| 1. |
- Gan, Mingming, et al.
(author)
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A ray tracing algorithm for intelligent transport systems in tunnels
- 2014
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In: [Host publication title missing].
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Conference paper (peer-reviewed)abstract
- It is well-known that the radio wave propagation mechanisms inside a tunnel are different from the typical outdoor and indoor situations. Since the tunnels represent a significant type of vehicular environments, understanding the channel characteristics for the in-tunnel scenario is crucial for intelligent transport systems design. A widely used tool for simulating channel characteristics for outdoor and indoor scenarios is a deterministic propagation prediction tool, known as ray tracing (RT). However, RT applied for tunnel scenarios has not been studied adequately. In this paper, we first evaluate the real-world in-tunnel vehicle-to-vehicle radio channel measurements on the basis of time-varying power delay profile analysis. Secondly we introduce a RT tool that includes influence of the moving objects, to predict wave propagation mechanisms in the tunnel. In order to reduce computational complexity of RT, we suggest to combine an approximate algorithm for the higher-order reflection components with conventional RT and use a novel subdivision algorithm for modeling the diffuse scattering. Combining the higher-order reflection algorithm with conventional RT allows us to obtain more accurate delay spread results. The numerical simulations show that contribution of both the higher-order reflection and the diffuse components are equally important for the in-tunnel scenarios.
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| 2. |
- Gan, Mingming, et al.
(author)
-
An effective subdivision algorithm for diffuse scattering of ray tracing
- 2014
-
In: [Host publication title missing].
-
Conference paper (peer-reviewed)abstract
- Accurate modeling of electromagnetic wave propagation by means of ray tracing (RT) includes not only specular reflection, penetration through dielectric blocks and diffraction, but also diffuse scattering mechanisms. The accuracy, supported by a precise description of the environment, is achieved at a very high computational complexity. This computational complexity scales directly with the number of propagation paths, of which the diffuse scattering paths comprise a large proportion. In this paper, we propose a general subdivision algorithm for diffuse scattering of RT in indoor scenarios based on concentric circles. The proper tile size is defined according to the system bandwidth. The method significantly reduces the computational complexity of RT with no loss in accuracy. The method is verified by evaluating the power delay profile (PDP), delay spread and angular spread.
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| 3. |
- Gan, Mingming, et al.
(author)
-
Modeling time-variant fast fading statistics of mobile peer-to-peer radio channels
- 2011
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In: [Host publication title missing]. - 1550-2252. - 9781424483327
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Conference paper (peer-reviewed)abstract
- Abstract in UndeterminedThe radio channels between nodes of an indoor peer-to-peer network show specific fast fading characteristics. Depending on the mobility and on the scattering properties of the environment, different kinds of fading distributions can occur: Ricean fading between static nodes, but also Rayleigh or even double-Rayleigh fading between mobile nodes. We investigate fast fading in indoor peer-to-peer networks based on radio channel measurements. It turns out that the fading statistics change over time. While the predominant fading mechanism is a combination of Rayleigh and double-Rayleigh fading, Ricean fading also occasionally occurs. On top of that, indoors, the statistics of the fast fading change over time even for small-motions of the nodes, since the propagation environment is inhomogeneous. We comprehensively model these effects using a hidden Markov model, parameterized from our measurements. The model is validated, revealing a convincing fit between the model and the measurements.
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