| Author | Pradhan, Arun Kumar |
| Call Number | AIT Thesis no.TC-99-1 |
| Subject(s) | Code division multiple access
|
| Note | A thesis submitted in partial fulfillment of the requirement for the degree of Master of Engineering.School of Advanced Technologies |
| Publisher | Asian Institute of Technology |
| Abstract | Parallel Concatenated Convolutional Codes (PCCCs), popularly termed as turbo
codes have been found to be a potential candidate for their use in future generation wideband
mobile radio communication systems. High data rate transmission required for the next
generation mobile radio systems causes the wideband signals to suffer from correlated
multipath fading. The performance. of turbo codes has been found to degrade significantly
with the increase in correlation. Their performance evaluation for moderate interleaving
delay with perfect channel estimation has proved its applicability for next generation higher
bit rate applications.
In this thesis, performance evaluation of turbo codes is carried out with a realistic
channel. Two channel estimation techniques, correlative estimation and recursive least square
(RLS) estimation, for downlink synchronous CDMA systems with BPSK modulation have
been incorporated in the Rake receiver. Performance of both estimation techniques has been
investigated and compared in a correlated fading environment.
Simulation results at low mobile speed show that performance of turbo codes with the
correlative channel estimation is comparable to the RLS estimation method where the
channel estimates are updated once every symbol interval. In such case, the performance loss
compared to the perfect case was found to be within 2 dB for the UMTS requirements of
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. It was also found that the RLS channel estimation with channel estimates
updated every chip interval perf01med quite near to the perfectly estimated case with a
difference of within 1 dB from the perfect case at lower mobile speed. Thus, turbo codes are
still found to be attractive even in the correlative channel with the above estimation
techniques where 2 dB performance loss can be accepted. |
| Year | 1999 |
| Type | Thesis |
| School | School of Advanced Technologies |
| Department | Department of Information and Communications Technologies (DICT) |
| Academic Program/FoS | Telecommunications (TC) |
| Chairperson(s) | Makelainen, Kimmo; |
| Examination Committee(s) | Ahmed, Kazi M.;Rajatheva, R.M.A.P.; |
| Scholarship Donor(s) | Government of Finland ; |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 1999 |