March 2008 Project: IEEE P802.15 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: <leor@research.att.com>, <dbritz@research.att.com> Abstract: Based upon basic Information Theory Principles provides preliminary link budget analysis in support of Giga bps TeraHertz short range communication links Purpose: Discussion Notice: This document has been prepared to assist the IEEE P802.15. It is offered as a basis for discussion and is not binding on the contributing individual(s) or organization(s). The material in this document is subject to change in form and content after further study. The contributor(s) reserve(s) the right to add, amend or withdraw material contained herein. Release: The contributor acknowledges and accepts that this contribution becomes the property of IEEE and may be made publicly available by P802.15. Leo Razoumov, David Britz, AT&T Labs

March 2008 Introduction 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 100GHz – 3THz 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. Leo Razoumov, David Britz, AT&T Labs

doc.: IEEE 802.15-<doc#> <month year> doc.: IEEE 802.15-<doc#> March 2008 System model Propagation model: Line-of-sight short range (d<10m) 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 non-coherent (PPM). Bandwidth: We assume that the spectral efficiency is at most 1bit/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. Leo Razoumov, David Britz, AT&T Labs <author>, <company>

Ideal Shannon THz system March 2008 Ideal Shannon THz system In what follows we assume a hemisphere Tx beam of 6 steradians and isotropic Rx antenna. Leo Razoumov, David Britz, AT&T Labs

More realistic link budget 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 Attenuation (GHz) (dB/km) 275 - 300 6 355 - 400 10 490 - 510 690 - 710 50 800 - 850 Leo Razoumov, David Britz, AT&T Labs

More realistic link budget (2) March 2008 More realistic link budget (2) Leo Razoumov, David Britz, AT&T Labs

Possible TeraHertz Applications March 2008 Possible TeraHertz Applications Short-distance high-data rate transfer for entertainment manifest and inventory control Leo Razoumov, David Britz, AT&T Labs

doc.: IEEE 802.15-<doc#> <month year> doc.: IEEE 802.15-<doc#> March 2008 100Gbs in-home by 2030? In Home Terahertz Network Electronic Entertainment, Gaming, Shopping, Smart Home And Medical Monitoring PAN’s Next Gen IRDA’s Education, Business Information And Telepresence Services FoodMart 3 Tiered Overlay / Underlay Fiber, FSOC, Terahertz Access Network Layers are transparent and non-interfering with each other 2005+ Vision Wireless Terahertz Wireless Terahertz Wireless 4G Radio FSOC IP Home QoS Networks Audio Video Telematics Vehicle Monitoring Etc… Entertainment GATEWAY Productivity Optical Fiber Metallic Narrowband Utility Legacy Eqpt. TV VCR Audio System Remote Control Camcorder... PC Printer Scanner... Environmental Security Medical & PAN’s Domestic apps… Phone Fax Leo Razoumov, David Britz, AT&T Labs <author>, <company>

March 2008 References [1] Rick Roberts “Link Budget Exploration for THz Communications”, IEEE 802.15-08-0107-00-0thz Leo Razoumov, David Britz, AT&T Labs