Browsing by Author "Chen, Po-Chia"

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Coverage Analysis for Dense Heterogeneous Networks with Cooperative NOMA
(2017-01-01)
Liu, Chun-Hung
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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.
Load-Aware Coordinated Multipoint Joint Transmission in Dense Heterogeneous Networks: Downlink Coverage and Throughput Limits
(2017-01-01)
Liu, Chun-Hung
;
Chen, Po-Chia
;
電機工程學系
;
Department of Electrical and Computer Engineering
In this paper, we propose a (cell) load-aware approach to performing the downlink coordinated multi-point joint transmission (JT-CoMP) scheme in a dense heterogeneous cellular network (HetNet) consisting M tiers of different kinds of base stations (BSs). Inspiring from the fact that there could exist a considerable number of the void BSs in a dense HetNet that are not associated by any users, this load-aware JT-CoMP scheme is able to coordinate the void BSs so as to enhance the downlink transmission of the non-void BSs. Using such a CoMP scheme, the fundamental upper and lower limits on the coverage and ergodic link throughput of a user with downlink MISO channel are accurately found in a low-complexity approximated form and they straightforwardly show that the load-aware JT-CoMP scheme has the capability of significantly increasing the coverage and ergodic link throughput of a user as long as the user intensity is not very much higher than the total intensity of the BSs. Numerical results validate the accuracy and correctness of the analytical results and demonstrate the huge gains of the coverage and the ergodic link throughput exploited by the proposed load-aware JT-CoMP scheme.