This paper focuses on analyzing the ergodic capacity performance of limited feedback (LFB) beamforming in multi-user distributed antenna system (DAS). In such a system, multi-user interference (MUI) is inevitably due ...This paper focuses on analyzing the ergodic capacity performance of limited feedback (LFB) beamforming in multi-user distributed antenna system (DAS). In such a system, multi-user interference (MUI) is inevitably due to the channel uncertainties caused by quantization error. Considering this, we propose a parameter named effective ergodic capacity rate (EECR), which denotes the capacity offset between finite rate feedback and perfect channel state information (CSI). The simulation results show that the derived approximated EECR is very tight to actual EECR. Based on the approximated EECR, an adaptive minimum bit feedback scheme is proposed, which can effectively reduce the overhead of feedback channel and the complexity of the system. The simulation results verify the effectiveness of the proposed scheme.展开更多
The paper first describes the characteristics of the new rural pension scheme and then analyzes some problems emergingin its implementation based on afield in Anhui province’s Dangtu County and Jiangsu province’s Ho...The paper first describes the characteristics of the new rural pension scheme and then analyzes some problems emergingin its implementation based on afield in Anhui province’s Dangtu County and Jiangsu province’s Hongze County inApril 2010.Unlike the urban pension system, the new rural pension scheme is of a voluntary nature, and unlike the oldrural pension scheme, the government subsidizes participants using fiscal revenue.However, in its implementation thereare some problems.The first involves the so-called "bundle scheme" that requires pensioners’ children to participate.Evidence from our field study shows that coverage is less than 80%, even with a "bundle scheme." On the country,the "bundle scheme" increases social costs and it should therefore be replaced with legal regulations.Next, the paperexplains why a majority of participants choose the minimum contribution level based on observations in the fieldstudy.This choice reflects the two-fold information asymmetry between the authority and rural residents.Based onthe field study, we suggest that the new rural pension authority listen to village cadres and farmers to increase farmers’awareness.展开更多
基金Sponsored by the National High Technology Research and Development Program of China(Grant No.2006AA01Z272 and 2009AA02Z412)the Beijing Municipal Science & Technology Commission(Grant No.D08080100620802)
文摘This paper focuses on analyzing the ergodic capacity performance of limited feedback (LFB) beamforming in multi-user distributed antenna system (DAS). In such a system, multi-user interference (MUI) is inevitably due to the channel uncertainties caused by quantization error. Considering this, we propose a parameter named effective ergodic capacity rate (EECR), which denotes the capacity offset between finite rate feedback and perfect channel state information (CSI). The simulation results show that the derived approximated EECR is very tight to actual EECR. Based on the approximated EECR, an adaptive minimum bit feedback scheme is proposed, which can effectively reduce the overhead of feedback channel and the complexity of the system. The simulation results verify the effectiveness of the proposed scheme.
文摘The paper first describes the characteristics of the new rural pension scheme and then analyzes some problems emergingin its implementation based on afield in Anhui province’s Dangtu County and Jiangsu province’s Hongze County inApril 2010.Unlike the urban pension system, the new rural pension scheme is of a voluntary nature, and unlike the oldrural pension scheme, the government subsidizes participants using fiscal revenue.However, in its implementation thereare some problems.The first involves the so-called "bundle scheme" that requires pensioners’ children to participate.Evidence from our field study shows that coverage is less than 80%, even with a "bundle scheme." On the country,the "bundle scheme" increases social costs and it should therefore be replaced with legal regulations.Next, the paperexplains why a majority of participants choose the minimum contribution level based on observations in the fieldstudy.This choice reflects the two-fold information asymmetry between the authority and rural residents.Based onthe field study, we suggest that the new rural pension authority listen to village cadres and farmers to increase farmers’awareness.
