Capacity, coding and modulation for ultra-wideband radio and multi-element-array systems.

摘要

Ultra Wideband (UWB) is a promising new technology proposed for short-range high data-rate wireless communications due to its low power consumption, multipath immunity, and license free usage. It is a good candidate for the physical layer of IEEE 802.15.3a group, also seen as a higher data rate solution for Wireless Personal Area Network (WPAN).; In this dissertation, research on coding and modulation for Impulse Radio Ultra Wideband (IR-UWB) radio systems is presented. Pattern Position Modulation (PAPM) is proposed in a multiple access environment. The Poisson arrival shot noise is used to model multiple access interference (MAI). Methods to find the probability of false and miss detection are given. The multiple access capacity is derived.; A novel Spatial Code Division Multiple Access (CDMA) system is also proposed. Such a system employs multiple receive antennas. Multiple users can be distinguished by their received pulse patterns. Capacity is shown to increase linearly with the number of receive antennas.; On top of PAPM modulation, a novel signal mapping system is designed and employed for turbo coding, where all the slot detection information is weighted to estimate the likelihood of each bit. Such likelihood can be used as the soft input for turbo decoding. Theoretical analysis and simulation are performed and results show good performance. Pattern position modulation is shown to be a good multiple access scheme with high capacity. Turbo coding with a simple mapping system for PAPM is proven to have good performance.; The capacity limits of fixed length Multi-Input-Multi-Output (MIMO) systems is investigated. For MIMO systems, simulation shows array length limits channel capacity. Capacity of MIMO and smart antenna systems are studied in line-of-sight environment and in the far field. Similar to a result by Telatar, smart antenna systems achieve higher capacity than MIMO systems when there is direct line of sight. In a multipath environment, smart antennas can be used effectively if transmitter knows reflectors perfectly. Otherwise, MIMO systems are good when the transmitter has no knowledge of the propagation environment.