Research On Bandwidth Allocation And Joint Power And Rate Control In Marine VHF Communication System

Marine VHF mobile communication mainly uses band of 30-300 MHz to establish near distance communications between ships, between a ship and a ground shore or between a ground shore and a helicopter. With the increasing of information demand, compared with the limited wireless bandwidth resources, the transmission businesses present an excessive tendency and have characteristic priority, so it is necessary to use the dynamic bandwidth allocation to provide a variety of communication businesses and ensure their transmission quality. The requirements of different businesses are different, for example, transmission rate, bit error rate and delay. In order to achieve multi-objective optimization of high reliability, maximum throughput and minimal energy consumption, it is essential to control power and rate base on genetic algorithm. The dynamic bandwidth allocation technology and joint power and rate control technology are the indispensable resource control technology in marine VHF communication system. The research has important significance and application value.Firstly, this thesis summarizes the application mechanism and allocation mechanism in current dynamic bandwidth allocation system and analyses the business model in marine VHF communication. In addition, the business priorities are divided, the communication channel propagation loss calculation model is established and the Genetic Algorithm is proposed to meet the multi-objective optimization demand. The basic content of dynamic bandwidth allocation and joint power and rate control provides theoretical basis for more in-depth research.Then, this thesis analyses the shortcomings of current resource allocation model and sets up a new resource allocation model for the dynamic bandwidth allocation in marine VHF communication system. Subsequently, the dynamic bandwidth allocation algorithm based on business priorities in battlefield environment has been proposed. The simulation results show that when the business arrive rate are same, this algorithm can reduce the blocking rate effectively. As well as, it can guarantee the transmission of the high priority business.Finally, this thesis proposes that in order to achieve multi-objective optimization, the system can complete the search for the optimal transmission power and rate by Genetic Algorithms, all businesses can switch to the corresponding communication modes based on their transmission requirements. The simulation results show that this algorithm can reduce the outage probability and tremendously save system power, and, at the same time, can make the system maintain their capacity and information throughput on a higher level.