31-08-2013, 04:58 PM
Cellular Networks: Architectural and Functional Overview, Evolving Trends, and Clean Slate Design Paradigms
Cellular Networks: Architectural .ppt (Size: 336 KB / Downloads: 61)
Agenda
Basics & Technology Evolution
Architecture and Functionality (GSM, 3G and beyond)
Cellular future goals (2010 and beyond)
Emerging trends
Alternative wireless access technologies
Convergence
Comparison with Internet and sample scenario studies
Economics of operation
From a clean slate
Some More Basics
Uplink & Downlink separated in
Time: Time Division Duplex (TDD), or
Frequency: Frequency Division Duplex (FDD)
Information (voice, data) is digitized and bit streams modulated onto carrier
Modulation, data redundancy (coding), transmission power, data retransmissions (ARQ) adapted to varying wireless channel quality
Spatial attenuation of signal
Frequency or codes can be reused (frequency reuse)
Global System for Mobile communications (GSM)
900/1800 MHz band (US: 850/1900 MHz)
For 900 MHz band
Uplink: 890-915
Downlink: 935-960
25 MHz bandwidth - 124 carrier frequency channels, spaced 200KHz apart
Time Division Multiplexing for 8 full rate speech channels per frequency channel.
Circuit Switched Data with data rate of 9.6 kbps
Handset transmission power limited to 2 W in GSM850/900 and 1 W in GSM1800/1900.
UMTS and 3G technologies
(WCDMA & HSPA)
Universal Mobile Telecommunications System (UMTS) - WCDMA as the underlying interface
Supports up to 14 Mbps rates with HSDPA (typical present deployed rates per user 384kbps)
Frequency bands
1885-2025 Mhz (uplink), 2110-2200 Mhz (downlink)
US: 1710-1755 MHz and 2110-2155 MHz
W-CDMA has 5 Mhz wide radio channels (CDMA2000 transmits on one or several pairs of 1.25 Mhz radio channels).
HSDPA allows networks based on UMTS to have higher data rates (1.8. 3.6, 7.2, 14.4 Mbps via AMC, and HARQ, fast packet scheduling.
UMTS air interface forms Generic Radio Access Network (GeRAN) which can be connected to various backbone networks like the Internet, ISDN, GSM or UMTS.
Using PCMCIA or USB card, or cellular router customers are able to access 3G broadband services