# Energy-Efficient Hosting Rich Content from Mobile Platforms with Relative Proximity Sensing
## 1 Introduction  
The proliferation of mobile platforms has led to an increase in the use of the mobile web-based interactions [1]. Broadly deployed mobile devices, including many commercial off-the-shelf (COTS) such as smartphones and IoT devices are generally equipped with two indispensable communication modules: Wi-Fi and a cellular network interface. Users are willing to pay for mobile data plans, and can hence browse websites from a mobile platform, wherever they are, just as they would from a general computer system. However, in contrast to a general computer system, the mobile platform is with the user most of the time. This has led to a new class of applications that allow a user to push content over the Internet from the convenience of his mobile platform. For example, users use their mobile platforms to upload photos on _Instagram_[2], update status on _Facebook_[3], and send tweets across the globe using _Twitter_[4]. The trend is to make it easier not only for users to push interesting content to the Internet, but also for smart objects to make interactions with mobile platforms of users [5; 6]. In line with these trends, we propose Tiny-Web-Thing (_T-Wing_), a system that enables users to host and share content from their mobile devices. As shown in Figure 1, devices from all over the world can query for available mobile device webpages around a given location, and access them remotely. Furthermore, if devices are nearby, we enable them to share much richer content. Such a system enables several new applications. For example, when there is a happening or an event, users in the vicinity can share the occurrence worldwide within a short period of time. People can also use_T-Wing_ to advertise themselves, which can be useful for financial transactions, or even for breaking the ice among strangers, for example in a dating scenario. However, implementing _T-Wing_ is non-trivial. For example, all content could be hosted over Wi-Fi to enable sharing of rich content. Nearby mobile platforms, which are in Wi-Fi range, can discover and access content over the Wi-Fi network at high throughput. However, such an approach is impractical since keeping the Wi-Fi interface on all the time quickly drains the mobile platform's battery. This can be mitigated to some extent by turning the Wi-Fi interface on periodically, and broadcasting a beacon message. However, turning the Wi-Fi interface on and off may cause spikes in energy consumption [7]. Furthermore, in the absence of clever synchronization mechanisms among mobile platforms, such sleep and awake schedules would significantly increase the discovery time of two mobile platforms [8]. An alternative is for mobile platforms to transfer their content (along with their location) to a server on the Internet using the cellular network interface like Microblogs [9]. Although this approach is promising, it suffers from three problems when serving large content. First, the cellular uplink bandwidth is a severe constraint for mobile platforms in comparison to downlink bandwidth even in 4G (LTE) networks [10]. If several mobile platforms serve content using the same uplink connection, the experience when browsing mobile content will further degrade. Second, the battery power of mobile platforms is limited, and the cellular network interface causes significant energy drain when it is active [11; 12]. It has been shown to have much lower bits/Joule than Wi-Fi. Although the actual power consumption may be changed in accordance with the usage of a specific network technology, the difference in energy efficiency among the heterogeneous network technologies makes this work more useful [13; 14; 15]. Finally, users of mobile platforms may pay for cellular data usage on a pay-as-you-go pricing model. Nowadays, despite the ever-increasing need of people for staying 'connected' at any time and everywhere, in many areas of the world data connection is extremely expensive [16].