Research On Key Techniques Of Extended Distance UWB Network

The Ultra-Wideband (UWB) technology recently attracts people's attention and becomes a research focus in wireless communication domain due to its advantages of high data rate, low power consumption, low cost, anti-interference and low interception rate. The recent domestic and abroad research on UWB technology mostly focus on its advantages of high data rate and low power consumption, witch makes the application of UWB localized in short distance application domain. However, the advantages, such as anti-interference and low interception rate, of UWB technology makes the requirement of it more and more intense on the application of military communication, anti-terrorism, relief rescue, perspective detection and other special fields. Under these circumstances, the requirement of UWB technology asking it to extend its transmission distance and construct multi-hop network to increase coverage. With the extension of communication distance and the increase of network scale, in addition to the physical layer need new communication technology, the traditional network protocol of short distance UWB will also difficult to apply.This thesis does some further research on extended distance UWB network protocol, with the main content and innovation as follows:1. Aiming at the reservation conflict problem of channel slots between hidden nods under the circumstances of multi-hop, a new DRP collision-free mechanism based on ECMA-368 which is suitable for the extended UWB multi-hop network is proposed. This mechanism takes the thought of distributed reservation of ECMA-368MAC for reference. It can avoid 3-hop reservation conflict and increase the network throughput by adding a new extended DRP available IE and using a new multi-hop feedback distributed reservation negotiation process. Moreover, aiming at the randomness of the reservation termination when a reservation conflict occur, the proposed mechanism define a new DRP control field and adopt a method of prioritized DRP conflict resolution process so that in can guarantee the access priority of real time date transmission when reservation conflict appears. This mechanism is appropriate for the multi-hop and mobile environment of the extended UWB network with more load of audio and video business. The results of simulation illustrate the effectiveness.2. Aiming at the problem of occupied too many channel time slots and waste of channel resource when the traditional min-hop routing algorithm apply in the ECMA-368 standard UWB network, a UWB routing and rate assignment algorithm is proposed. This algorithm use a new routing metric, which taking the end-to-end PER and the total number of slots into consideration, and a new rate assignment approximation algorithm, which based on the perception of packet overhearing.This algorithm can obtain the path and the optimal transmission over it, which can make the slots occupied by the path minimized when satisfying the end-to-end PER constrain. So it can provide greater network throughput than the traditional DSR and GPSR. The results of simulation illustrate the effectiveness of this proposed algorithm.3. The further research found that the packet overhearing mechanism used in the rate assignment approximate algorithm can undertake further exploitation in the process of packet relaying. This thesis gives a method of reliable relaying, which based on the principle of packet overhearing. This method can improve the reliability of packet relaying. Meanwhile, this paper gives a method of exploiting the relaying time of overheard packets, which can avoid the overheard packets being repeatedly relayed and reduce the occupation of slots ulteriorly.The improving scheme of the MAC protocol of the extended UWB network proposed in this thesis has been applied in corresponding project.