Performance of cooperative uplink multicarrier CDMA system employing V-BLAST in frequency-selective rayleigh fading channels | |
| Author | Surachai Chieochan |
| Call Number | AIT Thesis no.TC-06-06 |
| Subject(s) | Code division multiple access MIMO systems |
| 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 |
| Series Statement | Thesis ; no. TC-06-06 |
| Abstract | In this thesis, a wireless system that mimics the scenario of the previously studied MIMO Multicarrier Code Division Multiple Access (MC-CDMA) system with Vertical Bell Laboratories Layered Space-Time (V-BLAST) and Multiuser Detection (MUD) is proposed and studied through simulation. In particular, the cooperative diversity technique is employed to allow single-antenna mobile terminals to communicate with a multiple-antenna destination terminal in such a manner that a virtual MIMO channel is formed to combat frequency-selective fading and to take advantage of the actual MIMO system. The simulation results show that the performance of the proposed system improves over that of the non-cooperative system at an 11 dB SNR or above, and approaches the performance of the MIMO counterpart as a degree of cooperation is increased through adaptivity of the protocols. In particular, only a 1 dB loss is observed at 10-3 BER while the performance is nearing the performance of the MIMO system. Given the same number of mobile terminals in the system, it is also found that the higher the number of relays per source, the better the system performance in terms of bit error rates, especially in the SNR region where cooperation is attractive. In particular, a 0.5 dB gain is acquired at 10-3 BER when 4 relays per source, instead of 2, are used to assist a 10.24 Mbps communication. The frame length also plays a crucial role in determining the system performance, and it is found that the shorter the frame length, the better the performance. Especially, a 1 dB gain is obtained at 10-3 BER when lowering the frame length from 64 to 32 bits. Further investigations on the effects of the number of receive antennas, the data rates, and the threshold levels reveal that an optimal value of each of these parameters exists for a particular setting of the system. Finally, it is observed that, no matter what type of cooperation protocols is used, the system with busy relays can never perform better than the system with idle relays |
| Year | 2006 |
| Corresponding Series Added Entry | Asian Institute of Technology. Thesis ; no. TC-06-06 |
| Type | Thesis |
| School | School of Engineering and Technology (SET) |
| 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.;Erke, Tapio J . ; |
| Scholarship Donor(s) | Royal Thai Government (RTG); |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 2006 |