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CS 5961: Networked Game Design Lecture 13 CS5961: Networked CS5961: Networked Game Design Game Design Introduction to Mobile Gaming

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CS 5961: Networked Game Design Lecture 13

CS5961: NetworkedCS5961: NetworkedGame DesignGame Design

Introduction to Mobile Gaming

CS 5961: Networked Game Design Lecture 13

Mobile GamingMobile Gaming (One of the?) fastest growing segments of game

industry– Mobile consoles (e.g., PSP, N-Gage, Nintendo DS)

– Mobile phones

Unique challenges– Constrained I/O (small screens, limited/slow input devices)

– Power-constrained (battery life issues)

– Wireless networks (slow, unreliable, power-hungry)

Unique opportunities– Cell phone market >> game console market

– Opportunities to exploit “real” social interaction

– Location-based games

CS 5961: Networked Game Design Lecture 13

Common Mobile Game GenresCommon Mobile Game Genres Standalone

– Miniature version of console/PC games non-interactive

– Often “casual” games (e.g., Tetris) very popular with women

Multi-player– Typically head-to-head or small groups

– Conventional games vs real-time trivia (e.g., sporting events)

Location-based / “mixed reality” / “alternate reality”– Exploit presence of GPS in modern phones

– Harder to determine “location” for generic wireless (triangulation)

– Ex.: GeoCaching, PacManhattan, Can You Find Me Now?

Social games / interaction-based– Virtual love, digital clubs, share w/ friends

– E.g., Avapeeps (Digital Chocolate) date other people’s avatars

CS 5961: Networked Game Design Lecture 13

Hardware PlatformsHardware Platforms Mobile consoles

– PSP, N-Gage, Nintendo DS

– 300+MHz cpu, vector unit, FPU

– 32MB+ embedded DRAM/Flash

– Display: 480x762 (PSP), 256x192 (DS)

– Support for 3D graphics/sound

– 802.11, USB, game inputs

Cell phones– Weak cpu, special cell circuits

– 12MB DRAM (RAZR), 32MB (Sidekick)

– Display: 176x220 (RAZR), 240x160 (SK)

– Usually no 3D graphics support

– SMS, 3G, Bluetooth

CS 5961: Networked Game Design Lecture 13

Development PlatformsDevelopment Platforms J2ME (Java 2 Micro Edition)

– Seems to be dominant software platform

– Portable across many hardware platforms

» Pretty much every cell phone has J2ME

– “Not most powerful or pretty, but pervasive”

BREW (Qualcomm)– Popular in the US (less so abroad)

– Better support for 3D graphics and sound

Symbian OS (Nokia)– Powerful OS/platform for high-end phones

– Typically more expensive games

ExEn, PalmOS, DoJa, WIPI, …

CS 5961: Networked Game Design Lecture 13

Common LimitationsCommon Limitations Low processing power & small screens

– Need to count on good game play over flashy graphics

– No uber powerful game AIs or high res 3D graphics

Limited sales channels typically cell providers– Hard to market games tend to rely on well known IP/genres

Wireless communications– Limited wide-area bandwidth, lossy, unstable

– Depending on technology, not pervasive (802.11/Bluetooth vs 3G)

Limited location accuracy– GPS is pretty good, but only to ~20meters (outside ok, inside not)

Proliferation of heterogeneous devices– Need to design for lowest common denominator

CS 5961: Networked Game Design Lecture 13

Technology IssuesTechnology Issues

CS 5961: Networked Game Design Lecture 13

Technical ChallengesTechnical Challenges Low-res displays Weak processors Small memory/storage capacity (no VM)

– Example: BREW could only access 200 bytes of dynamic data (2002)

Severe power constraints Wireless/mobile networking issues

CS 5961: Networked Game Design Lecture 13

Power-Aware ComputingPower-Aware Computing Mobile devices have limited battery power Major power consumers:

– Display / backlighting

– Wireless network

– “Vibrate”

– CPU / memory

Q: What kinds of things can you do to preserve power?

– Discuss

– Turn off units (disks, displays, network, …) when not being used

– Voltage scaling (often available in mobile processors)

– Power-aware scheduling (OS or app-based)

CS 5961: Networked Game Design Lecture 13

Wireless NetworksWireless Networks Wide range of wireless technologies

– Bluetooth (802.15): “personal area network”

– IRDA: short range, point-to-point

– 802.11: wireless LAN (variety of bandwidths and ranges)

» 802.11b: 2.4GHz (shared), 11 Mbps, ~300 feet indoor range

» 802.11g: 2.4GHz (shared), 11/54 Mbps, ~300 feet indoor range

– SMS: cell phone messaging (160 bytes max, 4+ sec latency)

– 2G/3G: high bandwidth digital cell based

– WiMAX: wireless MANs (802.11 on steroids)

Access points versus ad hoc Security (WEP, authentication, encryption, …)

CS 5961: Networked Game Design Lecture 13

Cellular Network TopologyCellular Network TopologyBase Station (BS)

Fixed Host (FH)

Wireless Cell

Internet

CS 5961: Networked Game Design Lecture 13

Wireless ChallengesWireless Challenges High bit error rates

– Congestion (shared channels, data corruption, …)

Asymmetric channels– Bandwidth asymmetry

– Differing latencies

High delays (compared to wired networks)– Channel reservation “slots”

– Transceivers often go into “sleep” mode for power savings

CS 5961: Networked Game Design Lecture 13

Programming Embedded Programming Embedded DevicesDevices Programming for small memory footprints

– Limited stack size must have predictable maximum size

– Compressed data adds to compute overhead

– Overlays careful memory management

– Memory allocation tools (manage different “flavors” of memory)

Need predictable execution times– Similar to “30Hz frame update” cycle

– Must do it in the face of disabled I/O devices (radio, display, …)

See Regehr’s Embedded System course for details

CS 5961: Networked Game Design Lecture 13

Location Tracking Location Tracking TechnologiesTechnologies GPS:

– Typical accuracy is 15 meters

– Signal can be disrupted by other electromagnetic radiation

– Limited effectiveness inside buildings (metal blocks signals)

WLAN triangulation:– Typical accuracy is 1-5 meters but high variance

– Requires multiple WLAN access points to triangulate signal power

– Somewhat effective indoors

– Multipath problems (reflections, signal loss)

RFID:– Can be highly accurate (under 1 meter), but very short range

– Increasingly common and available

CS 5961: Networked Game Design Lecture 13

Getting StartedGetting Started Develop on software emulators

– SDK/emulators typically free

Getting certified for deployment can cost a couple thousand dollars

– Need to test for compatibility & safety

To actually sell your game:– Need to partner with carriers (typical)…

– … or market via web to “expert users”

– Most cell users have no clue how to download and install applications

BREWtoolkit

J2MEtoolkit

CS 5961: Networked Game Design Lecture 13

Possible Future DevelopmentsPossible Future Developments Growth of interactive / “alternate reality” games

– Example: PacManhattan (NYU)

» Five players on the street, five in a control room

» Simple (cell voice based), but effective

– Successfully used as a form of viral marketing

Wearable computing– Computer is always with you unobtrusive as clothing

– Hands-free use, many sensors, embedded in real world

CS 5961: Networked Game Design Lecture 13

““10 Hot Trends in Mobile 10 Hot Trends in Mobile Gaming”Gaming”1. Advertising-supported games

2. Direct-to-consumer3. Next generation N-Gage4. More connectivity and multiplayer5. Tetris will sell millions of downloads6. More crossover with Web and online gaming7. 3D gaming will take off (handheld consoles)8. Flash Lite will make an impact9. Mobile game audio finally gets some props10. More camera and location-based games

Ref: http://www.pocketgamer.co.uk/r/Mobile/feature.asp?c=2075