Title :
Binary-Code-Allocation Scheme in DS-CDMA Systems
Author :
Kwan, Ho Yuet ; Lok, Tat M.
Author_Institution :
Chinese Univ. of Hong Kong, Shatin
Abstract :
In this paper, we consider a simple binary-transmitter adaptation in direct-sequence code-division multiple-access systems. We propose a binary-code-allocation scheme for reducing the multiple-access interference (MAI). In this scheme, a user is given an orthogonal binary sequence set. By choosing a better sequence from the sequence set, the user can maximize his/her signal to interference ratio. We examine the scheme analytically by both exact analysis and approximation in equal-power synchronous cases. Theoretically, it is found that the scheme can significantly reduce the MAI. It only involves a few bits of feedback information for the transmitter to adjust the sequences. The scheme can also be modified for multiuser adaptation in asynchronous channels. In a multiuser adaptation, simulations show that the users would have a significantly improved performance against the MAI, and the system throughput can also be increased. It is shown that this binary-code-allocation scheme is a simple, widely applicable, and robust binary-sequence-adaptation scheme
Keywords :
3G mobile communication; binary codes; code division multiple access; interference suppression; mobile radio; radiofrequency interference; spread spectrum communication; DS-CDMA systems; MAI; asynchronous channels; binary-code-allocation scheme; binary-transmitter adaptation; direct-sequence code-division multiple-access systems; multiple-access interference reduction; multiuser adaptation; orthogonal binary-sequence-adaptation scheme; signal to interference ratio; Binary sequences; Decorrelation; Detectors; Feedback; Multiaccess communication; Multiple access interference; Robustness; Throughput; Transmitters; Wireless communication; Binary sequence adaptation; orthogonal sequence set;
Journal_Title :
Vehicular Technology, IEEE Transactions on
DOI :
10.1109/TVT.2006.883804