Elevation angle research in three-dimension channel model using ray-tracing
9
Citation
1
Reference
10
Related Paper
Citation Trend
Abstract:
By adopting elevation domain beamforming and spatial domain multiplexing, 3 Dimensional (3D) Multiple Input and Multiple Output (MIMO) antenna system is the key technology in providing high throughput in modern communication systems. However, the conventional channel modeling method mainly focuses on 2 dimensional (2D) MIMO channels which neglect the vertical plane. It inspires scholars to do research on the characteristics of 3D channel models' elevation parameters. In this paper, we propose an automatic measurement approach for 3D MIMO channel by using ray-tracing algorithm. This method delivers the characteristics of the elevation angle for low-rise floors in Outdoor to Indoor (O2I) scenario, which have accurately matched the classical experimental results. In addition, further investigation for high-rise floors is successfully made by this proposed methodology as well.Keywords:
Elevation (ballistics)
Spatial multiplexing
In order to enable reliable spatial multiplexing transmission, an environment with rich scatterers is often required, which is not equipped in most railway running environment. So the MIMO channel with sparse scatterer and dominant LOS component in high-speed railway scenario is usually strongly spatial correlated and often fails to support a multiplexing transmission link. While it is actually not a pure LOS environment even in open plain or on a viaduct according to the existing engineering measurements. Hence, in high-speed railway environment, it is still highly possible to support partial multiplexing transmission if configuring a reasonable antenna placement structure with adequate antennas along the train body in the future. To target this problem, this paper investigates the solution of reconstructing the highly correlated railway channel into an equivalent channel with less correlation using the method of principal component analysis and thereon proposes an optimal partial multiplexing transmission solution to improve the link performance. With the proposed solution, the capacity in the distant area from the base station is verified to be significantly improved and that in close distance area is maintained meanwhile the condition number is reduced to be less than 10 to meet the required link quality.
Spatial multiplexing
Component (thermodynamics)
Cite
Citations (1)
It is well-known that using multiple antennas provides a substantial capacity and diversity increase for wireless communication systems. A multi-input multi-output (MIMO) technique that utilizes the channel knowledge both at the transmitter and the receiver is known as beamforming. Beamforming separates a MIMO channel into parallel subchannels. It was previously shown that uncoded beamforming achieves a diversity order of (N - S + 1)(M - S + 1) if S symbols are transmitted simultaneously for N transmit and M receive antennas. Hence, there is a significant drop in the diversity order (and performance) of the system with increased spatial multiplexing. In this paper, we introduce bit interleaved coded multiple beamforming and name the system BICMB. We provide interleaver design criteria such that the resulting system achieves full spatial multiplexing of min(N, M) and full spatial diversity of NM. Simulation results show that BICMB, due to its ability of maintaining the maximum diversity order even at full spatial multiplexing, provides substantial performance gain when compared to the best spatial multiplexing systems
Spatial multiplexing
Antenna diversity
Diversity gain
Transmit diversity
Cite
Citations (15)
Multiple-input multiple-output (MIMO) wireless communication systems can offer high data rates through spatial multiplexing or substantial diversity using transmit diversity. In this letter, switching between spatial multiplexing and transmit diversity is proposed as a simple way to improve the diversity performance of spatial multiplexing. In the proposed approach, for a fixed rate, either multiplexing or diversity is chosen based on the instantaneous channel state and the decision is conveyed to the transmitter via a low-rate feedback channel. The minimum Euclidean distance at the receiver is computed for spatial multiplexing and transmit diversity and is used to derive the selection criterion. Additionally, the Demmel condition number of the matrix channel is shown to provide a sufficient condition for multiplexing to outperform diversity. Monte Carlo simulations demonstrate improvement over either multiplexing or diversity individually in terms of bit error rate.
Spatial multiplexing
Transmit diversity
Antenna diversity
Cite
Citations (420)
MIMO spatial multiplexing is an essential feature to increase the communication data rates in current and future cellular systems. Currently, the ns-3 lte module leverages an abstraction model for 2x2 MIMO with spatial multiplexing of two streams; ...
Spatial multiplexing
Abstraction
Cite
Citations (2)
A contemporary perspective on the tradeoff between transmit antenna diversity and spatial multiplexing is provided. It is argued that, in the context of most modern wireless systems and for the operating points of interest, transmission techniques that utilize all available spatial degrees of freedom for multiplexing outperform techniques that explicitly sacrifice spatial multiplexing for diversity. In the context of such systems, therefore, there essentially is no decision to be made between transmit antenna diversity and spatial multiplexing in MIMO communication. Reaching this conclusion, however, requires that the channel and some key system features be adequately modeled and that suitable performance metrics be adopted; failure to do so may bring about starkly different conclusions. As a specific example, this contrast is illustrated using the 3GPP Long-Term Evolution system design.
Spatial multiplexing
Antenna diversity
Transmit diversity
Cite
Citations (3)
A contemporary perspective on transmit antenna diversity and spatial multiplexing is provided. It is argued that, in the context of most modern wireless systems and for the operating points of interest, transmission techniques that utilize all available spatial degrees of freedom for multiplexing outperform techniques that explicitly sacrifice spatial multiplexing for diversity. Reaching this conclusion, however, requires that the channel and some key system features be adequately modeled and that suitable performance metrics be adopted; failure to do so may bring about starkly different conclusions. As a specific example, this contrast is illustrated using the 3GPP long-term evolution system design.
Spatial multiplexing
Antenna diversity
Transmit diversity
Cite
Citations (221)
A novel compressive-sensing based signal multiplexing scheme is proposed in this paper to further improve the multiplexing gain for multiple input multiple output (MIMO) system. At the transmitter side, a Gaussian random measurement matrix in compressive sensing is employed before the traditional spatial multiplexing in order to carry more data streams on the available spatial multiplexing streams of the underlying MIMO system. At the receiver side, it is proposed to reformulate the detection of the multiplexing signal into two steps. In the first step, the traditional MIMO equalization can be used to restore the transmitted spatial multiplexing signal of the MIMO system. While in the second step, the standard optimization based detection algorithm assumed in the compressive sensing framework is utilized to restore the CS multiplexing data streams, wherein the exhaustive over-complete dictionary is used to guarantee the sparse representation of the CS multiplexing signal. In order to avoid the excessive complexity, the sub-block based dictionary and the sub-block based CS restoration is proposed. Finally, simulation results are presented to show the feasibility of the proposed CS based enhanced MIMO multiplexing scheme. And our efforts in this paper shed some lights on the great potential in further improving the spatial multiplexing gain for the MIMO system.
Spatial multiplexing
Cite
Citations (0)
This study concerns the evaluation of beamforming techniques in multi-user indoor environment at the mm-wave frequency band of 70 GHz using both measurements and ray tracing simulations carried out in a furnished small-office environment. The goal of the work is twofold: 1) to evaluate ray tracing as a reliable directional channel model for beamforming assessment and for real-time assistance in the beam-searching phase and 2) to evaluate simple beamforming schemes as means to enforce spatial division in a small-indoor environment. Results suggest that the considered ray tracing model can be reliable enough to reproduce the general performance trends of different beamforming schemes and to assist the beam-searching phase, therefore potentially reducing the related time delay and computational overhead.
Extremely high frequency
Beam tracing
Tracing
Cite
Citations (22)
In this chapter, we turn our attention to the second major class of MIMO processing techniques: spatial multiplexing. As we discussed in Chapter 1, spatial multiplexing refers to transmitting multiple independent data streams over multipath channels, without the need to increase the bandwidth. Unlike space-time coding, which is used to achieve spatial diversity and which transmits at most one modulation symbol per modulation symbol period (i.e., rs ≤ 1), spatial multiplexing techniques are capable of achieving spatial rates equal to min {Nt,Nr}; that is, rather than only transmitting one or fewer modulation symbols per symbol period, spatial multiplexing involves transmitting up to min{Nt, Nr} modulation symbols per symbol period, resulting in a concomitant increase in throughput relative to spatial diversity schemes. This improvement in throughput, however, is achieved at the expense of diversity gain, so the diversity gains associated with spatial multiplexing methods are normally significantly less than NtNr. This chapter describes several fundamental, practical techniques that are used to achieve spatial multiplexing.
Spatial multiplexing
Antenna diversity
Spatial modulation
Modulation (music)
Symbol rate
Cite
Citations (1)
Wireless links with multi-antenna transmitters and receivers can be used to provide increased diversity and/or large data-rates. It has been shown that multi-antenna communication systems can simultaneously achieve the maximum diversity and maximum rate (or multiplexing) gain. This paper proposes a modified version of traditional spatial multiplexing that allows the wireless system to obtain maximum diversity and multiplexing gain with a linear receiver. This diversity-multiplexing gain tradeoff is optimized by switching between transmit selection diversity and spatial multiplexing. We show that this system model can be easily implemented when the transmitter has no form of channel knowledge by using a limited number of feedback bits from the receiver to the transmitter. Simulation results show gains compared to selection diversity and spatial multiplexing.
Spatial multiplexing
Diversity gain
Antenna diversity
Cite
Citations (22)