Browsing by Author "Fu, I-Kang"

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An analysis on downlink capacity of multi-cell OFDMA systems under randomized inter-cell/sector interference
(2007)
Fu, I-Kang
;
Sheen, Wern-Ho
;
電信工程研究所
;
Institute of Communications Engineering
An analysis on downlink capacity of multi-cell OFDMA (orthogonal frequency division multiple access) systems is presented in this paper under a model of randomized multiple access interference, which is a result of applying random sub-carrier allocation among different cells/sectors. The analysis shows that the system capacity is either in the bandwidth-limited or power-limited region and that optimum tradeoff between capacity and coverage is achievable in a sense that given a required capacity the maximum coverage can be determined. The capacity is evaluated for different system setups, which are characterized by cell radius, reuse factor and types of antenna system with and without spatial division multiple access (SDMA). Three types of antenna are considered including omni-directional antenna, 3-sector antenna and switched-beam smart antenna. Numerical results show that the use of 3-sector and switched-beam smart antenna can enlarge the bandwidth-limited region and achieves a better capacity and coverage tradeoff.
Deployment and radio resource reuse in IEEE 802.16j multi-hop relay network in Manhattan-like environment
(2007)
Fu, I-Kang
;
Sheen, Wern-Ho
;
Ren, Fang-Ching
;
電信工程研究所
;
Institute of Communications Engineering
IEEE 802.16j is an amendment to the IEEE 802.16 broadband wireless access standard to enable the operation of multi-hop relay stations (RS). It aims to enhance the coverage, per user throughput and system capacity of IEEE 802.16e. Compared with base station (BS), RS does not need a wire-line backhaul and has much lower hardware complexity. Using RSs can significantly reduce the deployment cost of the system. In this paper, the RS deployment and radio-resource reuse strategies for IFEE 802.16j multi-hop relay (MR) networks are investigated. Simulation results show that the per-user throughput and system capacity of IEEE 802.16j MR network can be substantially improved by the proposed method.
Resource scheduling with directional antennas for multi-hop relay networks in Manhattan-like environment
(2007)
Lin, Shiang-Jiun
;
Sheen, Wern Ho
;
Fu, I-Kang
;
Huang, Chia-chi
;
電信工程研究所
Multi-hop relay (MR) networks have been proposed for user throughput improvement, coverage extension and/or capacity enhancement to the traditional mobile cellular networks. In particular, an MR network is being standardized by the IEEE 802.16j Task Group as an amendment to the IEEE 802.16e standard. This paper investigates the issue of resource scheduling for the IEEE 802.16j MR network in the Manhattan-like environment. New scheduling methods are proposed for the MR network with directional antennas equipped at both the base station and relay stations. Simulation results show that the system throughput can be dramatically increased by the proposed methods as compared to the system with omnidirectional antennas.