適地性服務是一種以使用者地理位置資訊為基礎的附加網路服務。隨著可攜式及行動裝置的顯著成長，愈來愈多適地性服務應用程式被開發在智慧型手機或是平板電腦上。舉例來說，導覽系統可以提供遊客所在地的周邊訊息。在過去，大部分的導覽系統僅考慮如何讓單一使用者透過網路和其地理位址取得周邊訊息。然而，行動裝置會受到電量及無線存取的限制。這篇論文的動機是去討論及分析群體導覽的可行性。為了讓使用者可以動態形成單躍點(one-hop)導覽群組，我們提出以行動社群網路為基準的群體導覽機制(MSN-GTS)。具有3G/3.5G/4G行動網路的成員會分享他的連線能力給那些只具有Wi-Fi連線能力的成員。因為這一群使用者會一同旅遊，我們提出的機制(MSN-GTS)能夠避免多重位置更新及冗餘資料下載。但是根據實驗結果，使用Wi-Fi做單躍點(one-hop)群體導覽會產生很高的封包遺失和高耗電量。因此，我們提出了部分下載機制以減少下載不必要的POI。根據實驗結果我們提出的方法可以有效的節省耗電量並增加下載檔案的使用率。

Location-based service (LBS) is a general class of add-on network services using the information on the geographical positions of users. With the significant growth of portable and mobile devices, more and more LBS applications are developed for smart phones or tablet PCs. For example, the touring service is able to provide the neighboring information for tourists. In the past, most touring services only consider how a single user gets the neighboring information from the Internet based on his current geo-location. However, mobile devices have limited battery life and limited wireless access capability. This paper is motivated to discuss and analyze the feasibility of the group touring service. A mobile social network-based group touring scheme (MSN-GTS) is proposed to let users be able to form a one-hop touring group dynamically. Members who subscribe the 3G/3.5G/4G cellular service would share their connections with other members who have only Wi-Fi access capacity. Since a group of users travel together, the proposed MSN-GTS is able to avoid multiple location updating and redundant data downloading. However, based on our experimental results, the one-hop touring group using the Wi-Fi interfaces induces high packet loss and high power consumption. Therefore, our MSN-GTS designs a partially downloaded mechanism to reduce unnecessary POI downloading. Our experimental results reveal that the proposed mechanism can save power and increase cache utilization efficiently.

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