Performance evaluation of an indoor ultra wideband channel for different pulse shape derivatives, path loss and modulation schemes | |
| Author | Mahfuz, Mohammad Upal |
| Call Number | AIT Thesis no.TC-05-6 |
| Subject(s) | Ultra-wideband devices Pulse modulation (Electronics) Digital communications |
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering, School of Engineering and Technology |
| Publisher | Asian Institute of Technology |
| Abstract | Ultra Wideband (UWB) communication systems are currently receiving a great deal of global attention because of its ability to provide higher data rate with low cost and relatively low power consumption. In this thesis, the indoor UWB radio channel characteristics are studied for three different schemes consisting of two different modulation methods, Pulse Position Modulation (PPM) and Bi-Phase Modulation (BPM) and two different multiple access techniques, Time Hopping (TH) and Direct Sequence (DS) multiple access methods. The effect of using higher order derivative pulses in UWB transmissions is studied. Considering the two-ray path loss model, the frequency dependence of relative dielectric constant of the reflecting surface has been included in the path loss behavior of UWB radios in indoor communications. The complete system is analyzed for various input pulse shapes based on higher order Gaussian derivative pulses, different data rates, different number of selective RAKE receiver arms, different pulse widths and finally, different detection methods in the receiver, named Hard Decision Detection (HDD) and Soft Decision Detection (SDD). Moreover, the performance of the system is examined in the presence of different Multiple User Interference (MUI) scenarios. Based on simulation results, the performance of TH-PPM, DS-BPM and TH-BPM systems are compared. Results show that higher order pulse derivatives have no significant influence on BER performance of any of TH-PPM, DS-BPM and TH-BPM systems. TH-PPM performs better in single user case, whereas TH-BPM shows an improved performance over DS-BPM. Results also show that the performance gap between minimum and maximum data rates in DS-BPM scheme is the smallest of all, suggesting that DS-BPM is the most robust scheme in presence of MUI. As system data rate requirement increases, BER performance degrades for all systems, showing an up-shift in BER curve. In TH-PPM scheme, increasing the number of selective RAKE arms provides reasonable gain in SNR, while the same does not give any mentionable advantage for DS-BPM and TH-BPM systems. The BER performance of different pulse widths was also studied for TH-PPM scheme. Finally, it has been concluded that TH-PPM system has performed comparatively better in single user case while DS-BPM and TH-BPM systems have performed better in the presence of MUI, and between them DS-BPM system is more robust in the presence of multiple user interference for UWB indoor communications. |
| Year | 2005 |
| Type | Thesis |
| School | School of Engineering and Technology (SET) |
| Department | Department of Information and Communications Technologies (DICT) |
| Academic Program/FoS | Telecommunications (TC) |
| Chairperson(s) | Ahmed, Kazi M. |
| Examination Committee(s) | Erke, Tapio J.;Rajatheva, R. M.A. P. |
| Scholarship Donor(s) | Asian Institute of Technology Fellowship & Government of France |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 2005 |