228 research outputs found
Achieving full diversity in multi-antenna two-way relay networks via symbol-based physical-layer network coding
No full textThis paper considers physical-layer network coding (PNC) with M-ary phase-shift keying (MPSK) modulation in two-way relay channel (TWRC). A low complexity detection technique, termed symbol-based PNC (SPNC), is proposed for the relay. In particular, attributing to the outer product operation imposed on the superposed MPSK signals at the relay, SPNC obtains the network-coded symbol (NCS) straightforwardly without having to detect individual symbols separately. Unlike the optimal multi-user detector (MUD) which searches over the combinations of all users’ modulation constellations, SPNC searches over only one modulation constellation, thus simplifies the NCS detection. Despite the reduced complexity, SPNC achieves full diversity in multi-antenna relay as the optimal MUD does. Specifically, antenna selection based SPNC (AS-SPNC) scheme and signal combining based SPNC (SC-SPNC) scheme are proposed. Our analysis of these two schemes not only confirms their full diversity performance, but also implies when SPNC is applied in multi-antenna relay, TWRC can be viewed as an effective single-input multiple-output (SIMO) system, in which AS-PNC and SC-PNC are equivalent to the general AS scheme and the maximal-ratio combining (MRC) scheme. Moreover, an asymptotic analysis of symbol error rate (SER) is provided for SC-PNC considering the case that the number of relay antennas is sufficiently large
Why do firms bribe? An empirical study in BRICS economies from 2002 to 2012
No full textThis article empirically studies why manufacturing firms bribe the government officials. Firm-level data focusing on the five BRICS countries (Brazil, Russia, India, China, and South Africa) was acquired from an Enterprise Survey conducted by the World Bank between 2002 and 2012. The BRICS countries represent typical emerging world economies. We acquired country-level data from multiple sources. We then studied both firm-level and country-level reasons why firms bribe and how much money they spend in bribing. We found that smaller size, slower expansion, and more infrastructural defects significantly increase bribery probability. Bribery also tends to occur more frequently in countries with faster development and more political rigidity. The 2007–2009 financial crisis also encouraged more bribery
Why do firms bribe? An empirical study in BRICS economies from 2002 to 2012
No full textThis article empirically studies why manufacturing firms bribe the government officials. Firm-level data focusing on the five BRICS countries (Brazil, Russia, India, China, and South Africa) was acquired from an Enterprise Survey conducted by the World Bank between 2002 and 2012. The BRICS countries represent typical emerging world economies. We acquired country-level data from multiple sources. We then studied both firm-level and country-level reasons why firms bribe and how much money they spend in bribing. We found that smaller size, slower expansion, and more infrastructural defects significantly increase bribery probability. Bribery also tends to occur more frequently in countries with faster development and more political rigidity. The 2007–2009 financial crisis also encouraged bribery
Export and gender difference in production contribution: A joint and non-linear analysis using panel and firm-level data
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