Browse > Article

Sub-band Spreading Technique for Adaptive Modulation in OFDM Systems  

Jung, Bang-Chul (KAIST Institute for Information Technology Convergence)
Kwon, Jae-Kyun (School of Electrical Engineering and Computer Science, Yeungnam University)
Jin, Hu (School of Electrical Engineering and Computer Science, KAIST)
Sung, Dan-Keun (School of Electrical Engineering and Computer Science, KAIST)
Publication Information
Journal of Communications and Networks / v.10, no.1, 2008 , pp. 71-78 More about this Journal
Abstract
We propose a sub-band spreading technique for adaptive modulation (AM) in orthogonal frequency division multiplexing (OFDM) systems in order to reduce signaling overheads and to average frequency selective fading channels causing different signal-to-noise ratio (SNR) values for subcarriers in each subband. The conventional sub-band based AM schemes can also reduce signaling overheads and complexity for allocating a resource per sub-band at a time. However, they may suffer from the channel variation in a sub-band when the sub-band size is larger than the channel coherence bandwidth (BW). The sub-band spreading at the transmitter enables the received symbols in each sub-band to have an identical reliability even in a frequency selective fading channel. We rigorously analyze the averaged SNR value at the receiver of the sub-band spreading system and the analyzed average SNR in a sub-band is used for an adaptation criterion. The proposed AM scheme outperforms the conventional sub-band based OFDM scheme without spreading, and it can yield better throughput performance than the conventional subcarrier based AM schemes when we consider the signaling overheads.
Keywords
Adaptive modulation (AM); orthogonal frequency division multiplexing (OFDM); sub-band spreading;
Citations & Related Records

Times Cited By Web Of Science : 0  (Related Records In Web of Science)
Times Cited By SCOPUS : 0
연도 인용수 순위
  • Reference
1 IEEE, P802.16-REVd/D5, 'Part 16:Air interface for fixed broadband wireless access systems,' May 2004
2 H. Atarashi, S. Abeta, and M. Sawahashi, 'Variable spreading factororthogonal frequency and code division multiplexing (VSF-OFCDM) for broadband packet wireless access,' IEICE Trans. Commun., vol. E86-B, no. 1, pp. 291-299, Jan. 2003
3 T. Keller and L. Hanzo, 'Adaptive multicarrier modulation: A convenient frame work for time-frequency processing in wireless communications,' Proc. IEEE, vol. 88, no.5, pp. 611-640, May 2000.   DOI   ScienceOn
4 K. Fazel and S. Kaiser, Multi-Carrier and Spread Spectrum Systems. Wiley, 2003
5 B. McNair, L. J. Cimini, Jr., and N. R. Sollenberger,'Performance of an experimental 384 kb/s 1900 MHz OFDM radio link in a wide-areae highmobility environment,' in Proc. IEEE VTC 2001-fall, Oct. 2001, pp. 475- 478
6 3GPP, TR 25.814, 'Physical layer aspects for evolved UTRA (release 7),' Nov. 2005
7 J. A. C. Bingham, 'Multicarrier modulation for data transmission: An idea whose time has come,' IEEE Commun. Mag, vol. 28, no.4, pp. 5-14, Apr. 1990   DOI   ScienceOn
8 R. F. H. Fischer, J. B. Huber, 'A new loading algorithm for discrete multitone transmission,' in Proc. IEEE GLOBECOM, Nov. 1996, pp. 724-728
9 M. Lei and P. Zhang, 'Subband bit and power loading for adaptive OFDM,' in Proc. IEEE VTC 2003-fall, vol. 3, Oct. 2003, pp. 1482-1486
10 B. S. Krongold, K. Ramchandran, and D. L. Jones, 'Computationally efficient optimal power allocation algorithms for multicarrier communication systems,' IEEE Trans. Commun, vol. 48, no. 1, pp. 23-27, Jan. 2000   DOI   ScienceOn
11 N. Maeda, H. Atarashi, and M. Sawahashi, 'Performance comparison of channel interleaving methods in frequency domain for VSF-OFCDM broadband wireless access in forward link,' IEICE Trans. Commun., vol. E86-B, no. 1, pp. 300-313, Jan. 2003
12 D. Hughes-Hartogs, 'Ensemble modem structure for imperfect transmission media,' U.S. Patents Nos., 4,679,227, July 1987; 4,731,816, Mar. 1988; and 4,833,796, May 1989
13 H. Steendam and M. Moeneclaey, 'Analysis and optimization of the performance of OFDM on frequency-selective time-selective fading channels,' IEEE Trans. Commun., vol. 47, pp.1811-1819, Dec. 1999   DOI   ScienceOn
14 T. Hishiyama, T. Shirai, M Itami, K. Itoh, and H. Aghvami, 'A study on controlling transmission power of carriers of OFDM signal combined with data symbol spreading in frequency domain,' IEICE Trans. Fundament., vol. E86-B, no. 8, pp. 2117-2124, Aug. 2003
15 P. S. Chow, J. M. Cioffi, and J. A. C. Bingham, 'A practical discrete transceiver loading algorithm for data transmission over spectrally shaped channels,' IEEE Trans. Commun, vol. 43, no.2/3/4, pp. 773-775, Feb./ Mar./Apr. 1995   DOI   ScienceOn
16 R. Van Nee and R. Prasad, OFDM for Wireless Multimedia Communications. Artech House Publishers, 2000
17 B. C. Jung, M. H. Sunwoo, and S. K. Oh, 'A new turbo-coded OFDM system using orthogonal code multiplexing,' in Proc. IEEE VTC 2002- spring, May. 2002, pp. 1448-1451
18 R. G. Gallager, Information Theory and Reliable Communication. New York: John Wiley & Sons, 1968