TLMN645 CLASS 10 Fall2002 US -Wide Wireless Data Systems (non-paging) Wireless Data System Applications • Field Service • Transportation and Dispatch • Point of sale • Public Safety • Healthcare • Wireless Telemetry • Electronic Message (wireless email) • Wireless Internet (WiFi) Applications Field Service Point of Sale Communication Source: Bell South Mobile Data Applications • Narrowband -low throughput- under 19.2 kb/s • Best for file sizes under10 -20 kB • Charge by the packet • Have store and forward capabilities Wireless Data, PDAs CDPD (Cellular Digital Packet Data) • Concept : Utilize idle cellular channels to send bursts of data at 19.2 kb/s (real data 9.6 kb/s • Concept: Transmitter hops around finding idle channels and leaves channels when they become active • Operation sometimes on dedicated channels CDPD CHARCTERISTICS • Data Rate 19.2 Kbits/ second • CDPD also supports IP multicast (one-to-many) service. • CDPD packets use forward error correction methods that reduce the effects of noise and interference on the airlink. • CDPD incorporates authentication and encryption to all packet transmissions over the airlink. CDPD Exploits Idle Time • Find a space and fill it. – The transmission across cellular telephone channels are more than 30% idle, even during heavy traffic times. CDPD exploits this idle time by detecting these times and utilize the otherwise wasted moment. It packages data in small packets and sends it in short bursts during idle time. This allows CDPD to not only enhance the efficiency of the cellular network but remain completely transparent within it. CDPD Infrastructure (two networks) CDPD is a separate overlay Source: Northwestern University CDPD Operations • Mobile Data Base Station (MDBS) is sited within the cell site and utilizes the same antenna structure as the cellular system • Each channel can be accessed by up to 30 CDPD users at a time since packet data • access by CSMA- all listen- no dedicated time slot for each user • Utilizes IP protocol Source: Northwestern University Parts of CDPD Network CDPD Coverage 2001 Verizon Mobile IP (CDPD) $55/ month unlimited (CDPD) -Maryland National Capitol Park Police Source: Wireless Data Forum CDPD from PDA Minstrel m500 Fits Palm m500 series Cingular Interactive (Previously Bell South Mobile Data ) • 1000 base stations in US, NJ control center • Focuses on airports, transportation corridors, hotels, i.e. business travelers • Operates on 12.5 kHz channels in 800/900 MHz • 8kb/s raw data rate, user throughput 4 kb/s • Packet data with FEC capable of repairing up to 20 consecutive errors Wireless Data Terminal (Cingular Interactive ) Wireless Data Infrastructure (example: Cingular Interactive Wireless Data) Wireline Local Control Center Switch New Jersey Base Station User Terminal Cingular Interactive Data National Coverage Cingular (Bell South) Mobitex Coverage Palm VII • Provides Internet Connectivity via Cingular Interactive • 260 cities • Web clippings rather than whole pages • Costing issues: – per byte charge Security for Cingular Interactive Motient History • Initially 1990 for field service IBM • Covers 430 markets & Puerto Rico, Vir. Is. • 25 kHz chs. in 800 MHz, 1600 base stns. • User throughput about 2 kb/s moving to 12.8 kb/s. Good indoor coverage (Explain) • Combined with American Mobile Satellite to form integrated network. Path chosen is the shortest delay (terrestrial, satellite) Motient Coverage Motient Coverage ARDIS Coverage Satellite Coverage Source: American Mobile GPRS • . AT&T Wireless has an aggressive schedule for it, intending to create a nationwide GPRS network by year's end (2002). • AT&T is about 60 percent done. It's already launched services using the network, offering a version of the wildly popular I-mode wireless Web service of NTT DoCoMo in Japan. NTT DoCoMo owns about 16 percent of AT&T Wireless. GPRS • Peak data rates for its GPRS service should reach 115 kilobits per second, though early results in launched markets have yielded between 20 kbps and 40 kbps at customer's handsets. GPRS Technology • GPRS currently supports an average data rate of 115 Kbps, but this speed is only achieved by dedicating all eight time slots to GPRS.3 Instead, carriers and terminal devices will typically be configured to handle a specific number of time slots for upstream and downstream data. For example, a GPRS device might be set to handle • a maximum of four slots downstream and two slots upstream. Under good radio conditions, this yields speeds of approximately 50 Kbps downstream and 20 Kbps upstream. GSM TIME SLOTS ATT GPRS Network (2002) • The network, which will cover 6,000 cities, will allow users to access services at up to 56 kilobits per second Available handsets (Motorola T193) sell for $50 • Add-on pricing plans for the T193 will start at $3 per month for 1 megabyte of data and 300 of the carriers Ping Pong text messages, and $10 for each additional megabyte. 1-megabyte of data is equal to about 500 phone screen pages GPRS Technology • The aggregate cell site bandwidth is shared by voice and data traffic. GPRS operators will vary in how they allocate the bandwidth. Typically, they will configure the networks to give precedence to voice traffic. SPRINT PCS VISION (3G) • Uses CDMA 2000 with bit rate 50-70 kbs • You pay $10 a month on top of most Sprint PCS voice plans for 2 megabytes (MB) of data sent or received; for $20 a month you get 8 MB. You pay an additional 2 cents for each kilobyte of data sent or received in excess of your monthly limit. • Picture sharing. Sprint is selling a $99 digital camera -- $69 out and plugged directly into the Samsung A500 or N400 phones. You can see the pictures on the phone's screen, and send them to friends -- either as e-mail or directly to the screens of other PCS Vision subscribers. SPRINT PCS VISION • PCS Vision made good use of the A500's color screen for features including: • Web access. PCS Vision phones can display Web graphics • Messaging. Electronic mail and short-text messages are easier to read on backlit color screens than the unlighted monochrome screens on older phones. • PCS Vision also supportslive text chat among its subscribers.instant messaging between computers. • Games. For a one-time fee of $1 to $4, PCS Vision subscribers can download simplified games. Blackberry Handhelds Blackberry Networks Use on GPRS and Mobitex • RIM 1902G™ OEM Radio Modem - Operates in the 850/1900 MHz frequency range in North America and is compatible with GSM/GPRS wide-area wireless data and voice communications networks. • RIM 902M™ OEM Radio Modem - Operates in the 900 MHz frequency range and is compatible with Mobitex wide-area wireless data communications networks. Wireless Data Future • Fresh out of bankruptcy (July 2002) wireless data company Motient Corp. is starting business anew hoping not to be overtaken by wireless 3G. • Motient's advantages include: covers all U.S. metropolitan service areas • Always-on packet data network; in-building penetration; • United Parcel Service's delivery personnel nationwide use Motient services when they log package pickup and delivery information via their specialized handheld devices.
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