Transcript Customer Premise Equipment

Cellular and PCS Technical
Issues
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Overview
• Cell Layout
• Signaling
• Mobile Handset Operation
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System Block Diagram
forward
Mobile
BTS
BSC
MTSO
PSTN
reverse
BTS
Base Tranceiver Station
BSC
Base Station Controller
Data Bases
MTSO Mobile Telephone Switching Office
Radio Link
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Voice Trunk
Data Trunk
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Frequency Reuse Pattern
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First Generation Standards
• AMPS - United States
• TACS - UK
• NTT - Japan
• NMT - Scandanavia
• MATS-E - France
• C-450 - Germany
• GSM - global
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North American AMPS
system
• 50MHz spectrum
• 30kHz per channel per direction
• 832 total full-duplex channels
• 4, 7, and 12 cell clusters used
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AMPS Specifics
• 832 channels (2 frequencies per channel)
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Forward: 869-894 MHz
Reverse: 824-849MHz
Forward/Reverse Spacing: 45MHz
Adjacent Channel Spacing: 30kHz
21 Control Channels per group
• Cell Sizes: 2-20km
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Mobile-Originated Call
Mobile
RCC
BTS
BSC
MTSO PSTN
MIN, ESN, dialed no
validation
FCC
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Ch No, SAT code, Power
FVC
SAT
RVC
SAT
FVC
RVC
Conversation
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Call Handoff
• Base Stations monitor the signal strength
• If strength drops below hand-off level, all
base stations are asked to look for the mobile;
strongest becomes new BS
• MTSO instructs the new base station to
activate a voice channel to receive the
handoff; BS starts transmitting the
Supervisory Audio Tone.
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Call Handoff cont…
• Current base station at MTSO
command sends signal to mobile giving
the new channel assignment.
• Mobile send a signaling tone burst, and
tunes to the new channel.
• Previous base station clears the call
path.
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Mobile Handset
• ESN - Electronic Serial Number
• Programmable NAM (Number
Assignment Module)
• Contains among other things
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System ID
First control channel to scan
A/B system selection
MIN (Mobile Identification Number)
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Mobile Identification Number
• MIN1 - Mobile System Id (3 digits)
– US: Area Code
– International: Mobil Carrier Identifcation
• MIN2 - Station Number
– US: NXX and line number
– International: international mobile number
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Hand-Off
MS
MS
BS
BS
MTSO
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Roaming
MTSO
Mobile
MTSO
Mobile
Mobile
Mobile
Mobile
Mobile
Mobile
Mobile
Mobile
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Intersystem Hand-Off
MS
MS
BS
BS
MTSO
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MTSO
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The “Shoe-Lace” Effect
MS
BS
BS
BS
BS
BS
BS
BS
BS
MS
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Multi-System Tandem
MS
MS
BS
MTSO
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BS
MTSO
MTSO
MTSO
MTSO
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Automatic Roaming
MS
BS
Request
MTSO
MTSO
Response
HLR
HLR
VLR
Billing Information
Service Profile
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Current Location
Temporary
Directory Number
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The “Trombone” Effect
MS
BS
MTSO
MTSO
Fixed Station
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Second Generation Systems
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Classes of Standards
• Analog Cellular
– FDMA - Frequency Division Multiple
Access
• Digital Cellular
– FDMA
– TDMA - Time Division Multiple Access
– CDMA - Code Division Multiple Access
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Access Methods
Frequency
Frequency
FDMA
Time
Frequency
Time
CDMA
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TDMA
Time
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Systems and Frequencies
• Advanced mobile phone service (AMPS)
– 824 to 849 MHz and 869 to 894
• Digital-advanced mobile phone service (DAMPS)
– 824 to 849 MHz and 869 to 894
• Global system for mobile communications
(GSM)
– 450 MHz, 890 to 960 MHz, 1.8 GHz, 1.9
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Systems cont.
• Personal communications service
(PCS)
– 1.9 GHz
• Nextel and other specialized mobile
radio (SMR)
– 816 MHz to 866 MHz
• Cellular digital packet data (CDPD)
– 824 to 894 MHz, 1.8 GHz to 1.9 GHz
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3rd Generation Wireless Service
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“3G” Definition
• From the FCC Web Site:
– 144 kbps (vehicular traffic) to 2 Mbps for
indoor traffic
– Common billing and user profile services
– Bandwidth on demand
– Fixed and variable bit rates
– Multimedia store-and-forward messaging
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Background
• ITU Specifications
– FPLMTS (future public land mobile
telecommunication systems)
– IMT-2000
• Frequency bands identified at the 1992
and 200 World Radio Conferences
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Technical Specs
• Wideband CDMA (5MHz channel)
• CDMA2000 (1.25-15MHz channels)
– Based on TIA/EIA 95 B
• CMDA Time Division Duplex
• TDMA Single Carrier
• DECT (TDMA/FDMA)
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Frequencies
• ITU Recommendations:
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1885-2025 MHz
2110-2200 MHz
806-960 MHz
1710-1885 MHz (1755-1850 studied by
NTIA)
– 2500-2690 MHz (Studied by FCC)
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