Efficient transmission design for machine type communications in future wireless communication systems

With a wide range of potential applications, the machine typ e communication (MTC) is gaining a tremendous interest among mobile network operators, s ystem designers, MTC specialist companies, and research institutes. The idea of having elec troni devices and systems automatically connected to each other without human interventi on is one of the most significant objectives for future wireless communications. Low data ra e transmission and the requirement for low energy consumption are two typical characteristics for MTC applications. In terms of supporting low cots MTC devices, industrial standards will be more efficient if designers can re-use many features of existing radio access technologies . Thi will yield a cost effective solution to support MTC in future communication systems. This th esis investigates efficient MTC waveform and receiver designs for superior signal transmis sion quality with low operational costs. In terms of the downlink receiver design, this thesis propos es a novel virtual carrier (VC) receiver system for MTC receivers, which aims to reduce the max i um bandwidth to improve the data processing efficiency and cost-efficiency by using a nalogue filters to extract only subcarriers of interest. For the VC receiver systems, we thus re duc the sampling rate in order to reduce the number of subsequent processing operations, w hich significantly reduces the analogue-to-digital converter (ADC) cost and power consum ption while providing high signal to interference noise ratio (SINR) and low bit to error ra te (BER) to support low data rate MTC devices. Our theoretical equations account for the inte rfer nce effect of aliasing on the sub-carrier location, and this helps the system designer to valuate what kind of filters and receiver sampling rate can be used to balance the energy cost and detection performance. In terms of the uplink waveform design, considering the enha nced number of MTC devices in the future communication systems, i.e. the fifth generati on (5G) communications, the same tight synchronisation as used in today appears not to be cost -effective or even possible. Synchronisation signals, which aim to provide a perfect time or frequency synchronisation in the current fourth generation (4G) communication systems (kno wn as the long-term evolution, LTE), is much more costly for low data rate MTC transmissions . The system bandwidth will be significantly reduced if a base station tries to synchronise all received signals among hundreds or thousands MTC devices in one transmission time period. In terms of relaxing the synchronisation requirements, this thesis compares and analyses t he side-lobe reduction performance for several candidate multi-carrier waveforms to avoid the se problems. We also propose the infinite impulse response universal filtered multi-carrier (UFMC) system and the overlap and add UFMC system, which significantly reduce the processing c omplexity compared with the state of the art UFMC techniques. This thesis derives closed -form expressions for the interference caused by time offsets between adjacent unsynchron ised MTC users. Our analytical equations can be used in both simple and complex time-offset transmission scenarios, and enable the system designer to evaluate the SINR, the theoretic al Shannon capacity and the BER performance. Declaration of originality I hereby declare that the research recorded in this thesis an d the thesis itself was composed and originated entirely by myself in the Institute for Digital C ommunications (IDCOM), School of Engineering, The University of Edinburgh. Shendi WANG September, 2016