons provided by a crowd of unequal workers, each worker being characterized by a specific degree of reliability, which reflects her ability to rank pairs of objects. More specifically, we assume that objects are endowed with intrinsic qualities and that the probability with which an object is preferred to another depends both on the difference between the qualities of the two competitors and on the reliability of the worker. We propose QUITE, a non-adaptive ranking algorithm that jointly estimates workers' reliabilities and qualities of objects. Performance of QUITE is compared in different scenarios against previously proposed algorithms. Finally, we show how QUITE can be naturally made adaptive
Bounds to Fair Rate Allocation and Communication Strategies in Source/Relay Wireless Networks
No full textWe analyze the achievable data rate of cooperative relaying strategies in networks where nodes operate in half-duplex mode. Nodes have to deliver their data to a gateway, at a certain rate, and may have limited energy capabilities, as in the case of energy-harvesting communication networks. Both the requested data rate and the available energy capabilities may vary from node to node. Under such constraints, we take an information-theoretic approach and derive cut-set upper bounds to the achievable rate. Furthermore, we devise two kinds of communication strategies, each aiming at a different objective. The former ensures a fair rate allocation to the network nodes, but it neglects their energy constraints. The latter does consider energy constraints by meeting the requirements on the average power consumption at each node and by providing fairness in the data rate allocation. We show the performance of the aforementioned communication strategies, highlighting their effectiveness and providing useful insights on the system behavio
Iterative SIC receiver scheme for non-orthogonally superimposed signals on top of OFDMA
Full text linkBlind receiver for space-time differentially-encoded CDMA systems on multipath fading channels
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