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The Internet employs many different types of communication networks. The mobile Internet and the location-enabled mobile devices have become increasingly popular, a new type of inspiring communication network is emerging, and we call it Near-me Area Network (NAN). It focuses on the communication among wireless devices in close proximity, creating a new kind of application domain. In this paper, we discuss about NAN, review to the existing applications, and most importantly point out the challenges for the NAN applications.
Internet system, mobile network, location-based service
There are different types of communications networks. A Local Area Network (LAN) refers to the network that covers a small geographic area such as a school or a company; a Metropolitan Area Network (MAN) usually spans a larger area such as a city or a state, whereas a Wide Aare Network (WAN) provides communication in a broad geographic area covering national and international locations. Besides, Personal Area Networks (PANs) also exist. A PAN is a wireless LAN with a very short range (up to a few meters), enabling computer devices (such as PDA and printer) to communicate with other nearby devices and computers. In recent years, due to the increasing popularity of location-enabled mobile devices, a new type of communication network is emerging, and we call it Near-me Area Network (NAN).
What is NAN?
A NAN is a logical communication network built on top of the existing physical network infrastructures that focuses on the communication among the wireless devices in close proximity. Unlike LAN in which the devices are in the same network segment and
share the same broadcast domain, the devices in a NAN can belong to different proprietary network infrastructures (e.g., different mobile carriers). So, even though two devices are geographically in close proximity, the communication path between them might, infact, traverse a long distance, going from a LAN through the Internet, and to another LAN. Although mobile devices have provided location- based services (LBS) for a long time , the concept of NAN and its applications have emerged only recently. The conventional LBS are typically offered by wireless carriers (in partnership with content providers) to their own subscribers. By making use of the geographical position of mobile devices, LBS provide users with information specific to their location, such as the nearest ATM or gas station. This kind of services focuses on a user's access to information, whereas the NAN applications focus on the two- way communications among the people within certain proximity. On the other hand, the NAN applications aren't always concerned with those people's exact location.
The Emergence of NANs
Some services are meaningful only to a group of people in close proximity, which has generated the need for NANs.
Ben is going to buy 3 bottles of red wine in ABC supermarket. The supermarket offers 30 percent discount upon purchase of 6 bottles. He then sends out message to the people nearby to see if they would like to buy the other 3 bottles of wine.
Susan bought a movie ticket in the cinema 15 minutes ago, but now she feels dizzy and cannot watch the film. In this case, she sends out
messages to the people around the cinema to see if anyone will purchase her ticket at 50 percent off.
In the theme park, the guests would like to know each ride's queue status so as to reduce the waiting time. Thus, each one takes a photo of the queue and shares it with other guests through the NAN application.
Ann works in Causeway Bay and she would like to find someone to have lunch together, she checks her friend list to see who is closest to her at this moment and invites that friend to join her.
Carol has just lost her son in the street, so she sends out her son's picture stored in her mobile device to the passers-by to see if they can find her son. Fig. 1. Illustrates this example.
Mobile devices within the same mobile carrier network can form a closed NAN. The carrier can identify a mobile device's location in the network (without GPS) using the triangulating process, which is based on the signal from cell towers (base stations) serving the mobile phone. If the carrier maintains a database of locations for all running mobile devices, various applications for user groups in close proximity are possible. A global wise NAN can be achieved through the mobile devices that possess both a GPS locater and Internet connectivity. The wide -area wireless connectivity to the Internet can be provided by a number of technologies such as WiFi/WiMAX, Exchanged Data rates for GSM Evolution (EDGE) and High speed Downlink Packet Access (HSDPA). After retrieving the current position returned from the GPS module, the application running in the mobile devices can exchange their locations through a server in the Internet. In this case, the application can discover the nearby users no matter which carrier they use.
towers (base stations) serving the mobile phone. If the carrier maintains a database of locations for all running mobile devices, various applications for user groups in close proximity are possible. A global wise NAN can be achieved through the mobile devices that possess both a GPS locater and Internet connectivity. The wide -area wireless connectivity to the Internet can be provided by a number of technologies such as WiFi/WiMAX, Exchanged Data rates for GSM Evolution (EDGE) and High speed Downlink Packet Access (HSDPA). After retrieving the current position returned from the GPS module, the application running in the mobile devices can exchange their locations through a server in the Internet. In this case, the application can discover the nearby users no matter which carrier they use.
Fig.1. An example of the use of NAN applications.
Fig.2. Communication in NAN
NearMe Networks provides Internet software customization services for affinity groups and small enterprise companies.Â In terms of tangible services, this includes Graphic Design, Web Development, Portal Services, and Software Development. The focus of the company is on the operational use of the Internet as a software delivery platform, providing tools such as content and document management, role based security, membership directory management, online databases, bulk email, and other common requirements. The software is then customized to the unique needs and processes of each customer and kept current through a standard service contract.
Halo Monitoring provides wearable health monitors that communicate information automatically to doctors, family members, or other caregivers to home-bound patients. NearMe pre-launched an initial site, and then worked closely with Halo to refine the site to exactly what Halo needed and wanted, and continue to support Halo staff. NearMe was heavily involved in the development of highly customized web portal components integrated into the Halo system.
Fig.3. Halo Monitoring
WHO'S NEAR ME - SOCIAL NETWORKING ON WINDOWS MOBILE
Who's Near Me is a social networking application that runs on Windows Mobile devices.Â Unlike traditional social networking services that focus on connecting you with your old and/or present friendships, Who's Near Me enables you to connect with people that you don't already know.Â The software application quickly shows you a list of other users in your area that are also currently using the application and allows you to connect with them anonymously for friendship, romance, networking, or just chatting. Your personal information is never disclosed. The software establishes your location using cell tower triangulation and displays a list of other users in your area.
How it works
After downloading the software onto your mobile phone from either this website or the Microsoft Windows Marketplace for Mobile, you launch the application and it uses information gathered from the connection between your mobile phone and various cellular networking towers to determine a rough estimation of your current geographical location.Â The software uses that to present you a list of other users in your area. You can anonymously browse the list of profiles, read what the users have written about themselves, even view their photos.Â If you find someone that looks interesting, you can initiate an anonymous text conversation.Â Your phone number, email address, and all other personal information is never disclosed; even if you initiate a text conversation.Â You are also not charged for any text message fees from your phone service provider as the messages go through our secure server and not the cell phone company!
Fig.4. Connecting to different people through NAN
B. To find places near you
NearMe applications give you a fast and easy way to find places near you. In addition, you
can set the area (in Km) where to search. With every found place you have some useful options:
-Add To contacts
-Open In maps
and other option is History: it keeps for you all places what you search for. NearMe is a simple application but useful
Fig.5. A map shown by NAN
Maps for mobile are a downloadable application that lets you view maps and satellite imagery, find local businesses, and get driving directions on your phone.
Google Maps on your phone makes it easy to
- Determine your current location with or without GPS
- Get driving and transit directions
- Get phone numbers and addresses for local businesses
-search in plain English
No need to know the address. You can type a business name or even a kind of a business, just like you would on Google.
-Search by voice
Speak your destination instead of typing (English only): "Navigate to the de Young Museum in San Francisco".
An indicator glows green, yellow, or red based on the current traffic along your route. Touch it to see traffic ahead of you
-Search along route
Search for any kind of business along your route, or turn on popular layers such as gas stations, restaurants, or parking.
View your route overlaid on 3D satellite views with Google's high-resolution aerial imagery.
Fig.6.Google Map in a NAN
Visualize turns with Street View imagery. Navigation automatically switches to Street View as you approach your destination.
-Car dock mode
Car dock mode makes it easy to use your device at arm's length (Android 2.0 devices or higher).
Select the Navigation icon from the launcher to start quickly; pick a destination by search (speak or type), contacts, starred items, or recent destinations.
Fig.7. The current place shown in a NAN
The application starts up displaying a globe representing the planet on the screen of your mobile. Select an area or city for a closer look.
Cluster of Networks
Fig.8. Formation of Cluster of Networks in a NAN
People in location 1 are connected to a system through their mobile. Similarly, people in location 2 and location 3 are also connected to their own system through the mobile. Now, all the location's system are connected to the ring
in the cluster of Networks. The cluster of Networks contains many rings, in which each ring represent the system in a location. The cluster of networks is then connected to central NAN which holds all the details. The representation is shown in Fig.8.
Existing NAN Prototypes and Applications
If an application is developed for the mobile devices that possess both a GPS receiver and the Internet connectivity, developing a NAN application to run in it isn't challenging. In this case, the device platform typically provides the application- programming interface (API) to return the location coordinates for programmers. After obtaining the value of the coordinate, the programmer can use the typical Socket programming or the existing protocol (e.g., HTTP) to talk to a central server in the Internet that updates the current locations of the present users. By using the location information, the application can provide various services, such as messaging the nearby people and sharing photos among them. The system architecture is shown in Fig.9.
Fig.9.A NAN is formed for those devices with both a GPS receiver and an Internet connection.
A. iPhone - a NAN Platform
As Apple's iPhone  supports 3G data speed and Assisted-GPS, it provides a very convenient platform for developers to create a variety of NAN applications. Some of them are shown below.
Handshake -- exchange contact information with another beside you:
Handshake  allows a user to easily pass its contact information to another user nearby without typing. For example, one day, Alice meets Bob and they want to exchange the contact information. They both launch Handshake, which identifies the fellow user nearby with the iPhone's built-in location service. After that, one can send their contact entry to another. This process is done without any typing and hence avoiding mistakes.
WhosHere -- meet new people with similar interests around you:
WhosHere  helps the user to meet other people nearby with similar interest. First, users fill out their profile and indicate the types of person they would like to meet. Then, WhosHere will show the people closest to the user that match the description. After that, users can send text message to each other within WhosHere itself. As can be seen, this NAN service eliminates the need to give out phone number, email or IP address, which provides another way of communication.
Loopt -- get alerted when friends are nearby:
Loopt  allows users to better connect friends on the fly. The operation of Loopt is simple. It first requires users to create a friend list. If the location sharing option is turned on, Loopt will regularly update its location to the server. By consulting the server, Loopt can show a user his/her friends, their location and distance from him/her, and the last time they updated their location. As a result, Loopt allows users to see their friends on a detailed map, get alerted when friends are nearby, exchange photo and other information, and explore places and events recommended by friends.
B. Fire Eagle - the central server
Yahoo's Fire Eagle  is a site (or a central service) that stores information about users' location, allowing other sites and applications to access it so as to provide services. Users can update their location to Fire Eagle manually on its official web site, or automatically via their mobile devices with the Fire-Eagle-enabled applications. Users can decide to disclose their location to any site or application, and choose how much detail to disclose (e.g., exact point, neighbourhood, city, state, country).
There are a lot of applications using Fire Eagle. For example, Outside.in Radar  uses the user's location to provide personalized news and discovers what's going on with 1,000 feet or closer. Brightkite  is another example, which allows users to share photos and notes with the people around them.
C. WhozThat - facilitating mobile social networks
WhozThat  is a system for NAN that integrates online social networks with mobile devices (e.g., smart phones). Its goal is to provide information about the people around the user, and the information obtained from the online social networking websites such as Face book and My Space.
In the system, the mobile devices are supposed to possess both a local wireless capability (e.g., Bluetooth or WiFi) and a wide- area wireless connection to the Internet. The mobile device running WhozThat will periodically advertises the identifier of the owner of that device. The identifier represents a pointer to his or her user profile on an online social networking website. When there are nearby devices also running WhozThat, the devices will get the identifier and then query the social networking site to retrieve the social networking profile of the associated identity.
Based on the profile information, various kinds of application can be built, particularly those context-aware applications. In , a context-ware music jukebox is demonstrated. With the use of the same approach mentioned above, the jukebox running WhozThat can receive the social network IDs advertised by the nearby WhozThat users. By checking the corresponding social network profiles that include the user's favourite music, the jukebox
can build song play lists that reflect the preferences of those users.
Challenges for the future NAN applications
In near-me area network applications, the major challenge is to determine what's "near me" technically and effectively, which primarily involves the appropriate presentation of a place and the accurate identification of a position. On the other hand, without the widespread availability of NAN-enabled mobile devices and the addressed privacy issues, the NAN applications could be hardly popular.
Representation of a place
The coordinate system used by the Global Positioning System (GPS) is the most popular system to describe locations. That is, a latitude/longitude pair can define a precise point on earth. However, as mentioned in , though locations described in coordinates are often useful, it is sometimes more appropriate to use more abstract concepts to express locations. For example, the place names like "Central Park" and "Times Square" can be used to identify the geographic areas of Central Park and Times Square respectively. Wilde  proposed a language called Place Markup Language to represent place name vocabularies and tried to integrate it with the Web architecture. This kind of expressions are sometimes more appropriate for the NAN applications that aims at the communications among the people in a particular location area.
Fig.10. Personal information given by a user
Identification of a position
If the user's position can be accurately identified, more sophisticated NAN applications can be designed based on the degree of proximity among the people. To determine the user's position, the GPS receiver of a mobile device must receive a radio signal from at least three satellites. The GPS accuracy is affected by the environmental conditions. The noise or interference near the receiver can create an error between 1 to 10 meters. If there are physical objects such as high-rise buildings that block the direct sight from the satellite to the receiver, an error up to 50 meters may occur. To overcome that, other technologies
have been developed, and Assisted-GPS (A-GPS) is the most popular one. A- GPS systems use outside sources, such as assistance
server to help the GPS receiver identify the geographical location. The GPS receiver communicates with the assistance server via a wireless link (such as WiFi connection). Therefore, A-GPS also requires the installation of the wireless link in the mobile devices.
However, since satellites are required in GPS and A-GPS to transmit the signals, they often do not work in-doors. The advantage of NAN applications can be maximized if the devices in the same indoor area can be discovered. For example, in a big exhibition hall, the applications can allow the people to exchange product information so as to facilitate the business. In order to describe an indoor area, extra efforts with short-range wireless technologies (such as WiFi and Bluetooth)  are needed. For example, a machine running a NAN application in an indoor area is used to regularly advertise the location of the indoor area (by coordinate) via WiFi, and whenever a mobile device joins the WiFi network, the NAN application running in the device can obtain the location information.
Besides tracking mobile devices, if a stationary device not equipped with a location related facility (e.g., a desktop computer) is allowed to join a NAN, developers must consider how to input this device location.
To maximize the advantages provided by NAN applications, the mobile devices that are both location- enabled and Internet-enabled have to be ubiquitous. It is because if the people near a user do not have a NAN-enabled device, a near -me network cannot be formed for the user. Today, most 3G phones can access the Internet, and the 3G technologies have already been available in many countries. Though the market share of GPS -enabled phones is relatively small today, many vendors have already forecasted the potential business opportunities in the future. Based on a market research report , annual shipments of GPS enabled phones will grow strongly over the period 2010-2012, and by 2012, such phones will account for 37% of all shipments (about 535 million).
For developers to build a NAN application on a mobile device, the software platform of the mobile device has to provide the corresponding application- programming interfaces (API) for NAN applications to access the information from the device's location facility such as the GPS receiver. Fortunately, the modern operating systems for mobile devices, such as Google's Android and iPhone, typically provide a rich set of useful
libraries for developers to use. However, those modern operating systems still have a small market share today.
On the other hand, a simple way to develop a NAN application is to install a server storing all the locations of the devices running the application. However, in this case, each NAN application requires the establishment of its own location server, and users employing multiple NAN applications have to maintain their status with multiple location servers. To ease the application development, a central location server with open standard protocols on which NAN applications can upload device locations and access the locations of other devices would be a great help.
In a NAN, personal information (such as current location) can easily be disclosed. Therefore, NAN applications should provide users with privacy control. For example, a user should able to specify different levels of detail about his or her location such as the exact point, neighbourhood, or city. Besides, users should be able to choose how much detail of personal information to disclose. The Fig.10 shows how a user can upload their information
The levels of detail can be: 1) anonymous (just used to show that a person is nearby), 2) a social ID (which can identify a person using a chosen pseudonym or a user name), and 3) a social ID and personal description (which should be used for authorized people such as friends). On the other hand, if different NAN applications are allowed to exchange location information of their device (through peer to peer communications or through a commonly agreed central location server), trust models will be necessary.
Considering the low costs for the GPS chip sets and the rapid development of mobile broadband technologies, it is anticipated that the mobile devices that are both location enabled and Internet -enabled will become widely prevalent in a near- to-mid-term future, which will positively boost the popularity of NAN applications.
On the other hand, we believe that there are still many exciting opportunities exist for the future design of NAN applications new
modes of location-enabled mobile devices, with new kinds of screens and location or communication functions.