MIMO systems with multifunctional recon gurable antennas.
| dc.contributor.author | Afsheen, Uzma | |
| dc.date.accessioned | 2020-08-12T01:02:35Z | |
| dc.date.available | 2020-08-12T01:02:35Z | |
| dc.date.issued | 2019 | en |
| dc.description.abstract | This work presents a novel class of space time trellis codes based on super quasi-orthogonal space time codes for a reconfigurable multi-input multi-output antenna system. We call them space time state trellis codes (STSTCs). The motivation is to design a code that has all the good properties of the super orthogonal space time trellis codes, but can also extract the additional diversity gain offered by reconfigurable antennas. It is shown through simulations that the proposed code outperforms the existing super orthogonal space time trellis code, which fails to achieve full diversity in a reconfigurable antenna system. The proposed code is essentially a three dimensional trellis code, allowing us to code across space, time and reconfigurable antenna states. STSTCs achieve the diversity order expected of four transmit antennas while using only two reconfigurable transmit antennas. These codes have been designed for two and four trellis states and for two and four branch trellis structures for BPSK and QPSK constellations. The proposed STSTCs exploit the additional degrees of diversity offered by reconfigurable antennas and changing propagation states, achieving full rate, full diversity and high coding gain. This work also gives pairwise error probability performance analysis for the proposed STSTCs in a quasi- static Rayleigh fading channel. It is also shown through the analysis and simulations, that traditional minimum coding gain distance (CGD) is not adequate criteria for code design and that additional gains can be achieved by considering the minimum CGD of minimum return path (MRP). This work also gives a code design criteria which is based not only on minimum CGD of the parallel path, but also on the minimum CGD MRP, and have also given rank of the partial valid path and the performance factor. This provides additional gains without requiring the complete distance spectrum to be evaluated. This work also presents a reconfigurable antenna codebook feedback scheme to reduce precoding codebook loss without increasing the number of feedback bits. The reconfigurable antenna codebook feedback MIMO system proposed aims to achieve the performance of large codebook size (NC ) with the benefits of small NC . With limited codebook cardinality, it is impossible to find a codebook entry at zero distance from the corresponding channel values and a loss is incurred. Increasing the number of possible channel conditions instead of increasing the codebook size and hence the number of feedback bits, is the basis of our underlying approach towards minimizing the loss due to codebook mismatch. Increasing the number of possible channel conditions while having limited codebook cardinality, gives new degrees of freedom, such as reduced codebook or quantization loss and overall improvement in SNR due to increased channel power if the channel states are carefully selected. Analysis and simulations show that increasing the number of receive antenna states (S) has the same effect as codebook size expansion when the codeword and state selection is based on minimizing the distance between channel and codeword. In addition, an optimal selection approach (OA) is proposed. It maximizes both the channel power and the direction by carefully selecting the channel state and the codeword. This work also considers two more selection approaches called Channel Direction (CD) and Channel Power (CP), to investigate the source of the gains achieved in OA . The SNR and rates achieved with perfect feedback in a traditional non-reconfigurable antenna system, can be exceeded with only S = 2, using the proposed OA selection. We also find that doubling S gives approximately 40% SNR gain as compared to S = 1, using the proposed OA selection. The effects of imperfect CSI are also considered. | en |
| dc.identifier.uri | https://hdl.handle.net/10092/100884 | |
| dc.identifier.uri | http://dx.doi.org/10.26021/1090 | |
| dc.language | English | |
| dc.language.iso | en | |
| dc.publisher | University of Canterbury | en |
| dc.rights | All Right Reserved | en |
| dc.rights.uri | https://canterbury.libguides.com/rights/theses | en |
| dc.title | MIMO systems with multifunctional recon gurable antennas. | en |
| dc.type | Theses / Dissertations | en |
| thesis.degree.discipline | Electrical Engineering | en |
| thesis.degree.grantor | University of Canterbury | en |
| thesis.degree.level | Doctoral | en |
| thesis.degree.name | Doctor of Philosophy | en |
| uc.bibnumber | 2941386 | |
| uc.college | Faculty of Engineering | en |