Chi-Cheng Lin, Winona State University CS412 Introduction to Computer Networking & Telecommunication DSL, Cable, and Mobile Telephone System

2 Topics l Digital Subscriber Line l Cable l Mobile Telephone System

3 Digital Subscriber Lines l Bandwidth versus distanced over category 3 UTP for DSL.

4 Digital Subscriber Lines l Operation of ADSL using discrete multitone modulation.

5 Figure 9.1 DMT

6 Figure 9.2 Bandwidth division

7 Digital Subscriber Lines l A typical ADSL equipment configuration.

8 Figure 9.3 ADSL modem

9 Figure 9.4 DSLAM

10 Wireless Local Loops l Architecture of an LMDS system.

11 Cable Television l Community Antenna Television l Internet over Cable l Spectrum Allocation l Cable Modems l ADSL versus Cable

12 Community Antenna Television l An early cable television system.

13 Internet over Cable l Cable television

14 Compared to Telephone System l The fixed telephone system.

15 Spectrum Allocation l Frequency allocation in a typical cable TV system used for Internet access

16 Cable Modems l Typical details of the upstream and downstream channels in North America.

17 Figure 9.8 Cable modem

18 Figure 9.9 CMTS

19 ADSL versus Cable l Discussions …

20 Mobile Telephone System l First-Generation Mobile Phones  Analog Voice l Second-Generation Mobile Phones  Digital Voice l Third-Generation Mobile Phones  Digital Voice and Data

21 Advanced Mobile Phone System l Area is divided into cells with an antenna control by a cell office in each cell l Cell offices communicate with MTSO l Transmission frequencies cannot be the same in adjacent cells l Cell size is not fixed  Smaller cells used in higher populated area

Figure 7-36 WCB/McGraw-Hill  The McGraw-Hill Companies, Inc., 1998 Cellular System

23 Advanced Mobile Phone System (a) Frequencies are not reused in adjacent cells. (b) To add more users, smaller cells can be used.

24 Figure 17.2 Frequency reuse patterns

25 Cellular Transmission l Traditionally analog  FM used to minimized noise l Digital transmission  CDPD (Cellular Digital Packet Data)  Low-speed digital service over existing cellular network  Based on OSI Model  Modem needed

26 Cellular System l Handoff  When a mobile telephone leaves a cell 1. Its base station notices the signal fading out 2. The base station asks all the surrounding base stations how much power they are getting from it 3. Ownership is transferred to the neighbor base station that receives strongest power 4. The telephone is informed of its new boss 5. If a call is in progress, it will be asked to switch to a new channel

27 Channels l 832 full-duplex channels  Each channel consists of 2 simplex channels  Transmission channels  ( )MHz/30KHz  832  Receiving channels  ( )MHz/30KHz  832 l Typically, actual number of voice channel per cell  45

28 Channel Categories l The 832 channels are divided into four categories  Control (base to mobile) to manage the system  Paging (base to mobile) to alert users to calls for them  Access (bidirectional) for call setup and channel assignment  Data (bidirectional) for voice, fax, or data

29 Second-Generation Mobile Phones l D-AMP l GSM l CDMA

30 D-AMPS Digital Advanced Mobile Phone System (a) A D-AMPS channel with three users. (b) A D-AMPS channel with six users.

31 GSM Global System for Mobile Communications l GSM uses 124 frequency channels, each of which uses an eight-slot TDM system

32 GSM l A portion of the GSM framing structure.

33 Third-Generation Mobile Phones: Digital Voice and Data l Basic services an IMT-2000 network should provide  High-quality voice transmission  Messaging  Replace , fax, SMS, chat, etc.  Multimedia  Music, videos, films, TV, etc.  Internet access  Web surfing, w/multimedia l 2.5G, 4G, …