July 2004 doc IEEE 802 15 04 0337

July 2004 doc. : IEEE 802. 15 -04 -0337 -00 -004 b Project: IEEE P 802. 15 Working Group for Wireless Personal Area Networks (WPANs) Submission Title: [802. 15. 4 Multipath] Date Submitted: [July 2004] Source: [Paul Gorday] Company: [Motorola] Address: [8000 W. Sunrise Blvd. , Plantation, FL, 33322, USA] Voice: [+1 561 723 4047], E-Mail: [paul. gorday@motorola. com] Re: [ IEEE 802. 15. 4 ] Abstract: [This contribution presents simulated performance of a simple 802. 15. 4 (2. 4 GHz PHY) receiver in multipath channel conditions. ] Purpose: [To encourage discussion. ] Notice: This document has been prepared to assist the IEEE P 802. 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 P 802. 15. Submission 1 Paul Gorday, Motorola

July 2004 doc. : IEEE 802. 15 -04 -0337 -00 -004 b Motivation • Proposed modifications to 868/915 MHz PHY consider additional multipath tolerance for longrange applications. • Provide benchmark simulation results for the 2. 4 GHz PHY, which would also apply to the proposed down-banded version. Submission 2 Paul Gorday, Motorola

July 2004 doc. : IEEE 802. 15 -04 -0337 -00 -004 b 2. 4 GHz PHY Simulation • Floating point simulation of optimum non-coherent demodulator. • Detection based on largest correlation peak (largest path) … No RAKE or equalizer. • Assume channel is constant throughout packet (quasistatic) and uncorrelated from packet to packet. • Record average packet error rate (PER) vs. Eb/No. Submission 3 Paul Gorday, Motorola

July 2004 doc. : IEEE 802. 15 -04 -0337 -00 -004 b 2. 4 GHz Channel Model • No channel model was specified by 802. 15. 4 • Commonly used diffuse exponential model – – 802. 11 Handbook [1] 802. 15. 3 a Narrowband Model [2] ETSI BRAN, HIPERLAN/2 [3] Many textbooks [e. g. , 4] • Detailed channel models are being developed by 802. 15. 4 a for a variety of environments, but are not finished. Submission 4 Paul Gorday, Motorola

July 2004 doc. : IEEE 802. 15 -04 -0337 -00 -004 b Diffuse Exponential Model • Exponential – average power decays exponentially • Fading - each delay bin has independent Rayleigh fading Normalized Average Power • Diffuse – each delay bin contains multipath energy C = Normalization Constant Ts = Simulation Sample Period Depicted: = 4 Ts • Single Parameter: - RMS delay spread = - Mean excess delay - Max excess delay (10 d. B) 2. 5 - Max excess delay (20 d. B) 5 Submission k (Bin #) 5 Paul Gorday, Motorola

July 2004 doc. : IEEE 802. 15 -04 -0337 -00 -004 b Results for 2. 4 GHz PHY • Acceptable performance for 400 ns RMS delay spread = 400 ns Mean excess delay 400 ns Max excess delay (10 d. B) 1 s Max excess delay (20 d. B) 2 s • Results scale with chip rate half-rate at 915 MHz would tolerate RMS delay spreads up to 800 ns Submission 6 Paul Gorday, Motorola

July 2004 doc. : IEEE 802. 15 -04 -0337 -00 -004 b 802. 11 a/HIPERLAN/2 Models [3] Channel Environment RMS Delay Spread (ns) A Typical office (NLOS) 50 B Typical large open space (NLOS) 100 C Large open space indoor (NLOS) 150 D Large open space indoor/outdoor (LOS) 140 E Large open space outdoor (NLOS) 250 Submission 7 Paul Gorday, Motorola

July 2004 doc. : IEEE 802. 15 -04 -0337 -00 -004 b IEEE 802. 11 Handbook [1] Submission Environment RMS Delay Spread (ns) Typical Home < 50 Typical Office ~ 100 Typical Manufacturing 200 -300 8 Paul Gorday, Motorola

July 2004 doc. : IEEE 802. 15 -04 -0337 -00 -004 b Factory/Office Measurements [4] Location Type Mean RMS Delay Spread (ns) Max RMS Delay Spread (ns) A Factory 16 40 B Factory 29 60 C Factory 52 152 D Factory 73 150 E Factory 33 146 F Office 16 48 G Office 39 55 H Office 55 146 Tx-Rx separation < 30 m Submission 9 Paul Gorday, Motorola

July 2004 doc. : IEEE 802. 15 -04 -0337 -00 -004 b Conclusions • 802. 15. 4 (2. 4 GHz PHY) with simple noncoherent demodulator can tolerate RMS delay spreads up to 400 ns sufficient for most WLAN applications, more than enough for WPAN applications. • Down-banded, half-rate 2. 4 GHz PHY would tolerate RMS delay spreads up to 800 ns. • Additional delay spread tolerance may be achievable with some increase in demodulator complexity. Submission 10 Paul Gorday, Motorola

July 2004 doc. : IEEE 802. 15 -04 -0337 -00 -004 b References [1] B. O’Hara and A. Petrick, IEEE 802. 11 Handbook – A Designer’s Companion, IEEE Press, 1999. [2] J. Foester, “Channel Modeling Sub-committee Report (Final), ” IEEE P 802. 15 -02/490 r 1 -SG 3 a, Feb. 2003. [3] J. Medbo and P. Schramm, “Channel Models for HIPERLAN/2, ” ETSI/BRAN doc. No. 3 ERI 085 B, 1998. [4] K. Pahlavan and A. Levesque, Wireless Information Networks, John Wiley & Sons, 1995. Submission 11 Paul Gorday, Motorola