Coordinated multipoint(CoM P)transmission and reception is a technique to reduce intercell interference and increase the cell edge throughput.In order to get maximum CoM P gain the networks and terminals involved in C...Coordinated multipoint(CoM P)transmission and reception is a technique to reduce intercell interference and increase the cell edge throughput.In order to get maximum CoM P gain the networks and terminals involved in CoM P communication should be robust against time and frequency offset due to asynchronism between terminals and base stations.However,the modulation techniques proposed in LTE-Advanced standard(SC-FDMA and OFDMA)are quite sensitive to frequency offset because of DFT/IDFT used in the modulation systems,which brings difficulties for commercial implementation of CoM P technique based on LTE-Advanced.To relax the synchronization requirement in CoM P system,in this paper we introduce a CoM P technique based on a new multicarrier modulation scheme-multicarrier time division multiple access(MC-TDMA).In comparison with SC-FDMA and OFDMA,the MC-TDMA modulation can significantly improve the CoM P performance in case of carrier frequency offset.Simulation shows that at 20%of carrier frequency offset the CoM P system with MC-TDMA modulation can also keep high performance,while the system with SC-FDMA and OFDMA is totally lost in work.展开更多
In a coordinated multipoint transmission system with centralized architecture for saving power consumption, total power metric is minimized while completely using the backhaul capacity and maintaining the minimum targ...In a coordinated multipoint transmission system with centralized architecture for saving power consumption, total power metric is minimized while completely using the backhaul capacity and maintaining the minimum target data rate. The problem is formulated as a mixed integer optimization problem, which is difficult to solve. To overcome this problem, a joint user selection and rate adaptation scheme is developed based on the water-filling rate adaptation with the given user set and the power saving criterion with the allocated rates.Numerical results demonstrate that compared with the norm-based and semi-orthogonal user selection algorithms,the proposed algorithm can significantly reduce the total power consumption. The proposed algorithm can also achieve near-optimal performance compared with the performance achieved by the exhaustive search-based method. In addition, the computational complexity of the proposed algorithm is reduced by heuristic iteration and search scope shrinking.展开更多
Precoding methods at the Base Station (BS) can be used to deal with the inter-cell interference and improve the signal quality of the user especially at the cell edge. In this paper, a novel Zero-Forcing (ZF) precodin...Precoding methods at the Base Station (BS) can be used to deal with the inter-cell interference and improve the signal quality of the user especially at the cell edge. In this paper, a novel Zero-Forcing (ZF) precoding method is proposed and investigated for multi-cell Multi-Input Multi-Output (MIMO) systems. We propose a relaxed ZF precoding method by relaxing the ZF criterion to some degree so that the inter-cell interference may not be zero. Complexity analysis shows that compared with the conventional ZF method, the additional computation complexity for the proposed method is trivial. Simulation results show that the proposed relaxed ZF method has better performance than the conventional ZF method in terms of the sum-rate, especially at low Signal to Noise Ratio (SNR).展开更多
文摘Coordinated multipoint(CoM P)transmission and reception is a technique to reduce intercell interference and increase the cell edge throughput.In order to get maximum CoM P gain the networks and terminals involved in CoM P communication should be robust against time and frequency offset due to asynchronism between terminals and base stations.However,the modulation techniques proposed in LTE-Advanced standard(SC-FDMA and OFDMA)are quite sensitive to frequency offset because of DFT/IDFT used in the modulation systems,which brings difficulties for commercial implementation of CoM P technique based on LTE-Advanced.To relax the synchronization requirement in CoM P system,in this paper we introduce a CoM P technique based on a new multicarrier modulation scheme-multicarrier time division multiple access(MC-TDMA).In comparison with SC-FDMA and OFDMA,the MC-TDMA modulation can significantly improve the CoM P performance in case of carrier frequency offset.Simulation shows that at 20%of carrier frequency offset the CoM P system with MC-TDMA modulation can also keep high performance,while the system with SC-FDMA and OFDMA is totally lost in work.
基金partly supported by the National Natural Science Foundation of China (No. 61401249)Specialized Research Fund for the Doctoral Program of Higher Education (SRFDP) (No. 20130002120001)Chuanxin Funding
文摘In a coordinated multipoint transmission system with centralized architecture for saving power consumption, total power metric is minimized while completely using the backhaul capacity and maintaining the minimum target data rate. The problem is formulated as a mixed integer optimization problem, which is difficult to solve. To overcome this problem, a joint user selection and rate adaptation scheme is developed based on the water-filling rate adaptation with the given user set and the power saving criterion with the allocated rates.Numerical results demonstrate that compared with the norm-based and semi-orthogonal user selection algorithms,the proposed algorithm can significantly reduce the total power consumption. The proposed algorithm can also achieve near-optimal performance compared with the performance achieved by the exhaustive search-based method. In addition, the computational complexity of the proposed algorithm is reduced by heuristic iteration and search scope shrinking.
基金Supported by Shantou Youth Scientific Research Fund(No.YR11002)Distinguished Youth Fund in Higher Education of Guangdong Province(No.2012LYM_0064)
文摘Precoding methods at the Base Station (BS) can be used to deal with the inter-cell interference and improve the signal quality of the user especially at the cell edge. In this paper, a novel Zero-Forcing (ZF) precoding method is proposed and investigated for multi-cell Multi-Input Multi-Output (MIMO) systems. We propose a relaxed ZF precoding method by relaxing the ZF criterion to some degree so that the inter-cell interference may not be zero. Complexity analysis shows that compared with the conventional ZF method, the additional computation complexity for the proposed method is trivial. Simulation results show that the proposed relaxed ZF method has better performance than the conventional ZF method in terms of the sum-rate, especially at low Signal to Noise Ratio (SNR).
