Research On Mobile Ad Hoc Network Routing Protocols

Routing of mobile Ad Hoc networks is a hotspot in wireless network research. With the improvements of theoretical research and manufacturing processes, MANET and WSN applications now transfer from the incipient specific areas like military, emergency to a wider range of civilian areas, including wildlife tracking, intelligent highways and pocket switched networks, etc. It is an urgent problem to improve the adaptability of routing protocols with various complex environments. This paper presents some solutions to optimize the routing in mobile Ad Hoc networks from the point of adaptability, expansibility and QoS.The main achievements of this paper are as follows:(1) To solve the expansibility problem of traditional flat routing protocols in ad hoc networks, an adaptive clustering routing transition protocol (ACRT) was proposed. ACRT adopts the idea of adaptive clustering and routing transition, and profits by the merits of passive clustering and gradual clustering. A series of simulations were made for ACRT, AODV, AODV-clustering and PC with fixed scale networks and dynamic scale networks. Simulation results indicate that ACRT has prominent superiority in expansibility and is a correct and efficient routing scheme.(2) This paper analyzed the principles and characteristics of path compression algorithms and proposed dynamic model which provided theoretical basis to improve or propose path compression algorithms. This model took the mobility and expansibility of Ad Hoc networks into account and was efficient to analyze and evaluate path compression algorithms. The quantitative relationship and probability expression for pivotal compression events were given based on the model. The simulation results of SHORT(Self-Healing and Optimizing Routing Techniques) and PCA(Path Compression Algorithm) show that it is a correct and efficient dynamic model for path compression. Finally, some suggestions and application scenarios about the model were proposed.(3) According to the shortcoming of current path compression algorithms, a dynamic model based path compression technique (DMPCT) has been proposed which can restrain the blindness for path compression efficiently. DMPCT lessens the ephemeral short-cuts and multiple short-cuts, and improves the path stability observably. Our Simulation results show that DMPCT achieves low original RREQ, low control overhead, low end-to end delay and high delivery rate compared with both AODV and PCA. Specially, DMPCT reduces the number of ephemeral short-cuts and multiple short-cuts which usually lead to unsteady paths. As an improvement path compression technique, DMPCT show great expansibility and stability for on-demand Ad Hoc routing.(4) This paper calculated the dynamic, real-time stable compression period probabilistically based on dynamic path compression model. A stability Module of path compression techniques (SMPC) has been proposed which can restrain the blindness for path compression efficiently and improve the stability of routes. SMPC introduces GPS based SMPC-ES and compression coverage based SMPC-MS to lessens the ephemeral short-cuts and multiple short-cuts. Our Simulation results show that SMPC based path compression techniques achieve low control overhead and end-to end delay compared to both AODV and PCA. It is a generic and efficient stability module of path compression techniques for on-demand Ad Hoc routing.(5) According to the shortcoming of traditional spray routing in dynamic opportunistic networks, a class of adaptive spray mechanisms were proposed in this paper. Adaptive spray mechanisms use relay nodes to make spray decisions in order to apperceive and react the change of network conditions exquisitely, and were least-cost delay-bounded routing protocols under specific spray mechanisms. Theoretic analysis of adaptive spray routing at aspects of routing cost, copy redundancy and expected delay were also given in this paper. Simulation results show that adaptive spray mechanisms show prominent superiority in routing cost, adaptability and expansibility, and were a class of correct and efficient delay-bounded opportunistic networks routing mechanisms.