Convergence of Optical and Wireless Convergence of Optical and Wireless Access Networks Access Networks Gee-Kung Chang Byers Eminent Scholar Chair Professor School of Electrical and Computer Engineering Georgia Institute of Technology Atlanta, GA 30332-0250 OFC 2008 Workshop San Diego, California February 25, 2008
Outline • Convergence of Broadband Networking • Integrated Optical Wireless Access Networks • Optical Wireless Signal Generation – Up-conversion of optical wireless signal – Multi-band wireless signals • Optical Wireless Network Architecture – Dual Services: Wired and Wireless – Wavelength Reuse for Full-duplex Connection • Technology Challenges • Conclusions 2
Broadband Networking Trends Meet the needs of future end-to-end, dynamic and flexible Internet services Convergence of Voice, Data, Video and Interactive Multimedia Services Convergence of Voice, Data, Video and Interactive Multimedia Services Convergence of High Speed DWDM Metro and WAN Networks Convergence of High Speed DWDM Metro and WAN Networks Convergence of Wireless and Wired Networks Convergence of Wireless and Wired Networks 3
Opportunities of using 60GHz mm-Wave for Wireless Services Space and fixed & mobile apps. Space and fixed & mobile apps. Wireless LAN Wireless LAN Prohibited Prohibited Japan Unlicensed Unlicensed E.U. Wireless LAN Wireless LAN Pt.- Pt. -to to- -Pt. Pt. Unlicensed Unlicensed U.S. M M S S I I 56 57 58 59 60 61 62 63 64 65 66 56 57 58 59 60 61 62 63 64 65 66 GHz GHz There is a license free band near There is a license free band near 60GHz. There is up to 8 GHz antenna 60GHz. There is up to 8 GHz antenna resonant bandwidth available for resonant bandwidth available for wireless communications . . wireless communications It can provide super broadband It can provide super broadband wireless data links at > 1Gb/s. wireless data links at > 1Gb/s. 4
Convergence of Broadband Access Networks 10Mb/s --- 100Mb/s 1Gb/s --- 10 Gb/s Next Generation Optical Wireless WiMAX WiFi Wireless 2.5, 3.5GHz 2.4GHz (802.11b/g) Access Networks 5GHz (802.11a) 10, 26GHz MVDS MBS 40GHz 60GHz UWB 3-10GHz MMDS LMDS Millimeter Region Capacity 2-3GHz 26-29GHz D a Frequency t a R a TDM- -PON PON TDM t WDM WDM e WDM GPON GPON PON PON PON Mobility Wireline 2.5Gb/s EPON EPON 1.25Gb/s BPON Copper Copper BPON 622Mb/s APON APON ADSL/ ADSL/ Fiber Fiber 10G TDM- -PON PON 155Mb/s 10G TDM Cable Cable <10Mb/s Time 5
Optical Wireless Network Applications Emerging applications requiring super broadband optical-wireless access: • HDTV distribution • Interactive multimedia games • High-speed wireless (>1Gb/s) data access • High Mobility Communications - Base Station handoff - vehicle speed, bandwidth, and packet length 6
Wireless over Optical Transport Technologies Data/Video Source RF Data/ Center Passive Optical/ RF Data/ Passive Optical/ optical Optical RF Data optical Optical RF Data interface Users network Interface Optical interface Users network Interface Metro Network Central Office Remote Node Base Station Wireless Optical mm-wave Optical networking, Radio air interface Network generation, modulation transmission and integration Bidirectional transmission and up-conversion with WDM PON Wired and wireless service delivery • Coverage • Bandwidth � Optical fiber links for long distance � >1 Gb/s for both directions • Multi-channel Capacity • Mobility � Seamless integration with WDM PON � RF wireless for roaming � All-optical methods for architecture connection design 7
Spectrum of Optical Wireless Signals 2.5Gbit/s DC: V π Optical Wireless Baseband DFB-LDMOD RF at 40GHz PD 20GHz m) Dual Stage Modulation using wer (dB Optical carrier suppression Po There are two components of electrical signals after all-optical up-conversion: 0 20 40 60 one part occupies the baseband, Frequency (GHz) the other occupies high-frequency band near 40 to 60GHz. 8
Up-Conversion Based on External Modulation 1 0 2.5 Gb/s 40GHz DSB B-T-B 0 Optical power (dBm) 4 0 G H z 4 0 G H z -1 0 -2 0 -3 0 -4 0 2km -5 0 MZM1 MZM2 -6 0 DFB LD -7 0 V π DC Bias: 0.5 1 5 5 4 .0 1 5 5 4 .5 1 5 5 5 .0 1 5 5 5 .5 W a v e le n g th (n m ) π Shift SSB 40GHz 2 10 40GHz 2.5 Gb/s B-T-B 0 Optical power (dBm) -10 -20 -30 -40 40km -50 DC: 0.5 V π MZM1 -60 DFB LD -70 1554.0 1554.5 1555.0 1555.5 Dual-arm MZM W avelength (nm) π OCS Shift B-T-B 10 2.5 Gb/s 40GHz 20GHz 0 Optical power (dBm) -10 -20 -30 40km -40 MZM1 V π DC: -50 DFB LD -60 Dual –arm MZM 1554.0 1554.5 1555.0 1555.5 Wavelength (nm) DSB: Double sideband; SSB: Single sideband; OCS: Optical carrier suppression 9
32-Channel DWDM ROF Transmission based on OCS external modulation 1ns/div Base Station Core or Metro network Central Office 10GHz Clock π Remote Node DFB LD 1 Shift 2.5 Gb/s MUX 1:4 20GHz 40km SMF 40km SMF TOF2 BERT EA Mixer V π 50GHz EDFA PIN Dual–arm MZM 100ps/div DFB LD 32 Demux AWG - 1 0 0 (i) (ii) - 1 0 - 2 0 Relative optical power Relative optical power - 2 0 - 3 0 - 3 0 - 4 0 - 4 0 - 5 0 - 5 0 - 6 0 - 6 0 - 7 0 - 7 0 1 5 3 5 1 5 4 0 1 5 4 5 1 5 5 0 1 5 5 5 1 5 6 0 1 5 3 6 1 5 4 4 1 5 5 2 1 5 6 0 W a v e le n g th (n m ) W a v e le n g th ( n m ) 10
Transmission of 32-Channel ROF Signals -3 4 Receiver sensitivity (dBm) B -T -B A fte r 4 0 k m -3 6 -3 8 -4 0 -4 2 32 DWDM ROF channels -4 4 1 5 3 5 1 5 4 0 1 5 4 5 1 5 5 0 1 5 5 5 1 5 6 0 W a v e le n g th (n m ) Power penalty is less 2dB for all channels. J. Yu, Z. Jia and G. K. Chang, ECOC 2005, Post Deadline, 2005, Th 4.5.4. 11
Key Technologies for RoF Signal Generation Multiple Bands RF Signal Multiple Bands RF Signal Generation: Generation: Microwave and Millimeter- -Wave Wave Microwave and Millimeter 12
Multiple RF Signal Generation Relative Optical Power (dBm) Data 1 Data 2 (ii) 0 750Mb/s 750Mb/s Microwave -20 -40 18GHz 6GHz -60 Mixer -80 1539 1540 1541 1nm Coupler EA 20km O/E SMF-28 12GHz 0.3nm Received power DFB-LD LN-MOD LPF TOF 1nm DC: Vpi IL Relative Optical Power (dBm) Data 2 (i) 0 Relative Optical Power (dBm) EDFA 0.3nm 0 -20 (iii) -20 -40 36GHz -40 mm-wave -60 -60 LPF -80 1539 1540 1541 -80 1539 1540 1541 Wavelength (nm) Data 1 Wavelength (nm) 13
Optical Wireless Access Network Architecture Design Full- -Duplex Operation Based on Duplex Operation Based on Full Wavelength Reuse for Upstream Wavelength Reuse for Upstream 14
Full-Duplex Colorless Transmission for Uplink ƒ mm-wave ƒ mm-wave CS BS Downlink Data Antenna Downlink RF MZM Duplexer PIN OC CW PM SMF FBG EA PS TD ƒ carrier Uplink Mixer Interleaver SOA Data Uplink Uplink Receiver � At CS, Phase modulation and the subsequent interleaver for optical mm-wave generation. � At BS, FBG is used to reflect the optical carrier while pass the downlink mm-wave signal. � At BS, SOA performs the function of both amplification and modulation. 15
Multi-Standards Wireless Transmission • Various wireless services can share common fiber infrastructure. • A testbed setup consisting of four wireless standards were simultaneously transmitted to stress the ROF distribution network. • 802.11g, WCDMA, GSM and PHS were combined electrically and distributed via 300m of MMF ROF system. 16
What’s Next? Wireless over fiber systems using ROF technologies operating in the 0.8-2.5GHz band have been demonstrated • Moving from RF and microwave to mm-wave carriers for high bandwidth services • Moving from point-to-point links to point to multiple points network architectures • Moving from low mobility wireless over fiber systems to high speed moving trains and planes - Howl’s Moving Castle? • Facilitating new system architecture and new applications 17
Future Considerations and Challenges (1) • Optical technology – Improve efficiency, simplicity and stability of signal generation and up-conversion for the optical wireless systems; – Increase the wavelength utilization efficiency in full- duplex operation when integration with WDM PON; – Mitigating the optical mm-wave signals transmission impairment, particularly for the dispersion tolerance. 18
Future Considerations and Challenges (2) • Electrical components and interfaces – Low profile, high gain, high frequency antenna and mixer design; – 40GHz, 60GHz and beyond optical millimeter carrier wave characteristics; – Improvement for wireless signals synchronization, interference and stability. mm-wave bands • O/E and E/O Interfaces – Requirement for power, noise, bandwidth and coding methods; – Standardization issues. 19
Conclusions • Optical wireless signal generation and up-conversion techniques play key roles in realizing RoF network. • A novel architecture is developed for bidirectional wireless and optical access network integrated with WDM-PON with wavelength reuse in base stations. – Demo of uncompressed HDTV over both wireline and wireless links • Technology challenges are ahead of us: – low-cost optical and RF components, – optical wireless system interface, – optical wireless protocols, and standardization. 20
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