Adaptive power allocation for Decode-and-Forward OFDM transmission with multi-hop relaying

We investigated the adaptive power allocation in an point-to-point orthogonal frequency Division multiplexing (OFDM) cooperative system subject to the individual power constraint with an objective of maximize the sum transmission rate, and derived the optimal power allocation by assuming independent and identically distributed (i.i.d.) sub-channels in each Decode-and-Forward (DF) relay. To improve the wireless coverage, we extended the conventional two-hop system model to a three-hop structure without considering the effect of inter-relay interference. The structure can effectively overcome the transmission bottleneck in the conventional two-hop system. This paper also considered relay selection for the proposed cooperative transmission. In other words, depending on the quality of the sub-channels, each relay decides whether to forward data itself. The simulation results shows that the sum rate of the proposed algorithm monotonically increases with the increasing of both the power of each node and sub-channel numbers. Numerical results prove the goodness of the three-hop model in terms of sum rate and validate the proposed theoretical analysis.

[1]  Mahtab Mirmohseni,et al.  Compress-and-forward strategy for relay channel with causal and non-causal channel state information , 2010, IET Commun..

[2]  Wei Yu,et al.  Dual methods for nonconvex spectrum optimization of multicarrier systems , 2006, IEEE Transactions on Communications.

[3]  W. Wang,et al.  Proportional fair-based joint subcarrier and power allocation in relay-enhanced orthogonal frequency division multiplexing systems , 2010, IET Commun..

[4]  Meixia Tao,et al.  Joint subcarrier-relay assignment and power allocation for decode-and-forward multi-relay OFDM systems , 2009, 2009 Fourth International Conference on Communications and Networking in China.

[5]  Chintha Tellambura,et al.  Improved OFDMA Uplink Transmission via Cooperation in the Presence of Frequency Offsets , 2008, IEEE GLOBECOM 2008 - 2008 IEEE Global Telecommunications Conference.

[6]  Andrew R. Nix,et al.  Resource Allocation Techniques for OFDMA-Based Decode-and-Forward Relaying Networks , 2008, VTC Spring 2008 - IEEE Vehicular Technology Conference.

[7]  Wenbo Wang,et al.  Subcarrier Allocation for OFDMA Relay Networks with Proportional Fair Constraint , 2009, 2009 IEEE International Conference on Communications.

[8]  Hsuan-Jung Su,et al.  Joint Subcarrier Pairing and Power Allocation for OFDM Transmission With Decode-and-Forward Relaying , 2010, IEEE Transactions on Signal Processing.

[9]  Jianwei Huang,et al.  Downlink Scheduling and Resource Allocation for OFDM Systems , 2006 .

[10]  Wu Tong,et al.  Power Allocation and Subcarrier Pairing Algorithm for Regenerative OFDM Relay System , 2007, 2007 IEEE 65th Vehicular Technology Conference - VTC2007-Spring.

[11]  Feifei Gao,et al.  Resource Allocation for Relay Aided Uplink Multiuser OFDMA System , 2010, 2010 IEEE Wireless Communication and Networking Conference.

[12]  Chintha Tellambura,et al.  Communication Theory Improved OFDMA uplink transmission via cooperative relaying in the presence of frequency offsets - Part I: Ergodic information rate analysis , 2009, Eur. Trans. Telecommun..

[13]  Keping Long,et al.  On Swarm Intelligence Inspired Self-Organized Networking: Its Bionic Mechanisms, Designing Principles and Optimization Approaches , 2014, IEEE Communications Surveys & Tutorials.

[14]  Armin Wittneben,et al.  On the Optimal Power Allocation for Nonregenerative OFDM Relay Links , 2006, 2006 IEEE International Conference on Communications.

[15]  Yi Huang,et al.  Asymmetric Resource Allocation for Decode-and-Forward Multi-Relay Systems , 2011, 2011 7th International Conference on Wireless Communications, Networking and Mobile Computing.

[16]  Vijay K. Bhargava,et al.  Optimal and Suboptimal Power Allocation Schemes for OFDM-based Cognitive Radio Systems , 2008, IEEE Transactions on Wireless Communications.

[17]  Wei Zhang,et al.  Cooperative OFDM Channel Estimation in the Presence of Frequency Offsets , 2009, IEEE Transactions on Vehicular Technology.

[18]  Wei Zhang,et al.  OFDMA uplink frequency offset estimation via cooperative relaying , 2009, IEEE Transactions on Wireless Communications.

[19]  Sae-Young Chung,et al.  Transmit Optimization for Relay-Based Cellular OFDMA Systems , 2007, 2007 IEEE International Conference on Communications.

[20]  Jia Guo,et al.  Dynamic Subchannel and Power Allocation in OFDMA-Based DF Cooperative Relay Networks , 2008, IEEE GLOBECOM 2008 - 2008 IEEE Global Telecommunications Conference.

[21]  Yi Gong,et al.  Cooperative OFDM Relaying for Opportunistic Spectrum Sharing: Protocol Design and Resource Allocation , 2012, IEEE Transactions on Wireless Communications.

[22]  Fan Zhang,et al.  Resource Allocation for Delay Differentiated Traffic in Multiuser OFDM Systems , 2008, IEEE Trans. Wirel. Commun..