Performance analysis of LDPC channel coding in 4G systems

Due to the degradation in wireless communication system by the burst errors in of fades under multipath environment, the efficient and the quality of received signals are questionable. Therefore, the error corrections are crucial part needed to satisfy the users. This paper focuses on performance analysis of channel coding in 4G systems. There are many codes, but this paper highlights on Viterbi Algorithm and LDPC codes with BPSK modulation and Additive white Gaussian noise(AWGN). The comparative performance of Viterbi algorithm and LDPC is explored in this paper. This comparison will be beneficial for next mobile communication system generations

Rate-compatible protograph LDPC code families with linear minimum distance

Digital communication coding methods are shown, which generate certain types of low-density parity-check (LDPC) codes built from protographs. A first method creates protographs having the linear minimum distance property and comprising at least one variable node with degree less than 3. A second method creates families of protographs of different rates, all having the linear minimum distance property, and structurally identical for all rates except for a rate-dependent designation of certain variable nodes as transmitted or non-transmitted. A third method creates families of protographs of different rates, all having the linear minimum distance property, and structurally identical for all rates except for a rate-dependent designation of the status of certain variable nodes as non-transmitted or set to zero. LDPC codes built from the protographs created by these methods can simultaneously have low error floors and low iterative decoding thresholds, and families of such codes of different rates can be decoded efficiently using a common decoding architecture

Entrepreneurial Discovery and Information Complexity in Knowledge-Intensive Industries

Why are some firms better able than others to exploit new opportunities? I posit that differences in the type and level of complexity of the information obtained through the entrepreneurial discovery process may be a meaningful indicator of the likelihood that a firm is able to exploit a new opportunity. Specifically, I investigate knowledge reproduction processes for product replication (internal copying) and imitation (external copying) as a means of exploiting opportunities and building competitive advantage. Integrating concepts from information theory and the knowledge-based view of the firm, I introduce a generalized model and quantitative methods for estimating the inherent complexity of any unit of knowledge, such as a strategy, technology, product, or service, as long as the unit is represented in algorithm form. Modeling organizations as information processing systems, I develop measures of the information complexity of an algorithm representing a unit of knowledge in terms of the minimum amount of data (algorithmic complexity) and the minimum number of instructions (computational complexity) required to fully describe and execute the algorithm. I apply this methodology to construct and analyze a unique historical dataset of 91 firms (diversifying and de novo entrants) and 853 new product introductions (1974-2009), in a knowledge-intensive industry, digital signal processing. I find that: (1) information complexity is negatively and significantly related to product replication and imitation; (2) replicators have the greatest advantage over imitators at moderate levels of information complexity; (3) intellectual property regimes strengthening the patentability of algorithms significantly increase product replication, without significantly decreasing imitation; (4) outbound licensing of patented technologies decreases product replication and increases imitation; (5) products introduced by de novo entrants are less likely to be replicated and more likely to be imitated than products introduced by diversifying entrants; and (6) diversifying entrants have the greatest advantage over de novo entrants at high and low levels of information complexity; neither type of entrant has a significant advantage at moderate levels of complexity. These empirical findings support and extend predictions from earlier simulation studies. The model is applicable to other aspects of organizational strategy and has important implications for researchers, managers, and policymakers.Doctor of Philosoph