Design And Implementation Of Small Cognitive Wireless Networks

Cognitive radio (CR) and cognitive wireless network (CRN) technology have drawn comprehensive attention in the early21st century. As a new technology, CRN can resolve the contradiction between the growing demand for communications and the scarce spectrum resources. A lot of achievement on CRN sprouted up throughout the world in recent years, and a number of experimental CRN platform were set up, but the research about the CRN technology for small-scale, short-distance, regional network has not been studied thoroughly.Based on the current research situation, the purpose of this paper is aiming at designing a small-scale, short-distance and regional cognitive wireless network. On the basis of a better understanding of the key technology of CRN, the following jobs are mainly studied in this paper:1) In This paper, we discussed the main features and researched emphasis of small-scale, short-distance and regional cognitive wireless network.2) The small-scale, short-distance CRN we designed in this paper is based on energy-detection technology. The CRN is based on a Central-controlled, Distributing-sensed and Point-to-point communication structure. A new selection method for dynamic common control channel is used in setting up the CRN.3) A network performance evaluation system based on program complexity, average successful rate of communication and average establish time of common control channel has been proposed for evaluating the performance of network.To build the whole system model and simulation environment network behavior simulation software OPNET is used in this paper. According to the simulation results, a weighted optimizing solution of communication quality based on "successful rate of communication" and "establish time of common channel" is designed and the corresponding normalized performance function is proposed. Then the main parameter which represented the number of common control channel is optimized.4) In this paper, we also studied the design method of communication strategy and communication protocols, hardware structure selection, program code writing, network debugging and many other items. We also designed and successfully debugged a small CRN experimental platform. The CRN experimental platform uses MSP430F2418as its main control chip and nRF905as RF chip. Based on this platform, several in-depth theoretical study and practices such as wireless perception algorithm, design of communication protocol, heterogeneous network interface, multi-hop network intelligent routing and data encryption can be carried out on the platform in the future.After several experiments, the CRN we designed in this paper can meet the requirement in transferring physical data and text data. At the end of the paper, shortcomings of our study are pointed out, and future improvements and forthcoming upgrades are discussed.