Low Complexity Greedy Power Allocation Algorithm for Proportional Resource Allocation in Multi-User OFDM Systems

Multi-User Orthogonal Frequency Division Multiplexing (MU-OFDM) is an efficient technique for achieving high downlink capacity in high-speed communication systems. A key issue in MU-OFDM is the allocation of the OFDM subcarriers and power to users sharing the channel. In this paper a proportional rate-adaptive resource allocation algorithm for MU-OFDM is presented. Subcarrier and power allocation are carried out sequentially to reduce the complexity. The low complexity proportional subcarriers allocation is followed by Greedy Power Allocation (GPA) to solve the rate-adaptive resource allocation problem with proportional rate constraints for MU-OFDM systems. It improves the work of Wong et al. in this area by introducing an optimal GPA that achieves approximate rate proportionality, while maximizing the total sum-rate capacity of MU-OFDM. It is shown through simulation that the proposed GPA algorithm performs better than the algorithm of Wong et al., by achieving higher total capacities with the same computational complexity, especially, at larger number of users and roughly satisfying user rate proportionality. Keywords—GPA, MU-OFDM, proportional resource allocation, sum-rate capacity.

[1]  Zhu Jinkang,et al.  An adaptive subcarrier allocation algorithm for multiuser OFDM system , 2003, 2003 IEEE 58th Vehicular Technology Conference. VTC 2003-Fall (IEEE Cat. No.03CH37484).

[2]  John M. Cioffi,et al.  A practical discrete multitone transceiver loading algorithm for data transmission over spectrally shaped channels , 1995, IEEE Trans. Commun..

[3]  Guocong Song,et al.  Adaptive subcarrier and power allocation in OFDM based on maximizing utility , 2003, The 57th IEEE Semiannual Vehicular Technology Conference, 2003. VTC 2003-Spring..

[4]  Srikrishna Bhashyam,et al.  A sub-optimal joint subcarrier and power allocation algorithm for multiuser OFDM , 2005, IEEE Communications Letters.

[5]  Kwang Bok Lee,et al.  Transmit power adaptation for multiuser OFDM systems , 2003, IEEE J. Sel. Areas Commun..

[6]  B.L. Evans,et al.  A low complexity algorithm for proportional resource allocation in OFDMA systems , 2004, IEEE Workshop onSignal Processing Systems, 2004. SIPS 2004..

[7]  Didem Kivanc-Tureli,et al.  Computationally efficient bandwidth allocation and power control for OFDMA , 2003, IEEE Trans. Wirel. Commun..

[8]  Guodong Zhang,et al.  Subcarrier and bit allocation for real-time services in multiuser OFDM systems , 2004, 2004 IEEE International Conference on Communications (IEEE Cat. No.04CH37577).

[9]  Robert F. H. Fischer,et al.  A new loading algorithm for discrete multitone transmission , 1996, Proceedings of GLOBECOM'96. 1996 IEEE Global Telecommunications Conference.

[10]  Alagan Anpalagan,et al.  Radio Resource Allocation Algorithms for the Downlink of Multiuser OFDM Communication Systems , 2009, IEEE Communications Surveys & Tutorials.

[11]  Jeffrey G. Andrews,et al.  Optimal power allocation in multiuser OFDM systems , 2003, GLOBECOM '03. IEEE Global Telecommunications Conference (IEEE Cat. No.03CH37489).

[12]  Hui Liu,et al.  An efficient multiuser loading algorithm for OFDM-based broadband wireless systems , 2000, Globecom '00 - IEEE. Global Telecommunications Conference. Conference Record (Cat. No.00CH37137).

[13]  Abbas Jamalipour,et al.  Wireless communications , 2005, GLOBECOM '05. IEEE Global Telecommunications Conference, 2005..

[14]  Christian Lüders,et al.  Theory and Applications of OFDM and CDMA: Wideband Wireless Communications , 2005 .

[15]  Stephan Weiss,et al.  Greedy power allocation for multicarrier systems with reduced complexity , 2010 .

[16]  Geoffrey Ye Li,et al.  Cross-layer optimization for OFDM wireless networks-part II: algorithm development , 2005, IEEE Transactions on Wireless Communications.

[17]  Tommy Svensson,et al.  Towards Systems Beyond 3G Based on Adaptive OFDMA Transmission , 2007, Proceedings of the IEEE.

[18]  Khaled Ben Letaief,et al.  Multiuser OFDM with adaptive subcarrier, bit, and power allocation , 1999, IEEE J. Sel. Areas Commun..

[19]  John M. Cioffi,et al.  Increase in capacity of multiuser OFDM system using dynamic subchannel allocation , 2000, VTC2000-Spring. 2000 IEEE 51st Vehicular Technology Conference Proceedings (Cat. No.00CH37026).