Browsing by Author "Yang, Jie-Ru"

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A Generalized Analytical Framework for Coverage Evaluation in mmWave Heterogeneous Cellular Networks in Urban Areas
(2017-01-01)
Liu, Chun-Hung
;
Liang, Di-Chun
;
Yang, Jie-Ru
;
Chen, Jie
;
電機工程學系
In this paper, we introduce a generalized analytical framework to evaluate the coverage probability in an mmWave heterogeneous cellular network (HetNet) consisting of UHF macrocell base stations (BSs) and mmWave small cell BSs deployed in an urban area. A generalized user association scheme that can cover a few user association schemes is formulated and applied in the mmWave HetNet. Two important statistical properties of the associated BS under this scheme are derived for the general line-of-sight and non line-of-sight pathloss channel models and they can be largely simplified if the power-law channel model is applied. Using the two statistical properties, the coverage probability of a downlink multiple-input-single-output channel is found in a compact form, which reveals that the coverage probability in the mmWave HetNet can be significantly improved if compared with the cellular network consisting of a single tier of mmWave small cell BSs. Numerical results not only validate the correctness of the coverage probability derived but also indicate that the mmWave HetNet has the potential to achieve a high coverage probability in an urban area.
Coverage Analysis for Dense Heterogeneous Networks with Cooperative NOMA
(2017-01-01)
Liu, Chun-Hung
;
Liang, Di-Chun
;
Chen, Po-Chia
;
Yang, Jie-Ru
;
電機工程學系
In a heterogeneous cellular network (HetNet) consisting of M tiers of densely-deployed base stations (BSs), consider that each of the BSs in the HetNet that are associated with multiple users is able to simultaneously schedule and serve two users in a downlink time slot by performing the (power-domain) non-orthogonal multiple access (NOMA) scheme. This paper aims at the preliminary study on the downlink coverage performance of the HetNet with the non-cooperative and the proposed cooperative NOMA schemes. First, we study the coverage probability of the NOMA users for the non-cooperative NOMA scheme in which no BSs are coordinated to jointly transmit the NOMA signals for a particular cell and the coverage probabilities of the two NOMA users of the BSs in each tier are derived. We show that the coverage probabilities can be largely reduced if allocated transmit powers for the NOMA users are not satisfied with some constraints. Next, we study and derive the coverage probabilities for the proposed cooperative NOMA scheme in which the void BSs that are not tagged by any users are coordinated to enhance the far NOMA user in a particular cell. Our analyses show that cooperative NOMA can significantly improve the coverage of all NOMA users as long as the transmit powers for the NOMA users are properly allocated.