Multiuser Detection
Fundamentals of wireless communication
Fundamentals of wireless communication
Errorless codes for over-loaded CDMA with active user detection
ICC'09 Proceedings of the 2009 IEEE international conference on Communications
Random sequence multisets for synchronous code-division multiple-access channels
IEEE Transactions on Information Theory
Spectral efficiency of CDMA with random spreading
IEEE Transactions on Information Theory
Multiuser detection for overloaded CDMA systems
IEEE Transactions on Information Theory
Performance of DS-CDMA systems with optimal hard-decision parallel interference cancellation
IEEE Transactions on Information Theory
Multi-user detection for DS-CDMA communications
IEEE Communications Magazine
Extending the capacity of multiple access channels
IEEE Communications Magazine
Adaptive multistage parallel interference cancellation for CDMA
IEEE Journal on Selected Areas in Communications
Successive interference cancellation with SISO decoding and EM channel estimation
IEEE Journal on Selected Areas in Communications
Bounds on the sum capacity of synchronous binary CDMA channels
IEEE Transactions on Information Theory
Errorless codes for over-loaded CDMA with active user detection
ICC'09 Proceedings of the 2009 IEEE international conference on Communications
Constructing and decoding GWBE codes using Kronecker products
IEEE Communications Letters
| Hi-index | 754.90 |
In this paper, we introduce a new class of codes for overloaded synchronous wireless and optical code-division multiple-access (CDMA) systems which increases the number of users for fixed number of chips without introducing any errors. Equivalently, the chip rate can be reduced for a given number of users, which implies bandwidth reduction for downlink wireless systems. An upper bound for the maximum number of users for a given number of chips is derived. Also, lower and upper bounds for the sum channel capacity of a binary overloaded CDMA are derived that can predict the existence of such overloaded codes. We also propose a simplified maximum likelihood method for decoding these types of overloaded codes. Although a high percentage of the overloading factor degrades the system performance in noisy channels, simulation results show that this degradation is not significant. More importantly, for moderate values of Eb/N0 (in the range of 6-10 dB) or higher, the proposed codes perform much better than the binary Welch bound equality sequences.