tailieunhanh - OFDM Physical Layer - Fundamentals, Standards, & Advances

Time Division Multiple Access (TDMA) is the most prevalent wireless access system to date GSM, ANSI-136, EDGE, DECT, PHS, Tetra. Direct Sequence Code Division Multiple Access (DS-CDMA) became commercial only in the mid 90’s IS-95 (A,B, HDR,1x,3x,.), cdma-2000 (3GPP2), W-CDMA (3GPP) | OFDM Physical Layer -- Fundamentals, Standards, & Advances K. Giridhar Associate Professor of Electrical Engineering Telecom and Computer Networks (TeNeT) Group IIT Madras, Chennai 600036 Instructional Workshop on Wireless Networks : Physical Layer Aspects DRDO-IISc Program on Mathematical Engineering, Feb. 14, 2003 IEEE Symp./ IISc -2001 KG/ICPWC-2000IIT Madras Contents Wireless Propagation -- Overview OFDM Fundamentals Comparing TDMA, CDMA, and OFDM OFDM Standards Case Study: IEEE OFDM WLAN Key Advances in Wireless Technology Space-Time Processing for OFDM Summary IEEE Symp./ IISc -2001 KG/ICPWC-2000IIT Madras Basics of Radio Propagation Distance Power 10-100 m (1-10 secs) -1 m (10-100 msecs) Exponential Long-term Fading Short-term Fading IEEE Symp./ IISc -2001 KG/ICPWC-2000IIT Madras Multi-path Propagation r(t) = a0 s(t-t0) + a1 s(t-t1) + a2 s(t-t2) + a3 s(t-t3) IEEE Symp./ IISc -2001 KG/ICPWC-2000IIT Madras Multi-path . | OFDM Physical Layer -- Fundamentals, Standards, & Advances K. Giridhar Associate Professor of Electrical Engineering Telecom and Computer Networks (TeNeT) Group IIT Madras, Chennai 600036 Instructional Workshop on Wireless Networks : Physical Layer Aspects DRDO-IISc Program on Mathematical Engineering, Feb. 14, 2003 IEEE Symp./ IISc -2001 KG/ICPWC-2000IIT Madras Contents Wireless Propagation -- Overview OFDM Fundamentals Comparing TDMA, CDMA, and OFDM OFDM Standards Case Study: IEEE OFDM WLAN Key Advances in Wireless Technology Space-Time Processing for OFDM Summary IEEE Symp./ IISc -2001 KG/ICPWC-2000IIT Madras Basics of Radio Propagation Distance Power 10-100 m (1-10 secs) -1 m (10-100 msecs) Exponential Long-term Fading Short-term Fading IEEE Symp./ IISc -2001 KG/ICPWC-2000IIT Madras Multi-path Propagation r(t) = a0 s(t-t0) + a1 s(t-t1) + a2 s(t-t2) + a3 s(t-t3) IEEE Symp./ IISc -2001 KG/ICPWC-2000IIT Madras Multi-path Propagation -- contd. r(t) = a0 s(t-t0) + a1 s(t-t1) + a2 s(t-t2) + a3 s(t-t3) channel Input (Tx signal) Output (Rx signal) Impulse Response h(t) t3 - t0 time a3 a0 freq. Frequency Response H(f) IEEE Symp./ IISc -2001 KG/ICPWC-2000IIT Madras Frequency Selective Fading Time secs secs secs Delay Spread rms = 5msecs Gain (in volts) Fading Frequency Selective Fading Channels can provide -- time diversity (can be exploited in DS-CDMA) -- frequency diversity (can be exploited in OFDM) IEEE Symp./ IISc -2001 KG/ICPWC-2000IIT Madras Contents Wireless Propagation -- Overview OFDM Fundamentals Comparing TDMA, CDMA, and OFDM OFDM Standards Case Study: IEEE OFDM WLAN Key Advances in Wireless Technology Space-Time Processing for OFDM Summary IEEE Symp./ IISc -2001 KG/ICPWC-2000IIT Madras TDMA, CDMA, and OFDM Wireless Systems Time Division Multiple Access (TDMA) is the most prevalent wireless access system to date GSM, ANSI-136, EDGE, DECT, PHS, Tetra Direct Sequence Code

• Quản trị mạng
• OFDM Wireless Systems
• Time Division Multiple Access
• Multiple Access Techniques
• Packet Switched Air Interface
• Generic OFDM Transmitter
• Phy Layer Issues
• Wireless Communications
• Multitaper Analysis
• OFDM Systems
• Multiple antenna systems
• space time processing
• Performance Characterization
• báo cáo khoa học
• báo cáo hóa học
• công trình nghiên cứu về hóa học
• tài liệu về hóa học
• cách trình bày báo cáo
• wireless lans
• network systems
• network equipment
• network operators
• network security
• computer network