Power-space functions in high speed railway wireless communications

Dong, Yunquan; Zhang, Chenshuang; Fan, Pingzhi

doi:10.1109/jcn.2015.000044

Cited by 18 publications

(14 citation statements)

References 10 publications

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“…which avoids the complexity of calculating S −1 r . SIR k denotes the SIR at the k-th subcarrier after approximately frequency equalization and W ′ r is the normalized AWGN and the noise power coefficient includes the remaining interference power γ 2 β /SIR k and the original normalized Gaussian noise power in (5). G ′ is the T x × T x matrix full of elements 1.…”

Section: A Orthogonal Property Ici Reduction Methods and Sir Analysimentioning

confidence: 99%

“…Previous works on HSR wireless communications mainly focus on the AWGN channels [5], [6] or the estimation of Doppler spread [14]- [17]. In this part, we derived the Doppler spread model in HSR scenarios with Rician fading model.…”

Section: Analysis On the Effects Of Nlos Pathsmentioning

confidence: 99%

“…Thereby, wireless propagation environments for HSR are extremely diverse, in which viaducts and tunnels are the two typical scenarios [2], [5]. In addition to tunnels, viaducts account for the vast majority of Chinese HSRs (more specifically, 86.5% of railways is elevated in the BeijingShanghai HSR [5]), and there are few multi-paths because of little scattering and reflection. Hence, line-of-sight (LOS) assumption is widely used and the investigation of LOS MIMO channels are presented in [5], [6].…”

Section: Introductionmentioning

confidence: 99%

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Location-Aware ICI Reduction in MIMO-OFDM Downlinks for High-Speed Railway Communication Systems

Chen

Liu

et al. 2018

IEEE Trans. Veh. Technol.

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High mobility may destroy the orthogonality of subcarriers in OFDM systems, resulting in intercarrier interference (ICI), which may greatly reduce the service quantity of high-speed railway (HSR) wireless communications. This paper focuses on ICI mitigation in the HSR downlinks with distributed transmit antennas. For such a system, its key feature is that the ICIs are caused by multiple carrier frequency offsets corresponding to multiple transmit antennas. Meanwhile, the channel of HSR is fast time varying, which is another big challenge in the system design. In order to get a good performance, low complexity real-time ICI reduction is necessary. To this end, we first analyzed the property of the ICI matrix in AWGN and Rician scenarios, respectively. Then, we propose corresponding low complexity ICI reduction methods based on location information. For evaluating the effectiveness of the proposed method, the expectation and variance of remaining interference after ICI reduction is analyzed with respect to Rician K-factor. In addition, the service quantity and the bandwidth and computation cost are also discussed. Numerical results are presented to verify our theoretical analysis and the effectiveness of proposed ICI reduction methods. One important observation is that our proposed ICI mitigation method can achieve almost the same service quantity with that obtained on the case without ICI when the train's velocity is 300km/h, that is, ICI has been completely eliminated. Numerical results also show that the scenarios with Rician K-factors over 30dB can be considered as AWGN scenarios, which may provide valuable insights on future system designs. Index Terms

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Section: A Orthogonal Property Ici Reduction Methods and Sir Analysimentioning

confidence: 99%

Section: Analysis On the Effects Of Nlos Pathsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Location-Aware ICI Reduction in MIMO-OFDM Downlinks for High-Speed Railway Communication Systems

Chen

Liu

et al. 2018

IEEE Trans. Veh. Technol.

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“…Furthermore, the total service volume of the train through the entire optimized coverage can also be calculated. Total service volume is defined as the integral of the instantaneous channel capacity over the coverage (Dong et al., 2015), which is

S = \sum_{i = 1,2} \int_{0}^{d} C_{i} false(λ false) d λ

…”

Section: System Modelmentioning

confidence: 99%

Adaptive Beamforming and Power Allocation for mmWave Communication in High‐Speed Railway

et al. 2021

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Millimeter wave (mmWave)-based massive multiple-input multiple-output (MIMO) beamforming technology is one of the key technologies in the fifth-generation (5G) network. In this paper, we apply mmWave to high-speed railway (HSR) communication scenario to meet its increasingly growing demands for tremendous data rate and reliable mobile services. The HSR mmWave communication system uses a control/user (C/U) plane separation structure; that is, control information and user information are transmitted through the high-frequency micro base station (BS) and the low-frequency macro BS, respectively. Then, an optimized beam width and power allocation scheme is proposed, which is combined with the mobile relay (MR) technology to utilize the architecture of the large-scale antenna beamforming. In the proposed scheme, we introduce a power factor related to the change of train speed. According to the power factor, the service beam width is adjusted dynamically and the transmit power of the beams from two simultaneously served mmWave access points (APs) is jointly calculated. Simulation results show that, compared with the traditional uniform beam width scheme, the proposed adaptive beam width and power allocation scheme can maximize the total service volume within the maximum transmit power range.

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“…Similarly, substitute h 12 , h 22 ∼ γ(m, 1) and P 2 = P into (5), (22) can be derived. This completes the proof.…”

Section: Appendix C Proof For Theoremmentioning

confidence: 99%

Toward Traffic Patterns in High-Speed Railway Communication Systems: Power Allocation and Access Selection

Xiong

Chen

et al. 2018

IEEE Trans. Veh. Technol.

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In high-speed railway (HSR) communication systems, distributed antenna is usually employed to support frequent handover and enhance the signal to noise ratio to user equipments. In this case, dynamic time-domain power allocation and antenna selection (PAWAS) could be jointly optimized to improve the system performances. This paper consider this problem in such a simple way where dynamic switching between multiple-input-multiple-output (MIMO) and single-input-multiple-output (SIMO) is allowed and exclusively utilized, while the channel states and traffic demand are taken into account. The channel states includes sparse and rich scattering terrains, and the traffic patterns includes delay-sensitive and delay-insensitive as well as hybrid. Some important results are obtained in theory. In sparse scattering terrains, for delay-sensitive traffic, the PAWAS can be viewed as the generalization of channel-inversion associated with transmit antenna selection. On the contrary, for delay-insensitive traffic, the power allocation with MIMO can be viewed as channel-inversion, but with SIMO, it is traditional waterfilling. For the hybrid traffic, the PAWAS can be partitioned as delay-sensitive and delay-insensitive parts by some specific strategies. In rich scattering terrains, the corresponding PAWAS is derived by some amendments in sparse scattering terrains and similar results are then presented.

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Power-space functions in high speed railway wireless communications

Cited by 18 publications

References 10 publications

Location-Aware ICI Reduction in MIMO-OFDM Downlinks for High-Speed Railway Communication Systems

Location-Aware ICI Reduction in MIMO-OFDM Downlinks for High-Speed Railway Communication Systems

Adaptive Beamforming and Power Allocation for mmWave Communication in High‐Speed Railway

Toward Traffic Patterns in High-Speed Railway Communication Systems: Power Allocation and Access Selection

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