Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs)

1. Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs) Submission Title: [System-level issues and solutions for 60 GHz radios] Date Submitted: [10 May 2007] Source: [Robert Pauley, Adam Rentschler] Company [Phiar Corp.] Address [2555 55th St., Bldg. D-104, Boulder CO, 80301] Voice: [(303) 443-0373], FAX: [], E-Mail: [pauley@phiar.com, adam@phiar.com] Re: [] Abstract: [System-level analysis of antenna options, modulation approaches. An implementation approach is introduced for distributed integrated AFE / antenna arrays.] Purpose: [To begin a debate among TG3c members on simplicity vs. complexity.] 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.

2. Complexity and abundance • “In every era, the winning companies are those that waste what is abundant… in order to save what is scarce.” -- George Gilder • Abundance: 7 GHz of bandwidth • The virtues of spectral inefficiency: • Lower power consumption • Lower cost • Faster development time • Larger market Relative widths... 802.11: ~100 MHz 60 GHz: 7 GHz wide

3. Spectral efficiency vs. power OFDM, 16 QAM – 2 ch. Plugged in devices OFDM, 16 QAM – 1 ch. >0.5 watts ASK, 2 bonded ch. power Gen. 2 solution (1 ch.) ASK, 1 ch. 1080i 1080p 1080p, 60 fps ASK, low rate ch. The ~1.8 B device market (2009) for portable consumer electronic products with multimedia functions Portable devices bitrate

4. Complexity and commerce OFDM ASK * HDTV Sources: Set top boxes, DVRs and DVD players. Sources: IDC Market projections, authors’ estimates. Potential Mkt.s Addressable Not addressable • No proposal will result in a radio that “does it all.” So, 802.15 TG3c should carefully consider the commercial implications of its choices. • Higher data rates are costly: OFDM is too power-hungry, we believe, to address the market for synching portable multimedia-capable devices. • ASK addresses a 3.6X larger market than alternative approaches: 2,268M units vs. 627 M units in calendar 2009.

5. Antenna coverage and gain: Critical to TG 3c’s success • Low TX power regulations necessitate high antenna gains • Consumers cannot be counted on to “point” antennas Options: • Electrically Steered Array (a.k.a. Phased Array): Aegis-class ship SPY-1 radar, THAAD, Iridium • Multiple fixed beams with switching (sector switching) • Beam forming: Butler matrix, Rottman lens, Luneberg lens, lens with focal plane array • Not realistic options for 60 GHz • Mechanically steered: dish, Risley prism, mirror, etc. • Not a realistic option for 60 GHz

6. Today’s phased arrays Pros: • Can replace multiple fixed-beam antennas • No mechanical movement • Potential low radar cross section (handy for the application shown here!) • Fast steering (probably no advantage for 60GHz) Cons: • Provides no diversity (unless sub-arrays) • Needs phase shifters/time delay units • Antenna beam optimization is complicated by combination of steering and handover • Gain losses due to projected area and mismatch • Elements may be packed closer to eliminate grating lobes (reduces array gain/element) • May require time delay control depending on bandwidth and dispersion requirements • Phase shifters in front end add losses • IF/baseband will have to be time delay units or DSP • Grating lobes may be acceptable on Rx, but not likely on Tx • No phase shifters available at 60GHz

7. High gain + broad coverage

8. Laptop use case • If cost and transmission line losses weren’t issues, where would you put your 60 GHz antennas on a laptop? • Antennas would be on the edges of the device, oriented for the best possible coverage. • Unfortunately, 60 GHz transmission line losses are ~ 0.7 dB/cm… YYY YYY YYY YYY YYY YYY YYY YYY YYY YYY YYY

9. Laptop use case • At 0.7 dB/cm in transmission losses, lots of signal is lost. • Potential solutions: • Localize antennas at theradio chipset to minimizelosses. (Coverage suffers.) • Duplicate your entire radioat each optimal antennalocation. (Cost suffers.) • Locate frequency conversionnear each antenna location:sounds good, given modulationthat doesn’t require an LO… YYY YYY YYY YYY -20 dB YYY YYY YYY -10 dB -15 dB YYY YYY YYY YYY

10. Implementation suggestion • Metal-insulator electronics make possible monolithically integrated AFE / antenna array assemblies on low cost RF substrates • Simple sector switching for coverage: • One AFE for LOS, • Multiple AFEs for NLOS applications • Identical chips for all use cases • Low power, small, cheap digital electronics • Direct down-conversion of a single carrier  VERY simple digital BB • Simple, low cost, proven antenna approach • Phased arrays are complex, costly and difficult to design • Local RF to baseband conversion allows optimal antenna and digital baseband locations

11. Concluding remarks • 60 GHz radios are hard to design • Spectrum is abundant; battery power is scarce • Abundant analog front ends allow simple, low power antenna and digital baseband designs • Differentiate from substitute technologies (Amimon, Tzero): wasters of abundant digital CMOS to save scarce spectrum...

12. Thank you. (Additional slides follow detailing the 3 primary types of phased array architectures.)

13. Phased array: active baseband combining • Adjustable time delays (not phase shifting) for each element: requires ~2 ps resolution over perhaps 16 elements  equivalent to ~500 GHz clock speed • Requires “n” baseband elements on the same chip

14. Phased array: active RF combining • Requires 60 GHz phase-shifters or time-delay units  unknown availability & costs • RF combiner required (n-way) • Requires n amplifiers

15. Phased array: passive RF combining • Requires 60 GHz phase-shifters or time-delay units  unknown availability & costs • RF combiner required (n-way) • Phase shifter (and RF combiner) losses contribute directly to noise figure • Requires fewer amplifiers than the active RF combining approach