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961.
AnalysisofStaggeredOFDMDataTransmissionWithReducedComplexityZhangLijun(DepartmentofTelecommunicationEngineering,NanjingUniver...  相似文献   
962.
基输水建筑物各基础工程中,严格按照设计要求完成各环节的施工工艺,是保证整个输水建筑工程质量的基础。本文以位于云南麻栗坝水库的东干渠渠首的城子渡槽工程施工为例,分别对工程概况以及施工工艺相关情况作了阐述。  相似文献   
963.
The authors have investigated the effects of different annealing temperatures in Ar atmosphere on the SiO2/4H-SiC interfaces by spectroscopic ellipsometry (SE) and atomic force microscopy (AFM). There is a strong correlation between the annealing temperatures and the quality of SiO2/4H-SiC interface. Annealing at 600 °C can significantly improve the quality of SiO2/4H-SiC interface with no transition layer. The reasons for such improvement in the quality of the SiO2/4H-SiC interface after moderate temperature annealing at 600 °C may be explained by the formation and consumption of carbon clusters and silicon oxycarbides during annealing.  相似文献   
964.
This paper studies the wireless two-way relay channel (TWRC), where two source nodes, S1 and S2, exchange information through an assisting relay node, R. It is assumed that R receives the sum signal from S1 and S2 in one timeslot, and then amplifies and forwards the received signal to both S1 and S2 in the next time-slot. By applying the principle of analogue network coding (ANC), each of S1 and S2 cancels the so-called "self-interference" in the received signal from R and then decodes the desired message. Assuming that S1 and S2 are each equipped with a single antenna and R with multi-antennas, this paper analyzes the capacity region of the ANC-based TWRC with linear processing (beamforming) at R. The capacity region contains all the achievable bidirectional rate-pairs of S1 and S2 under the given transmit power constraints at S1, S2, and R. We present the optimal relay beamforming structure as well as an efficient algorithm to compute the optimal beamforming matrix based on convex optimization techniques. Low-complexity suboptimal relay beamforming schemes are also presented, and their achievable rates are compared against the capacity with the optimal scheme.  相似文献   
965.
966.
In this paper, based on the analysis of the experimental data using a new post‐processing method for time‐domain channel measurements, a new double‐cluster statistical model for UWB systems with a bandwidth lower than 1 GHz in non‐line‐of‐sight (NLOS) indoor propagation environment is proposed. By using the proposed model, both the model itself and the parameter estimation of the corresponding model are simplified. By defining the polarity of a particular model parameter, the model has the flexibility to deal with both ‘soft NLOS’ and ‘hard NLOS’ indoor propagation environments. Therefore, the channel impulse responses (CIRs) generated by the proposed model ‘resemble’ the measured CIR better than the SV (Saleh‐‐Valenzuela)/IEEE 802.15.3a model not only in terms of the average values, but also in terms of the cumulative distribution functions (CDFs) of the small‐scale statistics. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   
967.
In this paper, we analyse the symbol error rate (SER) performance of adaptive relay selection schemes (ARS) in a general dual-hop multiple-relay network. Specifically, we provide a closed-form SER expression for ARS which is tight over the whole signal-to-noise ratio (SNR) region. In addition, the derived SER can be readily extended to conventional relay selection schemes, i.e. amplify-and-forward relay selection (AF-RS), perfect decode-and-forward relay selection (PDF-RS), adaptive decode-and-forward relay selection (ADF-RS), and cooperative-maximum-ratio-combining decode-and-forward relay selection (CDF-RS). Transmit power allocation based on the simplified SER is presented to improve the system performance. The analytical results are verified by computer simulations.  相似文献   
968.
Most of the existing cooperation methods select relay node(s) mainly based on the channel state information, but do not consider whether the selected relay nodes work or not. If the selected relays are invalidated, the performance of cooperative communication will deteriorate. To resolve the above problem, this paper investigates cooperative communication in IEEE 802.11 networks, and proposes a novel Spare Cooperative Method (SCM). SCM chooses a spare cooperation node to enhance the reliability of communication, and uses an enhanced handshaking mechanism to coordinate the access of source nodes and cooperation nodes to the wireless channel. The performance of SCM is comprehensively analyzed in terms of outage probability and saturated throughput. The analysis shows that SCM improves the performance of IEEE 802.11.  相似文献   
969.
许江湖  张明敏 《信号处理》2007,23(1):127-131
将PCI(Principal Component Inverse,主成分求逆)运用于白化滤波器,并分析了其白化性能和主成分的确定方法及其相关的问题。提出了基于修正PCI技术预白的水下目标回波检测方法,通过蒙特卡洛仿真显示该方法的检测性能优于传统的基于AR模型预白的检测方法。  相似文献   
970.
一种数字鉴相器的设计   总被引:1,自引:0,他引:1  
竺小松  张颂 《电子测试》2007,(11):69-70,26
本文通过理论推导,得出正切鉴相器的数学模型.并与常用的正弦鉴相器进行对比分析,通过仿真,得出其性能优于正弦鉴相器的结论.  相似文献   
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