Research And Application On Algorithm Of Differentiated Services In LBS Platform

The principle of Motion Location-based Services is that: end users can obtain their location information, including concretely the longitude-latitude coordinate, through mobile communication network, including GSM network and CDMA network. Then, it provides the service of value-added service with the help of marking method in electronic maps.Along with the computer network development and the multimedia application is emerging in endlessly, network service mode has already became a electronic trading and services platform from a information browse module and data communication platform. The users who use the Internet also have different applications with QoS: the users who are enterprises and business users want to get a much higher quality of service through pay mode; individual users want to ensure the quality of service provided with low cost. Therefore the existing services are not able to provide satisfactory service for all the users. Instead of this, the new network service can provide different services for different users. That is the reason that the differentiated service is called up.Due to the continuous development of the Internet and multimedia application technology, there are more and more Internet users; the roles of network services are from a single data type of communication network (such as Email, FTP, etc.) to voice, video, graphics and other multimedia information to send a comprehensive transmission network changes, the corresponding service model from the original Web-surfing and data communications transmits to the evolution of electronic trading and services. The quality service requirements of Internet users are not the same: the corporate and business users want to access a higher quality of service through the way of paying; individual users wish to use the possibly lowest cost to ensure the basic quality of service. Therefore, the original business which provides all users with equal and best-effort service network services has been unable to meet a variety of user needs, and it will be replaced by different users of business which is to provide different quality of service networks. Then we proposed of differentiated services.Differentiated services are considered the basis for next-generation Internet network structure which is provided Internet QoS in the level of traffic aggregation. The goal of differentiated services is simple and effective, in order to meet the practical application of the requirements for scalability.At present, the differentiated services can be divided into two types: the relative differentiated services and absolute differentiated services. Absolute differentiated services based on aggregate flows, using strict admission control and resource management mechanisms to ensure real-time application under the worst-case delay or packet loss and so on, through the semi-static resource reservation to provide users with the absolute quality of service. The relative differentiated services distinguish and give priority to deal with certain communications through the appropriate mechanisms which can only provide soft-QoS guarantees. The relative differentiated services divided the network traffic into N business levels, according to the forwarding quality, high-grade business access to better quality of service, at least not worse than low-grade business access to the quality of service.There are many scheduling algorithms to support Differentiated Services, including proportional delay differentiated services model, which provide relative quality assurance for different types of data packets according to pre-defined parameters, such as different types of data packets corresponding to the average processing time delay parameter with a certain percentage. Typical PDD algorithms, including Waiting Time Priority, Proportional Average Delay, Hybrid Proportional Delay, Adaptive WTP , Mean Delay Proportional, Little's Average Delay, Virtual Length. Through the analysis of these typical algorithms, we can found that: the original PLQ algorithm is based on queue length of priority, and the probabilistic approach is introduced. So low-priority queue algorithm "hunger" problem has been solute well, the system overhead is also reduced. But there is some shortcoming in the PLQ algorithm: there is no waiting time to consider grouping; priority queue length probability function is too simple; the best performance exist a big deviation in the system under low utilization ratio. These shortcomings affect the performance of the algorithm and accuracy.To deal with these aspects, this paper presents an improved algorithm based on the PLQ algorithm. This method is based on the original algorithm introduced a queue waiting time. The original PLQ algorithm weight the queue and queue length as scheduling parameters: if the queue is the greater weight, then the queue in the packet is a high probability of scheduling; if the queue length longer, the probabilities of the packet in the queue scheduling are higher. Alone with the product of these two parameters to consider in the queue packet scheduling order, the queue wait time parameter has also been set to adjustment algorithm of the equity.In order to verify the effectiveness and accuracy of the improved differentiated services algorithm, this article using the NS-2 network simulation software to simulated. By analyzing the flow, the relationship between delay and system utilization, indicating that the improved algorithm in line with the proportion of PDD model requirements, and found that the improved algorithm W-PLQ delay is relatively small , but also in improving the fairness of service there have been some improvements by comparing the original PLQ and the LAD classical algorithm. Finally, according to the actual needs of variety request of business for LBS mobile positioning platform, this paper re-design and re-deployment the system and then the proportional differentiated service model is applied to the system. The improved algorithm W-PLQ for differentiated services network from the operations of classification and scheduling, then the results was processed by positioning logic module returned to the user, so as to attain the objectives for providing satisfactory service to users with different levels of service requires.