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OFDM Platform Services, Technology, Architecture and Concepts

OFDM Platform Services, Technology, Architecture and Concepts. Marianna Goldhammer Director, Product Management. Provider view.

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OFDM Platform Services, Technology, Architecture and Concepts

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  1. OFDM PlatformServices, Technology, Architecture and Concepts Marianna Goldhammer Director, Product Management

  2. Provider view • “I believe that OFDM can get us to the next generation of services and availability, not so much because I just love OFDM but rather that it will increase our reachability, especially in the upstream," said WorldCom's Mapes. • “For example, a carrier could hypothetically cover a densely populated sector such as the San Francisco Bay area with 25 cells sites instead of 120.” – Telecommunications Online, feb. 2001.

  3. Target Markets • SME • SoHo • Telecommuters • High-end consumers • Mass deployment (ASIC phase)

  4. BreezeCOM OFDM Market by Segments BS Interfaces User Services Broadband Legacy Services >25GHz N*E1 10/100BaseT ATM 10/100BaseT QoS: Voice/Tel. Part. E1 Leased Line VPN 2.5-11GHz IP IP Broadband Telephony <2.4GHz Telephony Modem E1 Telephony

  5. Business market structure Source: ETSI BRAN HMAN DTR 101 856

  6. Residential Market Structure Source: ETSI BRAN HMAN DTR 101 856

  7. Services • Internet access • Telephony • VPN • Leased Line voice (with IP Mux) • Leased Line data • Point-to-Point IP backbone connection

  8. Multipath Multipath Multipath Multipath time frequency space

  9. Effect of Multipath: Inter-Symbol Interference (ISI) • Each bit becomes distorted by echoes • The symbols disturb each other Sent data Data and the echoes Resulting waveform

  10. OFDM Modulation Every sub-carrier is QAM modulated

  11. OFDM Technology - 1 • 48 orthogonal carriers,each 4, 16, 64QAM modulated • Time domain signal: IFFT • 4 carriers for clock pilots • FEC: Convolutional encoding, rates: ½, ¾ • SW Viterbi decoding • Symbol level bit interleaving

  12. Multipath effect on OFDM • Each subcarrier is scaled, but they still do not interfere with each other Sent signal Received signal

  13. Guard time and Multipath • The multipath corrupts the Guard Interval • The FFT (demodulation) region remains undistorted symbol GI FFT period Sent signal Received signal

  14. OFDM-Technology - 2 • Multi-pass resistance • Training symbol to learn the channel • Send known symbol (A, Phase) signal • Learn the distortions that the channel introduces • In QAM the adaptive equalization process is very long • Inter-symbol interval • To cover the reflections of the precedent symbol

  15. Performance MMDS, 3MHz channel; ETSI: 3.5MHz channel Sensitivity levels for Packet Error Rate = 1e-2

  16. Spectral Density (dB) 0 -5 -8 -10 -15 System Type E -20 -25 -27 -30 System Type F -32 -35 -38 System Type G -40 -45 -50 -55 f0 A, B C D E F Frequency Reference Points OFDM Masks – EN 301 021

  17. Frequencies • 3.5GHz, FDD • 3.5MHz • 1.75MHz and 3.5MHz, SW selectable • MMDS • 3MHz • 5.8GHz – ISM • 20MHz – UNII • 10MHz ?

  18. System Components • Subscriber Unit • 21dBm linear output power • Base Station Transceiver • Access Units • DSP, ASIC 1 phase: 21dBm output power • Controller/Sync. • Wireless Repeater • ASIC phase • Management Platform

  19. Capacity • A. DSP platform: • up to 12Mb/s • B. ASIC1, ASIC 2 platforms: • up 20MHz channel spacing • up to 70Mb/s

  20. System solution • Data optimized • Leased Line: • Voice: using E1/T1 to IP converters (IP MUX) • MIR = n*64kb/s for direct connection to Routers • Adaptor to E1 • Adaptor to V.35 / X.21 • Adaptor to ISDN • VoIP priority on Ethernet port using: • IP header ToS • IEEE 802.1p • QoS over the air • Collision free • Priority

  21. SU Interfaces • 10 BaseT • 1 - for general Internet • 2 – QoS port - for external VoIP / voice leased line • Voice ports: 1..2

  22. AU Interfaces • 10/100 BaseT for data • 10/100 BaseT with QoS

  23. Other aspects • Entry price: low • Base Station cost: low • price/line: low • good legacy services - data coexistence

  24. Operating concept • VLAN per service • Telephony • Leased Line • Private Network • General Internet access • CIR/MIR per subscriber (SU virtual VLAN port) • PPPoE for mass deployment • VLAN for Management

  25. QoS – network level • IEEE 802.1p • ToS, DiffServ fields in IP header • Internal VoIP – to be marked • External VoIP • to be given priority over the data

  26. QoS – air level • QoS traffic • No contention with data • Priority over data at AU level • Low delay as compared with the codec end-to-end delay • Retransmissions for high reliability • Leased line • Long voice frames • Highest priority – leased line

  27. Security • Encrypted association • Encrypted radio traffic – ASIC phase • VLAN – IEEE 802.1q • SU fire-wall

  28. SU fire wall • Broadcast filtering, • except ARP • PPPoE and DHCP - selectable • Static access lists • Management • VoIP ports • VPN ports • Leased line ports • Protocol filters • IP • PPPoE

  29. Spectral efficiency • Sectorized antenna • H,V polarization • Air Protocol • Bandwidth allocation for time sensitive services • High reliability for data • Support of half-duplex SU • Variable packet length • IP header compression • future

  30. Telephony • H.323 • MGCP (H.248, MEGACO)

  31. Class of Service • MIR, CIR per: • Customer • Service • Physical or virtual port

  32. Base Station redundancy • Power supply • At BCU level • Hot stand-by • ASIC 2 phase

  33. Deployment • SU needs no apriori preparation • PPPoE support • RSSI analog and digital indication • AU measures the RSSI per SU • ATPC • Mass deployment: indoor, one box, integrated antenna

  34. Load Balancing • Load balancing group • Load balancing id • According to the available bandwidth during the operation

  35. Management - 1 • Monitor – on Ethernet port, Windows application • Monitor access • challenge key • 3 access levels • SNMP ver. 3 – ASIC 2 phase • traps • FTP for SW download • 2 images

  36. Management 2 • Platforms • SNMPc • HP OV • HW and SW identifiers

  37. GFSK to OFDM migration • Good performance with 6 sectors deployment • GFSK: • 5 * 1.75MHz = 8.75MHz • OFDM • A. 3*3.5MHz = 10.5MHz, • B. 3*1.75MHz = 5.25MHz for 6sectors! • Total: • A: 19.25MHz • B: 14MHz

  38. Roadmap – release for trials • Phase 1 – DSP based – Q3 2001 • Phase 2 – ASIC1 based – Q2 2002 • Phase 3 – ASIC2 based – Q1 2003 • Residential deployment • Indoor only unit • No host processor

  39. Roadmap - 2 • DSP prototype • Demo trials • SME applications • SoHo • ASIC 2 product • Residential deployment • Full duplex • 802.16.3 air protocol

  40. Thank you!

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