Optimal Relay Location in Multi-Hop Cellular Systems

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.

[1]  Mohamed-Slim Alouini,et al.  Digital Communication Over Fading Channels: A Unified Approach to Performance Analysis , 2000 .

[2]  J. Habetha,et al.  Performance Evaluation of HiperLAN / 2 Multihop Ad Hoc Networks , 2001 .

[3]  Li-Chun Wang,et al.  A Cross-Layer Investigation for the Throughput Performance of CSMA/CA-Based WLANs With Directional Antennas and Capture Effect , 2007, IEEE Transactions on Vehicular Technology.

[4]  Armin Wittneben,et al.  Impact of Cooperative Relays on the Capacity of Rank-Deficient MIMO Channels , 2006 .

[5]  Guoqing Li,et al.  On the capacity of broadband relay networks , 2004, Conference Record of the Thirty-Eighth Asilomar Conference on Signals, Systems and Computers, 2004..

[6]  Halim Yanikomeroglu,et al.  Induced Cooperative Multi-user Diversity Relaying for Multi-hop Cellular Networks , 2006, 2006 IEEE 63rd Vehicular Technology Conference.

[7]  R. Pabst,et al.  Capacity of a relaying infrastructure for broadband radio coverage of urban areas , 2003, 2003 IEEE 58th Vehicular Technology Conference. VTC 2003-Fall (IEEE Cat. No.03CH37484).

[8]  Harish Viswanathan,et al.  Performance of cellular networks with relays and centralized scheduling , 2005, IEEE Transactions on Wireless Communications.

[9]  Michael Gastpar,et al.  On the capacity of wireless networks: the relay case , 2002, Proceedings.Twenty-First Annual Joint Conference of the IEEE Computer and Communications Societies.

[10]  M. Kaveh,et al.  Combating shadowing effects for systems with transmitter diversity by using collaboration among mobile users , 2002 .

[11]  Halim Yanikomeroglu,et al.  Coverage enhancement through two-hop relaying in cellular radio systems , 2002, 2002 IEEE Wireless Communications and Networking Conference Record. WCNC 2002 (Cat. No.02TH8609).

[12]  Halim Yanikomeroglu,et al.  Relayer selection strategies in cellular networks with peer-to-peer relaying , 2003, 2003 IEEE 58th Vehicular Technology Conference. VTC 2003-Fall (IEEE Cat. No.03CH37484).

[13]  David Tse,et al.  Mobility increases the capacity of ad hoc wireless networks , 2002, TNET.

[14]  Peiying Zhu,et al.  Multi-hop Relay System Evaluation Methodology (Channel Model and Performance Metric) , 2007 .

[15]  Markus Herdin.  A Chunk Based OFDM Amplify-and-Forward Relaying Scheme for 4G Mobile Radio Systems , 2006, 2006 IEEE International Conference on Communications.

[16]  Gordon L. Stuber,et al.  Principles of mobile communication (2nd ed.) , 2001 .

[17]  Gerhard Fettweis,et al.  Relay-based deployment concepts for wireless and mobile broadband radio , 2004, IEEE Communications Magazine.

[18]  Niklas Johansson,et al.  Multiuser diversity forwarding in multihop packet radio networks , 2005, IEEE Wireless Communications and Networking Conference, 2005.

[19]  C. Ball,et al.  Rapid Estimation Method for Data Capacity and Spectrum Efficiency in Cellular Networks , 2005 .