Browsing by Author "Lu, Youyi"

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On the Downlink Performance of Massive MIMO With Finite Antenna Elements in Multi-Cellular Networks
(2016-01-01)
Wang, Li-Chun
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Lu, Youyi
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交大名義發表
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National Chiao Tung University
In this paper, we present a close-form expression for the downlink throughput of a massive MIMO system with finite antenna elements in a multi-celluar systems. In practice, the performance of massive MIMO system is limited by the number of antenna elements. From the operator aspect, the cost of massive MIMO is a major concern. Thus, a massive MIMO system with finite antenna elements is of interest. On the other hand, as the number of antenna elements is not so large, the impact of co-channel interference from neighboring cells become a critical issue that should be taken into account. We consider the time-division duplexing (TDD) multi-celluar systems. Our system model accounts for the effects of channel estimation, pilot contamination, 2D channel and 1D antenna array, and our simulations take 3D channel and 2D antenna array into consideration in addition. We derive approximations of achievable rates with linear precoders, and validate by simulations. Our results can provide an evaluation framework for designing a practical massive MIMO system to find the performance tradeoff between the number of antenna elements and cost.
Performance Model And Deployment Strategy For Mm-wave Multi-Cellular Systems
(2016)
Lu, Youyi
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Hsu, Hung-Wei
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Wang, Li-Chun
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電信工程研究所
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Institute of Communications Engineering
The next generational wireless system require ubiquitous access to the huge volume of data. An interesting observation is that small cells, mm-Wave, and massive MIMO can orchestrate a blueprint of a high-capacity wireless system. We will propose a new cellular system architecture, in which mm-Wave small cells with massive MIMO for the 5G use case of broadband access providing Gbps data rate. The millimeter-wave band, is very attractive for the bandwidth-hungry 5G system. However, since different mm-Wave frequencies have different propagation conditions, how many small cells should be deployed is an issue. In this paper, we use ray-tracing based model to analyze the performance of mm-wave multicellular systems in a real scenario and give suggested number of small cells for guaranteeing different QoS. In addition, the directive property and high absorption by blockage of mmWave reveal the importance of LoS propagation conditions. Hence, we propose a grid strategy for mm-Wave small cell deployment to ensure the LoS scenario available for most of users. Simulation results show that this deployment strategy is especially effective when small cells are not-so-ultra dense.