Using Telephone and Cable Networks for Data Transmissions : Data Communication and Computer Networks Asst. Prof. Chaiporn Jaikaeo, Ph.D. Computer Engineering Department Kasetsart University, Bangkok, Thailand Adapted from lecture slides by Behrouz A. Forouzan © The McGraw-Hill Companies, Inc. All rights reserved

2 Outline Telephone lines Telephone lines Dial-up modems Dial-up modems Digital Subscriber Line (DSL) Digital Subscriber Line (DSL) Cable TV networks Cable TV networks

3 Telephone Lines Traditional telephone lines can carry frequencies between 300 and 3300 Hz Traditional telephone lines can carry frequencies between 300 and 3300 Hz Giving them a bandwidth of 3000 Hz Giving them a bandwidth of 3000 Hz All this range is used for transmitting voice All this range is used for transmitting voice A great deal of interference and distortion can be accepted without loss of intelligibility A great deal of interference and distortion can be accepted without loss of intelligibility

4 Telephone Line Bandwidth

5 Dial-Up Modems Modem stands for modulator/demodulator.

6 V.32 and V.32bis

7 56K Modems

8 Digital Subscriber Line (DSL) Provides higher-speed access to the Internet Provides higher-speed access to the Internet Supports high-speed digital communication over the existing local loops Supports high-speed digital communication over the existing local loops The existing local loops can handle bandwidths up to 1.1 MHz. The existing local loops can handle bandwidths up to 1.1 MHz.

9 ADSL ADSL – Asymmetric Digital Subscriber Line ADSL – Asymmetric Digital Subscriber Line Downstream bit rate > upstream bit rate Downstream bit rate > upstream bit rate Designed for residential users Designed for residential users Unsuitable for businesses Unsuitable for businesses ADSL operates on existing local loops ADSL operates on existing local loops Local loops can handle up to 1.1 MHz of bandwidth Local loops can handle up to 1.1 MHz of bandwidth The distance limit is ~18,000 feet The distance limit is ~18,000 feet The system uses a data rate based on the condition of the local loop line The system uses a data rate based on the condition of the local loop line

10 Bandwidth Division in ADSL

11 Discrete Multi-Tone Modulation Or DMT, based on OFDM (Orthogonal Frequency-Division Multiplexing) technique Or DMT, based on OFDM (Orthogonal Frequency-Division Multiplexing) technique

12 Allocation and modulation of each channel are determined adaptively 4 kHz Bandwidth Division

13 Voice – Channel 0 Voice – Channel 0 Idle – Channels 1-5 Idle – Channels 1-5 Upstream – Channels 6-30 Upstream – Channels data channels, 1 control channel 24 data channels, 1 control channel 1.44 Mbps (max) upstream bit rate 1.44 Mbps (max) upstream bit rate Actual bit rate: 64 Kbps to 1 Mbps Actual bit rate: 64 Kbps to 1 Mbps Downstream – Channels Downstream – Channels data channels, 1 control channel 224 data channels, 1 control channel 13.4 Mbps (max) downstream bit rate 13.4 Mbps (max) downstream bit rate Actual bit rate: 500 Kbps to 8 Mbps Actual bit rate: 500 Kbps to 8 Mbps Bandwidth Division

14 ADSL Customer Residence

15 DSL Access Multiplexer Or DSLAM Or DSLAM

16 Other DSL Technologies HDSL – High-bit-rate DSL HDSL – High-bit-rate DSL VDSL – Very-high-bit-rate DSL VDSL – Very-high-bit-rate DSL SDSL – Symmetric DSL SDSL – Symmetric DSL ADSL2 ADSL2 ADSL2+ ADSL2+ See also See also Source: AWARE. ADSL2 and ADSL2+ The new ADSL standard.

OFDM Orthogonal Frequency-Division Multiplexing Orthogonal Frequency-Division Multiplexing Widely used in wideband digital communications Widely used in wideband digital communications Digital TV Digital TV ADSL ADSL Powerline communications Powerline communications Wireless networks: Wi-Fi, WiMAX Wireless networks: Wi-Fi, WiMAX 4G mobile communications 4G mobile communications 17

OFDM Concept Sub-carriers are orthogonal to each other Sub-carriers are orthogonal to each other No cross-talk; guard bands not necessary No cross-talk; guard bands not necessary 18 Source:

Orthogonality in OFDM 19 Frequency (Hz) t 20 ms Hz t Hz t Hz

OFDM Implementation 20 Source: Wikipedia

21 Cable TV Networks Started as a video service provider, then moved to the business of Internet access Started as a video service provider, then moved to the business of Internet access

22 Hybrid Fiber-Coaxial Network Or HFC Or HFC Bidirectional communication is achieved Bidirectional communication is achieved

23 Data Transfer over CATV Standard: DOCSIS (Data Over Cable Service Interface Specification) Standard: DOCSIS (Data Over Cable Service Interface Specification) Division of coaxial cable band by Cable TV Division of coaxial cable band by Cable TV Theoretical downstream data rate is 30 Mbps Theoretical downstream data rate is 30 Mbps Theoretical upstream data rate is 12 Mbps Theoretical upstream data rate is 12 Mbps

24 Cable Modem

25 Cable Modem Transmission System Or CMTS Or CMTS

26 Fiber To The X Optical broadband network architectures Optical broadband network architectures Fiber-to-the-node Source: Wikipedia Fiber-to-the-curb Fiber-to-the-building Fiber-to-the-home