1. COMT 3911 Cellular/PCS, Wireless Data Technical Issues COMT 391 Wireless

2. COMT 3912 Overview Cell Layout Site Survey Signaling Mobile Operation

3. COMT 3913 System Block Diagram Cellular/PCS MobileBTSBSCMTSOPSTN Data Bases forward reverse BTSBase Tranceiver Station BSCBase Station Controller MTSOMobile Telephone Switching Office Radio LinkBearer Trunk Signaling Trunk

4. COMT 3914 Frequency Reuse Pattern

5. COMT 3915 Example: AMPS 50MHz spectrum 30kHz per channel per direction 832 total full-duplex channels 4, 7, and 12 cell clusters used

6. COMT 3916 AMPS cont. 832 channels (2 frequencies per channel) –Forward: 869-894 MHz –Reverse: 824-849MHz –Forward/Reverse Spacing: 45MHz –Adjacent Channel Spacing: 30kHz –21 Control Channels per group Cell Sizes: 2-20km

7. COMT 3917 Antenna Placement - high Good Coverage Co-Channel Interference Problems

8. COMT 3918 Buildings as Boundaries Cell Limits Defined Possible Adjacent Channel Interference

9. COMT 3919 Interference Co-Channel Interference Adjacent Channel Interference Outside Sources

10. COMT 39110 Signaling Channels Dedicated Control Channels (CC) –Mobile will scan for the strongest control channel when first switched on –System Identification –Number of Paging and Access Channels Paging Channels (PC) –Used to Initiate Calls to a Mobile Access Channels (AC) –Used to Initiate Calls from a Mobile

11. COMT 39111 Call Setup from Mobile Mobile receives AC numbers over PC Mobile finds the strongest AC Mobile signals (dials) over the AC to the Base Station and the MTSO MTSO transmits the Bearer Channel No.

12. COMT 39112 Mobile-Originated Call, AMPS MobileBTSBSCMTSOPSTN RCC MIN, ESN, dialed no validation FCC Ch No, SAT code, Power FVC SAT RVC SAT FVC RVC Conversation

13. COMT 39113 Call Setup to Mobile PSTN delivers call to MTSO MTSO transmits Mobile ID over all Paging Channels Mobile acknowledges on the strongest Access Channel MTSO selects the voice channel to use MTSO sends voice channel number to mobile

14. COMT 39114 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.

15. COMT 39115 Call Handoff cont… Current base station at MTSO command sends signal to mobile giving the new channel assignment. Mobile tunes to the new channel. Previous base station clears the call path.

16. COMT 39116 Mobile Handset ESN - Electronic Serial Number Programmable NAM (Number Assignment Module) Contains among other things –System ID –First control channel to scan –System selection preferences –MIN (Mobile Identification Number)

17. COMT 39117 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: internal mobile number

18. COMT 39118 Hand-Off MTSO BS MS

19. COMT 39119 Roaming Mobile MTSO Mobile MTSO Mobile

20. COMT 39120 Roaming Details MTSO BS MS MTSO HLR VLR Request Response Billing Information Service Profile Current Location Temporary Directory Number

21. COMT 39121 Intersystem Hand-Off MTSO BS MS MTSO

22. COMT 39122 The “Shoe-Lace” Effect BS MS

23. COMT 39123 Multi-System Tandem MTSO BS MS MTSO

24. COMT 39124 The “Trombone” Effect MTSO BS MS MTSO Fixed Station

25. COMT 39125 Security/Fraud Issues Security –Privacy of Conversations –Denial of Service Fraud –Illegally obtained ESN/MINs –Roaming-related (“tumbling” ESNs)

26. COMT 39126 Classes of Standards Analog Cellular –FDMA - Frequency Division Multiple Access Digital Cellular –FDMA –TDMA - Time Division Multiple Access –CDMA - Code Division Multiple Access

27. COMT 39127 Access Methods Frequency Time Frequency Time Frequency Time FDMA TDMA CDMA

28. COMT 39128 Standards Content Frequency Bands Channel Assignments Voice Encoding Access Method and Frame Structure Signaling Structure

29. COMT 39129 Wireless LAN Short range Single channel (“half-duplex”) Packet-based –Signaling packets –Bearer packets Authentication against back-end data base