Tree pruning is an effective algorithm to reduce the complexity of sphere detection （SD） for multiple-input multiple-output （MIMO） communication systems. How to determine the tree pruning rule, as well as by what ...Tree pruning is an effective algorithm to reduce the complexity of sphere detection （SD） for multiple-input multiple-output （MIMO） communication systems. How to determine the tree pruning rule, as well as by what the tradeoff between the performance and the complexity can be achieved, is still an open problem. In this paper, a tree pruning algorithm is proposed based on minimum mean square error （MMSE） detection. The proposed algorithm first preforms MMSE detection since the complexity of MMSE detection is very low. Then the pruning constraints will be set according to the scaled path metrics of the MMSE solution. The choice of the scale factors and their influences on the complexity and performance are also discussed. Through analysis and simulations, it is shown that the complexity is reduced significantly with negligible performance degradation and additional computations.展开更多
This article puts forward two novel user-grouping algorithms for grouped multi-carrier （MC）-code division multiple access （CDMA） systems. As is well known, the adaptive assignment for user-grouping plays an import...This article puts forward two novel user-grouping algorithms for grouped multi-carrier （MC）-code division multiple access （CDMA） systems. As is well known, the adaptive assignment for user-grouping plays an important role for link quality of multi-access transmissions. In the study, the capacity-maximizing problem of user-grouping is formulated. By using the Kuhn-Tucker condition, the optimal criterion is deduced and found to have a similar form with signal to noise plus interference （SINR）. However SINR includes the signal power that can only be determined after user-grouping. Therefore the optimal criterion will lead to an impractical application. To deal with it, the user＇s equivalent SINR for minimum mean square error （MMSE） detector is proposed and served as a suboptimal assignment criterion, based on which two kinds of user-grouping algorithms are proposed. In the algorithms, only partial channel information is needed at the base station, which saves a large part of the bandwidth occupied by feedback information. Computer simulations have evaluated an excellent performance of the proposed algorithms at both link quality and data rate. Meanwhile, the proposed algorithms have lower implementation complexity for practical reality.展开更多
MIMO technology was proposed as early as 1908 to cope with wireless channel fading.In 1995,Bell Labs was the first to discover the great potential of MIMO system in channel capacity,and in 1996,Foshini of Bell Labs fi...MIMO technology was proposed as early as 1908 to cope with wireless channel fading.In 1995,Bell Labs was the first to discover the great potential of MIMO system in channel capacity,and in 1996,Foshini of Bell Labs first proposed a space-time coding scheme,i.e.,the diagonal-Bell Labs hierarchical space-time model,which can obtain very high spectrum utilization,but due to the complexity of its structure,it is difficult to be applied in practice,and is now rarely investigated.1998,P.W.Wolniansky et al.gave a simple and practical space-time coding scheme on this basis,i.e.,the vertical-Bell Labs layered space-time model.In 1998,P.W.Wolniansky et al.gave a simple and practical space-time coding scheme on this basis,i.e.,Vertical Bell Labs Layered Space-Time(V-BLAST,Vertical Bell Labs Layered Space-Time)model,which can obtain very high spectrum utilisation and is easy to implement,and therefore has received wide attention once it was proposed.In this paper,we focus on airtime layered codes as well as the ZF detection algorithm and the MMSE detection algorithm in VBLAST systems and improve them to further enhance the performance of the two detection algorithms through sequential serial interference cancellation.展开更多
基金supported by the Hi-Tech Research and Development Program of China (2011AA01A204)the Beijing University of Posts and Telecommunications Research and Innovation Fund for Youths
文摘Tree pruning is an effective algorithm to reduce the complexity of sphere detection （SD） for multiple-input multiple-output （MIMO） communication systems. How to determine the tree pruning rule, as well as by what the tradeoff between the performance and the complexity can be achieved, is still an open problem. In this paper, a tree pruning algorithm is proposed based on minimum mean square error （MMSE） detection. The proposed algorithm first preforms MMSE detection since the complexity of MMSE detection is very low. Then the pruning constraints will be set according to the scaled path metrics of the MMSE solution. The choice of the scale factors and their influences on the complexity and performance are also discussed. Through analysis and simulations, it is shown that the complexity is reduced significantly with negligible performance degradation and additional computations.
基金the DoCoMo Beijing Labs Co. Ltd., Program for New Century Excellent Talents in Beijing University of Posts and Telecommunications (04-0112)
文摘This article puts forward two novel user-grouping algorithms for grouped multi-carrier （MC）-code division multiple access （CDMA） systems. As is well known, the adaptive assignment for user-grouping plays an important role for link quality of multi-access transmissions. In the study, the capacity-maximizing problem of user-grouping is formulated. By using the Kuhn-Tucker condition, the optimal criterion is deduced and found to have a similar form with signal to noise plus interference （SINR）. However SINR includes the signal power that can only be determined after user-grouping. Therefore the optimal criterion will lead to an impractical application. To deal with it, the user＇s equivalent SINR for minimum mean square error （MMSE） detector is proposed and served as a suboptimal assignment criterion, based on which two kinds of user-grouping algorithms are proposed. In the algorithms, only partial channel information is needed at the base station, which saves a large part of the bandwidth occupied by feedback information. Computer simulations have evaluated an excellent performance of the proposed algorithms at both link quality and data rate. Meanwhile, the proposed algorithms have lower implementation complexity for practical reality.
文摘MIMO technology was proposed as early as 1908 to cope with wireless channel fading.In 1995,Bell Labs was the first to discover the great potential of MIMO system in channel capacity,and in 1996,Foshini of Bell Labs first proposed a space-time coding scheme,i.e.,the diagonal-Bell Labs hierarchical space-time model,which can obtain very high spectrum utilization,but due to the complexity of its structure,it is difficult to be applied in practice,and is now rarely investigated.1998,P.W.Wolniansky et al.gave a simple and practical space-time coding scheme on this basis,i.e.,the vertical-Bell Labs layered space-time model.In 1998,P.W.Wolniansky et al.gave a simple and practical space-time coding scheme on this basis,i.e.,Vertical Bell Labs Layered Space-Time(V-BLAST,Vertical Bell Labs Layered Space-Time)model,which can obtain very high spectrum utilisation and is easy to implement,and therefore has received wide attention once it was proposed.In this paper,we focus on airtime layered codes as well as the ZF detection algorithm and the MMSE detection algorithm in VBLAST systems and improve them to further enhance the performance of the two detection algorithms through sequential serial interference cancellation.
