1c1e73b7f0ca7d4e8b0098c3b1c5a1a1.ppt
- Количество слайдов: 9
doc. : IEEE 802 -15 -08 -0133 -00 -0 thz March 2008 Project: IEEE P 802. 15 Working Group for Wireless Personal Area Networks (WPANs) Submission Title: Feasibility of Giga bps data rates at THz frequencies. Shannon based Link budget analysis. Date Submitted: March 17, 2008 Source: Leo Razoumov, David Britz, AT&T Labs Address: AT&T Shannon Labs, 180 Park Ave BLDG 103, Florham Park, NJ 07932, USA E-Mail:
March 2008 Introduction doc. : IEEE 802 -15 -08 -0133 -00 -0 thz High speed Terahertz communications research is still in its infancy and lots of technical issues pertinent to the specifics of Terahertz transceiver technology are yet to be researched, tried and standardized. The Terahertz frequency band lies in the range of 100 GHz – 3 THz in a “no man's land”, i. e it is right between conventional Radio Frequency and Optical Communications. It is not at all obvious that the conventional RF transceiver architecture would be a feasible design for Terahertz communications transceivers. With such a technological uncertainty of the transceiver implementation in analyzing the THz link performance we would prefer to avoid using receiver sensitivity numbers as in [1]. Instead, we base our analysis on the first principles of Shannon Theory. We will also use some “fetch” factors (such as Eb/No) that may depend on future FCC regulations but do not depend on the receiver architecture. Submission 2 Leo Razoumov, David Britz, AT&T Labs
doc. : IEEE 802 -15 -08 -0133 -00 -0 thz March 2008 System model • • Propagation model: Line-of-sight short range (d<10 m) link. Channel model: AWGN (appropriate for line-of-sight links) Modulation scheme: In this analysis we try not to lock into a specific modulation scheme. For instance, it could be coherent (BPSK) or noncoherent (PPM). Bandwidth: We assume that the spectral efficiency is at most 1 bit/Hz/sec. We believe that THz short range communications devices will be power-limited rather than bandwidth limited. In this case there is no need for fancy multilevel modulation schemes. Tx antenna gain: Computed based upon the Tx beam width Rx antenna gain: We assume that all the energy incidental upon the aperture of the receiver antenna is absorbed. No additional directivity gain is considered. Noise & Interference: Due to short communication range we assume the system to be Thermal Noise limited and neglect the interference from other devices. Submission 3 Leo Razoumov, David Britz, AT&T Labs
doc. : IEEE 802 -15 -08 -0133 -00 -0 thz March 2008 Ideal Shannon THz system In what follows we assume a hemisphere Tx beam of 6 steradians and isotropic Rx antenna. Submission 4 Leo Razoumov, David Britz, AT&T Labs
doc. : IEEE 802 -15 -08 -0133 -00 -0 thz March 2008 More realistic link budget • More realistically, one should include noise figure (implementation dependent) as well as Eb/No that is representative of non-coherent modulation schemes. Atmospheric Molecular Attenuation Modeled by IARU Better bands (GHz) 6 355 - 400 10 490 - 510 10 690 - 710 50 800 - 850 5 (d. B/km) 275 - 300 Submission Attenuation 50 Leo Razoumov, David Britz, AT&T Labs
doc. : IEEE 802 -15 -08 -0133 -00 -0 thz March 2008 More realistic link budget (2) Submission 6 Leo Razoumov, David Britz, AT&T Labs
March 2008 doc. : IEEE 802 -15 -08 -0133 -00 -0 thz Possible Tera. Hertz Applications Short-distance high-data rate transfer for entertainment manifest and inventory control Submission 7 Leo Razoumov, David Britz, AT&T Labs
doc. : IEEE 802 -15 -08 -0133 -00 -0 thz March 2008 100 Gbs in-home by 2030? In Home Terahertz Network Electronic Entertainment, Gaming, Shopping, Smart Home And Medical Monitoring PAN’s Education, Business Information And Telepresence Services Next Gen IRDA’s Food M Wireless 4 G Radio FSOC Layers are transparent and non-interfering with each other Optical Fiber GATEWAY 2005+ Vision IP Home Qo. S Networks art Wireless Terahertz Entertainment Productivity Legacy Utility Metallic Narrowband Eqpt. Audio Video Telematics Vehicle Monitoring Etc… TV VCR Audio System Remote Control Camcorder. . . PC Printer Scanner. . . Environmental Security Medical & PAN’s Domestic apps… Phone Fax 3 Tiered Overlay / Underlay Fiber, FSOC, Terahertz Access Network Submission 8 Leo Razoumov, David Britz, AT&T Labs
doc. : IEEE 802 -15 -08 -0133 -00 -0 thz March 2008 References • [1] Rick Roberts “Link Budget Exploration for THz Communications”, IEEE 802. 15 -08 -0107 -00 -0 thz Submission 9 Leo Razoumov, David Britz, AT&T Labs