Access Control Of The IR-UWB Network

IR-UWB is the carrierless communication technology using very narrow pulse, and its duty cycle is very low. In order to transmit pulse signal uniformly on the time domain, IR-UWB system uses the time-hopping sequence to control the transmission of pulse. By the time-hopping sequence IR-UWB system can provide many time-hopping logic channel, and the data can be transmitted concurrently on different logic channel. IR-UWB technology can be used to set up high speed wireless network in very short distance, and such network has center-controlled architecture, and many studies are taken for the access control of this sort of network. Furthermore, IR-UWB technology also can be used to set up low speed wireless network in very long distance, and such network has big coverage and distributive architecture, and more studies need to be taken on the access control of this sort of network.In this thesis many topics of IR-UWB network are discussed and studied, such as the generating method and the performance of the time-hopping sequence, the modeling of pulse collision, the way of sharing the wireless channel, the design of MAC protocol, the throughput of network, the transmission delay of data, and the supporting of QoS.The measure of correlation performance of time-hopping sequence in IR-UWB system is introduced, which is somewhat different from frequency-hopping sequence. The performance of rejecting multi-path interference depends on the auto-correlation property of the time-hopping sequence and the performance of rejecting multi-access interference is controlled by the cross-correlation property of the time-hopping sequence. A N_h-ary time-hopping sequence should be transformed to a 2-ary sequence, then the 2-ary sequence is used for computing correlation performance.Three families of time-hopping sequence are given, and correlation performance of them is studied and simulated. The time-hopping sequence has effect on PSD of transmitted signal, and the part which is affected by time-hopping sequence is studied. The spectrum properties of these three families of time-hopping sequence are simulated.The pulse collision model of IR-UWB network is analysed, and the probability of frame transmission failure caused by pulse collision is deduced approximately. With the benefit of time-hopping, very low duty cycle and time diversity transmission property of IR-UWB system, the performance degradation caused by pulse collision is not serious in low speed IR-UWB network.Detailed transmission and reception process, and the performance analysis of ALOHA IR-UWB network are given. The formulas of the throughput and the transmission delay are deduced. By simulation, it is proved that the performance of the ALOHA IR-UWB network is much better than the ALOHA carrier modulated technology network.UWB-RI MAC with the receiver controlled handshake is proposed, which improves on the sender-controlled handshake of UWB MACAW MAC. UWB-RI MAC is based on FI-RTS-CTS-DATA-ACK flow, and it has better performance than UWB MACAW MAC. The algorithm of UWB-RI MAC and performance simulation result is given, and the supporting to QoS and burst data transmission is proposed.A novel network model with simplex sensor data transmission for data collection WSN is proposed, and it decreases the complexity and cost of sensor node. This access control method consumes less power than duplexing network. The detailed procedure of the data transmission is described, and the simulation result of simplex transmission of intra-cluster is given.In this thesis, based on the study the property of IR-UWB system, several access control methods for distributive IR-UWB network are proposed, which make use of the advantage of IR-UWB system. And some problems on the distributive IR-UWB network are resolved.