Interference and performance analysis of filter-bank multicarrier modulation with precoding | |
| Author | Jayasinghe, Upul |
| Call Number | AIT Thesis no.TC-13-01 |
| Subject(s) | Modulation (Electronics) Multichannel communication Wireless communication systems |
| Note | A thesis submitted in partial fulfilment of the requirements for the degree of Master of Engineering in Telecommunications, School of Engineering and Technology |
| Publisher | Asian Institute of Technology |
| Series Statement | Thesis ; no. TC-13-01 |
| Abstract | The need for wireless services are on the exponential rise and the most parts of the wireless spectral resources have already been occupied. Therefore utilizing the remaining white spaces, in between already occupied spectrum is vital and in this regard multicarrier modulation( MCM) techniques have received great attention recently. MCM is used to avoid the frequency selective fading by dividing transmit signal with broader bandwidth in to several narrow band components and sending each of these components over separate carrier signals. Thereby it enhances the performance against frequency selective fading due to to multi path propagation as well as relative immunity to impulse noise. Furthermore, MCM reduces the inter symbol interference (ISI) as symbols are transmitted in a parallel manner. Currently, Orthogonal frequency division multiplexing (OFDM) is the most deployed version of multicarrier modulation technique, where number of parallel narrow band subcarriers are used to transmit a wideband data stream. It has been deployed in the industry for quite long time because of its robustness against impairments such as impulse noise and sudden channel fading than their single carrier counterparts. Also the implementation is relatively less complex as simple one tap equalizers can be used at each individual carrier in order equalize the channel. However in contrast to many advantages in OFDM, system it self has some drawbacks. Specially, rectangular pulses are used giving rise to orthogonality in the subcarrier domain and to avoid ISI guard bands or cyclic prefixes are needed which reduce the data rate and loss of spectral efficiency. If there are synchronization errors due to sync spectrum in subcarriers, there will be significant ICI. With the advent of MIMO systems this would be a significant challenge. In contrast to OFDM, filter bank multicarrier modulation scheme, also known as FBMC or OFDM/OQAM has received greater concern recently, due to its spectral efficiency compared to standard OFDM. Filter-bank systems are implemented with different pulse shapes with longer duration lasting several symbol durations. By careful design of prototype filters orthogonality conditions are maintained to a certain degree. This will make the spectral content more localized and there is also no need to have guard-bands as in OFDM and which save the spectrum significantly. However, intrinsic interference in FBMC causes a negative effect on the system performance depending on the channel condition. Therefore, in this research, interference in OFDM/OQAM systems is carefully analyzed and precoder based on signal to leakage plus noise ratio (SLNR) is introduced to overcome the effect of interference on the system when the channel is frequency selective. First the system is implemented in a more efficient way using inverse fast Fourier transform (IFFT). Then based on that model, the precoding matrix is generated. Finally through simulation and analysis, reduction of interference and improvement of performance are investigated. Later on investigated results are extend to MIMO-FBMC and more feasible structure with efficient beamforming scheme is implemented for multi user MIMO system in order to combat both multi-user interference as well intrinsic interference in FBMC modulation scheme. |
| Year | 2013 |
| Corresponding Series Added Entry | Asian Institute of Technology. Thesis ; no. TC-13-01 |
| 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. Premanandana; |
| Examination Committee(s) | Poompat Saengudomlert;Attaphongse Taparugssanagorn; |
| Scholarship Donor(s) | Thailand (HM King); |
| Degree | Thesis (M. Eng.) - Asian Institute of Technology, 2013 |