| With the rapid development of Internet and the growth of personal need for data communication, the development of global computer networks and communication technologies presents three major trends: wireless, broadband and IP-based. Just as the wired access system, the wireless access system has transformed from narrowband to broadband, voice service orientation to data, multimedia service orientation. Among the large number of broadband technologies, the mobile broadband wireless communication network technology established by the IEEE802.16e (Mobile WiMAX) has become the most impressive highlight of the communication technology field. Moreover, it is also playing an important part in the next generation communication network technology.In the mobile broadband wireless communication network, how to ensure the quality of service of communication when a mobile terminal moves between different base stations, and control the energy consumption powered mainly by battery to prolong the standby time are crucial issues for mobile broadband. In order to reduce the power consumption of a mobile station and the air interface resource utilization of serving base stations, this dissertation mainly focus on providing different power-saving control strategies for mobile terminals in the IEEE802.16e mobile broadband wireless communication network under different conditions, such as high-speed traffic business, low traffic business and the co-existence of multi-traffic services. Meanwhile, the modeling and simulation for power-saving mechanism of mobile terminals has been implemented based on the OPNET simulation platform.The main contributions of this dissertation are presented as follows:1. To improve the power saving class of type I (PSC I) proposed by IEEE802.16e for NRT-VR and Best Effort (BE) services, this dissertation presents a unified power saving mechanism based on power-increasing function. In particular, the proposed mechanism can combine with several existing classical sleep mode algorithms by adjusting the sleep interval with growth factor. Furthermore, the impact to sleep performance from different sleep parameter values and the growth trend of different sleep intervals has been studied thoroughly. Experiment results show that, power-increasing function with growth factor a setting to2(a=2) achieves considerable improvement in both energy saving and packet delay of mobile terminals compared with the recommended exponential-increasing function in IEEE802.16e.2. In the low traffic condition, the sleep mode in which a sleep cycle always increases from the fixed minimum sleep interval to the maximum sleep interval based on binary exponential increasing can generate unnecessarily high number of sleep cycles, thus leading to excessive listening and switching power consumption. In addition, arriving packets may fall into a relatively long sleep interval, causing a longer packet delay, which eventually reduces the quality of service. Thus a novel and highly efficient power saving mechanism P-PSCI is proposed that can dynamically adjust the values of sleep parameters based on the real-time prediction of the downlink inter-packet interval. In addition, the dissertation proposes three P-PSCI sleep mode algorithms for different adjustment functions:the power-function decreasing sleep algorithm PSCI-PFD, the exponential decreasing sleep algorithm PSCI-ED and the linear decreasing sleep algorithm PSCI-LD. Simulation results and theoretical analysis reveal that the P-PSCI can achieve much better results on reducing the power consumption and the packet delay due to the consideration of the traffic characteristics and rate changes, compared with the other sleep mode algorithms. Moreover, the power-function decreasing sleep algorithm (a=-2) achieves the best performance in both power saving and delay reducing.3. With multiple services existing on the mobile stations, the listening intervals in each sleep mode operation are not synchronized all the time. Thus this can bring out some negative impact on the actual energy-saving efficiency of the mobile terminal. To resolve this problem, this dissertation proposes a parameter set optimization strategy (Multi-PSC) that synchronizes all the connected listening intervals while different service connections coexist to achieve maximum energy saving of mobile terminals. In addition, the dissertation also establishes three corresponding parameter set optimization strategies:Multi-PSCI, Multi-PSCII and Multi-PSCI&PSCII, for the three typical scenarios of multiple connections co-existence:co-existence of multiple PSCI connections, co-existence of multiple PSCII connections of, and the co-existence of multiple PSCI and PSCII connections. Theoretical analysis and simulation experiments show that the Multi-PSC mechanism not only greatly improves the energy-saving efficiency of mobile terminals when multiple service connections exist, but also reduces the additional packet delay.4. Since the current mainstream simulation platforms do not offer simulation support for IEEE802.16e sleep mode, we adopt three-layer modeling mechanism of OPNET design and implement the simulation module of the IEEE802.16e sleep mode by extending OPNET WiMAX MAC process model, thus providing a convenient, fair, and credible simulation environment for the sleep mode.The dissertation performed an in-depth research on IEEE802.16e mobile terminal power-saving control strategy, and proposed a unified power saving mechanism based on the power function growth and power saving mechanism based on prediction for the PSCI, respectively. Moreover, the dissertation established parameter sets optimization strategy, Multi-PSC, for power saving of multiple service connections co-existence. Furthermore, it also designed and implemented the sleep mode simulation platform based on OPNET. These research findings not only have excellent application prospects for mobile WiMAX, but also entail impressive significance for future energy-saving research towards mobile terminals. |
PDF Full Text Request