Chen He | University of Illinois at Urbana-Champaign (original) (raw)
Address: Urbana, Illinois, United States
less
Uploads
Papers by Chen He
Iee Proceedings-control Theory and Applications, 1998
The ANN a-th order inverse system is composed of a single static artificial neural network and se... more The ANN a-th order inverse system is composed of a single static artificial neural network and several integrators. By combining the a-th order inverse system with an additional linear controller designed according to conventional theory of linear continuous systems, a composite control method is formed and the effective control of the original system can be completed. Simulation results show that this method applies to general linear or nonlinear continuous systems, with simple construction of the controller for easy implementation.
Recent successes in the development and self-assembly of nanoelectronic devices suggest that the ... more Recent successes in the development and self-assembly of nanoelectronic devices suggest that the ability to manufacture dense nanofabrics is on the near horizon. However, the tremendous increase in device density of nanoelectronics will be accompanied by a substantial increase in hard and soft faults, posing a major challenge to current design methodologies and tools. In this paper we propose a novel probabilistic design paradigm for defective but reconfigurable nanofabrics. The new design goal is to devise an appropriate structural/behavioral decomposition which improves scalability by constraining the reconfiguration process, while meeting a desired probability of successful instantiation, i.e, yield. Our approach not only addresses the scalability problem in configuring dense nanofabrics subject to defects, but gives a rich framework in which critical trade-offs among performance, yield, and per chip cost can be explored. We present a concrete instance of the approach and show extensive experimental results supporting these claims.
The 4G wireless communication system is envisioned to integrate cellular network (e.g. UMTS) and ... more The 4G wireless communication system is envisioned to integrate cellular network (e.g. UMTS) and wireless LAN (WLAN), in virtue of the individual coverage and capacity complementary characteristics. This paper describes a possible architecture integrating UMTS and 802.11 WLAN at SGSN. A functional entity, network interwork unit (NIU), is placed between the SGSN and WLAN access network side to hide the WLAN particularities. In this integrated architecture, mobile IP based vertical handover management increases the heterogeneous system signaling cost as well as handover latency, so one major task in the handover design is to reduce the unnecessary handover probability. This paper presents an analytical vertical handover initiation model based on the criteria of received signal strength (RSS) and distance. The handover performance evaluation criterion of interest is the handover probability. The numerical results show that our model is in line with the real cases when the distance between the base station (BS) of UMTS cell and the access point (AP) of WLAN is long or not.
In this paper, a novel interference coordination scheme based softer frequency reuse (SerFR) to m... more In this paper, a novel interference coordination scheme based softer frequency reuse (SerFR) to mitigate inter-cell interference in Orthogonal Frequency Division Multiple Access (OFDMA) cellular systems is presented. In OFDMA systems, inter-cell interference is the most important interference source. Inter-cell interference coordination is considered to improve coverage and increase date rate at cell edge. Soft Frequency Reuse (SFR) interference coordination
Multiantenna wireless systems have shown great promise in achieving high rates. We consider an OF... more Multiantenna wireless systems have shown great promise in achieving high rates. We consider an OFDM multiple transmit/receive antenna system. We propose a linear non-redundant block precoding scheme, that is applied at the input of the OFDM system. The coding spreads the symbols of each user over all subcarriers, thus increasing multipath diversity, and at the same time introduces some structure to the transmitted symbols, which can be exploited at the receiver to estimate the channel within a complex scalar ambiguity. The precoding does not increase power. 0-7803-7997-7/03/$17.00
Iee Proceedings-control Theory and Applications, 1998
The ANN a-th order inverse system is composed of a single static artificial neural network and se... more The ANN a-th order inverse system is composed of a single static artificial neural network and several integrators. By combining the a-th order inverse system with an additional linear controller designed according to conventional theory of linear continuous systems, a composite control method is formed and the effective control of the original system can be completed. Simulation results show that this method applies to general linear or nonlinear continuous systems, with simple construction of the controller for easy implementation.
Recent successes in the development and self-assembly of nanoelectronic devices suggest that the ... more Recent successes in the development and self-assembly of nanoelectronic devices suggest that the ability to manufacture dense nanofabrics is on the near horizon. However, the tremendous increase in device density of nanoelectronics will be accompanied by a substantial increase in hard and soft faults, posing a major challenge to current design methodologies and tools. In this paper we propose a novel probabilistic design paradigm for defective but reconfigurable nanofabrics. The new design goal is to devise an appropriate structural/behavioral decomposition which improves scalability by constraining the reconfiguration process, while meeting a desired probability of successful instantiation, i.e, yield. Our approach not only addresses the scalability problem in configuring dense nanofabrics subject to defects, but gives a rich framework in which critical trade-offs among performance, yield, and per chip cost can be explored. We present a concrete instance of the approach and show extensive experimental results supporting these claims.
The 4G wireless communication system is envisioned to integrate cellular network (e.g. UMTS) and ... more The 4G wireless communication system is envisioned to integrate cellular network (e.g. UMTS) and wireless LAN (WLAN), in virtue of the individual coverage and capacity complementary characteristics. This paper describes a possible architecture integrating UMTS and 802.11 WLAN at SGSN. A functional entity, network interwork unit (NIU), is placed between the SGSN and WLAN access network side to hide the WLAN particularities. In this integrated architecture, mobile IP based vertical handover management increases the heterogeneous system signaling cost as well as handover latency, so one major task in the handover design is to reduce the unnecessary handover probability. This paper presents an analytical vertical handover initiation model based on the criteria of received signal strength (RSS) and distance. The handover performance evaluation criterion of interest is the handover probability. The numerical results show that our model is in line with the real cases when the distance between the base station (BS) of UMTS cell and the access point (AP) of WLAN is long or not.
In this paper, a novel interference coordination scheme based softer frequency reuse (SerFR) to m... more In this paper, a novel interference coordination scheme based softer frequency reuse (SerFR) to mitigate inter-cell interference in Orthogonal Frequency Division Multiple Access (OFDMA) cellular systems is presented. In OFDMA systems, inter-cell interference is the most important interference source. Inter-cell interference coordination is considered to improve coverage and increase date rate at cell edge. Soft Frequency Reuse (SFR) interference coordination
Multiantenna wireless systems have shown great promise in achieving high rates. We consider an OF... more Multiantenna wireless systems have shown great promise in achieving high rates. We consider an OFDM multiple transmit/receive antenna system. We propose a linear non-redundant block precoding scheme, that is applied at the input of the OFDM system. The coding spreads the symbols of each user over all subcarriers, thus increasing multipath diversity, and at the same time introduces some structure to the transmitted symbols, which can be exploited at the receiver to estimate the channel within a complex scalar ambiguity. The precoding does not increase power. 0-7803-7997-7/03/$17.00