1. doc.: IEEE 802.15-04/514r0 Submission September 2004 Slide 1 Hiroyo Ogawa, NICT Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs) Submission Title: [Simple Integrated Space Diversity System for mmW WPAN channel] Date Submitted: [14 September, 2004] Source: [Yozo Shoji, Kiyoshi Hamaguchi, and Hiroyo Ogawa] Company [National Institute of Information and Communications Technology, I.A.A.] Address [3-4, Hikarino-Oka, Yokosuka, Kanagawa, 234-0051, Japan] Voice:[+81.46.847.5070], FAX: [+81.46.847.5079], E-Mail:[ hogawa@nict.go.jp ] Re: [] Abstract:[Description of diversity technology for mmW PAN channel model.] Purpose:[Contribution to mmW SG3c at September 2004 meeting.] 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. doc.: IEEE 802.15-04/514r0 Submission September 2004 Slide 2 Hiroyo Ogawa, NICT Simple Integrated Space Diversity System for mmW WPAN channel

3. doc.: IEEE 802.15-04/514r0 Submission September 2004 Slide 3 Hiroyo Ogawa, NICT Application of mmW PAN and Multipath Environment mmW WPAN is useful for sharing the electrical handouts or presentation data among attendee in a small meeting. Signal propagation on a desk causes multipath signal fading Channel is modeled by 2-path model

4. doc.: IEEE 802.15-04/514r0 Submission September 2004 Slide 4 Hiroyo Ogawa, NICT Signal fading under 2-path channel model Path loss seriously depends on the height of transceiver’s antenna When the height of transmission antenna is fixed, signal fading causes periodically The higher the transmission antenna is, the shorter period signal fading causes The use of Space Diversity Technique must be effective

5. doc.: IEEE 802.15-04/514r0 Submission September 2004 Slide 5 Hiroyo Ogawa, NICT Signal fading under 2-path channel model (cont ’ ) Path loss seriously depends on the transmission distance between transceivers Signal fading causes but not at periodical distance. The signal fading point depends on the height of antenna The use of Space Diversity Technique must be effective

6. doc.: IEEE 802.15-04/514r0 Submission September 2004 Slide 6 Hiroyo Ogawa, NICT mmW Self-heterodyne Signal Transmission and Integrated Space Diversity Receiver Receive signals with several receiver- modules integrated closely Self-heterodyne technique reduces the received signal’s phase difference between Rx modules from （ 2πf RF  ) into （ 2πf IF  ) Transmitter Receiver Transmit Local carrier along with RF modulated signal Square-law detection of the both received signals

7. doc.: IEEE 802.15-04/514r0 Submission September 2004 Slide 7 Hiroyo Ogawa, NICT mmW Self-heterodyne Signal Transmission and Integrated Space Diversity Receiver (cont ’ ) Transmitter Receiver Phase-noise and frequency offset free IF signal transmission without using expensive stable mmW local oscillator Signals are combined approximately in the same phase for overall direction of signal arrival under the condition of c  t << IF Space diversity reception effect (including diversity gain effect) is expected

8. doc.: IEEE 802.15-04/514r0 Submission September 2004 Slide 8 Hiroyo Ogawa, NICT Developed Experimental mmW Transceiver with Integrated Spaced Diversity System 19 mm

9. doc.: IEEE 802.15-04/514r0 Submission September 2004 Slide 9 Hiroyo Ogawa, NICT Developed Experimental mmW Transceiver with Integrated Spaced Diversity System (Cont ’ ) RF Center Frequency72.4 GHz RF transmission schemeDSB Self-heterodyne Communication schemeTDMA/TDD Transmission power10 mW IF input frequency range100 MHz ~ 800 MHz Total receiver noise figureAbout 8 dB Antenna gain5 dBi Type of AntennaLinear polarized wave-guide Other notesEach receiver-module can be independently turned on/off

10. doc.: IEEE 802.15-04/514r0 Submission September 2004 Slide 10 Hiroyo Ogawa, NICT Improvement Effect on received CNR performance Improves the detected IF power in proportion to the square of the number of receiver-modules Also increases the noise power in proportion to the number of receiver-modules Improves the received CNR in proportion to the number of receiver-module-array elements

11. doc.: IEEE 802.15-04/514r0 Submission September 2004 Slide 11 Hiroyo Ogawa, NICT Improvement Effect on received CNR performance (cont’) Improves the received CNR in proportion to the number of receiver-module-array elements 2 elements >> 3 dB 8 elements >> 9 dB Almost equal CNR improvement was obtained for the overall direction of signal arrival

12. doc.: IEEE 802.15-04/514r0 Submission September 2004 Slide 12 Hiroyo Ogawa, NICT Slight change of antenna height with single antenna receiver seriously degrades the received signal level periodically The use of several receiver-module can greatly compensate the signal fading Effect as a space-diversity receiver under multipath conditions

13. doc.: IEEE 802.15-04/514r0 Submission September 2004 Slide 13 Hiroyo Ogawa, NICT OFDM signal transmission experiment under multipath condition IF center frequency470 MHz Access schemeTDMA/TDD (based on HyperLAN2) ModulationBPSK, QPSK, 16QAM, 64QAM FEC1/2, 3/4, 9/16 Sampling rate Fs=1/T20 MHz Effective symbol time Tu64T 3.2μS Guard interval Tg16T 0.8μS Symbol length Ts80T 4.0μS Number of subcarrier N52 = 48(data) + 4(pilot) Subcarrier spacing  0.3125MHz (1/Tu) Signal bandwidth 16.25MHz (N *  )

14. doc.: IEEE 802.15-04/514r0 Submission September 2004 Slide 14 Hiroyo Ogawa, NICT OFDM signal transmission experiment under multipath condition (cont’) Serious BER degradation occurred at some distances with single antenna receiver system 4 x 2 Receiver-module- arrayed system enabled error free transmission of OFDM signal over 1 ~ 4 m distance

15. doc.: IEEE 802.15-04/514r0 Submission September 2004 Slide 15 Hiroyo Ogawa, NICT Conclusions The space diversity system is necessary under mmW PAN channel, especially when the system is used on desk or table Simple space diversity system based on self- heterodyne transmission technique, which can be integrated into small transceiver, was introduced It was experimentally proved that diversity gain was obtained for all direction of signal arrival and that signal fading can be effectively avoided