| Author | Ta Tri Nghia |
| Call Number | AIT Thesis no.TC-99-3 |
| Subject(s) | Code division multiple access
|
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering. School of Advanced Technologies |
| Publisher | Asian Institute of Technology |
| Abstract | In CDMA systems, multiuser receivers were designed to mitigate the effect on the
desired user of interference from other users that shared the same channel. In practical
systems, since complexity is the main obstacle of these receivers, trade off between their
performance and complexity should be considered. Due to the lower complexity, subtractive
interference cancellation approaches are attractive for practical implementation. In this thesis,
the performance of a multiuser receiver for a convolutional coded asynchronous CDMA
system is evaluated. In the receiver, a partial parallel interference canceller is used to combat
the multiple access interference (MAI). An approach used to calculate the weighting factors
for the canceller is proposed by minimizing the Euclidean distance between the actual
received signal and its estimate. Moreover, an iterative algorithm based on maximum a
posteriori (MAP) criteria is also used to improve the performance of the receiver.
The performance of the receiver over AWGN, frequency-flat Rayleigh fading and
frequency-selective Rayleigh fading channels is evaluated. Comparisons are also made with
the receivers using classical parallel interference cancellation (PIC) and constant-weightingfactor partial PIC. Simulation results show that this receiver outperforms the receivers using
classical PIC and constant-weighting-factor partial PIC. Especially, its performance has a
significant improvement over that of the above receivers in high loading system at the low
BER region. |
| Year | 1999 |
| Type | Thesis |
| School | School of Advanced Technologies |
| Department | Department of Information and Communications Technologies (DICT) |
| Academic Program/FoS | Telecommunications (TC) |
| Chairperson(s) | Rajatheva, R.M.A.P.; |
| Examination Committee(s) | Ahmed, Kazi M.;Makelainen, Kimmo; |
| Scholarship Donor(s) | ADB, Japan; |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 1999 |