Browsing by Author "Su, Wen-Shan"

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Design of optimal relay location in two-hop cellular systems
(2010-11-01)
Huang, Jane-Hwa
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Wang, Li-Chun
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Chang, Chung-Ju
;
Su, Wen-Shan
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電信工程研究所
Relay stations are usually used to enhance the signal strength for the users near cell boundary, thereby extending the cell coverage. However, transmission through a relay station needs two transmission phases. The first phase is from base station to relay station, and the second one is from relay station to mobile station. Thus, using relay station may decrease system capacity due to two-phase transmission time. As a result, whether or not data are transmitted by one-hop or two-hop phases should be determined according to both signal strength and throughput. In this paper, we investigate the optimal relay location aiming to maximize system capacity. We consider two relay selection rules for determining whether two-hop transmission will be used: signal strength-oriented and throughput-oriented selection rules. We find that the signal strength-oriented two-hop transmission may yield even lower system capacity than the one-hop transmission. In the throughput-oriented scheme, the two-hop transmission can achieve higher system capacity than the one-hop transmission. By simulations, we determine the optimal relay location and show the coverage enhancement by the relaying network. Extensive simulations are performed to investigate the impacts of relay transmission power and the number of relay stations on system capacity and optimal relay location. The simulation results reveal important insights into designing a relaying network with high system capacity.
Optimal relay location in multi-hop cellular systems
(2008)
Wang, Li-Chun
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Su, Wen-Shan
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Huang, Jane-Hwa
;
Chen, Anderson
;
Chang, Chung-Ju
Relay stations (RSs) are usually used to enhance the signal strength for the users close to the cell boundary. However, transmission through a relay station needs two transmission phases, i.e., one is from the base station to the relay station and the other is from relay station to mobile stations. Thus, relay may also decrease system capacity if two phase transmission time is considered. As a result, whether or not data are transmitted by one hop or two hop transmission should be determined based on both signal strength and throughput. In this paper, we investigate the optimal relay location aiming to maximize system capacity. We consider two relay selection rules for determining whether a two hop transmission is necessary: signal strength oriented and throughput oriented. We find that the signal strength oriented two hop transmission may yield even lower system capacity than the one hop transmission. Based on the throughput oriented rule, we find that the throughput in the two hop transmission can be higher than that in the one hop transmission at some locations. We also identify the optimal relay location that can achieve the highest system capacity.