| Wireless Ad Hoc networks are characterized by flexible and fast development, no acquirement for fixed infrastructure, very low cost and robustness, etc. The main advantages of UWB wireless communications are described in such words as high band width, high bit rate, low power consumption and so on. Combining wireless Ad Hoc networks with UWB transmission techniques could get a more flexible and higher speed wireless network to enormously promote the application and development of wireless networks.However, Wireless Ad Hoc networks and UWB techniques are all immature and no civilian. Considering the characteristics of wireless Ad Hoc networks, such as its multihop, the dynamic network topological structure, the restricted energy, it is a challenging task to design the MAC protocol and routing protocol. Although UWB communication systems have the intrinsic anti-multipath interference ability, but as the system transmission speed is very high, the inter symbol interference (ISI) caused by multipath will get serious. In addition, although UWB techniques have the lower power spectrum density, but the capturing time is also relatively longer, this means, longer packet header and higher transmission power are needed to reestablish the connection between the physical levels. Therefore it gets very necessary to avoid conflict and re-transmission of packets, as well as the higher cost routing reconstruction. The researchs of anti-interference at the physical level, MAC protocol design at the link level and the routing protocol design at the network level are the present research hotspots, are also the paper's main research objects.The paper's main contributions and correlative research works can be divided into the following three parts:(1) Giving the formula of the bit error probability (BEP) taking into account of more practical factors and the more quantitative research conclusions of the tolerance of multipath interference and intra-system interference in DS-UWB system.The direct sequence ultra-wide band DS-UWB system is the present typical physical level realization technology of UWB communication systems. In terms of discrete time Impulse response, namely discrete channel models, several kind of UWB channel model simulation data of the indoor channel models suggested by IEEE 802.15.3a were proposed in the paper, and the formula of BEP given by G. Durisi was corrected. On this basis, the tolerance of multipath interference and intra-system interference were explored. The following conclusions were presented: When the data rate is higher than 100Mbps, the system performance obviously degrades due to ISI. In this case, it is inapparent to reduce ISI by improving Signal-to-Noise ratio. Rake receiver with five fingers can be considered; when two asynchronous DS-UWB communication systems work together, the high-rate system generally does more interference to the low-rate system. Such intra-system interference can be restrained by increasing the length of pseudo noise (PN).(2) Proposing valid methods to further improve the competition performance of the broadcast MAC protocol FPRP for the wireless Ad Hoc networks and a unicast MAC protocol TPRP based on FPRP.The FPRP (Five-Phase Reservation Protocol) protocol is a representative dynamic TDMA protocol for the wireless Ad Hoc networks, which is possessed of such distinct performance as high reliability, operation parallelism, packet concurrency and extensibility. Farther improvement measures of the FPRP performance were proposed in the paper: The "hidden receiver terminal" problem was solved by the state conversion design for non-reserved node; The competition conflict caused by the centralization of competition period schedules was reduced by decentralizing the competition period. The distinguishing access service was provided by the algorithm design of competition probability and competition period arrangement in which the order of priority was considered. For providing the basic unicast service, according to the differences between the broadcast and unicast, the FPRP reservation procedure was revised, and a unicast FPRP-based protocol termed TPRP(Three-Phase Reservation Protocol) was proposed. The TPRP protocol has high performance likewise. Combining with the order of priority mechanism, TPRP may be used as a QoS MAC protocol.(3) Presenting a kind of high reliable and optimized QoS routing protocol RQRP_PE for wireless Ad Hoc networks.The RQRP_PE (A Reliable QoS Routing Protocol Based on Path-lifetime Estimation) protocol takes the path-bandwidth as the principal selection restraint, which has the selected route to meet the most important QoS resource request, depends on the path-lifetime to select route, which enhances the reliability of the selected route, and makes use of bandwidth reservation mechanism based on the order of priority to provide implement guarantee. The calculation of path-bandwidth and the prediction of path-lifetime are the foundation for the design of RQRP_PE protocol. Moreover, the calculation of path-bandwidth is a NP-complete problem. The reasonable calculation methods based on heuristics hop-hop were given in the paper. The predication method of the path-lifetime according to the distance between nodes is more suitable for UWB techniques. In the concrete design of the protocol, it improves the efficiency of the route discovering and maintenance and reduces the routing consummation that the destination node reserves route, memory the standby route and participate the maintenance of route. The simulation results indicated, comparing with the classical DSR protocol, that the RQRPPE protocol can effectively increase packets delivery rate, reduce the probability of reconstruction caused by broken-path, and decrease the average transmission delay.
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