Exploiting Wireless Broadcast Mechanism and Channel Allocation Strategy to Accomplish Power Saving Protocol Supporting Mobile Devices

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Project title

Code/計畫編號

NSC99-2221-E019-025

Translated Name/計畫中文名

無線廣播節能協定設計及廣播通道配置策略

Project Coordinator/計畫主持人

Haw-Yun Shin

Funding Organization/主管機關

National Science and Technology Council

Department/Unit

Department of Computer Science and Engineering

Website

https://www.grb.gov.tw/search/planDetail?id=2117719

Year

2010

Start date/計畫起

01-08-2010

Expected Completion/計畫迄

31-07-2011

Bugetid/研究經費

531千元

ResearchField/研究領域

資訊工程--硬體工程

為了減少移動裝置（Mobile Devices，簡稱MD）對經常使用的資訊重覆提出要求 (Request)，進而避免資訊在無線網路下載通道中重複傳送，資料廣播（Data broadcasting）是一種很有效率的資訊傳遞方法。節能(Power Saving)在無線網路環境中是重要議題，有二個重要參數用以評估資訊廣播系統的效能。一為調諧時間（Tuning time），另一為讀取時間（Access time）。調諧時間經常用來評估使用某一廣播技術時MD 省電的效能，而讀取時間則用以評估廣播系統的反應時間。現役及未來的無線網路系統皆提供廣播通道，要在有限頻寬的無線網路中提供多樣性的多媒體及數據服務，除利用適當數目的廣播通道傳送使用率較高的資訊之外，允入控制與通道配置策略是避免或預防網路壅塞的兩個重要控制機制。本計畫提出適用於現役及未來的無線網路系統的廣播通道排程機制及協定，改進過去所提出研究的不足，並兼顧未來無線多媒體傳輸的品質，使得移動用戶可快速讀取廣播訊息外，並實現省電節能的目的，同時對系統之廣播通道配置策略與系統允入控制進行效能分析。本計畫將找出適用於符合無線網路廣播系統實際環境的通道配置策略，同時考慮基地台系統架構、細胞涵蓋範圍大小、細胞重疊範圍大小、Handoff 頻率、交通流量等因素，經由分析及模擬對系統效能加以驗證。本計畫將以實際應用所需的實用技術為主要的研究方向，並兼顧學術前瞻性，為提高實用性，對於所作的研究，將討論其於WiMAX 及3G 實作之可行性。 Data broadcasting has emerged as an efficient means for the dissemination of information over asymmetry wireless networks. To avoid multiple retransmissions and to decrease the number of requests from mobile devices (MDs), frequently requested messages are periodically broadcasted on the downlink channels by a base station (BS), and MDs in its cell tune into these channels to extract the desired messages. Rarely requested messages are accessed by MDs by sending explicit requests over the uplink channels and then receiving messages on the downlink channels. Energy saving is an important issue in the wireless environment. The performance of broadcast systems is often characterized by two metrics: access time and tuning time. Access time refers to how fast the MD can access the requested data. It reflects the responsiveness of the system. Tuning time, on the other hand, refers to the duration for which the MD stays active. It measures the energy consumed by the MD in the active mode. A good broadcast system should achieve both low access time and low tuning time. Channel allocation schemes in a wireless network system environment can be either static or dynamic. Static allocation offers negligible channel acquisition time and zero message complexity and works well at a low system load; On the other hand, dynamic schemes provide better utilization of the channels at higher loads albeit at the cost of higher channel acquisition time and some additional control messages. In this proposal, we propose a broadcasting channel allocation schemes and admission control strategy for wireless network systems in supporting QoS for various multimedia services. We propose a multichannel broadcast paradigm that constructs the broadcast channels according to the access frequency of each type of message in order to save energy in mobile devices. The pinwheel scheduling algorithm (PSA) presented in this proposal is used to organize all types of messages in the broadcast channels in the most symmetrical distribution in order to reduce both the tuning and access time. The performance of the proposed mechanism is analyzed, and the improvement over existing methods is demonstrated by simulation and numerical analysis. Otherwise, the effect of the different channel allocation strategies, the cell dwell time, handoff dwell time, new call reneging time, overlap area with adjacent cells, handoff rate and traffic load on system performance is investigated. Based on those result, we expect to obtain an appropriate broadcasting channel allocation strategy in now and future wireless network.

Keyword(s)

節能
廣播系統
調諧時間
讀取時間
動態通道配置
無線網路
行動計算
mobile computing
wireless broadcast system
tuning time
access time

DSpace CRIS

Exploiting Wireless Broadcast Mechanism and Channel Allocation Strategy to Accomplish Power Saving Protocol Supporting Mobile Devices

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