Superposition Coding with Unequal Error Protection for the Uplink of Overloaded DS-CDMA System
详细信息 查看全文
- 作者：Yaseen H. Tahir (1) yalhasan@yahoo.com
Chee Kyun Ng (1) mpnck@eng.upm.edu.my
Nor K. Noordin (1) nknordin@eng.upm.edu.my
Borhanuddin Mohd. Ali (1) borhan@eng.upm.edu.my
Sabira Khatun (2) sabira@ump.edu.my - 关键词：Overloaded CDMA – ; Superposition coding – ; Multiuser receiver – ; Successive interference cancellation – ; UEP
- 刊名：Wireless Personal Communications
- 出版年：2012
- 出版时间：August 2012
- 年：2012
- 卷：65
- 期：3
- 页码：567-582
- 全文大小：729.6 KB
- 参考文献：1. Ng C. K., Noordin N. K., Ali B. M., Jamuar S. S., Ismail M. (2010) Spectrum efficiency enhancement in dynamic space coded multiple access (DSCMA) system. Wireless Personal Communications 53(2): 253–267
2. Welch L. (1974) Lower bounds on the maximum cross correlation of signals. IEEE Transactions on Information Theory 20(3): 397–399
3. Vanhaverbeke F., Moeneclaey M. (2003) Critical load of oversaturated systems with multistage successive interfernce cancellation. Proceedings of IEEE VTC 4: 2663–2666
4. Preetam K., Saswat C. (2008) OCDMA/OCDMA overloading scheme for cellular DS-CDMA using orthogonal gold codes and complex scrambling. IJ Communications Network and System Sciences 3: 207–283
5. Vanhaverbeke F., Moeneclaey M., Sari H. (2002) DS/CDMA with two sets of orthogonal spreading sequences and iterative detection. IEEE Communications Letters 4(9): 289–291
6. Vanhaverbeke F., Moeneclaey M. (2005) An improved overloading scheme for downlink CDMA. EURASIP Journal on Applied Signal Processing 5: 604–610
7. Kamar P., Chakrabarti S. (2010) Overloading scheme for cellular DS-CDMA using quasi-orthogonal sequences and iterative interference cancellation receiver. International Journal of Signal Processing 6(1): 50–55
8. Ali F. H, Honary B. (1994) Collaborative coding and decoding techniques for multiple access channels. IEE Proceedings Communications 141(2): 56–62
9. Ali F. H., Shakya I., Stipidis E. (2010) Collaborative spreading for the downlink of overloaded CDMA. Wiley Wireless Communications and Mobile Computing 10(3): 383–393
10. Bergmans P., Cover T. (1974) Cooperative broadcasting. IEEE Transactions on Information Theory 20(3): 317–324
11. Cover T. (1972) Broadcast channels. IEEE Transactions on Information Theory 18(1): 2–14
12. Cover, T. (October 1998). Comments on broadcast channels. IEEE Transactions on Information Theory, 44(6), 2524–2530.
13. Tahir, Y. H., Al-Hussaibi, W., Ng, C. K., Noordin, N. K., & Al-Hemyari, A. (December 2008). Unequal error protection for wireless data transmission using superposition coding with feedback. In Proceeding of the IEEE international conference on innovations in information technology (pp. 426–429). IEEE Xplore Press, USA.
14. Tahir Y. H., Ng C. K., Noordin N. K., Ali B. M., Khatum S. (2009) Unequally error protected wireless data transmission using channel state information and adaptive encoders. Computer Science 5(12): 1095–1100
15. Cronie, H. S. (June 2007). Superposition coding for power- and bandwidth efficient communication over the Gaussian channel. In Proceeding of the IEEE international symposium on information theory (pp. 2311–2316) IEEE Xplore Press, USA.
16. Al-Regib, G., Yucel, A., & Jarek, R. (May 2002). An unequal error protection method for progressively compressed 3-D meshes. In ICASSP’02 IEEE international conference, vol. 2 (pp. 2041–2044).
17. Karabulut G., Yongacoglu A. (2003) Superposition block coded modulation. IEEE CCECE 3: 1629–1632
18. Karabulut G., Yongacoglu A. (2004) Rate design rule for superposition coded modulation. IEEE CCECE 1: 365–368
19. Tse D., Viswanath P. (2005) Fundamentals of wireless communication. Cambridge University Press, Cambridge
20. Verd’u, S. (Aug. 1984). Optimum multiuser signal detection, Ph.D. Thesis, University of Illinois, Urbana-Champaign.
21. Verd’u S. (1986) Minimum probability of error for asynchronous Gaussian multiple-access channels. IEEE Transactions on Information Theory 32(1): 85–96 - 作者单位：1. Department of Computer and Communication Systems Engineering, Faculty of Engineering, Universiti Putra Malaysia, Serdang, Malaysia2. Faculty of Computer System and Software Engineering, Universiti Malaysia Pahang, Kuantan, Malaysia
- ISSN：1572-834X
文摘
The overloaded CDMA schemes exploited in direct sequence CDMA (DS-CDMA) systems are mainly to accommodate a greater number of users than the available spreading factor N. In this paper, a superposition coding CDMA (SPC-CDMA) with unequal error protection (UEP) is proposed as one of the overloaded CDMA schemes for the next generation mobile communication systems. It exploits the available power control in most base stations to adapt the transmitted power of active users in the uplink channel. In this scheme, the active users are divided into G groups and each group consists of K users. The K users share the same spreading sequence and are distinguished by different received power levels. At the receiver side, the system first performs despreading for group detection followed by multiuser receiver to estimate the K user signals in each group. It is shown through simulations that better performance are achieved compared to the conventional DS-CDMA and existing overloaded collaborative spreading CDMA (CS-CDMA) schemes, in additive white Gaussian noise (AWGN) and fading channels. Hence, the proposed scheme maximizes the system capacity K-fold compared to conventional DS-CDMA system without requiring extra spreading codes, with average signal to noise ratio (SNR) cost of only 1dB and 2 dB over AWGN and fading channels respectively at BER of 10−3. On the other hand, for the same N, K and power constraints, SPC-CDMA scheme achieves twofold increase in data rate with 0.7 and 4 dB gains over AWGN and fading channels respectively, compared with overloaded CS-CDMA scheme in the same system capacity. In addition, the proposed scheme can also attain different levels of UEP for different users’ requirements by adjusting their fractions of transmitted powers.