Zhang W.,Wuhan University |
Tian M.,Wuhan University |
He H.,Wuhan University |
Shen Z.,China Academy of Telecommunication Technology
Hsi-An Chiao Tung Ta Hsueh/Journal of Xi'an Jiaotong University | Year: 2011
Since the downlink outage probability expressed with bound value is not precise enough in co-channel interference-limited tiered networks, the stochastic geometry theory is used to model network framework and closed-expressions of per-tier downlink outage probability are derived based on the framework. The received signal to interference ratio (SIR) is formulated as a function of macrocell signal power and femtocell aggregated interference power. Then the probability for received SIR less than a threshold is derived according to the probability distribution of macrocell signal power in the condition on the aggregated interference power. The downlink outage probability is obtained by applying the probability distribution of aggregated interference power to calculate the expectation of conditioned outage probability. Simulation results show that the downlink outage probability in macrocell reduces about 20% and 5%, respectively, when the femtocell transmit power decreases 3.16 mW (the number of femtocells is 100 on average) or the number of femtocells decreases 20 on average (the femtocell transmit power is 100 mW).
Jin J.,Beijing University of Posts and Telecommunications |
Wang Y.,Xinyang Power Supply Company of Henan Electronic Power Company |
Li X.,Beijing University of Posts and Telecommunications |
Chen S.-Z.,China Academy of Telecommunication Technology
Beijing Youdian Daxue Xuebao/Journal of Beijing University of Posts and Telecommunications | Year: 2012
In the existing MapReduce framework, the single master is the performance bottleneck. As a result, the size of the cluster is limited. In order to break the bottleneck, a multi-master framework is proposed in this paper. The implementation is based on Apache Hadoop MapReduce. The main framework and signaling system are redesigned to sustain more than one master. Meanwhile a double-master hot backup scheme is designed to solve single master failure, so that the new framework is able to reduce the impact of master failure.
China Academy Of Telecommunication Technology | Date: 2012-09-25
Disclosed is a method for transmitting channel state information, for realizing the transmission of channel information which supports CoMP transmission. The method includes: a terminal receiving from a base station control signaling which indicates to the terminal to perform channel information feedback, the control signaling including indication information about a plurality of CSI-RS resources for performing aggregation feedback; the terminal obtaining the plurality of CSI-RS resources based on the indication information to perform channel estimation and constructing a channel matrix according to a PDSCH transmission solution over a preset CSI reference resource, the correlation between the signal over the plurality of CSI-RS resources and the signal of a UERS port and the constructed channel matrix and transmitting the CSI to the base station. Also disclosed is a device for implementing the method.
China Academy Of Telecommunication Technology | Date: 2013-03-04
Disclosed are a response information transmission method, system and device. A base station can configure at least two PUCCH transmission carriers for user equipment, accordingly, the user equipment can select at least one PUCCH transmission carrier from the at least two PUCCH transmission carriers which are configured by the base station to transmit response information fed back on a corresponding subframe, and accordingly, the base station can receive the response information which is fed back by the user equipment on at least one PUCCH transmission carrier. The technical solution increases the number of PUCCH transmission carriers, so that compared with the manner of only configuring one PUCCH transmission carrier in the prior art, the reconfiguration operations caused by the movement of user equipment can be reduced, thereby reducing the condition that UE cannot normally communicate in the process of reconfiguration, and reducing the signaling overhead caused by the reconfiguration operation.
Dai X.,China Academy of Telecommunication Technology |
Zou R.,Central South University |
An J.,Beijing Institute of Technology |
Li X.,Beijing Institute of Technology |
And 2 more authors.
IEEE Transactions on Vehicular Technology | Year: 2012
A companding-based transformation method is introduced to quasi-maximum-likelihood (ML) detectors, such as the QR-decomposition-based M-algorithm (QRD-M) and list sphere decoding, for coded multiple-input-multiple- output (MIMO) systems in this paper. The key idea of the proposed companding technique is to compress (i.e., down-weight) the dubious observation of the accumulated branch metric by taking into account its statistical characteristics so that, after companding, the estimation error of the unreliable detected information bits due to insufficient candidate size and/or channel estimation error is significantly mitigated without disproportionate compromise of the reliable information bits. By employing the proposed companding method, the original leptokurtically distributed log-likelihood ratio of the detected information bits becomes more Gaussian distributed. As an illustrative example, the QRD-M detector is employed in this paper. Numerical results show that the QRD-M detector based on the proposed companding paradigm achieves significant performance gain over the conventional method and approaches the performance of the ML detector for a 16-ary quadrature-amplitude-modulated (16-QAM) 4 × 4 MIMO multiplexing system with lower-than-linear-detector computational complexity. © 2006 IEEE.