Application of Superposition Coding for Subcarrier and Bit Allocation in Downlink OFDM Systems

Orthogonal frequency division multiplexing (OFDM) is well known for multicarrier modulation technique in which a high data rate stream is divided into different parallel lower data stream. In this paper, we study the margin adaptive - superposition coding (MA-SC) algorithm and rate adaptive - superposition coding (RA-SC) algorithm, where at most two user can share each subcarrier as compared to MA and RA algorithm, where each subcarrier is shared by only single user without SC scheme. We apply SC scheme over MA and RA to achieve maximum system throughput with separate power constraint for real and non real time users, ensuring that QoS requirement for real time and proportional fairness among non real time users is satisfied. The overall computational complexity of proposed modified RA-SC algorithm is same as RA algorithm. In the modified proposed MA-SC, complexity increases in some of the steps due to addition of SC scheme over MA algorithm, but overall complexity remains the same. Monte-Carlo simulations are being carried out to show that the proposed algorithm improves the performance in terms of power required and throughput.

[1]  Guanding Yu,et al.  Adaptive subcarrier and bit allocation in OFDMA systems supporting heterogeneous services , 2007, Wirel. Pers. Commun..

[2]  Yan Chen,et al.  Subcarrier and bit allocation for OFDMA systems with proportional fairness , 2006, IEEE Wireless Communications and Networking Conference, 2006. WCNC 2006..

[3]  Anis Jdidi,et al.  Resource allocation algorithm in downlink of OFDMA systems based on users' classification and superposition coding , 2009, 2009 3rd International Conference on Signals, Circuits and Systems (SCS).

[4]  Wei Wang,et al.  Resource allocation for heterogeneous services in multiuser OFDM systems , 2004, IEEE Global Telecommunications Conference, 2004. GLOBECOM '04..

[5]  Qinghe Du,et al.  Effective Capacity of Superposition Coding Based Mobile Multicast in Wireless Networks , 2009, 2009 IEEE International Conference on Communications.

[6]  A. Bouallegue,et al.  Greedy Algorithm for Dynamic Resource Allocation in Downlink of OFDMA System , 2005, 2005 2nd International Symposium on Wireless Communication Systems.

[7]  Chi-Ying Tsui,et al.  A real-time sub-carrier allocation scheme for multiple access downlink OFDM transmission , 1999, Gateway to 21st Century Communications Village. VTC 1999-Fall. IEEE VTS 50th Vehicular Technology Conference (Cat. No.99CH36324).

[8]  A. Bouallegue,et al.  A simple watermarking system , 2004, First International Symposium on Control, Communications and Signal Processing, 2004..

[9]  Yan Chen,et al.  A Novel Resource Allocation Algorithm for Real-time Services in Multiuser OFDM Systems , 2006, 2006 IEEE 63rd Vehicular Technology Conference.

[10]  Hichem Besbes,et al.  A Simple Superposition Coding Scheme for Optimizing Resource Allocation in Downlink OFDMA Systems , 2011, Wirel. Pers. Commun..

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

[12]  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..