碩士 / 國立臺灣大學 / 商學研究所 / 97 / In recent years wireless network popularity of the rapid development of related technology, includes the early analog mobile phone system, AMPS, then the GSM, TDMA and so on, to the now widely accepted 3G (WCDMA, CDMA2000, etc.). The wireless mobile phone system with our lives closely related to the WiFi wireless network in recent years is the emergence of a popular wireless networking. New standards for wireless network coverage has been expanded from several dozens of miles and miles. In particular, WiMAX technology and the most recent claims provide bandwidth of 75 Mbits per second and have a theoretical value of 50 kilometers covered. The organization designs the IEEE 802.16e, the latest standards with mobile broadband technology. Nevertheless, in a variety of specifications for wireless operations under the new arrangement with a wide range, makes the whole environment have become more complex. In the metropolitan cities, many obstacles have shielding effect of buildings, resulting in difficulties to achieve seamless transmission of wireless signals.
On the other hand, many European and American telecommunications market makers have aggressive actions on the wireless technology. The management of this technology strategy is the deployment of the many patent maps, through licensing and patent protection. As a result, it’s to ensure that this industry has become the source of their cash cow. They not only enjoy the right to charge market products and gain profits but also makes subsequent competitors attempting to enter this market become subtle. Therefore, it’s becoming more and more important that Taiwanese manufacturers in the industry can stand in a significant position and have the ability of control the powers to negotiate. And such study is our main motivation and purpose. We hope that from this important needs of industry, combining with information technology can develop a total new key invention.
Based on the above-mentioned motives and reasons, we chose the most critical handover decision problem in wireless mobile network as our main research objectives. After examining the issues for handover decision in the prior art, we found out that most prior art were based on the signal to noise ratio (SNR) between mobile devices and base stations and comparing the SNR rate with a threshold value. While it’s less than the thrshold, many different handover decision practices and selects the handover to the target base station. However, these approaches will face the following two problems and issues:
1. In a complex environment, due to many unexpected obstacles blocking the ways, it’s very difficult to achieve seamless connection. Even so, the output can also consume a lot of power.
2. The need from time to time for the scans and the requests in nearby areas, not only acquires and updates information on the neighboring base station but also requires a large amount of energy.
Therefore, based on the variety of drawbacks in previous inventions, we proceed the handover decision mechanism. With combining the development of modern information technology, we propose an optimal navigation handover decision mechanisms. The main idea of this method is to “draw a well-infomed local map” for a mobile device in terms of its nearby base stations. With such a map, a mobile device will be able to quickly and efficiently find the target handover to the next suitable choice of a base station. Basically, it only needs some positioning mechanism embedded in the system such as GPS, Global Positioning System or any other positioning means. Via the assistance, a mobile device can find out the best base station under current situation in a most energy efficient way. Through different scenario analysis, the best solution, respectively, by their choice of mechanism show as follows:
1. Navigation mechanism activation scenario: In this scenario, we can set the pre-planning the best base station to the mobile device based on the path the user attempts to navigate.
2. Positioning mechanism activation scenario: In this scenario, we can set best base station based on user’s local position map of base stations.
3. Other mechanism activation scenario: Different from 2nd scenario, we adopt other technologies such as RFID, etc. to assist the positioning/direction (noted as Lane Indicator) by a mobile device. Via communicating with the Line Indicator, handover decision can be made based on the direction of the mobile device.
Secondly, we further optimize the navigation handover decision method. It’s the so-called "prestored navigation handover". The main theory relies on each user has a fixed or highly relevant to itself track model. We can utilize the characteristics of the past record and the history of track as a reference. Therefore users don’t need to do address computing and information through the transmission link with the base station.
At present, mobile wireless network market is still in its emerging period, the majority of applications are mainly for voice transmission while data transmission or multimedia content is widely used gradually. Handover decision mechanism is in the need of innovation for a number of technical breakthroughs. This papers utilizing GPS and other current technology enables the handover decision between mobile devices and base stations to be more rapid and energy-saving. Based on the mechanism, we can file the patent application with its unique, innovative and integrated features for the concept. Also we look forward to competing with other major wireless network companies in the market.
| Identifer | oai:union.ndltd.org:TW/097NTU05318048 |
| Date | January 2009 |
| Creators | Yueh-Yi Wang, 王岳宜 |
| Contributors | 游張松 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 62 |
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