Geometry-based optimal power control was proposed in [14] to transform the power-control problem to a new geometrical problem on the position relationship between a line and some points. This scheme provides a novel v...
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In this paper, cluster centers are defined as local maxima in the density which is called density peaks. We use an algorithm based on density peaks to cluster multipath components (MPCs) whose parameters are estimated...
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Cyclically shifted partial transmit sequences (CS-PTS) has conventionally been used in SISO systems for PAPR reduction of OFDM signals. Compared to other techniques, CS-PTS attains superior performance. Nevertheless, ...
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ISBN:
(数字)9781728182988
ISBN:
(纸本)9781728182995
Cyclically shifted partial transmit sequences (CS-PTS) has conventionally been used in SISO systems for PAPR reduction of OFDM signals. Compared to other techniques, CS-PTS attains superior performance. Nevertheless, due to the exhaustive search requirement, it demands excessive computational complexity. In this paper, we adapt CS-PTS to operate in a MIMO framework, where singular value decomposition (SVD) precoding is employed. We also propose SWAN, a novel optimization method based on swarm intelligence to circumvent the exhaustive search. SWAN not only provides a significant reduction in computational complexity, but it also attains a fair balance between optimality and complexity. Through simulations, we show that SWAN achieves near-optimal performance at a much lower complexity than other competing approaches.
Rural-macro (RMa) is an important scenario for fifth generation (5G) deployment, and there is a strong diffraction in RMa making it difficult to distinguish between line-of-sight (LoS) and non-line-of-sight (NLoS) cas...
ISBN:
(纸本)9781785618154;9781785618161
Rural-macro (RMa) is an important scenario for fifth generation (5G) deployment, and there is a strong diffraction in RMa making it difficult to distinguish between line-of-sight (LoS) and non-line-of-sight (NLoS) case. Since the environmental condition is closely related to the dynamic range of channel impulse response (CIR), this paper studies the dynamic range impact on characteristics of three dimensional (3D) multiple-input multiple-output (MIMO) channels based on 3.5 GHz measurement campaign in RMa. The space-alternating generalized expectation-maximization (SAGE) algorithm is employed to estimate multipath component parameters. The channel statistical characteristics, channel capacity and eigenvalues of CIR matrix are calculated for different CIR dynamic ranges. The results show that the delay spread, the angle spread, the channel capacity and the sub-channel correlation are linearly related to the dynamic range of CIR. Thus, the results give a new perspective to study channel characteristics based on CIR dynamic range in RMa scenario.
The millimeter wave communication is important for future wireless systems. In this paper, the channel characteristics at 28 GHz in an indoor scenario are researched based on ray tracing (RT) simulation and measuremen...
The millimeter wave communication is important for future wireless systems. In this paper, the channel characteristics at 28 GHz in an indoor scenario are researched based on ray tracing (RT) simulation and measurement. In the RT simulation, various configurations, such as different number of reflections, diffractions and penetrations are used. As for the measurement, two setups are implemented in order to analyze more parameters. Setup one is that biconical antennas are used at both the transmitter (TX) and receiver (RX). The other setup is that horn antenna at RX is rotated 360° in azimuth with a step of 5° when an omni-directional antenna located at TX. Meanwhile, antenna is rotated one circle with an elevation angle of 10°, 0° and -10°, respectively. Path loss and K-factor are analyzed firstly, and analysis results indicate the RT result with 1 or 2 reflections, 1 diffractions and 5 penetrations in this conference room is closest to the measurement result and channel models in 3GPP TR 38.901. Then, the root mean square (RMS) delay spread and RMS angular spread are investigated, which shows the value of measurement is a bit larger than RT because of the limitation of azimuth and elevation step. According to all the results, 1-2 reflections, 1 diffraction and 5 penetrations can be used in RT for future analysis of indoor scenario at 28 GHz.
In this paper, cluster centers are defined as local maxima in the density which is called density peaks. We use an algorithm based on density peaks to cluster multipath components (MPCs) whose parameters are estimated...
ISBN:
(纸本)9781785618154;9781785618161
In this paper, cluster centers are defined as local maxima in the density which is called density peaks. We use an algorithm based on density peaks to cluster multipath components (MPCs) whose parameters are estimated by the space-alternating generalized expectation-maximization (SAGE) algorithm. To validate its performance, we apply it to the data from a channel measurement in an indoor scenario at 28 GHz and compare it to the widely used KPowerMeans algorithm with the same distance metric of multiple component distance (MCD). Through the results, we find it can cluster MPCs more accurately validated by Calinski-Harabasz (CH) and Davies-Bouldin (DB) indices. More importantly, it overcomes the shortcoming of setting the number of clusters manually because we can determine the cluster centers automatically. Besides, the efficiency of DP clustering is far superior to KPowerMeans because what it needs is only a distance matrix and we only need to compute it once. At the end, statistical analysis of clusters are presented to provide insights in channel modeling of millimeter wave.
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