- Enter The Plot!
- The Symbian Operating System— The Open Playground
- Java on the Handset—J2ME
- The Newer, Funnier WAP
- Playing with Messages
- Networking—An Integral Part of Mobile Games
- High Speed, High Action with Bluetooth
- Rock Your Opponents Miles Away— Gaming over GPRS
- And There's More... Over the Air
- The Network Is the Game
- Who Operates a Game Server?
- Spotting Your Target—Location-Aware Games
- Conclusion
Spotting Your Target—Location-Aware Games
Steve was one of the players who had proceeded to the IntenseMissions. Because his team members had signed up for them, they had given permission to be contacted if they happened to be in the area where The Plotters had been sighted. Nothing had been happening for a few days in the game when Steve was going to spend a Friday night downtown. To his pleasant surprise, as he arrived at the central subway station, he received a message from the game. The message told him that his team had been assigned to solve a mission in the area.
The map with the message revealed that this area contained a special level of The Plot Underworld. To enter the level, two real-life locations would have access points. The map also contained the last-known positions of Steve's teammates. He was instructed to first get together with either one of the two other members of the team that were also nearby.
Location-based games are the first step toward augmented reality, in which actual locations and real events are linked to imaginary stories in the game world. They are one of the first technologies with the potential to revolutionize the world of games. Several other, even more futuristic technologies are in store, such as see-through screens that allow imaginary objects to be added to a view seen by the player.
Usability is an issue that needs special attention in relation to developing compelling mobile games. A product with good usability is easy to use. We all know that cell phones are not well suited for inserting lengthy lines of text, especially during game play. Also, the amount of data provided to a gamer during a game should be designed so that it does not distract the player from the game itself. The tiny screen and the limited keypad pose a challenge to game developers.
One way to restrict information overflow is to focus on events taking place close to the game player or his actual geographic location. Moving from content to context helps a player sort information out more effectively and leaves more time for actual game play.
By knowing the location of the player, the game server is able to provide contextual information. If the location of a participant can be shared with other players and the game organizer, the game can be modified according to all participants' positions.
Handset-based location and network-based location are the two main techniques for determining where the cell phone user is.46 Today, network-based location provided by a carrier is more widely used (Table 3.2). In the United States, the Federal Communications Commission (FCC) mandated in the 1990s that all carriers in the country must provide the accurate location of emergency calls by 2001. Most carriers could not meet the deadline, but the infrastructure for location provisioning does, to a certain extent, exist at the moment.
In regions outside the United States, carriers have taken a slightly different path toward location-based services. Because the provisioning of accurate locations for cell phones is not compulsory, carriers have started to provide proximity-based services. They locate a cell phone with an accuracy ranging from a few hundred meters to several kilometers, depending on the density of the base stations. In urban areas, base stations are close to each other, and the location of a terminal can be pinpointed more accurately. Today, proximity-based services are used in many European cities to provide information about gas stations, hotels, and other points of interest.
Handset-based technologies are less common because few terminals can tell their own location. During recent years, some phone models have been equipped with a GPS receiver. A GPS phone can pinpoint its location within few meters. To be able to function, a GPS receiver must be used outdoors or through a window with a direct line of sight to the sky.
Another new way of providing handset-based location information is to install a custom application for a Symbian-equipped phone. The software is able to determine base stations nearby and send the information to a special location server. When a base station code is received, the server checks the location of that particular base station and sends the location back to the user (Table 3.3).
Table 3.2 Network-Based Location Technologies
|
|
Cell Site |
Triangulation |
GPS-Assisted Triangulation |
|
How does it work? |
A base station close to a cell phone owner can be located. A carrier has a register of all base stations and their location. |
Several base stations receive the cell phone signal; the location of the terminal is calculated based on signal strength. The carrier has a register of all base stations and their location. |
This is the same as triangulation, but a GPS receiver of a cell phone is used whenever possible. This is a mix of network- and terminal-based location technologies. |
|
Accuracy |
From a few hundred meters to several kilometers. More accurate in urban areas. |
Less than a few hundred meters. More accurate in urban areas. |
Less than 10 meters when the GPS can be used. |
|
Suitability for mobile gaming |
Better than nothing. Enables several proximity-based services. |
Suited for games in which the location of the user must be known with an accuracy of a few hundred meters. |
At the moment, there are no game-dedicated mobile terminals with a GPS receiver. |
When the location of the terminal is determined directly without carrier assistance, the party managing a location server needs to know the location of each base station accurately. Typically, a carrier owns this information, but in the future, there might be other parties providing the information as well. For example, virtual network operators (VNOs), the parties that rent network capacity from carriers, might have access to the data.
Table 3.3 Terminal-Based Location Technologies in Brief
|
|
GPS |
Software Based |
|
How does it work? |
The GPS system uses 24 space satellites orbiting the earth to provide accurate location for GPS receivers. |
The custom software of a terminal determines the closest base station and sends the information to a location server. |
|
Accuracy |
Less than 10 meters |
From a few hundred meters to several kilometers. More accurate in urban areas. |
|
Suitability for mobile gaming |
At the moment, there are no game-dedicated mobile terminals with a GPS receiver. |
Enables several proximity-based services. The open question—who operates the location server—remains a topic of discussion. |
After messaging with both of his team members, Steve agreed to rendezvous with Jason. He arrived at a pub they had chosen as the place to meet. Minutes passed, but Jason did not appear. Looking at his watch, Steve decided to request the tactical map from the game. It showed that Jason was just two blocks away. Sure enough, when Steve was putting his phone down, he felt Jason's tap on his shoulder. They could continue the mission....
Location is nothing more than latitude and longitude coordinates without content. In mobile games, the content can be either pushed to or pulled from the terminal. The difference in game play and user control is substantial. When content is pushed to a terminal, the gamer has registered for a service and has accepted that the game provider can track his location.
Earlier in the case scenario, Steve automatically received a message when he arrived in a new place. This is an example of a push service in which the locations of the players are tracked. Without the express permission of the gamers, this might be considered a violation of privacy.
Pull services operate differently. When Steve located Jason during the game, he used a pull service by sending a location request to the carrier. In response, he received both his current position and Jason's last recorded position. With pull services, a carrier does not have permission to track individuals constantly, but the players can decide when they want to participate and, at the same time, have their location tracked for game play purposes.
Both accuracy and timeliness have an impact on the sensitivity of the location information (see Figure 3.7). Naturally, accurate location-based services are more sensitive than proximity-based services. If the location of the user is known with an accuracy of 1 mile, the situation is different than when the whereabouts are known within a radius of 100 or 10 feet. In the same way, position data that is 5 minutes old is more sensitive than data that was tracked a week ago.
)
Figure
3.7 Privacy sensitivity of location information.
Game developers should cooperate with carriers to find appropriate solutions that tackle the privacy issues of location-based services. In all cases, the permission of the gamer is needed to facilitate a game with location information. Once granted, however, the potential to entertain and inform the mobile gamer grows exponentially. Location-based services are one of the most exciting areas that make mobile gaming mobile. Instead of sacrificing quality or complexity, mobility in this instance can add strength and diversity to gaming.