Performance Evaluation For M2M Services Over GSM/WLAN Systems

Machine to machine (M2M) communications are automated applications which involve machines or devices that communicate through a network without any human intervention. It’s an important mean to achieve mechanical automation and informationization. With the rapid development of information and communication technology (ICT), electronic components and sensor are getting miniaturization, which makes it possible for M2M applications to massively apply into industrial production. The development of M2M has drawn widespread attention around the world. Wireless communication network, for its wide coverage, high transmission efficiency and low cost, is considered as the best choice of M2M access technology. Due to the different characteristics of M2M services with traditional communication services, deploy the M2M application directly to the existing network will bring many problems and degrade the current network performance. Therefore, it’s necessary to evaluate the performance and valuable to study the resource management strategies for carrying M2M applications over existing wireless network.Base on the above demand, this article simulated and evaluated the performance of typical M2M applications over Global System for Mobile Communications (GSM) and the Wireless Local Area Network (WLAN). The main works are as follows:In the aspect of evaluating the smart metering service over GSM, this paper has simulated the random access performance with M2M and human-to-human (H2H) coexistent scenario, mainly focused on the random access delay. As massive M2M devices may apply to access network in a synchronized mode, three solutions are proposed to improve the network performance. Simulation results have shown that, changing priority, alter retransmitting parameters and deploy different backoff method can all help reducing the impact of M2M on the current H2H services.In the GSM network, the S-ALOHA random access algorithm is deployed. This article used a Markov chain model to study random access problem. Under the Poisson distribution arrival circumstance, an improved traffic load prediction method was proposed according to the feedback information of random access channel (RACH) status. And an optimized random access algorithm for the massive M2M devices’ random access was presented based on the current adaptive traffic load Slotted ALOHA (ATL S-ALOHA). Simulation results indicated that the proposed algorithm can effectively reduce the random access delay and improve network performance. It is a simple algorithm with small calculation amount and can perform high practicality.Intelligent traffic information service is a typical cyclical trigger M2M application. In this paper, the assessment of this service over WLAN was accomplished. WLAN technology is mature and widely spread, suitable as a supplement of cellular network in some signal blind area such as a high way tunnel. A simulation platform was build and the design of media access control layer was clearly introduce. Then the performance comparison of two different CSMA/CA (carrier sensed multiple access/collision avoid) mode was completed. Simulation results reveal that the simple acknowledgement mode of distributed coordinate function performances better than RTS/CTS (require to send/clear to send) mechanism under several indexes (including delay, average throughput and data drop rate).