Applications Of Interleave Devision Multiplexing In Wireless Communications

In order to support advanced services and applications, IMT-Advanced sets a fairly high standard in terms of requirements on data rate and system capacity. To meet these performance demands relies on two fundamental ways, i.e., improving spectrum efficiency and expanding the spectrum. Technologies such as multiple access technology, MIMO technology, and relay and distributed antennas would directly benefit the fulfillment of the technological requirements. Interleave devision multiplexing is a non-orthogonal multiplexing technique proposed recently and had attracted much research interests. It has several unique characteristics that make it very suitable for high-rate applications. Although it was firstly studied in multiple access senarios, it can also be applied in many other fields. Contribution of this thesiss is three-fold.Firstly, we study the IDM technique as a multiple access scheme, where we develop a new receiver structure named soft-rake for IDMA systems over multipath channels. Soft-rake is suitable for TDD downlinks, where the CSI is available to the transmitter from the previous uplink time slot, provided that the coherent time of the channel is long enough compared to the TDD time slot. Its overall complexity is similar to the soft-rake structure in literature, but a good part of it would be on the transmitter side as pre-equalization is used, thus reducing the receiver costs significantly. It also outperformes soft-rake in high SNR conditionsSecondly, we consider the application of interleave devision multiplexing in MIMO systems. MIMO systems based on interleave devision multiplexing have some desirable features over traditional MIMO schemes. For example it is asynchronous in nature, very flexible in terms of the number of transmit antennas. It also can switch between multiplexing and diversity mode without changing the system structure. The data rate can also be adjusted in a very convenient way, making it a very desirable choice for adaptive coding.Lastly we explore the possibility of employing interleave devision multiplexing in a cooperative communication system. It's well-known that only in higher frequency range can a sufficiently large band be found to support the high capacity of IMT-Advanced. However, the path loss and penetration loss is more significant for these frequency ranges, making it more difficult for the system to have a good coverage. Cooperative communication techniques can improve system capacity and coverage significantly. Therefore it has attracted a lot of research interests in recent years. The inherent characteristics of IDM-STC make it more suitable than traditional orthogonal space-time codes for cooperative networks. Chapter 5 of this thesis discusses the performance of IDM-STC in a cooperative network, under different scenarios.