Browsing by Author "Chiu, Che-Sheng"

Now showing 1 - 3 of 3

A Hybrid Inter-Cell Interference Mitigation Scheme for an OFDMA Downlink System
(2010-01-01)
Chiu, Che-Sheng
;
Huang, Chia-Chi
;
電信工程研究所
;
Institute of Communications Engineering
A number of inter-cell interference coordination schemes have been proposed to mitigate the inter-cell interference problem for orthogonal frequency division multiple access (OFDMA) systems and among them, partial frequency reuse is considered one of the most promising approaches. In this paper, we propose an inter-cell interference mitigation scheme for an OFDMA downlink system, which makes use of both partial frequency reuse and soft handover. The basic idea of this hybrid scheme is to dynamically select between a partial frequency reuse scheme and a soft handover scheme to provide better signal quality for cell edge users. Compared with the standard partial frequency reuse scheme, simulation results show that approximately one quarter of cell edge users can get improvements in signal quality as well as link spectral efficiency from using the proposed hybrid scheme. We also observe that by using our approach, there is a significant cell edge throughput gain over the standard partial frequency reuse scheme. Furthermore, based on a well defined data rate fairness criterion, we show that Our method achieves higher overall system capacity as compared with the standard partial frequency reuse scheme.
An Interference Coordination Scheme for Picocell Range Expansion in Heterogeneous Networks
(2012)
Chiu, Che-Sheng
;
Huang, Chia-Chi
;
電信工程研究所
;
Institute of Communications Engineering
Through deploying additional low-power nodes (LPNs) under the coverage area of a macrocell, heterogeneous network (HetNet) or multi-layered network deployments could be critical for operators to boost system capacity (per unit area). In order to extent the coverage region of open access LPNs and hence offload more traffics from macrocells, cell range expansion (CRE) strategy is suggested to apply in HetNets. However, when macrocells and LPNs share the same spectrum, the total network throughput could actually decrease due to CRE if the inter-layer interference couldn\'t be effectively managed. In this paper, we propose an inter-layer interference coordination scheme on the downlink side for an OFDMA co-channel macro-pico HetNet that carries out CRE technique. The idea of the proposed method is to coordinate frequency and power resources among macrocells and picocells with a set of resource allocation rules. Simulation results show that the proposed method can bring a significant increase in overall system capacity as well as reduce the user outage rate in the system, especially when aggressive CRE is applied.
Combined partial reuse and soft handover in OFDMA downlink transmission
(2008)
Chiu, Che-Sheng
;
Huang, Chia-Chi
;
電信工程研究所
;
Institute of Communications Engineering
The inter-cell interference problem is a key issue in a multi-cell OFDMA system. A number of inter-cell interference mitigation schemes have been suggested to address this problem and among them, partial reuse is considered a most promising one for emerging OFDMA systems. In this paper, we propose an inter-cell interference mitigation scheme for an OFDMA downlink system. The proposed scheme makes use of a combination of partial reuse and soft handover. The basic idea of the proposed scheme is to select the better signal quality among a partial reuse scheme and a soft handover scheme for the cell edge users. Compared to the conventional partial reuse scheme, simulation results show that the cell edge throughput can be significantly improved by using the proposed scheme. Furthermore, considering the data-rate fairness among the users, the results prove that our approach can give better average cell throughput as compared with the conventional partial reuse scheme, especially for a very fair system.